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- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/__pycache__/__init__.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/__init__.py +11 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/connectivity.py +811 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/cuts.py +612 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/edge_augmentation.py +1270 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/edge_kcomponents.py +592 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/kcomponents.py +223 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/kcutsets.py +235 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/stoerwagner.py +152 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/utils.py +88 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/classic.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/degree_seq.cpython-310.pyc +0 -0
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- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/atlas.dat.gz +3 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/classic.py +1068 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/directed.py +501 -0
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- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_duplication.cpython-310.pyc +0 -0
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- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_lattice.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_line.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_mycielski.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_random_clustered.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_random_graphs.cpython-310.pyc +0 -0
- evalkit_tf446/lib/python3.10/site-packages/networkx/generators/tests/__pycache__/test_small.cpython-310.pyc +0 -0
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/__pycache__/__init__.cpython-310.pyc
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evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/__init__.py
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"""Connectivity and cut algorithms"""
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from .connectivity import *
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from .cuts import *
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from .edge_augmentation import *
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from .edge_kcomponents import *
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from .disjoint_paths import *
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from .kcomponents import *
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from .kcutsets import *
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from .stoerwagner import *
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from .utils import *
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evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/connectivity.py
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|
| 1 |
+
"""
|
| 2 |
+
Flow based connectivity algorithms
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
import itertools
|
| 6 |
+
from operator import itemgetter
|
| 7 |
+
|
| 8 |
+
import networkx as nx
|
| 9 |
+
|
| 10 |
+
# Define the default maximum flow function to use in all flow based
|
| 11 |
+
# connectivity algorithms.
|
| 12 |
+
from networkx.algorithms.flow import (
|
| 13 |
+
boykov_kolmogorov,
|
| 14 |
+
build_residual_network,
|
| 15 |
+
dinitz,
|
| 16 |
+
edmonds_karp,
|
| 17 |
+
preflow_push,
|
| 18 |
+
shortest_augmenting_path,
|
| 19 |
+
)
|
| 20 |
+
|
| 21 |
+
default_flow_func = edmonds_karp
|
| 22 |
+
|
| 23 |
+
from .utils import build_auxiliary_edge_connectivity, build_auxiliary_node_connectivity
|
| 24 |
+
|
| 25 |
+
__all__ = [
|
| 26 |
+
"average_node_connectivity",
|
| 27 |
+
"local_node_connectivity",
|
| 28 |
+
"node_connectivity",
|
| 29 |
+
"local_edge_connectivity",
|
| 30 |
+
"edge_connectivity",
|
| 31 |
+
"all_pairs_node_connectivity",
|
| 32 |
+
]
|
| 33 |
+
|
| 34 |
+
|
| 35 |
+
@nx._dispatchable(graphs={"G": 0, "auxiliary?": 4}, preserve_graph_attrs={"auxiliary"})
|
| 36 |
+
def local_node_connectivity(
|
| 37 |
+
G, s, t, flow_func=None, auxiliary=None, residual=None, cutoff=None
|
| 38 |
+
):
|
| 39 |
+
r"""Computes local node connectivity for nodes s and t.
|
| 40 |
+
|
| 41 |
+
Local node connectivity for two non adjacent nodes s and t is the
|
| 42 |
+
minimum number of nodes that must be removed (along with their incident
|
| 43 |
+
edges) to disconnect them.
|
| 44 |
+
|
| 45 |
+
This is a flow based implementation of node connectivity. We compute the
|
| 46 |
+
maximum flow on an auxiliary digraph build from the original input
|
| 47 |
+
graph (see below for details).
|
| 48 |
+
|
| 49 |
+
Parameters
|
| 50 |
+
----------
|
| 51 |
+
G : NetworkX graph
|
| 52 |
+
Undirected graph
|
| 53 |
+
|
| 54 |
+
s : node
|
| 55 |
+
Source node
|
| 56 |
+
|
| 57 |
+
t : node
|
| 58 |
+
Target node
|
| 59 |
+
|
| 60 |
+
flow_func : function
|
| 61 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 62 |
+
The function has to accept at least three parameters: a Digraph,
|
| 63 |
+
a source node, and a target node. And return a residual network
|
| 64 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 65 |
+
details). If flow_func is None, the default maximum flow function
|
| 66 |
+
(:meth:`edmonds_karp`) is used. See below for details. The choice
|
| 67 |
+
of the default function may change from version to version and
|
| 68 |
+
should not be relied on. Default value: None.
|
| 69 |
+
|
| 70 |
+
auxiliary : NetworkX DiGraph
|
| 71 |
+
Auxiliary digraph to compute flow based node connectivity. It has
|
| 72 |
+
to have a graph attribute called mapping with a dictionary mapping
|
| 73 |
+
node names in G and in the auxiliary digraph. If provided
|
| 74 |
+
it will be reused instead of recreated. Default value: None.
|
| 75 |
+
|
| 76 |
+
residual : NetworkX DiGraph
|
| 77 |
+
Residual network to compute maximum flow. If provided it will be
|
| 78 |
+
reused instead of recreated. Default value: None.
|
| 79 |
+
|
| 80 |
+
cutoff : integer, float, or None (default: None)
|
| 81 |
+
If specified, the maximum flow algorithm will terminate when the
|
| 82 |
+
flow value reaches or exceeds the cutoff. This only works for flows
|
| 83 |
+
that support the cutoff parameter (most do) and is ignored otherwise.
|
| 84 |
+
|
| 85 |
+
Returns
|
| 86 |
+
-------
|
| 87 |
+
K : integer
|
| 88 |
+
local node connectivity for nodes s and t
|
| 89 |
+
|
| 90 |
+
Examples
|
| 91 |
+
--------
|
| 92 |
+
This function is not imported in the base NetworkX namespace, so you
|
| 93 |
+
have to explicitly import it from the connectivity package:
|
| 94 |
+
|
| 95 |
+
>>> from networkx.algorithms.connectivity import local_node_connectivity
|
| 96 |
+
|
| 97 |
+
We use in this example the platonic icosahedral graph, which has node
|
| 98 |
+
connectivity 5.
|
| 99 |
+
|
| 100 |
+
>>> G = nx.icosahedral_graph()
|
| 101 |
+
>>> local_node_connectivity(G, 0, 6)
|
| 102 |
+
5
|
| 103 |
+
|
| 104 |
+
If you need to compute local connectivity on several pairs of
|
| 105 |
+
nodes in the same graph, it is recommended that you reuse the
|
| 106 |
+
data structures that NetworkX uses in the computation: the
|
| 107 |
+
auxiliary digraph for node connectivity, and the residual
|
| 108 |
+
network for the underlying maximum flow computation.
|
| 109 |
+
|
| 110 |
+
Example of how to compute local node connectivity among
|
| 111 |
+
all pairs of nodes of the platonic icosahedral graph reusing
|
| 112 |
+
the data structures.
|
| 113 |
+
|
| 114 |
+
>>> import itertools
|
| 115 |
+
>>> # You also have to explicitly import the function for
|
| 116 |
+
>>> # building the auxiliary digraph from the connectivity package
|
| 117 |
+
>>> from networkx.algorithms.connectivity import build_auxiliary_node_connectivity
|
| 118 |
+
>>> H = build_auxiliary_node_connectivity(G)
|
| 119 |
+
>>> # And the function for building the residual network from the
|
| 120 |
+
>>> # flow package
|
| 121 |
+
>>> from networkx.algorithms.flow import build_residual_network
|
| 122 |
+
>>> # Note that the auxiliary digraph has an edge attribute named capacity
|
| 123 |
+
>>> R = build_residual_network(H, "capacity")
|
| 124 |
+
>>> result = dict.fromkeys(G, dict())
|
| 125 |
+
>>> # Reuse the auxiliary digraph and the residual network by passing them
|
| 126 |
+
>>> # as parameters
|
| 127 |
+
>>> for u, v in itertools.combinations(G, 2):
|
| 128 |
+
... k = local_node_connectivity(G, u, v, auxiliary=H, residual=R)
|
| 129 |
+
... result[u][v] = k
|
| 130 |
+
>>> all(result[u][v] == 5 for u, v in itertools.combinations(G, 2))
|
| 131 |
+
True
|
| 132 |
+
|
| 133 |
+
You can also use alternative flow algorithms for computing node
|
| 134 |
+
connectivity. For instance, in dense networks the algorithm
|
| 135 |
+
:meth:`shortest_augmenting_path` will usually perform better than
|
| 136 |
+
the default :meth:`edmonds_karp` which is faster for sparse
|
| 137 |
+
networks with highly skewed degree distributions. Alternative flow
|
| 138 |
+
functions have to be explicitly imported from the flow package.
|
| 139 |
+
|
| 140 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 141 |
+
>>> local_node_connectivity(G, 0, 6, flow_func=shortest_augmenting_path)
|
| 142 |
+
5
|
| 143 |
+
|
| 144 |
+
Notes
|
| 145 |
+
-----
|
| 146 |
+
This is a flow based implementation of node connectivity. We compute the
|
| 147 |
+
maximum flow using, by default, the :meth:`edmonds_karp` algorithm (see:
|
| 148 |
+
:meth:`maximum_flow`) on an auxiliary digraph build from the original
|
| 149 |
+
input graph:
|
| 150 |
+
|
| 151 |
+
For an undirected graph G having `n` nodes and `m` edges we derive a
|
| 152 |
+
directed graph H with `2n` nodes and `2m+n` arcs by replacing each
|
| 153 |
+
original node `v` with two nodes `v_A`, `v_B` linked by an (internal)
|
| 154 |
+
arc in H. Then for each edge (`u`, `v`) in G we add two arcs
|
| 155 |
+
(`u_B`, `v_A`) and (`v_B`, `u_A`) in H. Finally we set the attribute
|
| 156 |
+
capacity = 1 for each arc in H [1]_ .
|
| 157 |
+
|
| 158 |
+
For a directed graph G having `n` nodes and `m` arcs we derive a
|
| 159 |
+
directed graph H with `2n` nodes and `m+n` arcs by replacing each
|
| 160 |
+
original node `v` with two nodes `v_A`, `v_B` linked by an (internal)
|
| 161 |
+
arc (`v_A`, `v_B`) in H. Then for each arc (`u`, `v`) in G we add one arc
|
| 162 |
+
(`u_B`, `v_A`) in H. Finally we set the attribute capacity = 1 for
|
| 163 |
+
each arc in H.
|
| 164 |
+
|
| 165 |
+
This is equal to the local node connectivity because the value of
|
| 166 |
+
a maximum s-t-flow is equal to the capacity of a minimum s-t-cut.
|
| 167 |
+
|
| 168 |
+
See also
|
| 169 |
+
--------
|
| 170 |
+
:meth:`local_edge_connectivity`
|
| 171 |
+
:meth:`node_connectivity`
|
| 172 |
+
:meth:`minimum_node_cut`
|
| 173 |
+
:meth:`maximum_flow`
|
| 174 |
+
:meth:`edmonds_karp`
|
| 175 |
+
:meth:`preflow_push`
|
| 176 |
+
:meth:`shortest_augmenting_path`
|
| 177 |
+
|
| 178 |
+
References
|
| 179 |
+
----------
|
| 180 |
+
.. [1] Kammer, Frank and Hanjo Taubig. Graph Connectivity. in Brandes and
|
| 181 |
+
Erlebach, 'Network Analysis: Methodological Foundations', Lecture
|
| 182 |
+
Notes in Computer Science, Volume 3418, Springer-Verlag, 2005.
|
| 183 |
+
http://www.informatik.uni-augsburg.de/thi/personen/kammer/Graph_Connectivity.pdf
|
| 184 |
+
|
| 185 |
+
"""
|
| 186 |
+
if flow_func is None:
|
| 187 |
+
flow_func = default_flow_func
|
| 188 |
+
|
| 189 |
+
if auxiliary is None:
|
| 190 |
+
H = build_auxiliary_node_connectivity(G)
|
| 191 |
+
else:
|
| 192 |
+
H = auxiliary
|
| 193 |
+
|
| 194 |
+
mapping = H.graph.get("mapping", None)
|
| 195 |
+
if mapping is None:
|
| 196 |
+
raise nx.NetworkXError("Invalid auxiliary digraph.")
|
| 197 |
+
|
| 198 |
+
kwargs = {"flow_func": flow_func, "residual": residual}
|
| 199 |
+
|
| 200 |
+
if flow_func is not preflow_push:
|
| 201 |
+
kwargs["cutoff"] = cutoff
|
| 202 |
+
|
| 203 |
+
if flow_func is shortest_augmenting_path:
|
| 204 |
+
kwargs["two_phase"] = True
|
| 205 |
+
|
| 206 |
+
return nx.maximum_flow_value(H, f"{mapping[s]}B", f"{mapping[t]}A", **kwargs)
|
| 207 |
+
|
| 208 |
+
|
| 209 |
+
@nx._dispatchable
|
| 210 |
+
def node_connectivity(G, s=None, t=None, flow_func=None):
|
| 211 |
+
r"""Returns node connectivity for a graph or digraph G.
|
| 212 |
+
|
| 213 |
+
Node connectivity is equal to the minimum number of nodes that
|
| 214 |
+
must be removed to disconnect G or render it trivial. If source
|
| 215 |
+
and target nodes are provided, this function returns the local node
|
| 216 |
+
connectivity: the minimum number of nodes that must be removed to break
|
| 217 |
+
all paths from source to target in G.
|
| 218 |
+
|
| 219 |
+
Parameters
|
| 220 |
+
----------
|
| 221 |
+
G : NetworkX graph
|
| 222 |
+
Undirected graph
|
| 223 |
+
|
| 224 |
+
s : node
|
| 225 |
+
Source node. Optional. Default value: None.
|
| 226 |
+
|
| 227 |
+
t : node
|
| 228 |
+
Target node. Optional. Default value: None.
|
| 229 |
+
|
| 230 |
+
flow_func : function
|
| 231 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 232 |
+
The function has to accept at least three parameters: a Digraph,
|
| 233 |
+
a source node, and a target node. And return a residual network
|
| 234 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 235 |
+
details). If flow_func is None, the default maximum flow function
|
| 236 |
+
(:meth:`edmonds_karp`) is used. See below for details. The
|
| 237 |
+
choice of the default function may change from version
|
| 238 |
+
to version and should not be relied on. Default value: None.
|
| 239 |
+
|
| 240 |
+
Returns
|
| 241 |
+
-------
|
| 242 |
+
K : integer
|
| 243 |
+
Node connectivity of G, or local node connectivity if source
|
| 244 |
+
and target are provided.
|
| 245 |
+
|
| 246 |
+
Examples
|
| 247 |
+
--------
|
| 248 |
+
>>> # Platonic icosahedral graph is 5-node-connected
|
| 249 |
+
>>> G = nx.icosahedral_graph()
|
| 250 |
+
>>> nx.node_connectivity(G)
|
| 251 |
+
5
|
| 252 |
+
|
| 253 |
+
You can use alternative flow algorithms for the underlying maximum
|
| 254 |
+
flow computation. In dense networks the algorithm
|
| 255 |
+
:meth:`shortest_augmenting_path` will usually perform better
|
| 256 |
+
than the default :meth:`edmonds_karp`, which is faster for
|
| 257 |
+
sparse networks with highly skewed degree distributions. Alternative
|
| 258 |
+
flow functions have to be explicitly imported from the flow package.
|
| 259 |
+
|
| 260 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 261 |
+
>>> nx.node_connectivity(G, flow_func=shortest_augmenting_path)
|
| 262 |
+
5
|
| 263 |
+
|
| 264 |
+
If you specify a pair of nodes (source and target) as parameters,
|
| 265 |
+
this function returns the value of local node connectivity.
|
| 266 |
+
|
| 267 |
+
>>> nx.node_connectivity(G, 3, 7)
|
| 268 |
+
5
|
| 269 |
+
|
| 270 |
+
If you need to perform several local computations among different
|
| 271 |
+
pairs of nodes on the same graph, it is recommended that you reuse
|
| 272 |
+
the data structures used in the maximum flow computations. See
|
| 273 |
+
:meth:`local_node_connectivity` for details.
|
| 274 |
+
|
| 275 |
+
Notes
|
| 276 |
+
-----
|
| 277 |
+
This is a flow based implementation of node connectivity. The
|
| 278 |
+
algorithm works by solving $O((n-\delta-1+\delta(\delta-1)/2))$
|
| 279 |
+
maximum flow problems on an auxiliary digraph. Where $\delta$
|
| 280 |
+
is the minimum degree of G. For details about the auxiliary
|
| 281 |
+
digraph and the computation of local node connectivity see
|
| 282 |
+
:meth:`local_node_connectivity`. This implementation is based
|
| 283 |
+
on algorithm 11 in [1]_.
|
| 284 |
+
|
| 285 |
+
See also
|
| 286 |
+
--------
|
| 287 |
+
:meth:`local_node_connectivity`
|
| 288 |
+
:meth:`edge_connectivity`
|
| 289 |
+
:meth:`maximum_flow`
|
| 290 |
+
:meth:`edmonds_karp`
|
| 291 |
+
:meth:`preflow_push`
|
| 292 |
+
:meth:`shortest_augmenting_path`
|
| 293 |
+
|
| 294 |
+
References
|
| 295 |
+
----------
|
| 296 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms.
|
| 297 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 298 |
+
|
| 299 |
+
"""
|
| 300 |
+
if (s is not None and t is None) or (s is None and t is not None):
|
| 301 |
+
raise nx.NetworkXError("Both source and target must be specified.")
|
| 302 |
+
|
| 303 |
+
# Local node connectivity
|
| 304 |
+
if s is not None and t is not None:
|
| 305 |
+
if s not in G:
|
| 306 |
+
raise nx.NetworkXError(f"node {s} not in graph")
|
| 307 |
+
if t not in G:
|
| 308 |
+
raise nx.NetworkXError(f"node {t} not in graph")
|
| 309 |
+
return local_node_connectivity(G, s, t, flow_func=flow_func)
|
| 310 |
+
|
| 311 |
+
# Global node connectivity
|
| 312 |
+
if G.is_directed():
|
| 313 |
+
if not nx.is_weakly_connected(G):
|
| 314 |
+
return 0
|
| 315 |
+
iter_func = itertools.permutations
|
| 316 |
+
# It is necessary to consider both predecessors
|
| 317 |
+
# and successors for directed graphs
|
| 318 |
+
|
| 319 |
+
def neighbors(v):
|
| 320 |
+
return itertools.chain.from_iterable([G.predecessors(v), G.successors(v)])
|
| 321 |
+
|
| 322 |
+
else:
|
| 323 |
+
if not nx.is_connected(G):
|
| 324 |
+
return 0
|
| 325 |
+
iter_func = itertools.combinations
|
| 326 |
+
neighbors = G.neighbors
|
| 327 |
+
|
| 328 |
+
# Reuse the auxiliary digraph and the residual network
|
| 329 |
+
H = build_auxiliary_node_connectivity(G)
|
| 330 |
+
R = build_residual_network(H, "capacity")
|
| 331 |
+
kwargs = {"flow_func": flow_func, "auxiliary": H, "residual": R}
|
| 332 |
+
|
| 333 |
+
# Pick a node with minimum degree
|
| 334 |
+
# Node connectivity is bounded by degree.
|
| 335 |
+
v, K = min(G.degree(), key=itemgetter(1))
|
| 336 |
+
# compute local node connectivity with all its non-neighbors nodes
|
| 337 |
+
for w in set(G) - set(neighbors(v)) - {v}:
|
| 338 |
+
kwargs["cutoff"] = K
|
| 339 |
+
K = min(K, local_node_connectivity(G, v, w, **kwargs))
|
| 340 |
+
# Also for non adjacent pairs of neighbors of v
|
| 341 |
+
for x, y in iter_func(neighbors(v), 2):
|
| 342 |
+
if y in G[x]:
|
| 343 |
+
continue
|
| 344 |
+
kwargs["cutoff"] = K
|
| 345 |
+
K = min(K, local_node_connectivity(G, x, y, **kwargs))
|
| 346 |
+
|
| 347 |
+
return K
|
| 348 |
+
|
| 349 |
+
|
| 350 |
+
@nx._dispatchable
|
| 351 |
+
def average_node_connectivity(G, flow_func=None):
|
| 352 |
+
r"""Returns the average connectivity of a graph G.
|
| 353 |
+
|
| 354 |
+
The average connectivity `\bar{\kappa}` of a graph G is the average
|
| 355 |
+
of local node connectivity over all pairs of nodes of G [1]_ .
|
| 356 |
+
|
| 357 |
+
.. math::
|
| 358 |
+
|
| 359 |
+
\bar{\kappa}(G) = \frac{\sum_{u,v} \kappa_{G}(u,v)}{{n \choose 2}}
|
| 360 |
+
|
| 361 |
+
Parameters
|
| 362 |
+
----------
|
| 363 |
+
|
| 364 |
+
G : NetworkX graph
|
| 365 |
+
Undirected graph
|
| 366 |
+
|
| 367 |
+
flow_func : function
|
| 368 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 369 |
+
The function has to accept at least three parameters: a Digraph,
|
| 370 |
+
a source node, and a target node. And return a residual network
|
| 371 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 372 |
+
details). If flow_func is None, the default maximum flow function
|
| 373 |
+
(:meth:`edmonds_karp`) is used. See :meth:`local_node_connectivity`
|
| 374 |
+
for details. The choice of the default function may change from
|
| 375 |
+
version to version and should not be relied on. Default value: None.
|
| 376 |
+
|
| 377 |
+
Returns
|
| 378 |
+
-------
|
| 379 |
+
K : float
|
| 380 |
+
Average node connectivity
|
| 381 |
+
|
| 382 |
+
See also
|
| 383 |
+
--------
|
| 384 |
+
:meth:`local_node_connectivity`
|
| 385 |
+
:meth:`node_connectivity`
|
| 386 |
+
:meth:`edge_connectivity`
|
| 387 |
+
:meth:`maximum_flow`
|
| 388 |
+
:meth:`edmonds_karp`
|
| 389 |
+
:meth:`preflow_push`
|
| 390 |
+
:meth:`shortest_augmenting_path`
|
| 391 |
+
|
| 392 |
+
References
|
| 393 |
+
----------
|
| 394 |
+
.. [1] Beineke, L., O. Oellermann, and R. Pippert (2002). The average
|
| 395 |
+
connectivity of a graph. Discrete mathematics 252(1-3), 31-45.
|
| 396 |
+
http://www.sciencedirect.com/science/article/pii/S0012365X01001807
|
| 397 |
+
|
| 398 |
+
"""
|
| 399 |
+
if G.is_directed():
|
| 400 |
+
iter_func = itertools.permutations
|
| 401 |
+
else:
|
| 402 |
+
iter_func = itertools.combinations
|
| 403 |
+
|
| 404 |
+
# Reuse the auxiliary digraph and the residual network
|
| 405 |
+
H = build_auxiliary_node_connectivity(G)
|
| 406 |
+
R = build_residual_network(H, "capacity")
|
| 407 |
+
kwargs = {"flow_func": flow_func, "auxiliary": H, "residual": R}
|
| 408 |
+
|
| 409 |
+
num, den = 0, 0
|
| 410 |
+
for u, v in iter_func(G, 2):
|
| 411 |
+
num += local_node_connectivity(G, u, v, **kwargs)
|
| 412 |
+
den += 1
|
| 413 |
+
|
| 414 |
+
if den == 0: # Null Graph
|
| 415 |
+
return 0
|
| 416 |
+
return num / den
|
| 417 |
+
|
| 418 |
+
|
| 419 |
+
@nx._dispatchable
|
| 420 |
+
def all_pairs_node_connectivity(G, nbunch=None, flow_func=None):
|
| 421 |
+
"""Compute node connectivity between all pairs of nodes of G.
|
| 422 |
+
|
| 423 |
+
Parameters
|
| 424 |
+
----------
|
| 425 |
+
G : NetworkX graph
|
| 426 |
+
Undirected graph
|
| 427 |
+
|
| 428 |
+
nbunch: container
|
| 429 |
+
Container of nodes. If provided node connectivity will be computed
|
| 430 |
+
only over pairs of nodes in nbunch.
|
| 431 |
+
|
| 432 |
+
flow_func : function
|
| 433 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 434 |
+
The function has to accept at least three parameters: a Digraph,
|
| 435 |
+
a source node, and a target node. And return a residual network
|
| 436 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 437 |
+
details). If flow_func is None, the default maximum flow function
|
| 438 |
+
(:meth:`edmonds_karp`) is used. See below for details. The
|
| 439 |
+
choice of the default function may change from version
|
| 440 |
+
to version and should not be relied on. Default value: None.
|
| 441 |
+
|
| 442 |
+
Returns
|
| 443 |
+
-------
|
| 444 |
+
all_pairs : dict
|
| 445 |
+
A dictionary with node connectivity between all pairs of nodes
|
| 446 |
+
in G, or in nbunch if provided.
|
| 447 |
+
|
| 448 |
+
See also
|
| 449 |
+
--------
|
| 450 |
+
:meth:`local_node_connectivity`
|
| 451 |
+
:meth:`edge_connectivity`
|
| 452 |
+
:meth:`local_edge_connectivity`
|
| 453 |
+
:meth:`maximum_flow`
|
| 454 |
+
:meth:`edmonds_karp`
|
| 455 |
+
:meth:`preflow_push`
|
| 456 |
+
:meth:`shortest_augmenting_path`
|
| 457 |
+
|
| 458 |
+
"""
|
| 459 |
+
if nbunch is None:
|
| 460 |
+
nbunch = G
|
| 461 |
+
else:
|
| 462 |
+
nbunch = set(nbunch)
|
| 463 |
+
|
| 464 |
+
directed = G.is_directed()
|
| 465 |
+
if directed:
|
| 466 |
+
iter_func = itertools.permutations
|
| 467 |
+
else:
|
| 468 |
+
iter_func = itertools.combinations
|
| 469 |
+
|
| 470 |
+
all_pairs = {n: {} for n in nbunch}
|
| 471 |
+
|
| 472 |
+
# Reuse auxiliary digraph and residual network
|
| 473 |
+
H = build_auxiliary_node_connectivity(G)
|
| 474 |
+
mapping = H.graph["mapping"]
|
| 475 |
+
R = build_residual_network(H, "capacity")
|
| 476 |
+
kwargs = {"flow_func": flow_func, "auxiliary": H, "residual": R}
|
| 477 |
+
|
| 478 |
+
for u, v in iter_func(nbunch, 2):
|
| 479 |
+
K = local_node_connectivity(G, u, v, **kwargs)
|
| 480 |
+
all_pairs[u][v] = K
|
| 481 |
+
if not directed:
|
| 482 |
+
all_pairs[v][u] = K
|
| 483 |
+
|
| 484 |
+
return all_pairs
|
| 485 |
+
|
| 486 |
+
|
| 487 |
+
@nx._dispatchable(graphs={"G": 0, "auxiliary?": 4})
|
| 488 |
+
def local_edge_connectivity(
|
| 489 |
+
G, s, t, flow_func=None, auxiliary=None, residual=None, cutoff=None
|
| 490 |
+
):
|
| 491 |
+
r"""Returns local edge connectivity for nodes s and t in G.
|
| 492 |
+
|
| 493 |
+
Local edge connectivity for two nodes s and t is the minimum number
|
| 494 |
+
of edges that must be removed to disconnect them.
|
| 495 |
+
|
| 496 |
+
This is a flow based implementation of edge connectivity. We compute the
|
| 497 |
+
maximum flow on an auxiliary digraph build from the original
|
| 498 |
+
network (see below for details). This is equal to the local edge
|
| 499 |
+
connectivity because the value of a maximum s-t-flow is equal to the
|
| 500 |
+
capacity of a minimum s-t-cut (Ford and Fulkerson theorem) [1]_ .
|
| 501 |
+
|
| 502 |
+
Parameters
|
| 503 |
+
----------
|
| 504 |
+
G : NetworkX graph
|
| 505 |
+
Undirected or directed graph
|
| 506 |
+
|
| 507 |
+
s : node
|
| 508 |
+
Source node
|
| 509 |
+
|
| 510 |
+
t : node
|
| 511 |
+
Target node
|
| 512 |
+
|
| 513 |
+
flow_func : function
|
| 514 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 515 |
+
The function has to accept at least three parameters: a Digraph,
|
| 516 |
+
a source node, and a target node. And return a residual network
|
| 517 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 518 |
+
details). If flow_func is None, the default maximum flow function
|
| 519 |
+
(:meth:`edmonds_karp`) is used. See below for details. The
|
| 520 |
+
choice of the default function may change from version
|
| 521 |
+
to version and should not be relied on. Default value: None.
|
| 522 |
+
|
| 523 |
+
auxiliary : NetworkX DiGraph
|
| 524 |
+
Auxiliary digraph for computing flow based edge connectivity. If
|
| 525 |
+
provided it will be reused instead of recreated. Default value: None.
|
| 526 |
+
|
| 527 |
+
residual : NetworkX DiGraph
|
| 528 |
+
Residual network to compute maximum flow. If provided it will be
|
| 529 |
+
reused instead of recreated. Default value: None.
|
| 530 |
+
|
| 531 |
+
cutoff : integer, float, or None (default: None)
|
| 532 |
+
If specified, the maximum flow algorithm will terminate when the
|
| 533 |
+
flow value reaches or exceeds the cutoff. This only works for flows
|
| 534 |
+
that support the cutoff parameter (most do) and is ignored otherwise.
|
| 535 |
+
|
| 536 |
+
Returns
|
| 537 |
+
-------
|
| 538 |
+
K : integer
|
| 539 |
+
local edge connectivity for nodes s and t.
|
| 540 |
+
|
| 541 |
+
Examples
|
| 542 |
+
--------
|
| 543 |
+
This function is not imported in the base NetworkX namespace, so you
|
| 544 |
+
have to explicitly import it from the connectivity package:
|
| 545 |
+
|
| 546 |
+
>>> from networkx.algorithms.connectivity import local_edge_connectivity
|
| 547 |
+
|
| 548 |
+
We use in this example the platonic icosahedral graph, which has edge
|
| 549 |
+
connectivity 5.
|
| 550 |
+
|
| 551 |
+
>>> G = nx.icosahedral_graph()
|
| 552 |
+
>>> local_edge_connectivity(G, 0, 6)
|
| 553 |
+
5
|
| 554 |
+
|
| 555 |
+
If you need to compute local connectivity on several pairs of
|
| 556 |
+
nodes in the same graph, it is recommended that you reuse the
|
| 557 |
+
data structures that NetworkX uses in the computation: the
|
| 558 |
+
auxiliary digraph for edge connectivity, and the residual
|
| 559 |
+
network for the underlying maximum flow computation.
|
| 560 |
+
|
| 561 |
+
Example of how to compute local edge connectivity among
|
| 562 |
+
all pairs of nodes of the platonic icosahedral graph reusing
|
| 563 |
+
the data structures.
|
| 564 |
+
|
| 565 |
+
>>> import itertools
|
| 566 |
+
>>> # You also have to explicitly import the function for
|
| 567 |
+
>>> # building the auxiliary digraph from the connectivity package
|
| 568 |
+
>>> from networkx.algorithms.connectivity import build_auxiliary_edge_connectivity
|
| 569 |
+
>>> H = build_auxiliary_edge_connectivity(G)
|
| 570 |
+
>>> # And the function for building the residual network from the
|
| 571 |
+
>>> # flow package
|
| 572 |
+
>>> from networkx.algorithms.flow import build_residual_network
|
| 573 |
+
>>> # Note that the auxiliary digraph has an edge attribute named capacity
|
| 574 |
+
>>> R = build_residual_network(H, "capacity")
|
| 575 |
+
>>> result = dict.fromkeys(G, dict())
|
| 576 |
+
>>> # Reuse the auxiliary digraph and the residual network by passing them
|
| 577 |
+
>>> # as parameters
|
| 578 |
+
>>> for u, v in itertools.combinations(G, 2):
|
| 579 |
+
... k = local_edge_connectivity(G, u, v, auxiliary=H, residual=R)
|
| 580 |
+
... result[u][v] = k
|
| 581 |
+
>>> all(result[u][v] == 5 for u, v in itertools.combinations(G, 2))
|
| 582 |
+
True
|
| 583 |
+
|
| 584 |
+
You can also use alternative flow algorithms for computing edge
|
| 585 |
+
connectivity. For instance, in dense networks the algorithm
|
| 586 |
+
:meth:`shortest_augmenting_path` will usually perform better than
|
| 587 |
+
the default :meth:`edmonds_karp` which is faster for sparse
|
| 588 |
+
networks with highly skewed degree distributions. Alternative flow
|
| 589 |
+
functions have to be explicitly imported from the flow package.
|
| 590 |
+
|
| 591 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 592 |
+
>>> local_edge_connectivity(G, 0, 6, flow_func=shortest_augmenting_path)
|
| 593 |
+
5
|
| 594 |
+
|
| 595 |
+
Notes
|
| 596 |
+
-----
|
| 597 |
+
This is a flow based implementation of edge connectivity. We compute the
|
| 598 |
+
maximum flow using, by default, the :meth:`edmonds_karp` algorithm on an
|
| 599 |
+
auxiliary digraph build from the original input graph:
|
| 600 |
+
|
| 601 |
+
If the input graph is undirected, we replace each edge (`u`,`v`) with
|
| 602 |
+
two reciprocal arcs (`u`, `v`) and (`v`, `u`) and then we set the attribute
|
| 603 |
+
'capacity' for each arc to 1. If the input graph is directed we simply
|
| 604 |
+
add the 'capacity' attribute. This is an implementation of algorithm 1
|
| 605 |
+
in [1]_.
|
| 606 |
+
|
| 607 |
+
The maximum flow in the auxiliary network is equal to the local edge
|
| 608 |
+
connectivity because the value of a maximum s-t-flow is equal to the
|
| 609 |
+
capacity of a minimum s-t-cut (Ford and Fulkerson theorem).
|
| 610 |
+
|
| 611 |
+
See also
|
| 612 |
+
--------
|
| 613 |
+
:meth:`edge_connectivity`
|
| 614 |
+
:meth:`local_node_connectivity`
|
| 615 |
+
:meth:`node_connectivity`
|
| 616 |
+
:meth:`maximum_flow`
|
| 617 |
+
:meth:`edmonds_karp`
|
| 618 |
+
:meth:`preflow_push`
|
| 619 |
+
:meth:`shortest_augmenting_path`
|
| 620 |
+
|
| 621 |
+
References
|
| 622 |
+
----------
|
| 623 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms.
|
| 624 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 625 |
+
|
| 626 |
+
"""
|
| 627 |
+
if flow_func is None:
|
| 628 |
+
flow_func = default_flow_func
|
| 629 |
+
|
| 630 |
+
if auxiliary is None:
|
| 631 |
+
H = build_auxiliary_edge_connectivity(G)
|
| 632 |
+
else:
|
| 633 |
+
H = auxiliary
|
| 634 |
+
|
| 635 |
+
kwargs = {"flow_func": flow_func, "residual": residual}
|
| 636 |
+
|
| 637 |
+
if flow_func is not preflow_push:
|
| 638 |
+
kwargs["cutoff"] = cutoff
|
| 639 |
+
|
| 640 |
+
if flow_func is shortest_augmenting_path:
|
| 641 |
+
kwargs["two_phase"] = True
|
| 642 |
+
|
| 643 |
+
return nx.maximum_flow_value(H, s, t, **kwargs)
|
| 644 |
+
|
| 645 |
+
|
| 646 |
+
@nx._dispatchable
|
| 647 |
+
def edge_connectivity(G, s=None, t=None, flow_func=None, cutoff=None):
|
| 648 |
+
r"""Returns the edge connectivity of the graph or digraph G.
|
| 649 |
+
|
| 650 |
+
The edge connectivity is equal to the minimum number of edges that
|
| 651 |
+
must be removed to disconnect G or render it trivial. If source
|
| 652 |
+
and target nodes are provided, this function returns the local edge
|
| 653 |
+
connectivity: the minimum number of edges that must be removed to
|
| 654 |
+
break all paths from source to target in G.
|
| 655 |
+
|
| 656 |
+
Parameters
|
| 657 |
+
----------
|
| 658 |
+
G : NetworkX graph
|
| 659 |
+
Undirected or directed graph
|
| 660 |
+
|
| 661 |
+
s : node
|
| 662 |
+
Source node. Optional. Default value: None.
|
| 663 |
+
|
| 664 |
+
t : node
|
| 665 |
+
Target node. Optional. Default value: None.
|
| 666 |
+
|
| 667 |
+
flow_func : function
|
| 668 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 669 |
+
The function has to accept at least three parameters: a Digraph,
|
| 670 |
+
a source node, and a target node. And return a residual network
|
| 671 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 672 |
+
details). If flow_func is None, the default maximum flow function
|
| 673 |
+
(:meth:`edmonds_karp`) is used. See below for details. The
|
| 674 |
+
choice of the default function may change from version
|
| 675 |
+
to version and should not be relied on. Default value: None.
|
| 676 |
+
|
| 677 |
+
cutoff : integer, float, or None (default: None)
|
| 678 |
+
If specified, the maximum flow algorithm will terminate when the
|
| 679 |
+
flow value reaches or exceeds the cutoff. This only works for flows
|
| 680 |
+
that support the cutoff parameter (most do) and is ignored otherwise.
|
| 681 |
+
|
| 682 |
+
Returns
|
| 683 |
+
-------
|
| 684 |
+
K : integer
|
| 685 |
+
Edge connectivity for G, or local edge connectivity if source
|
| 686 |
+
and target were provided
|
| 687 |
+
|
| 688 |
+
Examples
|
| 689 |
+
--------
|
| 690 |
+
>>> # Platonic icosahedral graph is 5-edge-connected
|
| 691 |
+
>>> G = nx.icosahedral_graph()
|
| 692 |
+
>>> nx.edge_connectivity(G)
|
| 693 |
+
5
|
| 694 |
+
|
| 695 |
+
You can use alternative flow algorithms for the underlying
|
| 696 |
+
maximum flow computation. In dense networks the algorithm
|
| 697 |
+
:meth:`shortest_augmenting_path` will usually perform better
|
| 698 |
+
than the default :meth:`edmonds_karp`, which is faster for
|
| 699 |
+
sparse networks with highly skewed degree distributions.
|
| 700 |
+
Alternative flow functions have to be explicitly imported
|
| 701 |
+
from the flow package.
|
| 702 |
+
|
| 703 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 704 |
+
>>> nx.edge_connectivity(G, flow_func=shortest_augmenting_path)
|
| 705 |
+
5
|
| 706 |
+
|
| 707 |
+
If you specify a pair of nodes (source and target) as parameters,
|
| 708 |
+
this function returns the value of local edge connectivity.
|
| 709 |
+
|
| 710 |
+
>>> nx.edge_connectivity(G, 3, 7)
|
| 711 |
+
5
|
| 712 |
+
|
| 713 |
+
If you need to perform several local computations among different
|
| 714 |
+
pairs of nodes on the same graph, it is recommended that you reuse
|
| 715 |
+
the data structures used in the maximum flow computations. See
|
| 716 |
+
:meth:`local_edge_connectivity` for details.
|
| 717 |
+
|
| 718 |
+
Notes
|
| 719 |
+
-----
|
| 720 |
+
This is a flow based implementation of global edge connectivity.
|
| 721 |
+
For undirected graphs the algorithm works by finding a 'small'
|
| 722 |
+
dominating set of nodes of G (see algorithm 7 in [1]_ ) and
|
| 723 |
+
computing local maximum flow (see :meth:`local_edge_connectivity`)
|
| 724 |
+
between an arbitrary node in the dominating set and the rest of
|
| 725 |
+
nodes in it. This is an implementation of algorithm 6 in [1]_ .
|
| 726 |
+
For directed graphs, the algorithm does n calls to the maximum
|
| 727 |
+
flow function. This is an implementation of algorithm 8 in [1]_ .
|
| 728 |
+
|
| 729 |
+
See also
|
| 730 |
+
--------
|
| 731 |
+
:meth:`local_edge_connectivity`
|
| 732 |
+
:meth:`local_node_connectivity`
|
| 733 |
+
:meth:`node_connectivity`
|
| 734 |
+
:meth:`maximum_flow`
|
| 735 |
+
:meth:`edmonds_karp`
|
| 736 |
+
:meth:`preflow_push`
|
| 737 |
+
:meth:`shortest_augmenting_path`
|
| 738 |
+
:meth:`k_edge_components`
|
| 739 |
+
:meth:`k_edge_subgraphs`
|
| 740 |
+
|
| 741 |
+
References
|
| 742 |
+
----------
|
| 743 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms.
|
| 744 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 745 |
+
|
| 746 |
+
"""
|
| 747 |
+
if (s is not None and t is None) or (s is None and t is not None):
|
| 748 |
+
raise nx.NetworkXError("Both source and target must be specified.")
|
| 749 |
+
|
| 750 |
+
# Local edge connectivity
|
| 751 |
+
if s is not None and t is not None:
|
| 752 |
+
if s not in G:
|
| 753 |
+
raise nx.NetworkXError(f"node {s} not in graph")
|
| 754 |
+
if t not in G:
|
| 755 |
+
raise nx.NetworkXError(f"node {t} not in graph")
|
| 756 |
+
return local_edge_connectivity(G, s, t, flow_func=flow_func, cutoff=cutoff)
|
| 757 |
+
|
| 758 |
+
# Global edge connectivity
|
| 759 |
+
# reuse auxiliary digraph and residual network
|
| 760 |
+
H = build_auxiliary_edge_connectivity(G)
|
| 761 |
+
R = build_residual_network(H, "capacity")
|
| 762 |
+
kwargs = {"flow_func": flow_func, "auxiliary": H, "residual": R}
|
| 763 |
+
|
| 764 |
+
if G.is_directed():
|
| 765 |
+
# Algorithm 8 in [1]
|
| 766 |
+
if not nx.is_weakly_connected(G):
|
| 767 |
+
return 0
|
| 768 |
+
|
| 769 |
+
# initial value for \lambda is minimum degree
|
| 770 |
+
L = min(d for n, d in G.degree())
|
| 771 |
+
nodes = list(G)
|
| 772 |
+
n = len(nodes)
|
| 773 |
+
|
| 774 |
+
if cutoff is not None:
|
| 775 |
+
L = min(cutoff, L)
|
| 776 |
+
|
| 777 |
+
for i in range(n):
|
| 778 |
+
kwargs["cutoff"] = L
|
| 779 |
+
try:
|
| 780 |
+
L = min(L, local_edge_connectivity(G, nodes[i], nodes[i + 1], **kwargs))
|
| 781 |
+
except IndexError: # last node!
|
| 782 |
+
L = min(L, local_edge_connectivity(G, nodes[i], nodes[0], **kwargs))
|
| 783 |
+
return L
|
| 784 |
+
else: # undirected
|
| 785 |
+
# Algorithm 6 in [1]
|
| 786 |
+
if not nx.is_connected(G):
|
| 787 |
+
return 0
|
| 788 |
+
|
| 789 |
+
# initial value for \lambda is minimum degree
|
| 790 |
+
L = min(d for n, d in G.degree())
|
| 791 |
+
|
| 792 |
+
if cutoff is not None:
|
| 793 |
+
L = min(cutoff, L)
|
| 794 |
+
|
| 795 |
+
# A dominating set is \lambda-covering
|
| 796 |
+
# We need a dominating set with at least two nodes
|
| 797 |
+
for node in G:
|
| 798 |
+
D = nx.dominating_set(G, start_with=node)
|
| 799 |
+
v = D.pop()
|
| 800 |
+
if D:
|
| 801 |
+
break
|
| 802 |
+
else:
|
| 803 |
+
# in complete graphs the dominating sets will always be of one node
|
| 804 |
+
# thus we return min degree
|
| 805 |
+
return L
|
| 806 |
+
|
| 807 |
+
for w in D:
|
| 808 |
+
kwargs["cutoff"] = L
|
| 809 |
+
L = min(L, local_edge_connectivity(G, v, w, **kwargs))
|
| 810 |
+
|
| 811 |
+
return L
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/cuts.py
ADDED
|
@@ -0,0 +1,612 @@
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|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Flow based cut algorithms
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
import itertools
|
| 6 |
+
|
| 7 |
+
import networkx as nx
|
| 8 |
+
|
| 9 |
+
# Define the default maximum flow function to use in all flow based
|
| 10 |
+
# cut algorithms.
|
| 11 |
+
from networkx.algorithms.flow import build_residual_network, edmonds_karp
|
| 12 |
+
|
| 13 |
+
default_flow_func = edmonds_karp
|
| 14 |
+
|
| 15 |
+
from .utils import build_auxiliary_edge_connectivity, build_auxiliary_node_connectivity
|
| 16 |
+
|
| 17 |
+
__all__ = [
|
| 18 |
+
"minimum_st_node_cut",
|
| 19 |
+
"minimum_node_cut",
|
| 20 |
+
"minimum_st_edge_cut",
|
| 21 |
+
"minimum_edge_cut",
|
| 22 |
+
]
|
| 23 |
+
|
| 24 |
+
|
| 25 |
+
@nx._dispatchable(
|
| 26 |
+
graphs={"G": 0, "auxiliary?": 4},
|
| 27 |
+
preserve_edge_attrs={"auxiliary": {"capacity": float("inf")}},
|
| 28 |
+
preserve_graph_attrs={"auxiliary"},
|
| 29 |
+
)
|
| 30 |
+
def minimum_st_edge_cut(G, s, t, flow_func=None, auxiliary=None, residual=None):
|
| 31 |
+
"""Returns the edges of the cut-set of a minimum (s, t)-cut.
|
| 32 |
+
|
| 33 |
+
This function returns the set of edges of minimum cardinality that,
|
| 34 |
+
if removed, would destroy all paths among source and target in G.
|
| 35 |
+
Edge weights are not considered. See :meth:`minimum_cut` for
|
| 36 |
+
computing minimum cuts considering edge weights.
|
| 37 |
+
|
| 38 |
+
Parameters
|
| 39 |
+
----------
|
| 40 |
+
G : NetworkX graph
|
| 41 |
+
|
| 42 |
+
s : node
|
| 43 |
+
Source node for the flow.
|
| 44 |
+
|
| 45 |
+
t : node
|
| 46 |
+
Sink node for the flow.
|
| 47 |
+
|
| 48 |
+
auxiliary : NetworkX DiGraph
|
| 49 |
+
Auxiliary digraph to compute flow based node connectivity. It has
|
| 50 |
+
to have a graph attribute called mapping with a dictionary mapping
|
| 51 |
+
node names in G and in the auxiliary digraph. If provided
|
| 52 |
+
it will be reused instead of recreated. Default value: None.
|
| 53 |
+
|
| 54 |
+
flow_func : function
|
| 55 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 56 |
+
The function has to accept at least three parameters: a Digraph,
|
| 57 |
+
a source node, and a target node. And return a residual network
|
| 58 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 59 |
+
details). If flow_func is None, the default maximum flow function
|
| 60 |
+
(:meth:`edmonds_karp`) is used. See :meth:`node_connectivity` for
|
| 61 |
+
details. The choice of the default function may change from version
|
| 62 |
+
to version and should not be relied on. Default value: None.
|
| 63 |
+
|
| 64 |
+
residual : NetworkX DiGraph
|
| 65 |
+
Residual network to compute maximum flow. If provided it will be
|
| 66 |
+
reused instead of recreated. Default value: None.
|
| 67 |
+
|
| 68 |
+
Returns
|
| 69 |
+
-------
|
| 70 |
+
cutset : set
|
| 71 |
+
Set of edges that, if removed from the graph, will disconnect it.
|
| 72 |
+
|
| 73 |
+
See also
|
| 74 |
+
--------
|
| 75 |
+
:meth:`minimum_cut`
|
| 76 |
+
:meth:`minimum_node_cut`
|
| 77 |
+
:meth:`minimum_edge_cut`
|
| 78 |
+
:meth:`stoer_wagner`
|
| 79 |
+
:meth:`node_connectivity`
|
| 80 |
+
:meth:`edge_connectivity`
|
| 81 |
+
:meth:`maximum_flow`
|
| 82 |
+
:meth:`edmonds_karp`
|
| 83 |
+
:meth:`preflow_push`
|
| 84 |
+
:meth:`shortest_augmenting_path`
|
| 85 |
+
|
| 86 |
+
Examples
|
| 87 |
+
--------
|
| 88 |
+
This function is not imported in the base NetworkX namespace, so you
|
| 89 |
+
have to explicitly import it from the connectivity package:
|
| 90 |
+
|
| 91 |
+
>>> from networkx.algorithms.connectivity import minimum_st_edge_cut
|
| 92 |
+
|
| 93 |
+
We use in this example the platonic icosahedral graph, which has edge
|
| 94 |
+
connectivity 5.
|
| 95 |
+
|
| 96 |
+
>>> G = nx.icosahedral_graph()
|
| 97 |
+
>>> len(minimum_st_edge_cut(G, 0, 6))
|
| 98 |
+
5
|
| 99 |
+
|
| 100 |
+
If you need to compute local edge cuts on several pairs of
|
| 101 |
+
nodes in the same graph, it is recommended that you reuse the
|
| 102 |
+
data structures that NetworkX uses in the computation: the
|
| 103 |
+
auxiliary digraph for edge connectivity, and the residual
|
| 104 |
+
network for the underlying maximum flow computation.
|
| 105 |
+
|
| 106 |
+
Example of how to compute local edge cuts among all pairs of
|
| 107 |
+
nodes of the platonic icosahedral graph reusing the data
|
| 108 |
+
structures.
|
| 109 |
+
|
| 110 |
+
>>> import itertools
|
| 111 |
+
>>> # You also have to explicitly import the function for
|
| 112 |
+
>>> # building the auxiliary digraph from the connectivity package
|
| 113 |
+
>>> from networkx.algorithms.connectivity import build_auxiliary_edge_connectivity
|
| 114 |
+
>>> H = build_auxiliary_edge_connectivity(G)
|
| 115 |
+
>>> # And the function for building the residual network from the
|
| 116 |
+
>>> # flow package
|
| 117 |
+
>>> from networkx.algorithms.flow import build_residual_network
|
| 118 |
+
>>> # Note that the auxiliary digraph has an edge attribute named capacity
|
| 119 |
+
>>> R = build_residual_network(H, "capacity")
|
| 120 |
+
>>> result = dict.fromkeys(G, dict())
|
| 121 |
+
>>> # Reuse the auxiliary digraph and the residual network by passing them
|
| 122 |
+
>>> # as parameters
|
| 123 |
+
>>> for u, v in itertools.combinations(G, 2):
|
| 124 |
+
... k = len(minimum_st_edge_cut(G, u, v, auxiliary=H, residual=R))
|
| 125 |
+
... result[u][v] = k
|
| 126 |
+
>>> all(result[u][v] == 5 for u, v in itertools.combinations(G, 2))
|
| 127 |
+
True
|
| 128 |
+
|
| 129 |
+
You can also use alternative flow algorithms for computing edge
|
| 130 |
+
cuts. For instance, in dense networks the algorithm
|
| 131 |
+
:meth:`shortest_augmenting_path` will usually perform better than
|
| 132 |
+
the default :meth:`edmonds_karp` which is faster for sparse
|
| 133 |
+
networks with highly skewed degree distributions. Alternative flow
|
| 134 |
+
functions have to be explicitly imported from the flow package.
|
| 135 |
+
|
| 136 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 137 |
+
>>> len(minimum_st_edge_cut(G, 0, 6, flow_func=shortest_augmenting_path))
|
| 138 |
+
5
|
| 139 |
+
|
| 140 |
+
"""
|
| 141 |
+
if flow_func is None:
|
| 142 |
+
flow_func = default_flow_func
|
| 143 |
+
|
| 144 |
+
if auxiliary is None:
|
| 145 |
+
H = build_auxiliary_edge_connectivity(G)
|
| 146 |
+
else:
|
| 147 |
+
H = auxiliary
|
| 148 |
+
|
| 149 |
+
kwargs = {"capacity": "capacity", "flow_func": flow_func, "residual": residual}
|
| 150 |
+
|
| 151 |
+
cut_value, partition = nx.minimum_cut(H, s, t, **kwargs)
|
| 152 |
+
reachable, non_reachable = partition
|
| 153 |
+
# Any edge in the original graph linking the two sets in the
|
| 154 |
+
# partition is part of the edge cutset
|
| 155 |
+
cutset = set()
|
| 156 |
+
for u, nbrs in ((n, G[n]) for n in reachable):
|
| 157 |
+
cutset.update((u, v) for v in nbrs if v in non_reachable)
|
| 158 |
+
|
| 159 |
+
return cutset
|
| 160 |
+
|
| 161 |
+
|
| 162 |
+
@nx._dispatchable(
|
| 163 |
+
graphs={"G": 0, "auxiliary?": 4},
|
| 164 |
+
preserve_node_attrs={"auxiliary": {"id": None}},
|
| 165 |
+
preserve_graph_attrs={"auxiliary"},
|
| 166 |
+
)
|
| 167 |
+
def minimum_st_node_cut(G, s, t, flow_func=None, auxiliary=None, residual=None):
|
| 168 |
+
r"""Returns a set of nodes of minimum cardinality that disconnect source
|
| 169 |
+
from target in G.
|
| 170 |
+
|
| 171 |
+
This function returns the set of nodes of minimum cardinality that,
|
| 172 |
+
if removed, would destroy all paths among source and target in G.
|
| 173 |
+
|
| 174 |
+
Parameters
|
| 175 |
+
----------
|
| 176 |
+
G : NetworkX graph
|
| 177 |
+
|
| 178 |
+
s : node
|
| 179 |
+
Source node.
|
| 180 |
+
|
| 181 |
+
t : node
|
| 182 |
+
Target node.
|
| 183 |
+
|
| 184 |
+
flow_func : function
|
| 185 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 186 |
+
The function has to accept at least three parameters: a Digraph,
|
| 187 |
+
a source node, and a target node. And return a residual network
|
| 188 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 189 |
+
details). If flow_func is None, the default maximum flow function
|
| 190 |
+
(:meth:`edmonds_karp`) is used. See below for details. The choice
|
| 191 |
+
of the default function may change from version to version and
|
| 192 |
+
should not be relied on. Default value: None.
|
| 193 |
+
|
| 194 |
+
auxiliary : NetworkX DiGraph
|
| 195 |
+
Auxiliary digraph to compute flow based node connectivity. It has
|
| 196 |
+
to have a graph attribute called mapping with a dictionary mapping
|
| 197 |
+
node names in G and in the auxiliary digraph. If provided
|
| 198 |
+
it will be reused instead of recreated. Default value: None.
|
| 199 |
+
|
| 200 |
+
residual : NetworkX DiGraph
|
| 201 |
+
Residual network to compute maximum flow. If provided it will be
|
| 202 |
+
reused instead of recreated. Default value: None.
|
| 203 |
+
|
| 204 |
+
Returns
|
| 205 |
+
-------
|
| 206 |
+
cutset : set
|
| 207 |
+
Set of nodes that, if removed, would destroy all paths between
|
| 208 |
+
source and target in G.
|
| 209 |
+
|
| 210 |
+
Examples
|
| 211 |
+
--------
|
| 212 |
+
This function is not imported in the base NetworkX namespace, so you
|
| 213 |
+
have to explicitly import it from the connectivity package:
|
| 214 |
+
|
| 215 |
+
>>> from networkx.algorithms.connectivity import minimum_st_node_cut
|
| 216 |
+
|
| 217 |
+
We use in this example the platonic icosahedral graph, which has node
|
| 218 |
+
connectivity 5.
|
| 219 |
+
|
| 220 |
+
>>> G = nx.icosahedral_graph()
|
| 221 |
+
>>> len(minimum_st_node_cut(G, 0, 6))
|
| 222 |
+
5
|
| 223 |
+
|
| 224 |
+
If you need to compute local st cuts between several pairs of
|
| 225 |
+
nodes in the same graph, it is recommended that you reuse the
|
| 226 |
+
data structures that NetworkX uses in the computation: the
|
| 227 |
+
auxiliary digraph for node connectivity and node cuts, and the
|
| 228 |
+
residual network for the underlying maximum flow computation.
|
| 229 |
+
|
| 230 |
+
Example of how to compute local st node cuts reusing the data
|
| 231 |
+
structures:
|
| 232 |
+
|
| 233 |
+
>>> # You also have to explicitly import the function for
|
| 234 |
+
>>> # building the auxiliary digraph from the connectivity package
|
| 235 |
+
>>> from networkx.algorithms.connectivity import build_auxiliary_node_connectivity
|
| 236 |
+
>>> H = build_auxiliary_node_connectivity(G)
|
| 237 |
+
>>> # And the function for building the residual network from the
|
| 238 |
+
>>> # flow package
|
| 239 |
+
>>> from networkx.algorithms.flow import build_residual_network
|
| 240 |
+
>>> # Note that the auxiliary digraph has an edge attribute named capacity
|
| 241 |
+
>>> R = build_residual_network(H, "capacity")
|
| 242 |
+
>>> # Reuse the auxiliary digraph and the residual network by passing them
|
| 243 |
+
>>> # as parameters
|
| 244 |
+
>>> len(minimum_st_node_cut(G, 0, 6, auxiliary=H, residual=R))
|
| 245 |
+
5
|
| 246 |
+
|
| 247 |
+
You can also use alternative flow algorithms for computing minimum st
|
| 248 |
+
node cuts. For instance, in dense networks the algorithm
|
| 249 |
+
:meth:`shortest_augmenting_path` will usually perform better than
|
| 250 |
+
the default :meth:`edmonds_karp` which is faster for sparse
|
| 251 |
+
networks with highly skewed degree distributions. Alternative flow
|
| 252 |
+
functions have to be explicitly imported from the flow package.
|
| 253 |
+
|
| 254 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 255 |
+
>>> len(minimum_st_node_cut(G, 0, 6, flow_func=shortest_augmenting_path))
|
| 256 |
+
5
|
| 257 |
+
|
| 258 |
+
Notes
|
| 259 |
+
-----
|
| 260 |
+
This is a flow based implementation of minimum node cut. The algorithm
|
| 261 |
+
is based in solving a number of maximum flow computations to determine
|
| 262 |
+
the capacity of the minimum cut on an auxiliary directed network that
|
| 263 |
+
corresponds to the minimum node cut of G. It handles both directed
|
| 264 |
+
and undirected graphs. This implementation is based on algorithm 11
|
| 265 |
+
in [1]_.
|
| 266 |
+
|
| 267 |
+
See also
|
| 268 |
+
--------
|
| 269 |
+
:meth:`minimum_node_cut`
|
| 270 |
+
:meth:`minimum_edge_cut`
|
| 271 |
+
:meth:`stoer_wagner`
|
| 272 |
+
:meth:`node_connectivity`
|
| 273 |
+
:meth:`edge_connectivity`
|
| 274 |
+
:meth:`maximum_flow`
|
| 275 |
+
:meth:`edmonds_karp`
|
| 276 |
+
:meth:`preflow_push`
|
| 277 |
+
:meth:`shortest_augmenting_path`
|
| 278 |
+
|
| 279 |
+
References
|
| 280 |
+
----------
|
| 281 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms.
|
| 282 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 283 |
+
|
| 284 |
+
"""
|
| 285 |
+
if auxiliary is None:
|
| 286 |
+
H = build_auxiliary_node_connectivity(G)
|
| 287 |
+
else:
|
| 288 |
+
H = auxiliary
|
| 289 |
+
|
| 290 |
+
mapping = H.graph.get("mapping", None)
|
| 291 |
+
if mapping is None:
|
| 292 |
+
raise nx.NetworkXError("Invalid auxiliary digraph.")
|
| 293 |
+
if G.has_edge(s, t) or G.has_edge(t, s):
|
| 294 |
+
return {}
|
| 295 |
+
kwargs = {"flow_func": flow_func, "residual": residual, "auxiliary": H}
|
| 296 |
+
|
| 297 |
+
# The edge cut in the auxiliary digraph corresponds to the node cut in the
|
| 298 |
+
# original graph.
|
| 299 |
+
edge_cut = minimum_st_edge_cut(H, f"{mapping[s]}B", f"{mapping[t]}A", **kwargs)
|
| 300 |
+
# Each node in the original graph maps to two nodes of the auxiliary graph
|
| 301 |
+
node_cut = {H.nodes[node]["id"] for edge in edge_cut for node in edge}
|
| 302 |
+
return node_cut - {s, t}
|
| 303 |
+
|
| 304 |
+
|
| 305 |
+
@nx._dispatchable
|
| 306 |
+
def minimum_node_cut(G, s=None, t=None, flow_func=None):
|
| 307 |
+
r"""Returns a set of nodes of minimum cardinality that disconnects G.
|
| 308 |
+
|
| 309 |
+
If source and target nodes are provided, this function returns the
|
| 310 |
+
set of nodes of minimum cardinality that, if removed, would destroy
|
| 311 |
+
all paths among source and target in G. If not, it returns a set
|
| 312 |
+
of nodes of minimum cardinality that disconnects G.
|
| 313 |
+
|
| 314 |
+
Parameters
|
| 315 |
+
----------
|
| 316 |
+
G : NetworkX graph
|
| 317 |
+
|
| 318 |
+
s : node
|
| 319 |
+
Source node. Optional. Default value: None.
|
| 320 |
+
|
| 321 |
+
t : node
|
| 322 |
+
Target node. Optional. Default value: None.
|
| 323 |
+
|
| 324 |
+
flow_func : function
|
| 325 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 326 |
+
The function has to accept at least three parameters: a Digraph,
|
| 327 |
+
a source node, and a target node. And return a residual network
|
| 328 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 329 |
+
details). If flow_func is None, the default maximum flow function
|
| 330 |
+
(:meth:`edmonds_karp`) is used. See below for details. The
|
| 331 |
+
choice of the default function may change from version
|
| 332 |
+
to version and should not be relied on. Default value: None.
|
| 333 |
+
|
| 334 |
+
Returns
|
| 335 |
+
-------
|
| 336 |
+
cutset : set
|
| 337 |
+
Set of nodes that, if removed, would disconnect G. If source
|
| 338 |
+
and target nodes are provided, the set contains the nodes that
|
| 339 |
+
if removed, would destroy all paths between source and target.
|
| 340 |
+
|
| 341 |
+
Examples
|
| 342 |
+
--------
|
| 343 |
+
>>> # Platonic icosahedral graph has node connectivity 5
|
| 344 |
+
>>> G = nx.icosahedral_graph()
|
| 345 |
+
>>> node_cut = nx.minimum_node_cut(G)
|
| 346 |
+
>>> len(node_cut)
|
| 347 |
+
5
|
| 348 |
+
|
| 349 |
+
You can use alternative flow algorithms for the underlying maximum
|
| 350 |
+
flow computation. In dense networks the algorithm
|
| 351 |
+
:meth:`shortest_augmenting_path` will usually perform better
|
| 352 |
+
than the default :meth:`edmonds_karp`, which is faster for
|
| 353 |
+
sparse networks with highly skewed degree distributions. Alternative
|
| 354 |
+
flow functions have to be explicitly imported from the flow package.
|
| 355 |
+
|
| 356 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 357 |
+
>>> node_cut == nx.minimum_node_cut(G, flow_func=shortest_augmenting_path)
|
| 358 |
+
True
|
| 359 |
+
|
| 360 |
+
If you specify a pair of nodes (source and target) as parameters,
|
| 361 |
+
this function returns a local st node cut.
|
| 362 |
+
|
| 363 |
+
>>> len(nx.minimum_node_cut(G, 3, 7))
|
| 364 |
+
5
|
| 365 |
+
|
| 366 |
+
If you need to perform several local st cuts among different
|
| 367 |
+
pairs of nodes on the same graph, it is recommended that you reuse
|
| 368 |
+
the data structures used in the maximum flow computations. See
|
| 369 |
+
:meth:`minimum_st_node_cut` for details.
|
| 370 |
+
|
| 371 |
+
Notes
|
| 372 |
+
-----
|
| 373 |
+
This is a flow based implementation of minimum node cut. The algorithm
|
| 374 |
+
is based in solving a number of maximum flow computations to determine
|
| 375 |
+
the capacity of the minimum cut on an auxiliary directed network that
|
| 376 |
+
corresponds to the minimum node cut of G. It handles both directed
|
| 377 |
+
and undirected graphs. This implementation is based on algorithm 11
|
| 378 |
+
in [1]_.
|
| 379 |
+
|
| 380 |
+
See also
|
| 381 |
+
--------
|
| 382 |
+
:meth:`minimum_st_node_cut`
|
| 383 |
+
:meth:`minimum_cut`
|
| 384 |
+
:meth:`minimum_edge_cut`
|
| 385 |
+
:meth:`stoer_wagner`
|
| 386 |
+
:meth:`node_connectivity`
|
| 387 |
+
:meth:`edge_connectivity`
|
| 388 |
+
:meth:`maximum_flow`
|
| 389 |
+
:meth:`edmonds_karp`
|
| 390 |
+
:meth:`preflow_push`
|
| 391 |
+
:meth:`shortest_augmenting_path`
|
| 392 |
+
|
| 393 |
+
References
|
| 394 |
+
----------
|
| 395 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms.
|
| 396 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 397 |
+
|
| 398 |
+
"""
|
| 399 |
+
if (s is not None and t is None) or (s is None and t is not None):
|
| 400 |
+
raise nx.NetworkXError("Both source and target must be specified.")
|
| 401 |
+
|
| 402 |
+
# Local minimum node cut.
|
| 403 |
+
if s is not None and t is not None:
|
| 404 |
+
if s not in G:
|
| 405 |
+
raise nx.NetworkXError(f"node {s} not in graph")
|
| 406 |
+
if t not in G:
|
| 407 |
+
raise nx.NetworkXError(f"node {t} not in graph")
|
| 408 |
+
return minimum_st_node_cut(G, s, t, flow_func=flow_func)
|
| 409 |
+
|
| 410 |
+
# Global minimum node cut.
|
| 411 |
+
# Analog to the algorithm 11 for global node connectivity in [1].
|
| 412 |
+
if G.is_directed():
|
| 413 |
+
if not nx.is_weakly_connected(G):
|
| 414 |
+
raise nx.NetworkXError("Input graph is not connected")
|
| 415 |
+
iter_func = itertools.permutations
|
| 416 |
+
|
| 417 |
+
def neighbors(v):
|
| 418 |
+
return itertools.chain.from_iterable([G.predecessors(v), G.successors(v)])
|
| 419 |
+
|
| 420 |
+
else:
|
| 421 |
+
if not nx.is_connected(G):
|
| 422 |
+
raise nx.NetworkXError("Input graph is not connected")
|
| 423 |
+
iter_func = itertools.combinations
|
| 424 |
+
neighbors = G.neighbors
|
| 425 |
+
|
| 426 |
+
# Reuse the auxiliary digraph and the residual network.
|
| 427 |
+
H = build_auxiliary_node_connectivity(G)
|
| 428 |
+
R = build_residual_network(H, "capacity")
|
| 429 |
+
kwargs = {"flow_func": flow_func, "auxiliary": H, "residual": R}
|
| 430 |
+
|
| 431 |
+
# Choose a node with minimum degree.
|
| 432 |
+
v = min(G, key=G.degree)
|
| 433 |
+
# Initial node cutset is all neighbors of the node with minimum degree.
|
| 434 |
+
min_cut = set(G[v])
|
| 435 |
+
# Compute st node cuts between v and all its non-neighbors nodes in G.
|
| 436 |
+
for w in set(G) - set(neighbors(v)) - {v}:
|
| 437 |
+
this_cut = minimum_st_node_cut(G, v, w, **kwargs)
|
| 438 |
+
if len(min_cut) >= len(this_cut):
|
| 439 |
+
min_cut = this_cut
|
| 440 |
+
# Also for non adjacent pairs of neighbors of v.
|
| 441 |
+
for x, y in iter_func(neighbors(v), 2):
|
| 442 |
+
if y in G[x]:
|
| 443 |
+
continue
|
| 444 |
+
this_cut = minimum_st_node_cut(G, x, y, **kwargs)
|
| 445 |
+
if len(min_cut) >= len(this_cut):
|
| 446 |
+
min_cut = this_cut
|
| 447 |
+
|
| 448 |
+
return min_cut
|
| 449 |
+
|
| 450 |
+
|
| 451 |
+
@nx._dispatchable
|
| 452 |
+
def minimum_edge_cut(G, s=None, t=None, flow_func=None):
|
| 453 |
+
r"""Returns a set of edges of minimum cardinality that disconnects G.
|
| 454 |
+
|
| 455 |
+
If source and target nodes are provided, this function returns the
|
| 456 |
+
set of edges of minimum cardinality that, if removed, would break
|
| 457 |
+
all paths among source and target in G. If not, it returns a set of
|
| 458 |
+
edges of minimum cardinality that disconnects G.
|
| 459 |
+
|
| 460 |
+
Parameters
|
| 461 |
+
----------
|
| 462 |
+
G : NetworkX graph
|
| 463 |
+
|
| 464 |
+
s : node
|
| 465 |
+
Source node. Optional. Default value: None.
|
| 466 |
+
|
| 467 |
+
t : node
|
| 468 |
+
Target node. Optional. Default value: None.
|
| 469 |
+
|
| 470 |
+
flow_func : function
|
| 471 |
+
A function for computing the maximum flow among a pair of nodes.
|
| 472 |
+
The function has to accept at least three parameters: a Digraph,
|
| 473 |
+
a source node, and a target node. And return a residual network
|
| 474 |
+
that follows NetworkX conventions (see :meth:`maximum_flow` for
|
| 475 |
+
details). If flow_func is None, the default maximum flow function
|
| 476 |
+
(:meth:`edmonds_karp`) is used. See below for details. The
|
| 477 |
+
choice of the default function may change from version
|
| 478 |
+
to version and should not be relied on. Default value: None.
|
| 479 |
+
|
| 480 |
+
Returns
|
| 481 |
+
-------
|
| 482 |
+
cutset : set
|
| 483 |
+
Set of edges that, if removed, would disconnect G. If source
|
| 484 |
+
and target nodes are provided, the set contains the edges that
|
| 485 |
+
if removed, would destroy all paths between source and target.
|
| 486 |
+
|
| 487 |
+
Examples
|
| 488 |
+
--------
|
| 489 |
+
>>> # Platonic icosahedral graph has edge connectivity 5
|
| 490 |
+
>>> G = nx.icosahedral_graph()
|
| 491 |
+
>>> len(nx.minimum_edge_cut(G))
|
| 492 |
+
5
|
| 493 |
+
|
| 494 |
+
You can use alternative flow algorithms for the underlying
|
| 495 |
+
maximum flow computation. In dense networks the algorithm
|
| 496 |
+
:meth:`shortest_augmenting_path` will usually perform better
|
| 497 |
+
than the default :meth:`edmonds_karp`, which is faster for
|
| 498 |
+
sparse networks with highly skewed degree distributions.
|
| 499 |
+
Alternative flow functions have to be explicitly imported
|
| 500 |
+
from the flow package.
|
| 501 |
+
|
| 502 |
+
>>> from networkx.algorithms.flow import shortest_augmenting_path
|
| 503 |
+
>>> len(nx.minimum_edge_cut(G, flow_func=shortest_augmenting_path))
|
| 504 |
+
5
|
| 505 |
+
|
| 506 |
+
If you specify a pair of nodes (source and target) as parameters,
|
| 507 |
+
this function returns the value of local edge connectivity.
|
| 508 |
+
|
| 509 |
+
>>> nx.edge_connectivity(G, 3, 7)
|
| 510 |
+
5
|
| 511 |
+
|
| 512 |
+
If you need to perform several local computations among different
|
| 513 |
+
pairs of nodes on the same graph, it is recommended that you reuse
|
| 514 |
+
the data structures used in the maximum flow computations. See
|
| 515 |
+
:meth:`local_edge_connectivity` for details.
|
| 516 |
+
|
| 517 |
+
Notes
|
| 518 |
+
-----
|
| 519 |
+
This is a flow based implementation of minimum edge cut. For
|
| 520 |
+
undirected graphs the algorithm works by finding a 'small' dominating
|
| 521 |
+
set of nodes of G (see algorithm 7 in [1]_) and computing the maximum
|
| 522 |
+
flow between an arbitrary node in the dominating set and the rest of
|
| 523 |
+
nodes in it. This is an implementation of algorithm 6 in [1]_. For
|
| 524 |
+
directed graphs, the algorithm does n calls to the max flow function.
|
| 525 |
+
The function raises an error if the directed graph is not weakly
|
| 526 |
+
connected and returns an empty set if it is weakly connected.
|
| 527 |
+
It is an implementation of algorithm 8 in [1]_.
|
| 528 |
+
|
| 529 |
+
See also
|
| 530 |
+
--------
|
| 531 |
+
:meth:`minimum_st_edge_cut`
|
| 532 |
+
:meth:`minimum_node_cut`
|
| 533 |
+
:meth:`stoer_wagner`
|
| 534 |
+
:meth:`node_connectivity`
|
| 535 |
+
:meth:`edge_connectivity`
|
| 536 |
+
:meth:`maximum_flow`
|
| 537 |
+
:meth:`edmonds_karp`
|
| 538 |
+
:meth:`preflow_push`
|
| 539 |
+
:meth:`shortest_augmenting_path`
|
| 540 |
+
|
| 541 |
+
References
|
| 542 |
+
----------
|
| 543 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms.
|
| 544 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 545 |
+
|
| 546 |
+
"""
|
| 547 |
+
if (s is not None and t is None) or (s is None and t is not None):
|
| 548 |
+
raise nx.NetworkXError("Both source and target must be specified.")
|
| 549 |
+
|
| 550 |
+
# reuse auxiliary digraph and residual network
|
| 551 |
+
H = build_auxiliary_edge_connectivity(G)
|
| 552 |
+
R = build_residual_network(H, "capacity")
|
| 553 |
+
kwargs = {"flow_func": flow_func, "residual": R, "auxiliary": H}
|
| 554 |
+
|
| 555 |
+
# Local minimum edge cut if s and t are not None
|
| 556 |
+
if s is not None and t is not None:
|
| 557 |
+
if s not in G:
|
| 558 |
+
raise nx.NetworkXError(f"node {s} not in graph")
|
| 559 |
+
if t not in G:
|
| 560 |
+
raise nx.NetworkXError(f"node {t} not in graph")
|
| 561 |
+
return minimum_st_edge_cut(H, s, t, **kwargs)
|
| 562 |
+
|
| 563 |
+
# Global minimum edge cut
|
| 564 |
+
# Analog to the algorithm for global edge connectivity
|
| 565 |
+
if G.is_directed():
|
| 566 |
+
# Based on algorithm 8 in [1]
|
| 567 |
+
if not nx.is_weakly_connected(G):
|
| 568 |
+
raise nx.NetworkXError("Input graph is not connected")
|
| 569 |
+
|
| 570 |
+
# Initial cutset is all edges of a node with minimum degree
|
| 571 |
+
node = min(G, key=G.degree)
|
| 572 |
+
min_cut = set(G.edges(node))
|
| 573 |
+
nodes = list(G)
|
| 574 |
+
n = len(nodes)
|
| 575 |
+
for i in range(n):
|
| 576 |
+
try:
|
| 577 |
+
this_cut = minimum_st_edge_cut(H, nodes[i], nodes[i + 1], **kwargs)
|
| 578 |
+
if len(this_cut) <= len(min_cut):
|
| 579 |
+
min_cut = this_cut
|
| 580 |
+
except IndexError: # Last node!
|
| 581 |
+
this_cut = minimum_st_edge_cut(H, nodes[i], nodes[0], **kwargs)
|
| 582 |
+
if len(this_cut) <= len(min_cut):
|
| 583 |
+
min_cut = this_cut
|
| 584 |
+
|
| 585 |
+
return min_cut
|
| 586 |
+
|
| 587 |
+
else: # undirected
|
| 588 |
+
# Based on algorithm 6 in [1]
|
| 589 |
+
if not nx.is_connected(G):
|
| 590 |
+
raise nx.NetworkXError("Input graph is not connected")
|
| 591 |
+
|
| 592 |
+
# Initial cutset is all edges of a node with minimum degree
|
| 593 |
+
node = min(G, key=G.degree)
|
| 594 |
+
min_cut = set(G.edges(node))
|
| 595 |
+
# A dominating set is \lambda-covering
|
| 596 |
+
# We need a dominating set with at least two nodes
|
| 597 |
+
for node in G:
|
| 598 |
+
D = nx.dominating_set(G, start_with=node)
|
| 599 |
+
v = D.pop()
|
| 600 |
+
if D:
|
| 601 |
+
break
|
| 602 |
+
else:
|
| 603 |
+
# in complete graphs the dominating set will always be of one node
|
| 604 |
+
# thus we return min_cut, which now contains the edges of a node
|
| 605 |
+
# with minimum degree
|
| 606 |
+
return min_cut
|
| 607 |
+
for w in D:
|
| 608 |
+
this_cut = minimum_st_edge_cut(H, v, w, **kwargs)
|
| 609 |
+
if len(this_cut) <= len(min_cut):
|
| 610 |
+
min_cut = this_cut
|
| 611 |
+
|
| 612 |
+
return min_cut
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/edge_augmentation.py
ADDED
|
@@ -0,0 +1,1270 @@
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|
| 1 |
+
"""
|
| 2 |
+
Algorithms for finding k-edge-augmentations
|
| 3 |
+
|
| 4 |
+
A k-edge-augmentation is a set of edges, that once added to a graph, ensures
|
| 5 |
+
that the graph is k-edge-connected; i.e. the graph cannot be disconnected
|
| 6 |
+
unless k or more edges are removed. Typically, the goal is to find the
|
| 7 |
+
augmentation with minimum weight. In general, it is not guaranteed that a
|
| 8 |
+
k-edge-augmentation exists.
|
| 9 |
+
|
| 10 |
+
See Also
|
| 11 |
+
--------
|
| 12 |
+
:mod:`edge_kcomponents` : algorithms for finding k-edge-connected components
|
| 13 |
+
:mod:`connectivity` : algorithms for determining edge connectivity.
|
| 14 |
+
"""
|
| 15 |
+
|
| 16 |
+
import itertools as it
|
| 17 |
+
import math
|
| 18 |
+
from collections import defaultdict, namedtuple
|
| 19 |
+
|
| 20 |
+
import networkx as nx
|
| 21 |
+
from networkx.utils import not_implemented_for, py_random_state
|
| 22 |
+
|
| 23 |
+
__all__ = ["k_edge_augmentation", "is_k_edge_connected", "is_locally_k_edge_connected"]
|
| 24 |
+
|
| 25 |
+
|
| 26 |
+
@not_implemented_for("directed")
|
| 27 |
+
@not_implemented_for("multigraph")
|
| 28 |
+
@nx._dispatchable
|
| 29 |
+
def is_k_edge_connected(G, k):
|
| 30 |
+
"""Tests to see if a graph is k-edge-connected.
|
| 31 |
+
|
| 32 |
+
Is it impossible to disconnect the graph by removing fewer than k edges?
|
| 33 |
+
If so, then G is k-edge-connected.
|
| 34 |
+
|
| 35 |
+
Parameters
|
| 36 |
+
----------
|
| 37 |
+
G : NetworkX graph
|
| 38 |
+
An undirected graph.
|
| 39 |
+
|
| 40 |
+
k : integer
|
| 41 |
+
edge connectivity to test for
|
| 42 |
+
|
| 43 |
+
Returns
|
| 44 |
+
-------
|
| 45 |
+
boolean
|
| 46 |
+
True if G is k-edge-connected.
|
| 47 |
+
|
| 48 |
+
See Also
|
| 49 |
+
--------
|
| 50 |
+
:func:`is_locally_k_edge_connected`
|
| 51 |
+
|
| 52 |
+
Examples
|
| 53 |
+
--------
|
| 54 |
+
>>> G = nx.barbell_graph(10, 0)
|
| 55 |
+
>>> nx.is_k_edge_connected(G, k=1)
|
| 56 |
+
True
|
| 57 |
+
>>> nx.is_k_edge_connected(G, k=2)
|
| 58 |
+
False
|
| 59 |
+
"""
|
| 60 |
+
if k < 1:
|
| 61 |
+
raise ValueError(f"k must be positive, not {k}")
|
| 62 |
+
# First try to quickly determine if G is not k-edge-connected
|
| 63 |
+
if G.number_of_nodes() < k + 1:
|
| 64 |
+
return False
|
| 65 |
+
elif any(d < k for n, d in G.degree()):
|
| 66 |
+
return False
|
| 67 |
+
else:
|
| 68 |
+
# Otherwise perform the full check
|
| 69 |
+
if k == 1:
|
| 70 |
+
return nx.is_connected(G)
|
| 71 |
+
elif k == 2:
|
| 72 |
+
return nx.is_connected(G) and not nx.has_bridges(G)
|
| 73 |
+
else:
|
| 74 |
+
return nx.edge_connectivity(G, cutoff=k) >= k
|
| 75 |
+
|
| 76 |
+
|
| 77 |
+
@not_implemented_for("directed")
|
| 78 |
+
@not_implemented_for("multigraph")
|
| 79 |
+
@nx._dispatchable
|
| 80 |
+
def is_locally_k_edge_connected(G, s, t, k):
|
| 81 |
+
"""Tests to see if an edge in a graph is locally k-edge-connected.
|
| 82 |
+
|
| 83 |
+
Is it impossible to disconnect s and t by removing fewer than k edges?
|
| 84 |
+
If so, then s and t are locally k-edge-connected in G.
|
| 85 |
+
|
| 86 |
+
Parameters
|
| 87 |
+
----------
|
| 88 |
+
G : NetworkX graph
|
| 89 |
+
An undirected graph.
|
| 90 |
+
|
| 91 |
+
s : node
|
| 92 |
+
Source node
|
| 93 |
+
|
| 94 |
+
t : node
|
| 95 |
+
Target node
|
| 96 |
+
|
| 97 |
+
k : integer
|
| 98 |
+
local edge connectivity for nodes s and t
|
| 99 |
+
|
| 100 |
+
Returns
|
| 101 |
+
-------
|
| 102 |
+
boolean
|
| 103 |
+
True if s and t are locally k-edge-connected in G.
|
| 104 |
+
|
| 105 |
+
See Also
|
| 106 |
+
--------
|
| 107 |
+
:func:`is_k_edge_connected`
|
| 108 |
+
|
| 109 |
+
Examples
|
| 110 |
+
--------
|
| 111 |
+
>>> from networkx.algorithms.connectivity import is_locally_k_edge_connected
|
| 112 |
+
>>> G = nx.barbell_graph(10, 0)
|
| 113 |
+
>>> is_locally_k_edge_connected(G, 5, 15, k=1)
|
| 114 |
+
True
|
| 115 |
+
>>> is_locally_k_edge_connected(G, 5, 15, k=2)
|
| 116 |
+
False
|
| 117 |
+
>>> is_locally_k_edge_connected(G, 1, 5, k=2)
|
| 118 |
+
True
|
| 119 |
+
"""
|
| 120 |
+
if k < 1:
|
| 121 |
+
raise ValueError(f"k must be positive, not {k}")
|
| 122 |
+
|
| 123 |
+
# First try to quickly determine s, t is not k-locally-edge-connected in G
|
| 124 |
+
if G.degree(s) < k or G.degree(t) < k:
|
| 125 |
+
return False
|
| 126 |
+
else:
|
| 127 |
+
# Otherwise perform the full check
|
| 128 |
+
if k == 1:
|
| 129 |
+
return nx.has_path(G, s, t)
|
| 130 |
+
else:
|
| 131 |
+
localk = nx.connectivity.local_edge_connectivity(G, s, t, cutoff=k)
|
| 132 |
+
return localk >= k
|
| 133 |
+
|
| 134 |
+
|
| 135 |
+
@not_implemented_for("directed")
|
| 136 |
+
@not_implemented_for("multigraph")
|
| 137 |
+
@nx._dispatchable
|
| 138 |
+
def k_edge_augmentation(G, k, avail=None, weight=None, partial=False):
|
| 139 |
+
"""Finds set of edges to k-edge-connect G.
|
| 140 |
+
|
| 141 |
+
Adding edges from the augmentation to G make it impossible to disconnect G
|
| 142 |
+
unless k or more edges are removed. This function uses the most efficient
|
| 143 |
+
function available (depending on the value of k and if the problem is
|
| 144 |
+
weighted or unweighted) to search for a minimum weight subset of available
|
| 145 |
+
edges that k-edge-connects G. In general, finding a k-edge-augmentation is
|
| 146 |
+
NP-hard, so solutions are not guaranteed to be minimal. Furthermore, a
|
| 147 |
+
k-edge-augmentation may not exist.
|
| 148 |
+
|
| 149 |
+
Parameters
|
| 150 |
+
----------
|
| 151 |
+
G : NetworkX graph
|
| 152 |
+
An undirected graph.
|
| 153 |
+
|
| 154 |
+
k : integer
|
| 155 |
+
Desired edge connectivity
|
| 156 |
+
|
| 157 |
+
avail : dict or a set of 2 or 3 tuples
|
| 158 |
+
The available edges that can be used in the augmentation.
|
| 159 |
+
|
| 160 |
+
If unspecified, then all edges in the complement of G are available.
|
| 161 |
+
Otherwise, each item is an available edge (with an optional weight).
|
| 162 |
+
|
| 163 |
+
In the unweighted case, each item is an edge ``(u, v)``.
|
| 164 |
+
|
| 165 |
+
In the weighted case, each item is a 3-tuple ``(u, v, d)`` or a dict
|
| 166 |
+
with items ``(u, v): d``. The third item, ``d``, can be a dictionary
|
| 167 |
+
or a real number. If ``d`` is a dictionary ``d[weight]``
|
| 168 |
+
correspondings to the weight.
|
| 169 |
+
|
| 170 |
+
weight : string
|
| 171 |
+
key to use to find weights if ``avail`` is a set of 3-tuples where the
|
| 172 |
+
third item in each tuple is a dictionary.
|
| 173 |
+
|
| 174 |
+
partial : boolean
|
| 175 |
+
If partial is True and no feasible k-edge-augmentation exists, then all
|
| 176 |
+
a partial k-edge-augmentation is generated. Adding the edges in a
|
| 177 |
+
partial augmentation to G, minimizes the number of k-edge-connected
|
| 178 |
+
components and maximizes the edge connectivity between those
|
| 179 |
+
components. For details, see :func:`partial_k_edge_augmentation`.
|
| 180 |
+
|
| 181 |
+
Yields
|
| 182 |
+
------
|
| 183 |
+
edge : tuple
|
| 184 |
+
Edges that, once added to G, would cause G to become k-edge-connected.
|
| 185 |
+
If partial is False, an error is raised if this is not possible.
|
| 186 |
+
Otherwise, generated edges form a partial augmentation, which
|
| 187 |
+
k-edge-connects any part of G where it is possible, and maximally
|
| 188 |
+
connects the remaining parts.
|
| 189 |
+
|
| 190 |
+
Raises
|
| 191 |
+
------
|
| 192 |
+
NetworkXUnfeasible
|
| 193 |
+
If partial is False and no k-edge-augmentation exists.
|
| 194 |
+
|
| 195 |
+
NetworkXNotImplemented
|
| 196 |
+
If the input graph is directed or a multigraph.
|
| 197 |
+
|
| 198 |
+
ValueError:
|
| 199 |
+
If k is less than 1
|
| 200 |
+
|
| 201 |
+
Notes
|
| 202 |
+
-----
|
| 203 |
+
When k=1 this returns an optimal solution.
|
| 204 |
+
|
| 205 |
+
When k=2 and ``avail`` is None, this returns an optimal solution.
|
| 206 |
+
Otherwise when k=2, this returns a 2-approximation of the optimal solution.
|
| 207 |
+
|
| 208 |
+
For k>3, this problem is NP-hard and this uses a randomized algorithm that
|
| 209 |
+
produces a feasible solution, but provides no guarantees on the
|
| 210 |
+
solution weight.
|
| 211 |
+
|
| 212 |
+
Examples
|
| 213 |
+
--------
|
| 214 |
+
>>> # Unweighted cases
|
| 215 |
+
>>> G = nx.path_graph((1, 2, 3, 4))
|
| 216 |
+
>>> G.add_node(5)
|
| 217 |
+
>>> sorted(nx.k_edge_augmentation(G, k=1))
|
| 218 |
+
[(1, 5)]
|
| 219 |
+
>>> sorted(nx.k_edge_augmentation(G, k=2))
|
| 220 |
+
[(1, 5), (5, 4)]
|
| 221 |
+
>>> sorted(nx.k_edge_augmentation(G, k=3))
|
| 222 |
+
[(1, 4), (1, 5), (2, 5), (3, 5), (4, 5)]
|
| 223 |
+
>>> complement = list(nx.k_edge_augmentation(G, k=5, partial=True))
|
| 224 |
+
>>> G.add_edges_from(complement)
|
| 225 |
+
>>> nx.edge_connectivity(G)
|
| 226 |
+
4
|
| 227 |
+
|
| 228 |
+
>>> # Weighted cases
|
| 229 |
+
>>> G = nx.path_graph((1, 2, 3, 4))
|
| 230 |
+
>>> G.add_node(5)
|
| 231 |
+
>>> # avail can be a tuple with a dict
|
| 232 |
+
>>> avail = [(1, 5, {"weight": 11}), (2, 5, {"weight": 10})]
|
| 233 |
+
>>> sorted(nx.k_edge_augmentation(G, k=1, avail=avail, weight="weight"))
|
| 234 |
+
[(2, 5)]
|
| 235 |
+
>>> # or avail can be a 3-tuple with a real number
|
| 236 |
+
>>> avail = [(1, 5, 11), (2, 5, 10), (4, 3, 1), (4, 5, 51)]
|
| 237 |
+
>>> sorted(nx.k_edge_augmentation(G, k=2, avail=avail))
|
| 238 |
+
[(1, 5), (2, 5), (4, 5)]
|
| 239 |
+
>>> # or avail can be a dict
|
| 240 |
+
>>> avail = {(1, 5): 11, (2, 5): 10, (4, 3): 1, (4, 5): 51}
|
| 241 |
+
>>> sorted(nx.k_edge_augmentation(G, k=2, avail=avail))
|
| 242 |
+
[(1, 5), (2, 5), (4, 5)]
|
| 243 |
+
>>> # If augmentation is infeasible, then a partial solution can be found
|
| 244 |
+
>>> avail = {(1, 5): 11}
|
| 245 |
+
>>> sorted(nx.k_edge_augmentation(G, k=2, avail=avail, partial=True))
|
| 246 |
+
[(1, 5)]
|
| 247 |
+
"""
|
| 248 |
+
try:
|
| 249 |
+
if k <= 0:
|
| 250 |
+
raise ValueError(f"k must be a positive integer, not {k}")
|
| 251 |
+
elif G.number_of_nodes() < k + 1:
|
| 252 |
+
msg = f"impossible to {k} connect in graph with less than {k + 1} nodes"
|
| 253 |
+
raise nx.NetworkXUnfeasible(msg)
|
| 254 |
+
elif avail is not None and len(avail) == 0:
|
| 255 |
+
if not nx.is_k_edge_connected(G, k):
|
| 256 |
+
raise nx.NetworkXUnfeasible("no available edges")
|
| 257 |
+
aug_edges = []
|
| 258 |
+
elif k == 1:
|
| 259 |
+
aug_edges = one_edge_augmentation(
|
| 260 |
+
G, avail=avail, weight=weight, partial=partial
|
| 261 |
+
)
|
| 262 |
+
elif k == 2:
|
| 263 |
+
aug_edges = bridge_augmentation(G, avail=avail, weight=weight)
|
| 264 |
+
else:
|
| 265 |
+
# raise NotImplementedError(f'not implemented for k>2. k={k}')
|
| 266 |
+
aug_edges = greedy_k_edge_augmentation(
|
| 267 |
+
G, k=k, avail=avail, weight=weight, seed=0
|
| 268 |
+
)
|
| 269 |
+
# Do eager evaluation so we can catch any exceptions
|
| 270 |
+
# Before executing partial code.
|
| 271 |
+
yield from list(aug_edges)
|
| 272 |
+
except nx.NetworkXUnfeasible:
|
| 273 |
+
if partial:
|
| 274 |
+
# Return all available edges
|
| 275 |
+
if avail is None:
|
| 276 |
+
aug_edges = complement_edges(G)
|
| 277 |
+
else:
|
| 278 |
+
# If we can't k-edge-connect the entire graph, try to
|
| 279 |
+
# k-edge-connect as much as possible
|
| 280 |
+
aug_edges = partial_k_edge_augmentation(
|
| 281 |
+
G, k=k, avail=avail, weight=weight
|
| 282 |
+
)
|
| 283 |
+
yield from aug_edges
|
| 284 |
+
else:
|
| 285 |
+
raise
|
| 286 |
+
|
| 287 |
+
|
| 288 |
+
@nx._dispatchable
|
| 289 |
+
def partial_k_edge_augmentation(G, k, avail, weight=None):
|
| 290 |
+
"""Finds augmentation that k-edge-connects as much of the graph as possible.
|
| 291 |
+
|
| 292 |
+
When a k-edge-augmentation is not possible, we can still try to find a
|
| 293 |
+
small set of edges that partially k-edge-connects as much of the graph as
|
| 294 |
+
possible. All possible edges are generated between remaining parts.
|
| 295 |
+
This minimizes the number of k-edge-connected subgraphs in the resulting
|
| 296 |
+
graph and maximizes the edge connectivity between those subgraphs.
|
| 297 |
+
|
| 298 |
+
Parameters
|
| 299 |
+
----------
|
| 300 |
+
G : NetworkX graph
|
| 301 |
+
An undirected graph.
|
| 302 |
+
|
| 303 |
+
k : integer
|
| 304 |
+
Desired edge connectivity
|
| 305 |
+
|
| 306 |
+
avail : dict or a set of 2 or 3 tuples
|
| 307 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 308 |
+
|
| 309 |
+
weight : string
|
| 310 |
+
key to use to find weights if ``avail`` is a set of 3-tuples.
|
| 311 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 312 |
+
|
| 313 |
+
Yields
|
| 314 |
+
------
|
| 315 |
+
edge : tuple
|
| 316 |
+
Edges in the partial augmentation of G. These edges k-edge-connect any
|
| 317 |
+
part of G where it is possible, and maximally connects the remaining
|
| 318 |
+
parts. In other words, all edges from avail are generated except for
|
| 319 |
+
those within subgraphs that have already become k-edge-connected.
|
| 320 |
+
|
| 321 |
+
Notes
|
| 322 |
+
-----
|
| 323 |
+
Construct H that augments G with all edges in avail.
|
| 324 |
+
Find the k-edge-subgraphs of H.
|
| 325 |
+
For each k-edge-subgraph, if the number of nodes is more than k, then find
|
| 326 |
+
the k-edge-augmentation of that graph and add it to the solution. Then add
|
| 327 |
+
all edges in avail between k-edge subgraphs to the solution.
|
| 328 |
+
|
| 329 |
+
See Also
|
| 330 |
+
--------
|
| 331 |
+
:func:`k_edge_augmentation`
|
| 332 |
+
|
| 333 |
+
Examples
|
| 334 |
+
--------
|
| 335 |
+
>>> G = nx.path_graph((1, 2, 3, 4, 5, 6, 7))
|
| 336 |
+
>>> G.add_node(8)
|
| 337 |
+
>>> avail = [(1, 3), (1, 4), (1, 5), (2, 4), (2, 5), (3, 5), (1, 8)]
|
| 338 |
+
>>> sorted(partial_k_edge_augmentation(G, k=2, avail=avail))
|
| 339 |
+
[(1, 5), (1, 8)]
|
| 340 |
+
"""
|
| 341 |
+
|
| 342 |
+
def _edges_between_disjoint(H, only1, only2):
|
| 343 |
+
"""finds edges between disjoint nodes"""
|
| 344 |
+
only1_adj = {u: set(H.adj[u]) for u in only1}
|
| 345 |
+
for u, neighbs in only1_adj.items():
|
| 346 |
+
# Find the neighbors of u in only1 that are also in only2
|
| 347 |
+
neighbs12 = neighbs.intersection(only2)
|
| 348 |
+
for v in neighbs12:
|
| 349 |
+
yield (u, v)
|
| 350 |
+
|
| 351 |
+
avail_uv, avail_w = _unpack_available_edges(avail, weight=weight, G=G)
|
| 352 |
+
|
| 353 |
+
# Find which parts of the graph can be k-edge-connected
|
| 354 |
+
H = G.copy()
|
| 355 |
+
H.add_edges_from(
|
| 356 |
+
(
|
| 357 |
+
(u, v, {"weight": w, "generator": (u, v)})
|
| 358 |
+
for (u, v), w in zip(avail, avail_w)
|
| 359 |
+
)
|
| 360 |
+
)
|
| 361 |
+
k_edge_subgraphs = list(nx.k_edge_subgraphs(H, k=k))
|
| 362 |
+
|
| 363 |
+
# Generate edges to k-edge-connect internal subgraphs
|
| 364 |
+
for nodes in k_edge_subgraphs:
|
| 365 |
+
if len(nodes) > 1:
|
| 366 |
+
# Get the k-edge-connected subgraph
|
| 367 |
+
C = H.subgraph(nodes).copy()
|
| 368 |
+
# Find the internal edges that were available
|
| 369 |
+
sub_avail = {
|
| 370 |
+
d["generator"]: d["weight"]
|
| 371 |
+
for (u, v, d) in C.edges(data=True)
|
| 372 |
+
if "generator" in d
|
| 373 |
+
}
|
| 374 |
+
# Remove potential augmenting edges
|
| 375 |
+
C.remove_edges_from(sub_avail.keys())
|
| 376 |
+
# Find a subset of these edges that makes the component
|
| 377 |
+
# k-edge-connected and ignore the rest
|
| 378 |
+
yield from nx.k_edge_augmentation(C, k=k, avail=sub_avail)
|
| 379 |
+
|
| 380 |
+
# Generate all edges between CCs that could not be k-edge-connected
|
| 381 |
+
for cc1, cc2 in it.combinations(k_edge_subgraphs, 2):
|
| 382 |
+
for u, v in _edges_between_disjoint(H, cc1, cc2):
|
| 383 |
+
d = H.get_edge_data(u, v)
|
| 384 |
+
edge = d.get("generator", None)
|
| 385 |
+
if edge is not None:
|
| 386 |
+
yield edge
|
| 387 |
+
|
| 388 |
+
|
| 389 |
+
@not_implemented_for("multigraph")
|
| 390 |
+
@not_implemented_for("directed")
|
| 391 |
+
@nx._dispatchable
|
| 392 |
+
def one_edge_augmentation(G, avail=None, weight=None, partial=False):
|
| 393 |
+
"""Finds minimum weight set of edges to connect G.
|
| 394 |
+
|
| 395 |
+
Equivalent to :func:`k_edge_augmentation` when k=1. Adding the resulting
|
| 396 |
+
edges to G will make it 1-edge-connected. The solution is optimal for both
|
| 397 |
+
weighted and non-weighted variants.
|
| 398 |
+
|
| 399 |
+
Parameters
|
| 400 |
+
----------
|
| 401 |
+
G : NetworkX graph
|
| 402 |
+
An undirected graph.
|
| 403 |
+
|
| 404 |
+
avail : dict or a set of 2 or 3 tuples
|
| 405 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 406 |
+
|
| 407 |
+
weight : string
|
| 408 |
+
key to use to find weights if ``avail`` is a set of 3-tuples.
|
| 409 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 410 |
+
|
| 411 |
+
partial : boolean
|
| 412 |
+
If partial is True and no feasible k-edge-augmentation exists, then the
|
| 413 |
+
augmenting edges minimize the number of connected components.
|
| 414 |
+
|
| 415 |
+
Yields
|
| 416 |
+
------
|
| 417 |
+
edge : tuple
|
| 418 |
+
Edges in the one-augmentation of G
|
| 419 |
+
|
| 420 |
+
Raises
|
| 421 |
+
------
|
| 422 |
+
NetworkXUnfeasible
|
| 423 |
+
If partial is False and no one-edge-augmentation exists.
|
| 424 |
+
|
| 425 |
+
Notes
|
| 426 |
+
-----
|
| 427 |
+
Uses either :func:`unconstrained_one_edge_augmentation` or
|
| 428 |
+
:func:`weighted_one_edge_augmentation` depending on whether ``avail`` is
|
| 429 |
+
specified. Both algorithms are based on finding a minimum spanning tree.
|
| 430 |
+
As such both algorithms find optimal solutions and run in linear time.
|
| 431 |
+
|
| 432 |
+
See Also
|
| 433 |
+
--------
|
| 434 |
+
:func:`k_edge_augmentation`
|
| 435 |
+
"""
|
| 436 |
+
if avail is None:
|
| 437 |
+
return unconstrained_one_edge_augmentation(G)
|
| 438 |
+
else:
|
| 439 |
+
return weighted_one_edge_augmentation(
|
| 440 |
+
G, avail=avail, weight=weight, partial=partial
|
| 441 |
+
)
|
| 442 |
+
|
| 443 |
+
|
| 444 |
+
@not_implemented_for("multigraph")
|
| 445 |
+
@not_implemented_for("directed")
|
| 446 |
+
@nx._dispatchable
|
| 447 |
+
def bridge_augmentation(G, avail=None, weight=None):
|
| 448 |
+
"""Finds the a set of edges that bridge connects G.
|
| 449 |
+
|
| 450 |
+
Equivalent to :func:`k_edge_augmentation` when k=2, and partial=False.
|
| 451 |
+
Adding the resulting edges to G will make it 2-edge-connected. If no
|
| 452 |
+
constraints are specified the returned set of edges is minimum an optimal,
|
| 453 |
+
otherwise the solution is approximated.
|
| 454 |
+
|
| 455 |
+
Parameters
|
| 456 |
+
----------
|
| 457 |
+
G : NetworkX graph
|
| 458 |
+
An undirected graph.
|
| 459 |
+
|
| 460 |
+
avail : dict or a set of 2 or 3 tuples
|
| 461 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 462 |
+
|
| 463 |
+
weight : string
|
| 464 |
+
key to use to find weights if ``avail`` is a set of 3-tuples.
|
| 465 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 466 |
+
|
| 467 |
+
Yields
|
| 468 |
+
------
|
| 469 |
+
edge : tuple
|
| 470 |
+
Edges in the bridge-augmentation of G
|
| 471 |
+
|
| 472 |
+
Raises
|
| 473 |
+
------
|
| 474 |
+
NetworkXUnfeasible
|
| 475 |
+
If no bridge-augmentation exists.
|
| 476 |
+
|
| 477 |
+
Notes
|
| 478 |
+
-----
|
| 479 |
+
If there are no constraints the solution can be computed in linear time
|
| 480 |
+
using :func:`unconstrained_bridge_augmentation`. Otherwise, the problem
|
| 481 |
+
becomes NP-hard and is the solution is approximated by
|
| 482 |
+
:func:`weighted_bridge_augmentation`.
|
| 483 |
+
|
| 484 |
+
See Also
|
| 485 |
+
--------
|
| 486 |
+
:func:`k_edge_augmentation`
|
| 487 |
+
"""
|
| 488 |
+
if G.number_of_nodes() < 3:
|
| 489 |
+
raise nx.NetworkXUnfeasible("impossible to bridge connect less than 3 nodes")
|
| 490 |
+
if avail is None:
|
| 491 |
+
return unconstrained_bridge_augmentation(G)
|
| 492 |
+
else:
|
| 493 |
+
return weighted_bridge_augmentation(G, avail, weight=weight)
|
| 494 |
+
|
| 495 |
+
|
| 496 |
+
# --- Algorithms and Helpers ---
|
| 497 |
+
|
| 498 |
+
|
| 499 |
+
def _ordered(u, v):
|
| 500 |
+
"""Returns the nodes in an undirected edge in lower-triangular order"""
|
| 501 |
+
return (u, v) if u < v else (v, u)
|
| 502 |
+
|
| 503 |
+
|
| 504 |
+
def _unpack_available_edges(avail, weight=None, G=None):
|
| 505 |
+
"""Helper to separate avail into edges and corresponding weights"""
|
| 506 |
+
if weight is None:
|
| 507 |
+
weight = "weight"
|
| 508 |
+
if isinstance(avail, dict):
|
| 509 |
+
avail_uv = list(avail.keys())
|
| 510 |
+
avail_w = list(avail.values())
|
| 511 |
+
else:
|
| 512 |
+
|
| 513 |
+
def _try_getitem(d):
|
| 514 |
+
try:
|
| 515 |
+
return d[weight]
|
| 516 |
+
except TypeError:
|
| 517 |
+
return d
|
| 518 |
+
|
| 519 |
+
avail_uv = [tup[0:2] for tup in avail]
|
| 520 |
+
avail_w = [1 if len(tup) == 2 else _try_getitem(tup[-1]) for tup in avail]
|
| 521 |
+
|
| 522 |
+
if G is not None:
|
| 523 |
+
# Edges already in the graph are filtered
|
| 524 |
+
flags = [not G.has_edge(u, v) for u, v in avail_uv]
|
| 525 |
+
avail_uv = list(it.compress(avail_uv, flags))
|
| 526 |
+
avail_w = list(it.compress(avail_w, flags))
|
| 527 |
+
return avail_uv, avail_w
|
| 528 |
+
|
| 529 |
+
|
| 530 |
+
MetaEdge = namedtuple("MetaEdge", ("meta_uv", "uv", "w"))
|
| 531 |
+
|
| 532 |
+
|
| 533 |
+
def _lightest_meta_edges(mapping, avail_uv, avail_w):
|
| 534 |
+
"""Maps available edges in the original graph to edges in the metagraph.
|
| 535 |
+
|
| 536 |
+
Parameters
|
| 537 |
+
----------
|
| 538 |
+
mapping : dict
|
| 539 |
+
mapping produced by :func:`collapse`, that maps each node in the
|
| 540 |
+
original graph to a node in the meta graph
|
| 541 |
+
|
| 542 |
+
avail_uv : list
|
| 543 |
+
list of edges
|
| 544 |
+
|
| 545 |
+
avail_w : list
|
| 546 |
+
list of edge weights
|
| 547 |
+
|
| 548 |
+
Notes
|
| 549 |
+
-----
|
| 550 |
+
Each node in the metagraph is a k-edge-connected component in the original
|
| 551 |
+
graph. We don't care about any edge within the same k-edge-connected
|
| 552 |
+
component, so we ignore self edges. We also are only interested in the
|
| 553 |
+
minimum weight edge bridging each k-edge-connected component so, we group
|
| 554 |
+
the edges by meta-edge and take the lightest in each group.
|
| 555 |
+
|
| 556 |
+
Examples
|
| 557 |
+
--------
|
| 558 |
+
>>> # Each group represents a meta-node
|
| 559 |
+
>>> groups = ([1, 2, 3], [4, 5], [6])
|
| 560 |
+
>>> mapping = {n: meta_n for meta_n, ns in enumerate(groups) for n in ns}
|
| 561 |
+
>>> avail_uv = [(1, 2), (3, 6), (1, 4), (5, 2), (6, 1), (2, 6), (3, 1)]
|
| 562 |
+
>>> avail_w = [20, 99, 20, 15, 50, 99, 20]
|
| 563 |
+
>>> sorted(_lightest_meta_edges(mapping, avail_uv, avail_w))
|
| 564 |
+
[MetaEdge(meta_uv=(0, 1), uv=(5, 2), w=15), MetaEdge(meta_uv=(0, 2), uv=(6, 1), w=50)]
|
| 565 |
+
"""
|
| 566 |
+
grouped_wuv = defaultdict(list)
|
| 567 |
+
for w, (u, v) in zip(avail_w, avail_uv):
|
| 568 |
+
# Order the meta-edge so it can be used as a dict key
|
| 569 |
+
meta_uv = _ordered(mapping[u], mapping[v])
|
| 570 |
+
# Group each available edge using the meta-edge as a key
|
| 571 |
+
grouped_wuv[meta_uv].append((w, u, v))
|
| 572 |
+
|
| 573 |
+
# Now that all available edges are grouped, choose one per group
|
| 574 |
+
for (mu, mv), choices_wuv in grouped_wuv.items():
|
| 575 |
+
# Ignore available edges within the same meta-node
|
| 576 |
+
if mu != mv:
|
| 577 |
+
# Choose the lightest available edge belonging to each meta-edge
|
| 578 |
+
w, u, v = min(choices_wuv)
|
| 579 |
+
yield MetaEdge((mu, mv), (u, v), w)
|
| 580 |
+
|
| 581 |
+
|
| 582 |
+
@nx._dispatchable
|
| 583 |
+
def unconstrained_one_edge_augmentation(G):
|
| 584 |
+
"""Finds the smallest set of edges to connect G.
|
| 585 |
+
|
| 586 |
+
This is a variant of the unweighted MST problem.
|
| 587 |
+
If G is not empty, a feasible solution always exists.
|
| 588 |
+
|
| 589 |
+
Parameters
|
| 590 |
+
----------
|
| 591 |
+
G : NetworkX graph
|
| 592 |
+
An undirected graph.
|
| 593 |
+
|
| 594 |
+
Yields
|
| 595 |
+
------
|
| 596 |
+
edge : tuple
|
| 597 |
+
Edges in the one-edge-augmentation of G
|
| 598 |
+
|
| 599 |
+
See Also
|
| 600 |
+
--------
|
| 601 |
+
:func:`one_edge_augmentation`
|
| 602 |
+
:func:`k_edge_augmentation`
|
| 603 |
+
|
| 604 |
+
Examples
|
| 605 |
+
--------
|
| 606 |
+
>>> G = nx.Graph([(1, 2), (2, 3), (4, 5)])
|
| 607 |
+
>>> G.add_nodes_from([6, 7, 8])
|
| 608 |
+
>>> sorted(unconstrained_one_edge_augmentation(G))
|
| 609 |
+
[(1, 4), (4, 6), (6, 7), (7, 8)]
|
| 610 |
+
"""
|
| 611 |
+
ccs1 = list(nx.connected_components(G))
|
| 612 |
+
C = collapse(G, ccs1)
|
| 613 |
+
# When we are not constrained, we can just make a meta graph tree.
|
| 614 |
+
meta_nodes = list(C.nodes())
|
| 615 |
+
# build a path in the metagraph
|
| 616 |
+
meta_aug = list(zip(meta_nodes, meta_nodes[1:]))
|
| 617 |
+
# map that path to the original graph
|
| 618 |
+
inverse = defaultdict(list)
|
| 619 |
+
for k, v in C.graph["mapping"].items():
|
| 620 |
+
inverse[v].append(k)
|
| 621 |
+
for mu, mv in meta_aug:
|
| 622 |
+
yield (inverse[mu][0], inverse[mv][0])
|
| 623 |
+
|
| 624 |
+
|
| 625 |
+
@nx._dispatchable
|
| 626 |
+
def weighted_one_edge_augmentation(G, avail, weight=None, partial=False):
|
| 627 |
+
"""Finds the minimum weight set of edges to connect G if one exists.
|
| 628 |
+
|
| 629 |
+
This is a variant of the weighted MST problem.
|
| 630 |
+
|
| 631 |
+
Parameters
|
| 632 |
+
----------
|
| 633 |
+
G : NetworkX graph
|
| 634 |
+
An undirected graph.
|
| 635 |
+
|
| 636 |
+
avail : dict or a set of 2 or 3 tuples
|
| 637 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 638 |
+
|
| 639 |
+
weight : string
|
| 640 |
+
key to use to find weights if ``avail`` is a set of 3-tuples.
|
| 641 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 642 |
+
|
| 643 |
+
partial : boolean
|
| 644 |
+
If partial is True and no feasible k-edge-augmentation exists, then the
|
| 645 |
+
augmenting edges minimize the number of connected components.
|
| 646 |
+
|
| 647 |
+
Yields
|
| 648 |
+
------
|
| 649 |
+
edge : tuple
|
| 650 |
+
Edges in the subset of avail chosen to connect G.
|
| 651 |
+
|
| 652 |
+
See Also
|
| 653 |
+
--------
|
| 654 |
+
:func:`one_edge_augmentation`
|
| 655 |
+
:func:`k_edge_augmentation`
|
| 656 |
+
|
| 657 |
+
Examples
|
| 658 |
+
--------
|
| 659 |
+
>>> G = nx.Graph([(1, 2), (2, 3), (4, 5)])
|
| 660 |
+
>>> G.add_nodes_from([6, 7, 8])
|
| 661 |
+
>>> # any edge not in avail has an implicit weight of infinity
|
| 662 |
+
>>> avail = [(1, 3), (1, 5), (4, 7), (4, 8), (6, 1), (8, 1), (8, 2)]
|
| 663 |
+
>>> sorted(weighted_one_edge_augmentation(G, avail))
|
| 664 |
+
[(1, 5), (4, 7), (6, 1), (8, 1)]
|
| 665 |
+
>>> # find another solution by giving large weights to edges in the
|
| 666 |
+
>>> # previous solution (note some of the old edges must be used)
|
| 667 |
+
>>> avail = [(1, 3), (1, 5, 99), (4, 7, 9), (6, 1, 99), (8, 1, 99), (8, 2)]
|
| 668 |
+
>>> sorted(weighted_one_edge_augmentation(G, avail))
|
| 669 |
+
[(1, 5), (4, 7), (6, 1), (8, 2)]
|
| 670 |
+
"""
|
| 671 |
+
avail_uv, avail_w = _unpack_available_edges(avail, weight=weight, G=G)
|
| 672 |
+
# Collapse CCs in the original graph into nodes in a metagraph
|
| 673 |
+
# Then find an MST of the metagraph instead of the original graph
|
| 674 |
+
C = collapse(G, nx.connected_components(G))
|
| 675 |
+
mapping = C.graph["mapping"]
|
| 676 |
+
# Assign each available edge to an edge in the metagraph
|
| 677 |
+
candidate_mapping = _lightest_meta_edges(mapping, avail_uv, avail_w)
|
| 678 |
+
# nx.set_edge_attributes(C, name='weight', values=0)
|
| 679 |
+
C.add_edges_from(
|
| 680 |
+
(mu, mv, {"weight": w, "generator": uv})
|
| 681 |
+
for (mu, mv), uv, w in candidate_mapping
|
| 682 |
+
)
|
| 683 |
+
# Find MST of the meta graph
|
| 684 |
+
meta_mst = nx.minimum_spanning_tree(C)
|
| 685 |
+
if not partial and not nx.is_connected(meta_mst):
|
| 686 |
+
raise nx.NetworkXUnfeasible("Not possible to connect G with available edges")
|
| 687 |
+
# Yield the edge that generated the meta-edge
|
| 688 |
+
for mu, mv, d in meta_mst.edges(data=True):
|
| 689 |
+
if "generator" in d:
|
| 690 |
+
edge = d["generator"]
|
| 691 |
+
yield edge
|
| 692 |
+
|
| 693 |
+
|
| 694 |
+
@nx._dispatchable
|
| 695 |
+
def unconstrained_bridge_augmentation(G):
|
| 696 |
+
"""Finds an optimal 2-edge-augmentation of G using the fewest edges.
|
| 697 |
+
|
| 698 |
+
This is an implementation of the algorithm detailed in [1]_.
|
| 699 |
+
The basic idea is to construct a meta-graph of bridge-ccs, connect leaf
|
| 700 |
+
nodes of the trees to connect the entire graph, and finally connect the
|
| 701 |
+
leafs of the tree in dfs-preorder to bridge connect the entire graph.
|
| 702 |
+
|
| 703 |
+
Parameters
|
| 704 |
+
----------
|
| 705 |
+
G : NetworkX graph
|
| 706 |
+
An undirected graph.
|
| 707 |
+
|
| 708 |
+
Yields
|
| 709 |
+
------
|
| 710 |
+
edge : tuple
|
| 711 |
+
Edges in the bridge augmentation of G
|
| 712 |
+
|
| 713 |
+
Notes
|
| 714 |
+
-----
|
| 715 |
+
Input: a graph G.
|
| 716 |
+
First find the bridge components of G and collapse each bridge-cc into a
|
| 717 |
+
node of a metagraph graph C, which is guaranteed to be a forest of trees.
|
| 718 |
+
|
| 719 |
+
C contains p "leafs" --- nodes with exactly one incident edge.
|
| 720 |
+
C contains q "isolated nodes" --- nodes with no incident edges.
|
| 721 |
+
|
| 722 |
+
Theorem: If p + q > 1, then at least :math:`ceil(p / 2) + q` edges are
|
| 723 |
+
needed to bridge connect C. This algorithm achieves this min number.
|
| 724 |
+
|
| 725 |
+
The method first adds enough edges to make G into a tree and then pairs
|
| 726 |
+
leafs in a simple fashion.
|
| 727 |
+
|
| 728 |
+
Let n be the number of trees in C. Let v(i) be an isolated vertex in the
|
| 729 |
+
i-th tree if one exists, otherwise it is a pair of distinct leafs nodes
|
| 730 |
+
in the i-th tree. Alternating edges from these sets (i.e. adding edges
|
| 731 |
+
A1 = [(v(i)[0], v(i + 1)[1]), v(i + 1)[0], v(i + 2)[1])...]) connects C
|
| 732 |
+
into a tree T. This tree has p' = p + 2q - 2(n -1) leafs and no isolated
|
| 733 |
+
vertices. A1 has n - 1 edges. The next step finds ceil(p' / 2) edges to
|
| 734 |
+
biconnect any tree with p' leafs.
|
| 735 |
+
|
| 736 |
+
Convert T into an arborescence T' by picking an arbitrary root node with
|
| 737 |
+
degree >= 2 and directing all edges away from the root. Note the
|
| 738 |
+
implementation implicitly constructs T'.
|
| 739 |
+
|
| 740 |
+
The leafs of T are the nodes with no existing edges in T'.
|
| 741 |
+
Order the leafs of T' by DFS preorder. Then break this list in half
|
| 742 |
+
and add the zipped pairs to A2.
|
| 743 |
+
|
| 744 |
+
The set A = A1 + A2 is the minimum augmentation in the metagraph.
|
| 745 |
+
|
| 746 |
+
To convert this to edges in the original graph
|
| 747 |
+
|
| 748 |
+
References
|
| 749 |
+
----------
|
| 750 |
+
.. [1] Eswaran, Kapali P., and R. Endre Tarjan. (1975) Augmentation problems.
|
| 751 |
+
http://epubs.siam.org/doi/abs/10.1137/0205044
|
| 752 |
+
|
| 753 |
+
See Also
|
| 754 |
+
--------
|
| 755 |
+
:func:`bridge_augmentation`
|
| 756 |
+
:func:`k_edge_augmentation`
|
| 757 |
+
|
| 758 |
+
Examples
|
| 759 |
+
--------
|
| 760 |
+
>>> G = nx.path_graph((1, 2, 3, 4, 5, 6, 7))
|
| 761 |
+
>>> sorted(unconstrained_bridge_augmentation(G))
|
| 762 |
+
[(1, 7)]
|
| 763 |
+
>>> G = nx.path_graph((1, 2, 3, 2, 4, 5, 6, 7))
|
| 764 |
+
>>> sorted(unconstrained_bridge_augmentation(G))
|
| 765 |
+
[(1, 3), (3, 7)]
|
| 766 |
+
>>> G = nx.Graph([(0, 1), (0, 2), (1, 2)])
|
| 767 |
+
>>> G.add_node(4)
|
| 768 |
+
>>> sorted(unconstrained_bridge_augmentation(G))
|
| 769 |
+
[(1, 4), (4, 0)]
|
| 770 |
+
"""
|
| 771 |
+
# -----
|
| 772 |
+
# Mapping of terms from (Eswaran and Tarjan):
|
| 773 |
+
# G = G_0 - the input graph
|
| 774 |
+
# C = G_0' - the bridge condensation of G. (This is a forest of trees)
|
| 775 |
+
# A1 = A_1 - the edges to connect the forest into a tree
|
| 776 |
+
# leaf = pendant - a node with degree of 1
|
| 777 |
+
|
| 778 |
+
# alpha(v) = maps the node v in G to its meta-node in C
|
| 779 |
+
# beta(x) = maps the meta-node x in C to any node in the bridge
|
| 780 |
+
# component of G corresponding to x.
|
| 781 |
+
|
| 782 |
+
# find the 2-edge-connected components of G
|
| 783 |
+
bridge_ccs = list(nx.connectivity.bridge_components(G))
|
| 784 |
+
# condense G into an forest C
|
| 785 |
+
C = collapse(G, bridge_ccs)
|
| 786 |
+
|
| 787 |
+
# Choose pairs of distinct leaf nodes in each tree. If this is not
|
| 788 |
+
# possible then make a pair using the single isolated node in the tree.
|
| 789 |
+
vset1 = [
|
| 790 |
+
tuple(cc) * 2 # case1: an isolated node
|
| 791 |
+
if len(cc) == 1
|
| 792 |
+
else sorted(cc, key=C.degree)[0:2] # case2: pair of leaf nodes
|
| 793 |
+
for cc in nx.connected_components(C)
|
| 794 |
+
]
|
| 795 |
+
if len(vset1) > 1:
|
| 796 |
+
# Use this set to construct edges that connect C into a tree.
|
| 797 |
+
nodes1 = [vs[0] for vs in vset1]
|
| 798 |
+
nodes2 = [vs[1] for vs in vset1]
|
| 799 |
+
A1 = list(zip(nodes1[1:], nodes2))
|
| 800 |
+
else:
|
| 801 |
+
A1 = []
|
| 802 |
+
# Connect each tree in the forest to construct an arborescence
|
| 803 |
+
T = C.copy()
|
| 804 |
+
T.add_edges_from(A1)
|
| 805 |
+
|
| 806 |
+
# If there are only two leaf nodes, we simply connect them.
|
| 807 |
+
leafs = [n for n, d in T.degree() if d == 1]
|
| 808 |
+
if len(leafs) == 1:
|
| 809 |
+
A2 = []
|
| 810 |
+
if len(leafs) == 2:
|
| 811 |
+
A2 = [tuple(leafs)]
|
| 812 |
+
else:
|
| 813 |
+
# Choose an arbitrary non-leaf root
|
| 814 |
+
try:
|
| 815 |
+
root = next(n for n, d in T.degree() if d > 1)
|
| 816 |
+
except StopIteration: # no nodes found with degree > 1
|
| 817 |
+
return
|
| 818 |
+
# order the leaves of C by (induced directed) preorder
|
| 819 |
+
v2 = [n for n in nx.dfs_preorder_nodes(T, root) if T.degree(n) == 1]
|
| 820 |
+
# connecting first half of the leafs in pre-order to the second
|
| 821 |
+
# half will bridge connect the tree with the fewest edges.
|
| 822 |
+
half = math.ceil(len(v2) / 2)
|
| 823 |
+
A2 = list(zip(v2[:half], v2[-half:]))
|
| 824 |
+
|
| 825 |
+
# collect the edges used to augment the original forest
|
| 826 |
+
aug_tree_edges = A1 + A2
|
| 827 |
+
|
| 828 |
+
# Construct the mapping (beta) from meta-nodes to regular nodes
|
| 829 |
+
inverse = defaultdict(list)
|
| 830 |
+
for k, v in C.graph["mapping"].items():
|
| 831 |
+
inverse[v].append(k)
|
| 832 |
+
# sort so we choose minimum degree nodes first
|
| 833 |
+
inverse = {
|
| 834 |
+
mu: sorted(mapped, key=lambda u: (G.degree(u), u))
|
| 835 |
+
for mu, mapped in inverse.items()
|
| 836 |
+
}
|
| 837 |
+
|
| 838 |
+
# For each meta-edge, map back to an arbitrary pair in the original graph
|
| 839 |
+
G2 = G.copy()
|
| 840 |
+
for mu, mv in aug_tree_edges:
|
| 841 |
+
# Find the first available edge that doesn't exist and return it
|
| 842 |
+
for u, v in it.product(inverse[mu], inverse[mv]):
|
| 843 |
+
if not G2.has_edge(u, v):
|
| 844 |
+
G2.add_edge(u, v)
|
| 845 |
+
yield u, v
|
| 846 |
+
break
|
| 847 |
+
|
| 848 |
+
|
| 849 |
+
@nx._dispatchable
|
| 850 |
+
def weighted_bridge_augmentation(G, avail, weight=None):
|
| 851 |
+
"""Finds an approximate min-weight 2-edge-augmentation of G.
|
| 852 |
+
|
| 853 |
+
This is an implementation of the approximation algorithm detailed in [1]_.
|
| 854 |
+
It chooses a set of edges from avail to add to G that renders it
|
| 855 |
+
2-edge-connected if such a subset exists. This is done by finding a
|
| 856 |
+
minimum spanning arborescence of a specially constructed metagraph.
|
| 857 |
+
|
| 858 |
+
Parameters
|
| 859 |
+
----------
|
| 860 |
+
G : NetworkX graph
|
| 861 |
+
An undirected graph.
|
| 862 |
+
|
| 863 |
+
avail : set of 2 or 3 tuples.
|
| 864 |
+
candidate edges (with optional weights) to choose from
|
| 865 |
+
|
| 866 |
+
weight : string
|
| 867 |
+
key to use to find weights if avail is a set of 3-tuples where the
|
| 868 |
+
third item in each tuple is a dictionary.
|
| 869 |
+
|
| 870 |
+
Yields
|
| 871 |
+
------
|
| 872 |
+
edge : tuple
|
| 873 |
+
Edges in the subset of avail chosen to bridge augment G.
|
| 874 |
+
|
| 875 |
+
Notes
|
| 876 |
+
-----
|
| 877 |
+
Finding a weighted 2-edge-augmentation is NP-hard.
|
| 878 |
+
Any edge not in ``avail`` is considered to have a weight of infinity.
|
| 879 |
+
The approximation factor is 2 if ``G`` is connected and 3 if it is not.
|
| 880 |
+
Runs in :math:`O(m + n log(n))` time
|
| 881 |
+
|
| 882 |
+
References
|
| 883 |
+
----------
|
| 884 |
+
.. [1] Khuller, Samir, and Ramakrishna Thurimella. (1993) Approximation
|
| 885 |
+
algorithms for graph augmentation.
|
| 886 |
+
http://www.sciencedirect.com/science/article/pii/S0196677483710102
|
| 887 |
+
|
| 888 |
+
See Also
|
| 889 |
+
--------
|
| 890 |
+
:func:`bridge_augmentation`
|
| 891 |
+
:func:`k_edge_augmentation`
|
| 892 |
+
|
| 893 |
+
Examples
|
| 894 |
+
--------
|
| 895 |
+
>>> G = nx.path_graph((1, 2, 3, 4))
|
| 896 |
+
>>> # When the weights are equal, (1, 4) is the best
|
| 897 |
+
>>> avail = [(1, 4, 1), (1, 3, 1), (2, 4, 1)]
|
| 898 |
+
>>> sorted(weighted_bridge_augmentation(G, avail))
|
| 899 |
+
[(1, 4)]
|
| 900 |
+
>>> # Giving (1, 4) a high weight makes the two edge solution the best.
|
| 901 |
+
>>> avail = [(1, 4, 1000), (1, 3, 1), (2, 4, 1)]
|
| 902 |
+
>>> sorted(weighted_bridge_augmentation(G, avail))
|
| 903 |
+
[(1, 3), (2, 4)]
|
| 904 |
+
>>> # ------
|
| 905 |
+
>>> G = nx.path_graph((1, 2, 3, 4))
|
| 906 |
+
>>> G.add_node(5)
|
| 907 |
+
>>> avail = [(1, 5, 11), (2, 5, 10), (4, 3, 1), (4, 5, 1)]
|
| 908 |
+
>>> sorted(weighted_bridge_augmentation(G, avail=avail))
|
| 909 |
+
[(1, 5), (4, 5)]
|
| 910 |
+
>>> avail = [(1, 5, 11), (2, 5, 10), (4, 3, 1), (4, 5, 51)]
|
| 911 |
+
>>> sorted(weighted_bridge_augmentation(G, avail=avail))
|
| 912 |
+
[(1, 5), (2, 5), (4, 5)]
|
| 913 |
+
"""
|
| 914 |
+
|
| 915 |
+
if weight is None:
|
| 916 |
+
weight = "weight"
|
| 917 |
+
|
| 918 |
+
# If input G is not connected the approximation factor increases to 3
|
| 919 |
+
if not nx.is_connected(G):
|
| 920 |
+
H = G.copy()
|
| 921 |
+
connectors = list(one_edge_augmentation(H, avail=avail, weight=weight))
|
| 922 |
+
H.add_edges_from(connectors)
|
| 923 |
+
|
| 924 |
+
yield from connectors
|
| 925 |
+
else:
|
| 926 |
+
connectors = []
|
| 927 |
+
H = G
|
| 928 |
+
|
| 929 |
+
if len(avail) == 0:
|
| 930 |
+
if nx.has_bridges(H):
|
| 931 |
+
raise nx.NetworkXUnfeasible("no augmentation possible")
|
| 932 |
+
|
| 933 |
+
avail_uv, avail_w = _unpack_available_edges(avail, weight=weight, G=H)
|
| 934 |
+
|
| 935 |
+
# Collapse input into a metagraph. Meta nodes are bridge-ccs
|
| 936 |
+
bridge_ccs = nx.connectivity.bridge_components(H)
|
| 937 |
+
C = collapse(H, bridge_ccs)
|
| 938 |
+
|
| 939 |
+
# Use the meta graph to shrink avail to a small feasible subset
|
| 940 |
+
mapping = C.graph["mapping"]
|
| 941 |
+
# Choose the minimum weight feasible edge in each group
|
| 942 |
+
meta_to_wuv = {
|
| 943 |
+
(mu, mv): (w, uv)
|
| 944 |
+
for (mu, mv), uv, w in _lightest_meta_edges(mapping, avail_uv, avail_w)
|
| 945 |
+
}
|
| 946 |
+
|
| 947 |
+
# Mapping of terms from (Khuller and Thurimella):
|
| 948 |
+
# C : G_0 = (V, E^0)
|
| 949 |
+
# This is the metagraph where each node is a 2-edge-cc in G.
|
| 950 |
+
# The edges in C represent bridges in the original graph.
|
| 951 |
+
# (mu, mv) : E - E^0 # they group both avail and given edges in E
|
| 952 |
+
# T : \Gamma
|
| 953 |
+
# D : G^D = (V, E_D)
|
| 954 |
+
|
| 955 |
+
# The paper uses ancestor because children point to parents, which is
|
| 956 |
+
# contrary to networkx standards. So, we actually need to run
|
| 957 |
+
# nx.least_common_ancestor on the reversed Tree.
|
| 958 |
+
|
| 959 |
+
# Pick an arbitrary leaf from C as the root
|
| 960 |
+
try:
|
| 961 |
+
root = next(n for n, d in C.degree() if d == 1)
|
| 962 |
+
except StopIteration: # no nodes found with degree == 1
|
| 963 |
+
return
|
| 964 |
+
# Root C into a tree TR by directing all edges away from the root
|
| 965 |
+
# Note in their paper T directs edges towards the root
|
| 966 |
+
TR = nx.dfs_tree(C, root)
|
| 967 |
+
|
| 968 |
+
# Add to D the directed edges of T and set their weight to zero
|
| 969 |
+
# This indicates that it costs nothing to use edges that were given.
|
| 970 |
+
D = nx.reverse(TR).copy()
|
| 971 |
+
|
| 972 |
+
nx.set_edge_attributes(D, name="weight", values=0)
|
| 973 |
+
|
| 974 |
+
# The LCA of mu and mv in T is the shared ancestor of mu and mv that is
|
| 975 |
+
# located farthest from the root.
|
| 976 |
+
lca_gen = nx.tree_all_pairs_lowest_common_ancestor(
|
| 977 |
+
TR, root=root, pairs=meta_to_wuv.keys()
|
| 978 |
+
)
|
| 979 |
+
|
| 980 |
+
for (mu, mv), lca in lca_gen:
|
| 981 |
+
w, uv = meta_to_wuv[(mu, mv)]
|
| 982 |
+
if lca == mu:
|
| 983 |
+
# If u is an ancestor of v in TR, then add edge u->v to D
|
| 984 |
+
D.add_edge(lca, mv, weight=w, generator=uv)
|
| 985 |
+
elif lca == mv:
|
| 986 |
+
# If v is an ancestor of u in TR, then add edge v->u to D
|
| 987 |
+
D.add_edge(lca, mu, weight=w, generator=uv)
|
| 988 |
+
else:
|
| 989 |
+
# If neither u nor v is a ancestor of the other in TR
|
| 990 |
+
# let t = lca(TR, u, v) and add edges t->u and t->v
|
| 991 |
+
# Track the original edge that GENERATED these edges.
|
| 992 |
+
D.add_edge(lca, mu, weight=w, generator=uv)
|
| 993 |
+
D.add_edge(lca, mv, weight=w, generator=uv)
|
| 994 |
+
|
| 995 |
+
# Then compute a minimum rooted branching
|
| 996 |
+
try:
|
| 997 |
+
# Note the original edges must be directed towards to root for the
|
| 998 |
+
# branching to give us a bridge-augmentation.
|
| 999 |
+
A = _minimum_rooted_branching(D, root)
|
| 1000 |
+
except nx.NetworkXException as err:
|
| 1001 |
+
# If there is no branching then augmentation is not possible
|
| 1002 |
+
raise nx.NetworkXUnfeasible("no 2-edge-augmentation possible") from err
|
| 1003 |
+
|
| 1004 |
+
# For each edge e, in the branching that did not belong to the directed
|
| 1005 |
+
# tree T, add the corresponding edge that **GENERATED** it (this is not
|
| 1006 |
+
# necessarily e itself!)
|
| 1007 |
+
|
| 1008 |
+
# ensure the third case does not generate edges twice
|
| 1009 |
+
bridge_connectors = set()
|
| 1010 |
+
for mu, mv in A.edges():
|
| 1011 |
+
data = D.get_edge_data(mu, mv)
|
| 1012 |
+
if "generator" in data:
|
| 1013 |
+
# Add the avail edge that generated the branching edge.
|
| 1014 |
+
edge = data["generator"]
|
| 1015 |
+
bridge_connectors.add(edge)
|
| 1016 |
+
|
| 1017 |
+
yield from bridge_connectors
|
| 1018 |
+
|
| 1019 |
+
|
| 1020 |
+
def _minimum_rooted_branching(D, root):
|
| 1021 |
+
"""Helper function to compute a minimum rooted branching (aka rooted
|
| 1022 |
+
arborescence)
|
| 1023 |
+
|
| 1024 |
+
Before the branching can be computed, the directed graph must be rooted by
|
| 1025 |
+
removing the predecessors of root.
|
| 1026 |
+
|
| 1027 |
+
A branching / arborescence of rooted graph G is a subgraph that contains a
|
| 1028 |
+
directed path from the root to every other vertex. It is the directed
|
| 1029 |
+
analog of the minimum spanning tree problem.
|
| 1030 |
+
|
| 1031 |
+
References
|
| 1032 |
+
----------
|
| 1033 |
+
[1] Khuller, Samir (2002) Advanced Algorithms Lecture 24 Notes.
|
| 1034 |
+
https://web.archive.org/web/20121030033722/https://www.cs.umd.edu/class/spring2011/cmsc651/lec07.pdf
|
| 1035 |
+
"""
|
| 1036 |
+
rooted = D.copy()
|
| 1037 |
+
# root the graph by removing all predecessors to `root`.
|
| 1038 |
+
rooted.remove_edges_from([(u, root) for u in D.predecessors(root)])
|
| 1039 |
+
# Then compute the branching / arborescence.
|
| 1040 |
+
A = nx.minimum_spanning_arborescence(rooted)
|
| 1041 |
+
return A
|
| 1042 |
+
|
| 1043 |
+
|
| 1044 |
+
@nx._dispatchable(returns_graph=True)
|
| 1045 |
+
def collapse(G, grouped_nodes):
|
| 1046 |
+
"""Collapses each group of nodes into a single node.
|
| 1047 |
+
|
| 1048 |
+
This is similar to condensation, but works on undirected graphs.
|
| 1049 |
+
|
| 1050 |
+
Parameters
|
| 1051 |
+
----------
|
| 1052 |
+
G : NetworkX Graph
|
| 1053 |
+
|
| 1054 |
+
grouped_nodes: list or generator
|
| 1055 |
+
Grouping of nodes to collapse. The grouping must be disjoint.
|
| 1056 |
+
If grouped_nodes are strongly_connected_components then this is
|
| 1057 |
+
equivalent to :func:`condensation`.
|
| 1058 |
+
|
| 1059 |
+
Returns
|
| 1060 |
+
-------
|
| 1061 |
+
C : NetworkX Graph
|
| 1062 |
+
The collapsed graph C of G with respect to the node grouping. The node
|
| 1063 |
+
labels are integers corresponding to the index of the component in the
|
| 1064 |
+
list of grouped_nodes. C has a graph attribute named 'mapping' with a
|
| 1065 |
+
dictionary mapping the original nodes to the nodes in C to which they
|
| 1066 |
+
belong. Each node in C also has a node attribute 'members' with the set
|
| 1067 |
+
of original nodes in G that form the group that the node in C
|
| 1068 |
+
represents.
|
| 1069 |
+
|
| 1070 |
+
Examples
|
| 1071 |
+
--------
|
| 1072 |
+
>>> # Collapses a graph using disjoint groups, but not necessarily connected
|
| 1073 |
+
>>> G = nx.Graph([(1, 0), (2, 3), (3, 1), (3, 4), (4, 5), (5, 6), (5, 7)])
|
| 1074 |
+
>>> G.add_node("A")
|
| 1075 |
+
>>> grouped_nodes = [{0, 1, 2, 3}, {5, 6, 7}]
|
| 1076 |
+
>>> C = collapse(G, grouped_nodes)
|
| 1077 |
+
>>> members = nx.get_node_attributes(C, "members")
|
| 1078 |
+
>>> sorted(members.keys())
|
| 1079 |
+
[0, 1, 2, 3]
|
| 1080 |
+
>>> member_values = set(map(frozenset, members.values()))
|
| 1081 |
+
>>> assert {0, 1, 2, 3} in member_values
|
| 1082 |
+
>>> assert {4} in member_values
|
| 1083 |
+
>>> assert {5, 6, 7} in member_values
|
| 1084 |
+
>>> assert {"A"} in member_values
|
| 1085 |
+
"""
|
| 1086 |
+
mapping = {}
|
| 1087 |
+
members = {}
|
| 1088 |
+
C = G.__class__()
|
| 1089 |
+
i = 0 # required if G is empty
|
| 1090 |
+
remaining = set(G.nodes())
|
| 1091 |
+
for i, group in enumerate(grouped_nodes):
|
| 1092 |
+
group = set(group)
|
| 1093 |
+
assert remaining.issuperset(
|
| 1094 |
+
group
|
| 1095 |
+
), "grouped nodes must exist in G and be disjoint"
|
| 1096 |
+
remaining.difference_update(group)
|
| 1097 |
+
members[i] = group
|
| 1098 |
+
mapping.update((n, i) for n in group)
|
| 1099 |
+
# remaining nodes are in their own group
|
| 1100 |
+
for i, node in enumerate(remaining, start=i + 1):
|
| 1101 |
+
group = {node}
|
| 1102 |
+
members[i] = group
|
| 1103 |
+
mapping.update((n, i) for n in group)
|
| 1104 |
+
number_of_groups = i + 1
|
| 1105 |
+
C.add_nodes_from(range(number_of_groups))
|
| 1106 |
+
C.add_edges_from(
|
| 1107 |
+
(mapping[u], mapping[v]) for u, v in G.edges() if mapping[u] != mapping[v]
|
| 1108 |
+
)
|
| 1109 |
+
# Add a list of members (ie original nodes) to each node (ie scc) in C.
|
| 1110 |
+
nx.set_node_attributes(C, name="members", values=members)
|
| 1111 |
+
# Add mapping dict as graph attribute
|
| 1112 |
+
C.graph["mapping"] = mapping
|
| 1113 |
+
return C
|
| 1114 |
+
|
| 1115 |
+
|
| 1116 |
+
@nx._dispatchable
|
| 1117 |
+
def complement_edges(G):
|
| 1118 |
+
"""Returns only the edges in the complement of G
|
| 1119 |
+
|
| 1120 |
+
Parameters
|
| 1121 |
+
----------
|
| 1122 |
+
G : NetworkX Graph
|
| 1123 |
+
|
| 1124 |
+
Yields
|
| 1125 |
+
------
|
| 1126 |
+
edge : tuple
|
| 1127 |
+
Edges in the complement of G
|
| 1128 |
+
|
| 1129 |
+
Examples
|
| 1130 |
+
--------
|
| 1131 |
+
>>> G = nx.path_graph((1, 2, 3, 4))
|
| 1132 |
+
>>> sorted(complement_edges(G))
|
| 1133 |
+
[(1, 3), (1, 4), (2, 4)]
|
| 1134 |
+
>>> G = nx.path_graph((1, 2, 3, 4), nx.DiGraph())
|
| 1135 |
+
>>> sorted(complement_edges(G))
|
| 1136 |
+
[(1, 3), (1, 4), (2, 1), (2, 4), (3, 1), (3, 2), (4, 1), (4, 2), (4, 3)]
|
| 1137 |
+
>>> G = nx.complete_graph(1000)
|
| 1138 |
+
>>> sorted(complement_edges(G))
|
| 1139 |
+
[]
|
| 1140 |
+
"""
|
| 1141 |
+
G_adj = G._adj # Store as a variable to eliminate attribute lookup
|
| 1142 |
+
if G.is_directed():
|
| 1143 |
+
for u, v in it.combinations(G.nodes(), 2):
|
| 1144 |
+
if v not in G_adj[u]:
|
| 1145 |
+
yield (u, v)
|
| 1146 |
+
if u not in G_adj[v]:
|
| 1147 |
+
yield (v, u)
|
| 1148 |
+
else:
|
| 1149 |
+
for u, v in it.combinations(G.nodes(), 2):
|
| 1150 |
+
if v not in G_adj[u]:
|
| 1151 |
+
yield (u, v)
|
| 1152 |
+
|
| 1153 |
+
|
| 1154 |
+
def _compat_shuffle(rng, input):
|
| 1155 |
+
"""wrapper around rng.shuffle for python 2 compatibility reasons"""
|
| 1156 |
+
rng.shuffle(input)
|
| 1157 |
+
|
| 1158 |
+
|
| 1159 |
+
@not_implemented_for("multigraph")
|
| 1160 |
+
@not_implemented_for("directed")
|
| 1161 |
+
@py_random_state(4)
|
| 1162 |
+
@nx._dispatchable
|
| 1163 |
+
def greedy_k_edge_augmentation(G, k, avail=None, weight=None, seed=None):
|
| 1164 |
+
"""Greedy algorithm for finding a k-edge-augmentation
|
| 1165 |
+
|
| 1166 |
+
Parameters
|
| 1167 |
+
----------
|
| 1168 |
+
G : NetworkX graph
|
| 1169 |
+
An undirected graph.
|
| 1170 |
+
|
| 1171 |
+
k : integer
|
| 1172 |
+
Desired edge connectivity
|
| 1173 |
+
|
| 1174 |
+
avail : dict or a set of 2 or 3 tuples
|
| 1175 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 1176 |
+
|
| 1177 |
+
weight : string
|
| 1178 |
+
key to use to find weights if ``avail`` is a set of 3-tuples.
|
| 1179 |
+
For more details, see :func:`k_edge_augmentation`.
|
| 1180 |
+
|
| 1181 |
+
seed : integer, random_state, or None (default)
|
| 1182 |
+
Indicator of random number generation state.
|
| 1183 |
+
See :ref:`Randomness<randomness>`.
|
| 1184 |
+
|
| 1185 |
+
Yields
|
| 1186 |
+
------
|
| 1187 |
+
edge : tuple
|
| 1188 |
+
Edges in the greedy augmentation of G
|
| 1189 |
+
|
| 1190 |
+
Notes
|
| 1191 |
+
-----
|
| 1192 |
+
The algorithm is simple. Edges are incrementally added between parts of the
|
| 1193 |
+
graph that are not yet locally k-edge-connected. Then edges are from the
|
| 1194 |
+
augmenting set are pruned as long as local-edge-connectivity is not broken.
|
| 1195 |
+
|
| 1196 |
+
This algorithm is greedy and does not provide optimality guarantees. It
|
| 1197 |
+
exists only to provide :func:`k_edge_augmentation` with the ability to
|
| 1198 |
+
generate a feasible solution for arbitrary k.
|
| 1199 |
+
|
| 1200 |
+
See Also
|
| 1201 |
+
--------
|
| 1202 |
+
:func:`k_edge_augmentation`
|
| 1203 |
+
|
| 1204 |
+
Examples
|
| 1205 |
+
--------
|
| 1206 |
+
>>> G = nx.path_graph((1, 2, 3, 4, 5, 6, 7))
|
| 1207 |
+
>>> sorted(greedy_k_edge_augmentation(G, k=2))
|
| 1208 |
+
[(1, 7)]
|
| 1209 |
+
>>> sorted(greedy_k_edge_augmentation(G, k=1, avail=[]))
|
| 1210 |
+
[]
|
| 1211 |
+
>>> G = nx.path_graph((1, 2, 3, 4, 5, 6, 7))
|
| 1212 |
+
>>> avail = {(u, v): 1 for (u, v) in complement_edges(G)}
|
| 1213 |
+
>>> # randomized pruning process can produce different solutions
|
| 1214 |
+
>>> sorted(greedy_k_edge_augmentation(G, k=4, avail=avail, seed=2))
|
| 1215 |
+
[(1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (2, 4), (2, 6), (3, 7), (5, 7)]
|
| 1216 |
+
>>> sorted(greedy_k_edge_augmentation(G, k=4, avail=avail, seed=3))
|
| 1217 |
+
[(1, 3), (1, 5), (1, 6), (2, 4), (2, 6), (3, 7), (4, 7), (5, 7)]
|
| 1218 |
+
"""
|
| 1219 |
+
# Result set
|
| 1220 |
+
aug_edges = []
|
| 1221 |
+
|
| 1222 |
+
done = is_k_edge_connected(G, k)
|
| 1223 |
+
if done:
|
| 1224 |
+
return
|
| 1225 |
+
if avail is None:
|
| 1226 |
+
# all edges are available
|
| 1227 |
+
avail_uv = list(complement_edges(G))
|
| 1228 |
+
avail_w = [1] * len(avail_uv)
|
| 1229 |
+
else:
|
| 1230 |
+
# Get the unique set of unweighted edges
|
| 1231 |
+
avail_uv, avail_w = _unpack_available_edges(avail, weight=weight, G=G)
|
| 1232 |
+
|
| 1233 |
+
# Greedy: order lightest edges. Use degree sum to tie-break
|
| 1234 |
+
tiebreaker = [sum(map(G.degree, uv)) for uv in avail_uv]
|
| 1235 |
+
avail_wduv = sorted(zip(avail_w, tiebreaker, avail_uv))
|
| 1236 |
+
avail_uv = [uv for w, d, uv in avail_wduv]
|
| 1237 |
+
|
| 1238 |
+
# Incrementally add edges in until we are k-connected
|
| 1239 |
+
H = G.copy()
|
| 1240 |
+
for u, v in avail_uv:
|
| 1241 |
+
done = False
|
| 1242 |
+
if not is_locally_k_edge_connected(H, u, v, k=k):
|
| 1243 |
+
# Only add edges in parts that are not yet locally k-edge-connected
|
| 1244 |
+
aug_edges.append((u, v))
|
| 1245 |
+
H.add_edge(u, v)
|
| 1246 |
+
# Did adding this edge help?
|
| 1247 |
+
if H.degree(u) >= k and H.degree(v) >= k:
|
| 1248 |
+
done = is_k_edge_connected(H, k)
|
| 1249 |
+
if done:
|
| 1250 |
+
break
|
| 1251 |
+
|
| 1252 |
+
# Check for feasibility
|
| 1253 |
+
if not done:
|
| 1254 |
+
raise nx.NetworkXUnfeasible("not able to k-edge-connect with available edges")
|
| 1255 |
+
|
| 1256 |
+
# Randomized attempt to reduce the size of the solution
|
| 1257 |
+
_compat_shuffle(seed, aug_edges)
|
| 1258 |
+
for u, v in list(aug_edges):
|
| 1259 |
+
# Don't remove if we know it would break connectivity
|
| 1260 |
+
if H.degree(u) <= k or H.degree(v) <= k:
|
| 1261 |
+
continue
|
| 1262 |
+
H.remove_edge(u, v)
|
| 1263 |
+
aug_edges.remove((u, v))
|
| 1264 |
+
if not is_k_edge_connected(H, k=k):
|
| 1265 |
+
# If removing this edge breaks feasibility, undo
|
| 1266 |
+
H.add_edge(u, v)
|
| 1267 |
+
aug_edges.append((u, v))
|
| 1268 |
+
|
| 1269 |
+
# Generate results
|
| 1270 |
+
yield from aug_edges
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/edge_kcomponents.py
ADDED
|
@@ -0,0 +1,592 @@
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|
| 1 |
+
"""
|
| 2 |
+
Algorithms for finding k-edge-connected components and subgraphs.
|
| 3 |
+
|
| 4 |
+
A k-edge-connected component (k-edge-cc) is a maximal set of nodes in G, such
|
| 5 |
+
that all pairs of node have an edge-connectivity of at least k.
|
| 6 |
+
|
| 7 |
+
A k-edge-connected subgraph (k-edge-subgraph) is a maximal set of nodes in G,
|
| 8 |
+
such that the subgraph of G defined by the nodes has an edge-connectivity at
|
| 9 |
+
least k.
|
| 10 |
+
"""
|
| 11 |
+
|
| 12 |
+
import itertools as it
|
| 13 |
+
from functools import partial
|
| 14 |
+
|
| 15 |
+
import networkx as nx
|
| 16 |
+
from networkx.utils import arbitrary_element, not_implemented_for
|
| 17 |
+
|
| 18 |
+
__all__ = [
|
| 19 |
+
"k_edge_components",
|
| 20 |
+
"k_edge_subgraphs",
|
| 21 |
+
"bridge_components",
|
| 22 |
+
"EdgeComponentAuxGraph",
|
| 23 |
+
]
|
| 24 |
+
|
| 25 |
+
|
| 26 |
+
@not_implemented_for("multigraph")
|
| 27 |
+
@nx._dispatchable
|
| 28 |
+
def k_edge_components(G, k):
|
| 29 |
+
"""Generates nodes in each maximal k-edge-connected component in G.
|
| 30 |
+
|
| 31 |
+
Parameters
|
| 32 |
+
----------
|
| 33 |
+
G : NetworkX graph
|
| 34 |
+
|
| 35 |
+
k : Integer
|
| 36 |
+
Desired edge connectivity
|
| 37 |
+
|
| 38 |
+
Returns
|
| 39 |
+
-------
|
| 40 |
+
k_edge_components : a generator of k-edge-ccs. Each set of returned nodes
|
| 41 |
+
will have k-edge-connectivity in the graph G.
|
| 42 |
+
|
| 43 |
+
See Also
|
| 44 |
+
--------
|
| 45 |
+
:func:`local_edge_connectivity`
|
| 46 |
+
:func:`k_edge_subgraphs` : similar to this function, but the subgraph
|
| 47 |
+
defined by the nodes must also have k-edge-connectivity.
|
| 48 |
+
:func:`k_components` : similar to this function, but uses node-connectivity
|
| 49 |
+
instead of edge-connectivity
|
| 50 |
+
|
| 51 |
+
Raises
|
| 52 |
+
------
|
| 53 |
+
NetworkXNotImplemented
|
| 54 |
+
If the input graph is a multigraph.
|
| 55 |
+
|
| 56 |
+
ValueError:
|
| 57 |
+
If k is less than 1
|
| 58 |
+
|
| 59 |
+
Notes
|
| 60 |
+
-----
|
| 61 |
+
Attempts to use the most efficient implementation available based on k.
|
| 62 |
+
If k=1, this is simply connected components for directed graphs and
|
| 63 |
+
connected components for undirected graphs.
|
| 64 |
+
If k=2 on an efficient bridge connected component algorithm from _[1] is
|
| 65 |
+
run based on the chain decomposition.
|
| 66 |
+
Otherwise, the algorithm from _[2] is used.
|
| 67 |
+
|
| 68 |
+
Examples
|
| 69 |
+
--------
|
| 70 |
+
>>> import itertools as it
|
| 71 |
+
>>> from networkx.utils import pairwise
|
| 72 |
+
>>> paths = [
|
| 73 |
+
... (1, 2, 4, 3, 1, 4),
|
| 74 |
+
... (5, 6, 7, 8, 5, 7, 8, 6),
|
| 75 |
+
... ]
|
| 76 |
+
>>> G = nx.Graph()
|
| 77 |
+
>>> G.add_nodes_from(it.chain(*paths))
|
| 78 |
+
>>> G.add_edges_from(it.chain(*[pairwise(path) for path in paths]))
|
| 79 |
+
>>> # note this returns {1, 4} unlike k_edge_subgraphs
|
| 80 |
+
>>> sorted(map(sorted, nx.k_edge_components(G, k=3)))
|
| 81 |
+
[[1, 4], [2], [3], [5, 6, 7, 8]]
|
| 82 |
+
|
| 83 |
+
References
|
| 84 |
+
----------
|
| 85 |
+
.. [1] https://en.wikipedia.org/wiki/Bridge_%28graph_theory%29
|
| 86 |
+
.. [2] Wang, Tianhao, et al. (2015) A simple algorithm for finding all
|
| 87 |
+
k-edge-connected components.
|
| 88 |
+
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136264
|
| 89 |
+
"""
|
| 90 |
+
# Compute k-edge-ccs using the most efficient algorithms available.
|
| 91 |
+
if k < 1:
|
| 92 |
+
raise ValueError("k cannot be less than 1")
|
| 93 |
+
if G.is_directed():
|
| 94 |
+
if k == 1:
|
| 95 |
+
return nx.strongly_connected_components(G)
|
| 96 |
+
else:
|
| 97 |
+
# TODO: investigate https://arxiv.org/abs/1412.6466 for k=2
|
| 98 |
+
aux_graph = EdgeComponentAuxGraph.construct(G)
|
| 99 |
+
return aux_graph.k_edge_components(k)
|
| 100 |
+
else:
|
| 101 |
+
if k == 1:
|
| 102 |
+
return nx.connected_components(G)
|
| 103 |
+
elif k == 2:
|
| 104 |
+
return bridge_components(G)
|
| 105 |
+
else:
|
| 106 |
+
aux_graph = EdgeComponentAuxGraph.construct(G)
|
| 107 |
+
return aux_graph.k_edge_components(k)
|
| 108 |
+
|
| 109 |
+
|
| 110 |
+
@not_implemented_for("multigraph")
|
| 111 |
+
@nx._dispatchable
|
| 112 |
+
def k_edge_subgraphs(G, k):
|
| 113 |
+
"""Generates nodes in each maximal k-edge-connected subgraph in G.
|
| 114 |
+
|
| 115 |
+
Parameters
|
| 116 |
+
----------
|
| 117 |
+
G : NetworkX graph
|
| 118 |
+
|
| 119 |
+
k : Integer
|
| 120 |
+
Desired edge connectivity
|
| 121 |
+
|
| 122 |
+
Returns
|
| 123 |
+
-------
|
| 124 |
+
k_edge_subgraphs : a generator of k-edge-subgraphs
|
| 125 |
+
Each k-edge-subgraph is a maximal set of nodes that defines a subgraph
|
| 126 |
+
of G that is k-edge-connected.
|
| 127 |
+
|
| 128 |
+
See Also
|
| 129 |
+
--------
|
| 130 |
+
:func:`edge_connectivity`
|
| 131 |
+
:func:`k_edge_components` : similar to this function, but nodes only
|
| 132 |
+
need to have k-edge-connectivity within the graph G and the subgraphs
|
| 133 |
+
might not be k-edge-connected.
|
| 134 |
+
|
| 135 |
+
Raises
|
| 136 |
+
------
|
| 137 |
+
NetworkXNotImplemented
|
| 138 |
+
If the input graph is a multigraph.
|
| 139 |
+
|
| 140 |
+
ValueError:
|
| 141 |
+
If k is less than 1
|
| 142 |
+
|
| 143 |
+
Notes
|
| 144 |
+
-----
|
| 145 |
+
Attempts to use the most efficient implementation available based on k.
|
| 146 |
+
If k=1, or k=2 and the graph is undirected, then this simply calls
|
| 147 |
+
`k_edge_components`. Otherwise the algorithm from _[1] is used.
|
| 148 |
+
|
| 149 |
+
Examples
|
| 150 |
+
--------
|
| 151 |
+
>>> import itertools as it
|
| 152 |
+
>>> from networkx.utils import pairwise
|
| 153 |
+
>>> paths = [
|
| 154 |
+
... (1, 2, 4, 3, 1, 4),
|
| 155 |
+
... (5, 6, 7, 8, 5, 7, 8, 6),
|
| 156 |
+
... ]
|
| 157 |
+
>>> G = nx.Graph()
|
| 158 |
+
>>> G.add_nodes_from(it.chain(*paths))
|
| 159 |
+
>>> G.add_edges_from(it.chain(*[pairwise(path) for path in paths]))
|
| 160 |
+
>>> # note this does not return {1, 4} unlike k_edge_components
|
| 161 |
+
>>> sorted(map(sorted, nx.k_edge_subgraphs(G, k=3)))
|
| 162 |
+
[[1], [2], [3], [4], [5, 6, 7, 8]]
|
| 163 |
+
|
| 164 |
+
References
|
| 165 |
+
----------
|
| 166 |
+
.. [1] Zhou, Liu, et al. (2012) Finding maximal k-edge-connected subgraphs
|
| 167 |
+
from a large graph. ACM International Conference on Extending Database
|
| 168 |
+
Technology 2012 480-–491.
|
| 169 |
+
https://openproceedings.org/2012/conf/edbt/ZhouLYLCL12.pdf
|
| 170 |
+
"""
|
| 171 |
+
if k < 1:
|
| 172 |
+
raise ValueError("k cannot be less than 1")
|
| 173 |
+
if G.is_directed():
|
| 174 |
+
if k <= 1:
|
| 175 |
+
# For directed graphs ,
|
| 176 |
+
# When k == 1, k-edge-ccs and k-edge-subgraphs are the same
|
| 177 |
+
return k_edge_components(G, k)
|
| 178 |
+
else:
|
| 179 |
+
return _k_edge_subgraphs_nodes(G, k)
|
| 180 |
+
else:
|
| 181 |
+
if k <= 2:
|
| 182 |
+
# For undirected graphs,
|
| 183 |
+
# when k <= 2, k-edge-ccs and k-edge-subgraphs are the same
|
| 184 |
+
return k_edge_components(G, k)
|
| 185 |
+
else:
|
| 186 |
+
return _k_edge_subgraphs_nodes(G, k)
|
| 187 |
+
|
| 188 |
+
|
| 189 |
+
def _k_edge_subgraphs_nodes(G, k):
|
| 190 |
+
"""Helper to get the nodes from the subgraphs.
|
| 191 |
+
|
| 192 |
+
This allows k_edge_subgraphs to return a generator.
|
| 193 |
+
"""
|
| 194 |
+
for C in general_k_edge_subgraphs(G, k):
|
| 195 |
+
yield set(C.nodes())
|
| 196 |
+
|
| 197 |
+
|
| 198 |
+
@not_implemented_for("directed")
|
| 199 |
+
@not_implemented_for("multigraph")
|
| 200 |
+
@nx._dispatchable
|
| 201 |
+
def bridge_components(G):
|
| 202 |
+
"""Finds all bridge-connected components G.
|
| 203 |
+
|
| 204 |
+
Parameters
|
| 205 |
+
----------
|
| 206 |
+
G : NetworkX undirected graph
|
| 207 |
+
|
| 208 |
+
Returns
|
| 209 |
+
-------
|
| 210 |
+
bridge_components : a generator of 2-edge-connected components
|
| 211 |
+
|
| 212 |
+
|
| 213 |
+
See Also
|
| 214 |
+
--------
|
| 215 |
+
:func:`k_edge_subgraphs` : this function is a special case for an
|
| 216 |
+
undirected graph where k=2.
|
| 217 |
+
:func:`biconnected_components` : similar to this function, but is defined
|
| 218 |
+
using 2-node-connectivity instead of 2-edge-connectivity.
|
| 219 |
+
|
| 220 |
+
Raises
|
| 221 |
+
------
|
| 222 |
+
NetworkXNotImplemented
|
| 223 |
+
If the input graph is directed or a multigraph.
|
| 224 |
+
|
| 225 |
+
Notes
|
| 226 |
+
-----
|
| 227 |
+
Bridge-connected components are also known as 2-edge-connected components.
|
| 228 |
+
|
| 229 |
+
Examples
|
| 230 |
+
--------
|
| 231 |
+
>>> # The barbell graph with parameter zero has a single bridge
|
| 232 |
+
>>> G = nx.barbell_graph(5, 0)
|
| 233 |
+
>>> from networkx.algorithms.connectivity.edge_kcomponents import bridge_components
|
| 234 |
+
>>> sorted(map(sorted, bridge_components(G)))
|
| 235 |
+
[[0, 1, 2, 3, 4], [5, 6, 7, 8, 9]]
|
| 236 |
+
"""
|
| 237 |
+
H = G.copy()
|
| 238 |
+
H.remove_edges_from(nx.bridges(G))
|
| 239 |
+
yield from nx.connected_components(H)
|
| 240 |
+
|
| 241 |
+
|
| 242 |
+
class EdgeComponentAuxGraph:
|
| 243 |
+
r"""A simple algorithm to find all k-edge-connected components in a graph.
|
| 244 |
+
|
| 245 |
+
Constructing the auxiliary graph (which may take some time) allows for the
|
| 246 |
+
k-edge-ccs to be found in linear time for arbitrary k.
|
| 247 |
+
|
| 248 |
+
Notes
|
| 249 |
+
-----
|
| 250 |
+
This implementation is based on [1]_. The idea is to construct an auxiliary
|
| 251 |
+
graph from which the k-edge-ccs can be extracted in linear time. The
|
| 252 |
+
auxiliary graph is constructed in $O(|V|\cdot F)$ operations, where F is the
|
| 253 |
+
complexity of max flow. Querying the components takes an additional $O(|V|)$
|
| 254 |
+
operations. This algorithm can be slow for large graphs, but it handles an
|
| 255 |
+
arbitrary k and works for both directed and undirected inputs.
|
| 256 |
+
|
| 257 |
+
The undirected case for k=1 is exactly connected components.
|
| 258 |
+
The undirected case for k=2 is exactly bridge connected components.
|
| 259 |
+
The directed case for k=1 is exactly strongly connected components.
|
| 260 |
+
|
| 261 |
+
References
|
| 262 |
+
----------
|
| 263 |
+
.. [1] Wang, Tianhao, et al. (2015) A simple algorithm for finding all
|
| 264 |
+
k-edge-connected components.
|
| 265 |
+
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136264
|
| 266 |
+
|
| 267 |
+
Examples
|
| 268 |
+
--------
|
| 269 |
+
>>> import itertools as it
|
| 270 |
+
>>> from networkx.utils import pairwise
|
| 271 |
+
>>> from networkx.algorithms.connectivity import EdgeComponentAuxGraph
|
| 272 |
+
>>> # Build an interesting graph with multiple levels of k-edge-ccs
|
| 273 |
+
>>> paths = [
|
| 274 |
+
... (1, 2, 3, 4, 1, 3, 4, 2), # a 3-edge-cc (a 4 clique)
|
| 275 |
+
... (5, 6, 7, 5), # a 2-edge-cc (a 3 clique)
|
| 276 |
+
... (1, 5), # combine first two ccs into a 1-edge-cc
|
| 277 |
+
... (0,), # add an additional disconnected 1-edge-cc
|
| 278 |
+
... ]
|
| 279 |
+
>>> G = nx.Graph()
|
| 280 |
+
>>> G.add_nodes_from(it.chain(*paths))
|
| 281 |
+
>>> G.add_edges_from(it.chain(*[pairwise(path) for path in paths]))
|
| 282 |
+
>>> # Constructing the AuxGraph takes about O(n ** 4)
|
| 283 |
+
>>> aux_graph = EdgeComponentAuxGraph.construct(G)
|
| 284 |
+
>>> # Once constructed, querying takes O(n)
|
| 285 |
+
>>> sorted(map(sorted, aux_graph.k_edge_components(k=1)))
|
| 286 |
+
[[0], [1, 2, 3, 4, 5, 6, 7]]
|
| 287 |
+
>>> sorted(map(sorted, aux_graph.k_edge_components(k=2)))
|
| 288 |
+
[[0], [1, 2, 3, 4], [5, 6, 7]]
|
| 289 |
+
>>> sorted(map(sorted, aux_graph.k_edge_components(k=3)))
|
| 290 |
+
[[0], [1, 2, 3, 4], [5], [6], [7]]
|
| 291 |
+
>>> sorted(map(sorted, aux_graph.k_edge_components(k=4)))
|
| 292 |
+
[[0], [1], [2], [3], [4], [5], [6], [7]]
|
| 293 |
+
|
| 294 |
+
The auxiliary graph is primarily used for k-edge-ccs but it
|
| 295 |
+
can also speed up the queries of k-edge-subgraphs by refining the
|
| 296 |
+
search space.
|
| 297 |
+
|
| 298 |
+
>>> import itertools as it
|
| 299 |
+
>>> from networkx.utils import pairwise
|
| 300 |
+
>>> from networkx.algorithms.connectivity import EdgeComponentAuxGraph
|
| 301 |
+
>>> paths = [
|
| 302 |
+
... (1, 2, 4, 3, 1, 4),
|
| 303 |
+
... ]
|
| 304 |
+
>>> G = nx.Graph()
|
| 305 |
+
>>> G.add_nodes_from(it.chain(*paths))
|
| 306 |
+
>>> G.add_edges_from(it.chain(*[pairwise(path) for path in paths]))
|
| 307 |
+
>>> aux_graph = EdgeComponentAuxGraph.construct(G)
|
| 308 |
+
>>> sorted(map(sorted, aux_graph.k_edge_subgraphs(k=3)))
|
| 309 |
+
[[1], [2], [3], [4]]
|
| 310 |
+
>>> sorted(map(sorted, aux_graph.k_edge_components(k=3)))
|
| 311 |
+
[[1, 4], [2], [3]]
|
| 312 |
+
"""
|
| 313 |
+
|
| 314 |
+
# @not_implemented_for('multigraph') # TODO: fix decor for classmethods
|
| 315 |
+
@classmethod
|
| 316 |
+
def construct(EdgeComponentAuxGraph, G):
|
| 317 |
+
"""Builds an auxiliary graph encoding edge-connectivity between nodes.
|
| 318 |
+
|
| 319 |
+
Notes
|
| 320 |
+
-----
|
| 321 |
+
Given G=(V, E), initialize an empty auxiliary graph A.
|
| 322 |
+
Choose an arbitrary source node s. Initialize a set N of available
|
| 323 |
+
nodes (that can be used as the sink). The algorithm picks an
|
| 324 |
+
arbitrary node t from N - {s}, and then computes the minimum st-cut
|
| 325 |
+
(S, T) with value w. If G is directed the minimum of the st-cut or
|
| 326 |
+
the ts-cut is used instead. Then, the edge (s, t) is added to the
|
| 327 |
+
auxiliary graph with weight w. The algorithm is called recursively
|
| 328 |
+
first using S as the available nodes and s as the source, and then
|
| 329 |
+
using T and t. Recursion stops when the source is the only available
|
| 330 |
+
node.
|
| 331 |
+
|
| 332 |
+
Parameters
|
| 333 |
+
----------
|
| 334 |
+
G : NetworkX graph
|
| 335 |
+
"""
|
| 336 |
+
# workaround for classmethod decorator
|
| 337 |
+
not_implemented_for("multigraph")(lambda G: G)(G)
|
| 338 |
+
|
| 339 |
+
def _recursive_build(H, A, source, avail):
|
| 340 |
+
# Terminate once the flow has been compute to every node.
|
| 341 |
+
if {source} == avail:
|
| 342 |
+
return
|
| 343 |
+
# pick an arbitrary node as the sink
|
| 344 |
+
sink = arbitrary_element(avail - {source})
|
| 345 |
+
# find the minimum cut and its weight
|
| 346 |
+
value, (S, T) = nx.minimum_cut(H, source, sink)
|
| 347 |
+
if H.is_directed():
|
| 348 |
+
# check if the reverse direction has a smaller cut
|
| 349 |
+
value_, (T_, S_) = nx.minimum_cut(H, sink, source)
|
| 350 |
+
if value_ < value:
|
| 351 |
+
value, S, T = value_, S_, T_
|
| 352 |
+
# add edge with weight of cut to the aux graph
|
| 353 |
+
A.add_edge(source, sink, weight=value)
|
| 354 |
+
# recursively call until all but one node is used
|
| 355 |
+
_recursive_build(H, A, source, avail.intersection(S))
|
| 356 |
+
_recursive_build(H, A, sink, avail.intersection(T))
|
| 357 |
+
|
| 358 |
+
# Copy input to ensure all edges have unit capacity
|
| 359 |
+
H = G.__class__()
|
| 360 |
+
H.add_nodes_from(G.nodes())
|
| 361 |
+
H.add_edges_from(G.edges(), capacity=1)
|
| 362 |
+
|
| 363 |
+
# A is the auxiliary graph to be constructed
|
| 364 |
+
# It is a weighted undirected tree
|
| 365 |
+
A = nx.Graph()
|
| 366 |
+
|
| 367 |
+
# Pick an arbitrary node as the source
|
| 368 |
+
if H.number_of_nodes() > 0:
|
| 369 |
+
source = arbitrary_element(H.nodes())
|
| 370 |
+
# Initialize a set of elements that can be chosen as the sink
|
| 371 |
+
avail = set(H.nodes())
|
| 372 |
+
|
| 373 |
+
# This constructs A
|
| 374 |
+
_recursive_build(H, A, source, avail)
|
| 375 |
+
|
| 376 |
+
# This class is a container the holds the auxiliary graph A and
|
| 377 |
+
# provides access the k_edge_components function.
|
| 378 |
+
self = EdgeComponentAuxGraph()
|
| 379 |
+
self.A = A
|
| 380 |
+
self.H = H
|
| 381 |
+
return self
|
| 382 |
+
|
| 383 |
+
def k_edge_components(self, k):
|
| 384 |
+
"""Queries the auxiliary graph for k-edge-connected components.
|
| 385 |
+
|
| 386 |
+
Parameters
|
| 387 |
+
----------
|
| 388 |
+
k : Integer
|
| 389 |
+
Desired edge connectivity
|
| 390 |
+
|
| 391 |
+
Returns
|
| 392 |
+
-------
|
| 393 |
+
k_edge_components : a generator of k-edge-ccs
|
| 394 |
+
|
| 395 |
+
Notes
|
| 396 |
+
-----
|
| 397 |
+
Given the auxiliary graph, the k-edge-connected components can be
|
| 398 |
+
determined in linear time by removing all edges with weights less than
|
| 399 |
+
k from the auxiliary graph. The resulting connected components are the
|
| 400 |
+
k-edge-ccs in the original graph.
|
| 401 |
+
"""
|
| 402 |
+
if k < 1:
|
| 403 |
+
raise ValueError("k cannot be less than 1")
|
| 404 |
+
A = self.A
|
| 405 |
+
# "traverse the auxiliary graph A and delete all edges with weights less
|
| 406 |
+
# than k"
|
| 407 |
+
aux_weights = nx.get_edge_attributes(A, "weight")
|
| 408 |
+
# Create a relevant graph with the auxiliary edges with weights >= k
|
| 409 |
+
R = nx.Graph()
|
| 410 |
+
R.add_nodes_from(A.nodes())
|
| 411 |
+
R.add_edges_from(e for e, w in aux_weights.items() if w >= k)
|
| 412 |
+
|
| 413 |
+
# Return the nodes that are k-edge-connected in the original graph
|
| 414 |
+
yield from nx.connected_components(R)
|
| 415 |
+
|
| 416 |
+
def k_edge_subgraphs(self, k):
|
| 417 |
+
"""Queries the auxiliary graph for k-edge-connected subgraphs.
|
| 418 |
+
|
| 419 |
+
Parameters
|
| 420 |
+
----------
|
| 421 |
+
k : Integer
|
| 422 |
+
Desired edge connectivity
|
| 423 |
+
|
| 424 |
+
Returns
|
| 425 |
+
-------
|
| 426 |
+
k_edge_subgraphs : a generator of k-edge-subgraphs
|
| 427 |
+
|
| 428 |
+
Notes
|
| 429 |
+
-----
|
| 430 |
+
Refines the k-edge-ccs into k-edge-subgraphs. The running time is more
|
| 431 |
+
than $O(|V|)$.
|
| 432 |
+
|
| 433 |
+
For single values of k it is faster to use `nx.k_edge_subgraphs`.
|
| 434 |
+
But for multiple values of k, it can be faster to build AuxGraph and
|
| 435 |
+
then use this method.
|
| 436 |
+
"""
|
| 437 |
+
if k < 1:
|
| 438 |
+
raise ValueError("k cannot be less than 1")
|
| 439 |
+
H = self.H
|
| 440 |
+
A = self.A
|
| 441 |
+
# "traverse the auxiliary graph A and delete all edges with weights less
|
| 442 |
+
# than k"
|
| 443 |
+
aux_weights = nx.get_edge_attributes(A, "weight")
|
| 444 |
+
# Create a relevant graph with the auxiliary edges with weights >= k
|
| 445 |
+
R = nx.Graph()
|
| 446 |
+
R.add_nodes_from(A.nodes())
|
| 447 |
+
R.add_edges_from(e for e, w in aux_weights.items() if w >= k)
|
| 448 |
+
|
| 449 |
+
# Return the components whose subgraphs are k-edge-connected
|
| 450 |
+
for cc in nx.connected_components(R):
|
| 451 |
+
if len(cc) < k:
|
| 452 |
+
# Early return optimization
|
| 453 |
+
for node in cc:
|
| 454 |
+
yield {node}
|
| 455 |
+
else:
|
| 456 |
+
# Call subgraph solution to refine the results
|
| 457 |
+
C = H.subgraph(cc)
|
| 458 |
+
yield from k_edge_subgraphs(C, k)
|
| 459 |
+
|
| 460 |
+
|
| 461 |
+
def _low_degree_nodes(G, k, nbunch=None):
|
| 462 |
+
"""Helper for finding nodes with degree less than k."""
|
| 463 |
+
# Nodes with degree less than k cannot be k-edge-connected.
|
| 464 |
+
if G.is_directed():
|
| 465 |
+
# Consider both in and out degree in the directed case
|
| 466 |
+
seen = set()
|
| 467 |
+
for node, degree in G.out_degree(nbunch):
|
| 468 |
+
if degree < k:
|
| 469 |
+
seen.add(node)
|
| 470 |
+
yield node
|
| 471 |
+
for node, degree in G.in_degree(nbunch):
|
| 472 |
+
if node not in seen and degree < k:
|
| 473 |
+
seen.add(node)
|
| 474 |
+
yield node
|
| 475 |
+
else:
|
| 476 |
+
# Only the degree matters in the undirected case
|
| 477 |
+
for node, degree in G.degree(nbunch):
|
| 478 |
+
if degree < k:
|
| 479 |
+
yield node
|
| 480 |
+
|
| 481 |
+
|
| 482 |
+
def _high_degree_components(G, k):
|
| 483 |
+
"""Helper for filtering components that can't be k-edge-connected.
|
| 484 |
+
|
| 485 |
+
Removes and generates each node with degree less than k. Then generates
|
| 486 |
+
remaining components where all nodes have degree at least k.
|
| 487 |
+
"""
|
| 488 |
+
# Iteratively remove parts of the graph that are not k-edge-connected
|
| 489 |
+
H = G.copy()
|
| 490 |
+
singletons = set(_low_degree_nodes(H, k))
|
| 491 |
+
while singletons:
|
| 492 |
+
# Only search neighbors of removed nodes
|
| 493 |
+
nbunch = set(it.chain.from_iterable(map(H.neighbors, singletons)))
|
| 494 |
+
nbunch.difference_update(singletons)
|
| 495 |
+
H.remove_nodes_from(singletons)
|
| 496 |
+
for node in singletons:
|
| 497 |
+
yield {node}
|
| 498 |
+
singletons = set(_low_degree_nodes(H, k, nbunch))
|
| 499 |
+
|
| 500 |
+
# Note: remaining connected components may not be k-edge-connected
|
| 501 |
+
if G.is_directed():
|
| 502 |
+
yield from nx.strongly_connected_components(H)
|
| 503 |
+
else:
|
| 504 |
+
yield from nx.connected_components(H)
|
| 505 |
+
|
| 506 |
+
|
| 507 |
+
@nx._dispatchable(returns_graph=True)
|
| 508 |
+
def general_k_edge_subgraphs(G, k):
|
| 509 |
+
"""General algorithm to find all maximal k-edge-connected subgraphs in `G`.
|
| 510 |
+
|
| 511 |
+
Parameters
|
| 512 |
+
----------
|
| 513 |
+
G : nx.Graph
|
| 514 |
+
Graph in which all maximal k-edge-connected subgraphs will be found.
|
| 515 |
+
|
| 516 |
+
k : int
|
| 517 |
+
|
| 518 |
+
Yields
|
| 519 |
+
------
|
| 520 |
+
k_edge_subgraphs : Graph instances that are k-edge-subgraphs
|
| 521 |
+
Each k-edge-subgraph contains a maximal set of nodes that defines a
|
| 522 |
+
subgraph of `G` that is k-edge-connected.
|
| 523 |
+
|
| 524 |
+
Notes
|
| 525 |
+
-----
|
| 526 |
+
Implementation of the basic algorithm from [1]_. The basic idea is to find
|
| 527 |
+
a global minimum cut of the graph. If the cut value is at least k, then the
|
| 528 |
+
graph is a k-edge-connected subgraph and can be added to the results.
|
| 529 |
+
Otherwise, the cut is used to split the graph in two and the procedure is
|
| 530 |
+
applied recursively. If the graph is just a single node, then it is also
|
| 531 |
+
added to the results. At the end, each result is either guaranteed to be
|
| 532 |
+
a single node or a subgraph of G that is k-edge-connected.
|
| 533 |
+
|
| 534 |
+
This implementation contains optimizations for reducing the number of calls
|
| 535 |
+
to max-flow, but there are other optimizations in [1]_ that could be
|
| 536 |
+
implemented.
|
| 537 |
+
|
| 538 |
+
References
|
| 539 |
+
----------
|
| 540 |
+
.. [1] Zhou, Liu, et al. (2012) Finding maximal k-edge-connected subgraphs
|
| 541 |
+
from a large graph. ACM International Conference on Extending Database
|
| 542 |
+
Technology 2012 480-–491.
|
| 543 |
+
https://openproceedings.org/2012/conf/edbt/ZhouLYLCL12.pdf
|
| 544 |
+
|
| 545 |
+
Examples
|
| 546 |
+
--------
|
| 547 |
+
>>> from networkx.utils import pairwise
|
| 548 |
+
>>> paths = [
|
| 549 |
+
... (11, 12, 13, 14, 11, 13, 14, 12), # a 4-clique
|
| 550 |
+
... (21, 22, 23, 24, 21, 23, 24, 22), # another 4-clique
|
| 551 |
+
... # connect the cliques with high degree but low connectivity
|
| 552 |
+
... (50, 13),
|
| 553 |
+
... (12, 50, 22),
|
| 554 |
+
... (13, 102, 23),
|
| 555 |
+
... (14, 101, 24),
|
| 556 |
+
... ]
|
| 557 |
+
>>> G = nx.Graph(it.chain(*[pairwise(path) for path in paths]))
|
| 558 |
+
>>> sorted(len(k_sg) for k_sg in k_edge_subgraphs(G, k=3))
|
| 559 |
+
[1, 1, 1, 4, 4]
|
| 560 |
+
"""
|
| 561 |
+
if k < 1:
|
| 562 |
+
raise ValueError("k cannot be less than 1")
|
| 563 |
+
|
| 564 |
+
# Node pruning optimization (incorporates early return)
|
| 565 |
+
# find_ccs is either connected_components/strongly_connected_components
|
| 566 |
+
find_ccs = partial(_high_degree_components, k=k)
|
| 567 |
+
|
| 568 |
+
# Quick return optimization
|
| 569 |
+
if G.number_of_nodes() < k:
|
| 570 |
+
for node in G.nodes():
|
| 571 |
+
yield G.subgraph([node]).copy()
|
| 572 |
+
return
|
| 573 |
+
|
| 574 |
+
# Intermediate results
|
| 575 |
+
R0 = {G.subgraph(cc).copy() for cc in find_ccs(G)}
|
| 576 |
+
# Subdivide CCs in the intermediate results until they are k-conn
|
| 577 |
+
while R0:
|
| 578 |
+
G1 = R0.pop()
|
| 579 |
+
if G1.number_of_nodes() == 1:
|
| 580 |
+
yield G1
|
| 581 |
+
else:
|
| 582 |
+
# Find a global minimum cut
|
| 583 |
+
cut_edges = nx.minimum_edge_cut(G1)
|
| 584 |
+
cut_value = len(cut_edges)
|
| 585 |
+
if cut_value < k:
|
| 586 |
+
# G1 is not k-edge-connected, so subdivide it
|
| 587 |
+
G1.remove_edges_from(cut_edges)
|
| 588 |
+
for cc in find_ccs(G1):
|
| 589 |
+
R0.add(G1.subgraph(cc).copy())
|
| 590 |
+
else:
|
| 591 |
+
# Otherwise we found a k-edge-connected subgraph
|
| 592 |
+
yield G1
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/kcomponents.py
ADDED
|
@@ -0,0 +1,223 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Moody and White algorithm for k-components
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
from collections import defaultdict
|
| 6 |
+
from itertools import combinations
|
| 7 |
+
from operator import itemgetter
|
| 8 |
+
|
| 9 |
+
import networkx as nx
|
| 10 |
+
|
| 11 |
+
# Define the default maximum flow function.
|
| 12 |
+
from networkx.algorithms.flow import edmonds_karp
|
| 13 |
+
from networkx.utils import not_implemented_for
|
| 14 |
+
|
| 15 |
+
default_flow_func = edmonds_karp
|
| 16 |
+
|
| 17 |
+
__all__ = ["k_components"]
|
| 18 |
+
|
| 19 |
+
|
| 20 |
+
@not_implemented_for("directed")
|
| 21 |
+
@nx._dispatchable
|
| 22 |
+
def k_components(G, flow_func=None):
|
| 23 |
+
r"""Returns the k-component structure of a graph G.
|
| 24 |
+
|
| 25 |
+
A `k`-component is a maximal subgraph of a graph G that has, at least,
|
| 26 |
+
node connectivity `k`: we need to remove at least `k` nodes to break it
|
| 27 |
+
into more components. `k`-components have an inherent hierarchical
|
| 28 |
+
structure because they are nested in terms of connectivity: a connected
|
| 29 |
+
graph can contain several 2-components, each of which can contain
|
| 30 |
+
one or more 3-components, and so forth.
|
| 31 |
+
|
| 32 |
+
Parameters
|
| 33 |
+
----------
|
| 34 |
+
G : NetworkX graph
|
| 35 |
+
|
| 36 |
+
flow_func : function
|
| 37 |
+
Function to perform the underlying flow computations. Default value
|
| 38 |
+
:meth:`edmonds_karp`. This function performs better in sparse graphs with
|
| 39 |
+
right tailed degree distributions. :meth:`shortest_augmenting_path` will
|
| 40 |
+
perform better in denser graphs.
|
| 41 |
+
|
| 42 |
+
Returns
|
| 43 |
+
-------
|
| 44 |
+
k_components : dict
|
| 45 |
+
Dictionary with all connectivity levels `k` in the input Graph as keys
|
| 46 |
+
and a list of sets of nodes that form a k-component of level `k` as
|
| 47 |
+
values.
|
| 48 |
+
|
| 49 |
+
Raises
|
| 50 |
+
------
|
| 51 |
+
NetworkXNotImplemented
|
| 52 |
+
If the input graph is directed.
|
| 53 |
+
|
| 54 |
+
Examples
|
| 55 |
+
--------
|
| 56 |
+
>>> # Petersen graph has 10 nodes and it is triconnected, thus all
|
| 57 |
+
>>> # nodes are in a single component on all three connectivity levels
|
| 58 |
+
>>> G = nx.petersen_graph()
|
| 59 |
+
>>> k_components = nx.k_components(G)
|
| 60 |
+
|
| 61 |
+
Notes
|
| 62 |
+
-----
|
| 63 |
+
Moody and White [1]_ (appendix A) provide an algorithm for identifying
|
| 64 |
+
k-components in a graph, which is based on Kanevsky's algorithm [2]_
|
| 65 |
+
for finding all minimum-size node cut-sets of a graph (implemented in
|
| 66 |
+
:meth:`all_node_cuts` function):
|
| 67 |
+
|
| 68 |
+
1. Compute node connectivity, k, of the input graph G.
|
| 69 |
+
|
| 70 |
+
2. Identify all k-cutsets at the current level of connectivity using
|
| 71 |
+
Kanevsky's algorithm.
|
| 72 |
+
|
| 73 |
+
3. Generate new graph components based on the removal of
|
| 74 |
+
these cutsets. Nodes in a cutset belong to both sides
|
| 75 |
+
of the induced cut.
|
| 76 |
+
|
| 77 |
+
4. If the graph is neither complete nor trivial, return to 1;
|
| 78 |
+
else end.
|
| 79 |
+
|
| 80 |
+
This implementation also uses some heuristics (see [3]_ for details)
|
| 81 |
+
to speed up the computation.
|
| 82 |
+
|
| 83 |
+
See also
|
| 84 |
+
--------
|
| 85 |
+
node_connectivity
|
| 86 |
+
all_node_cuts
|
| 87 |
+
biconnected_components : special case of this function when k=2
|
| 88 |
+
k_edge_components : similar to this function, but uses edge-connectivity
|
| 89 |
+
instead of node-connectivity
|
| 90 |
+
|
| 91 |
+
References
|
| 92 |
+
----------
|
| 93 |
+
.. [1] Moody, J. and D. White (2003). Social cohesion and embeddedness:
|
| 94 |
+
A hierarchical conception of social groups.
|
| 95 |
+
American Sociological Review 68(1), 103--28.
|
| 96 |
+
http://www2.asanet.org/journals/ASRFeb03MoodyWhite.pdf
|
| 97 |
+
|
| 98 |
+
.. [2] Kanevsky, A. (1993). Finding all minimum-size separating vertex
|
| 99 |
+
sets in a graph. Networks 23(6), 533--541.
|
| 100 |
+
http://onlinelibrary.wiley.com/doi/10.1002/net.3230230604/abstract
|
| 101 |
+
|
| 102 |
+
.. [3] Torrents, J. and F. Ferraro (2015). Structural Cohesion:
|
| 103 |
+
Visualization and Heuristics for Fast Computation.
|
| 104 |
+
https://arxiv.org/pdf/1503.04476v1
|
| 105 |
+
|
| 106 |
+
"""
|
| 107 |
+
# Dictionary with connectivity level (k) as keys and a list of
|
| 108 |
+
# sets of nodes that form a k-component as values. Note that
|
| 109 |
+
# k-components can overlap (but only k - 1 nodes).
|
| 110 |
+
k_components = defaultdict(list)
|
| 111 |
+
# Define default flow function
|
| 112 |
+
if flow_func is None:
|
| 113 |
+
flow_func = default_flow_func
|
| 114 |
+
# Bicomponents as a base to check for higher order k-components
|
| 115 |
+
for component in nx.connected_components(G):
|
| 116 |
+
# isolated nodes have connectivity 0
|
| 117 |
+
comp = set(component)
|
| 118 |
+
if len(comp) > 1:
|
| 119 |
+
k_components[1].append(comp)
|
| 120 |
+
bicomponents = [G.subgraph(c) for c in nx.biconnected_components(G)]
|
| 121 |
+
for bicomponent in bicomponents:
|
| 122 |
+
bicomp = set(bicomponent)
|
| 123 |
+
# avoid considering dyads as bicomponents
|
| 124 |
+
if len(bicomp) > 2:
|
| 125 |
+
k_components[2].append(bicomp)
|
| 126 |
+
for B in bicomponents:
|
| 127 |
+
if len(B) <= 2:
|
| 128 |
+
continue
|
| 129 |
+
k = nx.node_connectivity(B, flow_func=flow_func)
|
| 130 |
+
if k > 2:
|
| 131 |
+
k_components[k].append(set(B))
|
| 132 |
+
# Perform cuts in a DFS like order.
|
| 133 |
+
cuts = list(nx.all_node_cuts(B, k=k, flow_func=flow_func))
|
| 134 |
+
stack = [(k, _generate_partition(B, cuts, k))]
|
| 135 |
+
while stack:
|
| 136 |
+
(parent_k, partition) = stack[-1]
|
| 137 |
+
try:
|
| 138 |
+
nodes = next(partition)
|
| 139 |
+
C = B.subgraph(nodes)
|
| 140 |
+
this_k = nx.node_connectivity(C, flow_func=flow_func)
|
| 141 |
+
if this_k > parent_k and this_k > 2:
|
| 142 |
+
k_components[this_k].append(set(C))
|
| 143 |
+
cuts = list(nx.all_node_cuts(C, k=this_k, flow_func=flow_func))
|
| 144 |
+
if cuts:
|
| 145 |
+
stack.append((this_k, _generate_partition(C, cuts, this_k)))
|
| 146 |
+
except StopIteration:
|
| 147 |
+
stack.pop()
|
| 148 |
+
|
| 149 |
+
# This is necessary because k-components may only be reported at their
|
| 150 |
+
# maximum k level. But we want to return a dictionary in which keys are
|
| 151 |
+
# connectivity levels and values list of sets of components, without
|
| 152 |
+
# skipping any connectivity level. Also, it's possible that subsets of
|
| 153 |
+
# an already detected k-component appear at a level k. Checking for this
|
| 154 |
+
# in the while loop above penalizes the common case. Thus we also have to
|
| 155 |
+
# _consolidate all connectivity levels in _reconstruct_k_components.
|
| 156 |
+
return _reconstruct_k_components(k_components)
|
| 157 |
+
|
| 158 |
+
|
| 159 |
+
def _consolidate(sets, k):
|
| 160 |
+
"""Merge sets that share k or more elements.
|
| 161 |
+
|
| 162 |
+
See: http://rosettacode.org/wiki/Set_consolidation
|
| 163 |
+
|
| 164 |
+
The iterative python implementation posted there is
|
| 165 |
+
faster than this because of the overhead of building a
|
| 166 |
+
Graph and calling nx.connected_components, but it's not
|
| 167 |
+
clear for us if we can use it in NetworkX because there
|
| 168 |
+
is no licence for the code.
|
| 169 |
+
|
| 170 |
+
"""
|
| 171 |
+
G = nx.Graph()
|
| 172 |
+
nodes = dict(enumerate(sets))
|
| 173 |
+
G.add_nodes_from(nodes)
|
| 174 |
+
G.add_edges_from(
|
| 175 |
+
(u, v) for u, v in combinations(nodes, 2) if len(nodes[u] & nodes[v]) >= k
|
| 176 |
+
)
|
| 177 |
+
for component in nx.connected_components(G):
|
| 178 |
+
yield set.union(*[nodes[n] for n in component])
|
| 179 |
+
|
| 180 |
+
|
| 181 |
+
def _generate_partition(G, cuts, k):
|
| 182 |
+
def has_nbrs_in_partition(G, node, partition):
|
| 183 |
+
return any(n in partition for n in G[node])
|
| 184 |
+
|
| 185 |
+
components = []
|
| 186 |
+
nodes = {n for n, d in G.degree() if d > k} - {n for cut in cuts for n in cut}
|
| 187 |
+
H = G.subgraph(nodes)
|
| 188 |
+
for cc in nx.connected_components(H):
|
| 189 |
+
component = set(cc)
|
| 190 |
+
for cut in cuts:
|
| 191 |
+
for node in cut:
|
| 192 |
+
if has_nbrs_in_partition(G, node, cc):
|
| 193 |
+
component.add(node)
|
| 194 |
+
if len(component) < G.order():
|
| 195 |
+
components.append(component)
|
| 196 |
+
yield from _consolidate(components, k + 1)
|
| 197 |
+
|
| 198 |
+
|
| 199 |
+
def _reconstruct_k_components(k_comps):
|
| 200 |
+
result = {}
|
| 201 |
+
max_k = max(k_comps)
|
| 202 |
+
for k in reversed(range(1, max_k + 1)):
|
| 203 |
+
if k == max_k:
|
| 204 |
+
result[k] = list(_consolidate(k_comps[k], k))
|
| 205 |
+
elif k not in k_comps:
|
| 206 |
+
result[k] = list(_consolidate(result[k + 1], k))
|
| 207 |
+
else:
|
| 208 |
+
nodes_at_k = set.union(*k_comps[k])
|
| 209 |
+
to_add = [c for c in result[k + 1] if any(n not in nodes_at_k for n in c)]
|
| 210 |
+
if to_add:
|
| 211 |
+
result[k] = list(_consolidate(k_comps[k] + to_add, k))
|
| 212 |
+
else:
|
| 213 |
+
result[k] = list(_consolidate(k_comps[k], k))
|
| 214 |
+
return result
|
| 215 |
+
|
| 216 |
+
|
| 217 |
+
def build_k_number_dict(kcomps):
|
| 218 |
+
result = {}
|
| 219 |
+
for k, comps in sorted(kcomps.items(), key=itemgetter(0)):
|
| 220 |
+
for comp in comps:
|
| 221 |
+
for node in comp:
|
| 222 |
+
result[node] = k
|
| 223 |
+
return result
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/kcutsets.py
ADDED
|
@@ -0,0 +1,235 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Kanevsky all minimum node k cutsets algorithm.
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
import copy
|
| 6 |
+
from collections import defaultdict
|
| 7 |
+
from itertools import combinations
|
| 8 |
+
from operator import itemgetter
|
| 9 |
+
|
| 10 |
+
import networkx as nx
|
| 11 |
+
from networkx.algorithms.flow import (
|
| 12 |
+
build_residual_network,
|
| 13 |
+
edmonds_karp,
|
| 14 |
+
shortest_augmenting_path,
|
| 15 |
+
)
|
| 16 |
+
|
| 17 |
+
from .utils import build_auxiliary_node_connectivity
|
| 18 |
+
|
| 19 |
+
default_flow_func = edmonds_karp
|
| 20 |
+
|
| 21 |
+
|
| 22 |
+
__all__ = ["all_node_cuts"]
|
| 23 |
+
|
| 24 |
+
|
| 25 |
+
@nx._dispatchable
|
| 26 |
+
def all_node_cuts(G, k=None, flow_func=None):
|
| 27 |
+
r"""Returns all minimum k cutsets of an undirected graph G.
|
| 28 |
+
|
| 29 |
+
This implementation is based on Kanevsky's algorithm [1]_ for finding all
|
| 30 |
+
minimum-size node cut-sets of an undirected graph G; ie the set (or sets)
|
| 31 |
+
of nodes of cardinality equal to the node connectivity of G. Thus if
|
| 32 |
+
removed, would break G into two or more connected components.
|
| 33 |
+
|
| 34 |
+
Parameters
|
| 35 |
+
----------
|
| 36 |
+
G : NetworkX graph
|
| 37 |
+
Undirected graph
|
| 38 |
+
|
| 39 |
+
k : Integer
|
| 40 |
+
Node connectivity of the input graph. If k is None, then it is
|
| 41 |
+
computed. Default value: None.
|
| 42 |
+
|
| 43 |
+
flow_func : function
|
| 44 |
+
Function to perform the underlying flow computations. Default value is
|
| 45 |
+
:func:`~networkx.algorithms.flow.edmonds_karp`. This function performs
|
| 46 |
+
better in sparse graphs with right tailed degree distributions.
|
| 47 |
+
:func:`~networkx.algorithms.flow.shortest_augmenting_path` will
|
| 48 |
+
perform better in denser graphs.
|
| 49 |
+
|
| 50 |
+
|
| 51 |
+
Returns
|
| 52 |
+
-------
|
| 53 |
+
cuts : a generator of node cutsets
|
| 54 |
+
Each node cutset has cardinality equal to the node connectivity of
|
| 55 |
+
the input graph.
|
| 56 |
+
|
| 57 |
+
Examples
|
| 58 |
+
--------
|
| 59 |
+
>>> # A two-dimensional grid graph has 4 cutsets of cardinality 2
|
| 60 |
+
>>> G = nx.grid_2d_graph(5, 5)
|
| 61 |
+
>>> cutsets = list(nx.all_node_cuts(G))
|
| 62 |
+
>>> len(cutsets)
|
| 63 |
+
4
|
| 64 |
+
>>> all(2 == len(cutset) for cutset in cutsets)
|
| 65 |
+
True
|
| 66 |
+
>>> nx.node_connectivity(G)
|
| 67 |
+
2
|
| 68 |
+
|
| 69 |
+
Notes
|
| 70 |
+
-----
|
| 71 |
+
This implementation is based on the sequential algorithm for finding all
|
| 72 |
+
minimum-size separating vertex sets in a graph [1]_. The main idea is to
|
| 73 |
+
compute minimum cuts using local maximum flow computations among a set
|
| 74 |
+
of nodes of highest degree and all other non-adjacent nodes in the Graph.
|
| 75 |
+
Once we find a minimum cut, we add an edge between the high degree
|
| 76 |
+
node and the target node of the local maximum flow computation to make
|
| 77 |
+
sure that we will not find that minimum cut again.
|
| 78 |
+
|
| 79 |
+
See also
|
| 80 |
+
--------
|
| 81 |
+
node_connectivity
|
| 82 |
+
edmonds_karp
|
| 83 |
+
shortest_augmenting_path
|
| 84 |
+
|
| 85 |
+
References
|
| 86 |
+
----------
|
| 87 |
+
.. [1] Kanevsky, A. (1993). Finding all minimum-size separating vertex
|
| 88 |
+
sets in a graph. Networks 23(6), 533--541.
|
| 89 |
+
http://onlinelibrary.wiley.com/doi/10.1002/net.3230230604/abstract
|
| 90 |
+
|
| 91 |
+
"""
|
| 92 |
+
if not nx.is_connected(G):
|
| 93 |
+
raise nx.NetworkXError("Input graph is disconnected.")
|
| 94 |
+
|
| 95 |
+
# Address some corner cases first.
|
| 96 |
+
# For complete Graphs
|
| 97 |
+
|
| 98 |
+
if nx.density(G) == 1:
|
| 99 |
+
yield from ()
|
| 100 |
+
return
|
| 101 |
+
|
| 102 |
+
# Initialize data structures.
|
| 103 |
+
# Keep track of the cuts already computed so we do not repeat them.
|
| 104 |
+
seen = []
|
| 105 |
+
# Even-Tarjan reduction is what we call auxiliary digraph
|
| 106 |
+
# for node connectivity.
|
| 107 |
+
H = build_auxiliary_node_connectivity(G)
|
| 108 |
+
H_nodes = H.nodes # for speed
|
| 109 |
+
mapping = H.graph["mapping"]
|
| 110 |
+
# Keep a copy of original predecessors, H will be modified later.
|
| 111 |
+
# Shallow copy is enough.
|
| 112 |
+
original_H_pred = copy.copy(H._pred)
|
| 113 |
+
R = build_residual_network(H, "capacity")
|
| 114 |
+
kwargs = {"capacity": "capacity", "residual": R}
|
| 115 |
+
# Define default flow function
|
| 116 |
+
if flow_func is None:
|
| 117 |
+
flow_func = default_flow_func
|
| 118 |
+
if flow_func is shortest_augmenting_path:
|
| 119 |
+
kwargs["two_phase"] = True
|
| 120 |
+
# Begin the actual algorithm
|
| 121 |
+
# step 1: Find node connectivity k of G
|
| 122 |
+
if k is None:
|
| 123 |
+
k = nx.node_connectivity(G, flow_func=flow_func)
|
| 124 |
+
# step 2:
|
| 125 |
+
# Find k nodes with top degree, call it X:
|
| 126 |
+
X = {n for n, d in sorted(G.degree(), key=itemgetter(1), reverse=True)[:k]}
|
| 127 |
+
# Check if X is a k-node-cutset
|
| 128 |
+
if _is_separating_set(G, X):
|
| 129 |
+
seen.append(X)
|
| 130 |
+
yield X
|
| 131 |
+
|
| 132 |
+
for x in X:
|
| 133 |
+
# step 3: Compute local connectivity flow of x with all other
|
| 134 |
+
# non adjacent nodes in G
|
| 135 |
+
non_adjacent = set(G) - {x} - set(G[x])
|
| 136 |
+
for v in non_adjacent:
|
| 137 |
+
# step 4: compute maximum flow in an Even-Tarjan reduction H of G
|
| 138 |
+
# and step 5: build the associated residual network R
|
| 139 |
+
R = flow_func(H, f"{mapping[x]}B", f"{mapping[v]}A", **kwargs)
|
| 140 |
+
flow_value = R.graph["flow_value"]
|
| 141 |
+
|
| 142 |
+
if flow_value == k:
|
| 143 |
+
# Find the nodes incident to the flow.
|
| 144 |
+
E1 = flowed_edges = [
|
| 145 |
+
(u, w) for (u, w, d) in R.edges(data=True) if d["flow"] != 0
|
| 146 |
+
]
|
| 147 |
+
VE1 = incident_nodes = {n for edge in E1 for n in edge}
|
| 148 |
+
# Remove saturated edges form the residual network.
|
| 149 |
+
# Note that reversed edges are introduced with capacity 0
|
| 150 |
+
# in the residual graph and they need to be removed too.
|
| 151 |
+
saturated_edges = [
|
| 152 |
+
(u, w, d)
|
| 153 |
+
for (u, w, d) in R.edges(data=True)
|
| 154 |
+
if d["capacity"] == d["flow"] or d["capacity"] == 0
|
| 155 |
+
]
|
| 156 |
+
R.remove_edges_from(saturated_edges)
|
| 157 |
+
R_closure = nx.transitive_closure(R)
|
| 158 |
+
# step 6: shrink the strongly connected components of
|
| 159 |
+
# residual flow network R and call it L.
|
| 160 |
+
L = nx.condensation(R)
|
| 161 |
+
cmap = L.graph["mapping"]
|
| 162 |
+
inv_cmap = defaultdict(list)
|
| 163 |
+
for n, scc in cmap.items():
|
| 164 |
+
inv_cmap[scc].append(n)
|
| 165 |
+
# Find the incident nodes in the condensed graph.
|
| 166 |
+
VE1 = {cmap[n] for n in VE1}
|
| 167 |
+
# step 7: Compute all antichains of L;
|
| 168 |
+
# they map to closed sets in H.
|
| 169 |
+
# Any edge in H that links a closed set is part of a cutset.
|
| 170 |
+
for antichain in nx.antichains(L):
|
| 171 |
+
# Only antichains that are subsets of incident nodes counts.
|
| 172 |
+
# Lemma 8 in reference.
|
| 173 |
+
if not set(antichain).issubset(VE1):
|
| 174 |
+
continue
|
| 175 |
+
# Nodes in an antichain of the condensation graph of
|
| 176 |
+
# the residual network map to a closed set of nodes that
|
| 177 |
+
# define a node partition of the auxiliary digraph H
|
| 178 |
+
# through taking all of antichain's predecessors in the
|
| 179 |
+
# transitive closure.
|
| 180 |
+
S = set()
|
| 181 |
+
for scc in antichain:
|
| 182 |
+
S.update(inv_cmap[scc])
|
| 183 |
+
S_ancestors = set()
|
| 184 |
+
for n in S:
|
| 185 |
+
S_ancestors.update(R_closure._pred[n])
|
| 186 |
+
S.update(S_ancestors)
|
| 187 |
+
if f"{mapping[x]}B" not in S or f"{mapping[v]}A" in S:
|
| 188 |
+
continue
|
| 189 |
+
# Find the cutset that links the node partition (S,~S) in H
|
| 190 |
+
cutset = set()
|
| 191 |
+
for u in S:
|
| 192 |
+
cutset.update((u, w) for w in original_H_pred[u] if w not in S)
|
| 193 |
+
# The edges in H that form the cutset are internal edges
|
| 194 |
+
# (ie edges that represent a node of the original graph G)
|
| 195 |
+
if any(H_nodes[u]["id"] != H_nodes[w]["id"] for u, w in cutset):
|
| 196 |
+
continue
|
| 197 |
+
node_cut = {H_nodes[u]["id"] for u, _ in cutset}
|
| 198 |
+
|
| 199 |
+
if len(node_cut) == k:
|
| 200 |
+
# The cut is invalid if it includes internal edges of
|
| 201 |
+
# end nodes. The other half of Lemma 8 in ref.
|
| 202 |
+
if x in node_cut or v in node_cut:
|
| 203 |
+
continue
|
| 204 |
+
if node_cut not in seen:
|
| 205 |
+
yield node_cut
|
| 206 |
+
seen.append(node_cut)
|
| 207 |
+
|
| 208 |
+
# Add an edge (x, v) to make sure that we do not
|
| 209 |
+
# find this cutset again. This is equivalent
|
| 210 |
+
# of adding the edge in the input graph
|
| 211 |
+
# G.add_edge(x, v) and then regenerate H and R:
|
| 212 |
+
# Add edges to the auxiliary digraph.
|
| 213 |
+
# See build_residual_network for convention we used
|
| 214 |
+
# in residual graphs.
|
| 215 |
+
H.add_edge(f"{mapping[x]}B", f"{mapping[v]}A", capacity=1)
|
| 216 |
+
H.add_edge(f"{mapping[v]}B", f"{mapping[x]}A", capacity=1)
|
| 217 |
+
# Add edges to the residual network.
|
| 218 |
+
R.add_edge(f"{mapping[x]}B", f"{mapping[v]}A", capacity=1)
|
| 219 |
+
R.add_edge(f"{mapping[v]}A", f"{mapping[x]}B", capacity=0)
|
| 220 |
+
R.add_edge(f"{mapping[v]}B", f"{mapping[x]}A", capacity=1)
|
| 221 |
+
R.add_edge(f"{mapping[x]}A", f"{mapping[v]}B", capacity=0)
|
| 222 |
+
|
| 223 |
+
# Add again the saturated edges to reuse the residual network
|
| 224 |
+
R.add_edges_from(saturated_edges)
|
| 225 |
+
|
| 226 |
+
|
| 227 |
+
def _is_separating_set(G, cut):
|
| 228 |
+
"""Assumes that the input graph is connected"""
|
| 229 |
+
if len(cut) == len(G) - 1:
|
| 230 |
+
return True
|
| 231 |
+
|
| 232 |
+
H = nx.restricted_view(G, cut, [])
|
| 233 |
+
if nx.is_connected(H):
|
| 234 |
+
return False
|
| 235 |
+
return True
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/stoerwagner.py
ADDED
|
@@ -0,0 +1,152 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Stoer-Wagner minimum cut algorithm.
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
from itertools import islice
|
| 6 |
+
|
| 7 |
+
import networkx as nx
|
| 8 |
+
|
| 9 |
+
from ...utils import BinaryHeap, arbitrary_element, not_implemented_for
|
| 10 |
+
|
| 11 |
+
__all__ = ["stoer_wagner"]
|
| 12 |
+
|
| 13 |
+
|
| 14 |
+
@not_implemented_for("directed")
|
| 15 |
+
@not_implemented_for("multigraph")
|
| 16 |
+
@nx._dispatchable(edge_attrs="weight")
|
| 17 |
+
def stoer_wagner(G, weight="weight", heap=BinaryHeap):
|
| 18 |
+
r"""Returns the weighted minimum edge cut using the Stoer-Wagner algorithm.
|
| 19 |
+
|
| 20 |
+
Determine the minimum edge cut of a connected graph using the
|
| 21 |
+
Stoer-Wagner algorithm. In weighted cases, all weights must be
|
| 22 |
+
nonnegative.
|
| 23 |
+
|
| 24 |
+
The running time of the algorithm depends on the type of heaps used:
|
| 25 |
+
|
| 26 |
+
============== =============================================
|
| 27 |
+
Type of heap Running time
|
| 28 |
+
============== =============================================
|
| 29 |
+
Binary heap $O(n (m + n) \log n)$
|
| 30 |
+
Fibonacci heap $O(nm + n^2 \log n)$
|
| 31 |
+
Pairing heap $O(2^{2 \sqrt{\log \log n}} nm + n^2 \log n)$
|
| 32 |
+
============== =============================================
|
| 33 |
+
|
| 34 |
+
Parameters
|
| 35 |
+
----------
|
| 36 |
+
G : NetworkX graph
|
| 37 |
+
Edges of the graph are expected to have an attribute named by the
|
| 38 |
+
weight parameter below. If this attribute is not present, the edge is
|
| 39 |
+
considered to have unit weight.
|
| 40 |
+
|
| 41 |
+
weight : string
|
| 42 |
+
Name of the weight attribute of the edges. If the attribute is not
|
| 43 |
+
present, unit weight is assumed. Default value: 'weight'.
|
| 44 |
+
|
| 45 |
+
heap : class
|
| 46 |
+
Type of heap to be used in the algorithm. It should be a subclass of
|
| 47 |
+
:class:`MinHeap` or implement a compatible interface.
|
| 48 |
+
|
| 49 |
+
If a stock heap implementation is to be used, :class:`BinaryHeap` is
|
| 50 |
+
recommended over :class:`PairingHeap` for Python implementations without
|
| 51 |
+
optimized attribute accesses (e.g., CPython) despite a slower
|
| 52 |
+
asymptotic running time. For Python implementations with optimized
|
| 53 |
+
attribute accesses (e.g., PyPy), :class:`PairingHeap` provides better
|
| 54 |
+
performance. Default value: :class:`BinaryHeap`.
|
| 55 |
+
|
| 56 |
+
Returns
|
| 57 |
+
-------
|
| 58 |
+
cut_value : integer or float
|
| 59 |
+
The sum of weights of edges in a minimum cut.
|
| 60 |
+
|
| 61 |
+
partition : pair of node lists
|
| 62 |
+
A partitioning of the nodes that defines a minimum cut.
|
| 63 |
+
|
| 64 |
+
Raises
|
| 65 |
+
------
|
| 66 |
+
NetworkXNotImplemented
|
| 67 |
+
If the graph is directed or a multigraph.
|
| 68 |
+
|
| 69 |
+
NetworkXError
|
| 70 |
+
If the graph has less than two nodes, is not connected or has a
|
| 71 |
+
negative-weighted edge.
|
| 72 |
+
|
| 73 |
+
Examples
|
| 74 |
+
--------
|
| 75 |
+
>>> G = nx.Graph()
|
| 76 |
+
>>> G.add_edge("x", "a", weight=3)
|
| 77 |
+
>>> G.add_edge("x", "b", weight=1)
|
| 78 |
+
>>> G.add_edge("a", "c", weight=3)
|
| 79 |
+
>>> G.add_edge("b", "c", weight=5)
|
| 80 |
+
>>> G.add_edge("b", "d", weight=4)
|
| 81 |
+
>>> G.add_edge("d", "e", weight=2)
|
| 82 |
+
>>> G.add_edge("c", "y", weight=2)
|
| 83 |
+
>>> G.add_edge("e", "y", weight=3)
|
| 84 |
+
>>> cut_value, partition = nx.stoer_wagner(G)
|
| 85 |
+
>>> cut_value
|
| 86 |
+
4
|
| 87 |
+
"""
|
| 88 |
+
n = len(G)
|
| 89 |
+
if n < 2:
|
| 90 |
+
raise nx.NetworkXError("graph has less than two nodes.")
|
| 91 |
+
if not nx.is_connected(G):
|
| 92 |
+
raise nx.NetworkXError("graph is not connected.")
|
| 93 |
+
|
| 94 |
+
# Make a copy of the graph for internal use.
|
| 95 |
+
G = nx.Graph(
|
| 96 |
+
(u, v, {"weight": e.get(weight, 1)}) for u, v, e in G.edges(data=True) if u != v
|
| 97 |
+
)
|
| 98 |
+
G.__networkx_cache__ = None # Disable caching
|
| 99 |
+
|
| 100 |
+
for u, v, e in G.edges(data=True):
|
| 101 |
+
if e["weight"] < 0:
|
| 102 |
+
raise nx.NetworkXError("graph has a negative-weighted edge.")
|
| 103 |
+
|
| 104 |
+
cut_value = float("inf")
|
| 105 |
+
nodes = set(G)
|
| 106 |
+
contractions = [] # contracted node pairs
|
| 107 |
+
|
| 108 |
+
# Repeatedly pick a pair of nodes to contract until only one node is left.
|
| 109 |
+
for i in range(n - 1):
|
| 110 |
+
# Pick an arbitrary node u and create a set A = {u}.
|
| 111 |
+
u = arbitrary_element(G)
|
| 112 |
+
A = {u}
|
| 113 |
+
# Repeatedly pick the node "most tightly connected" to A and add it to
|
| 114 |
+
# A. The tightness of connectivity of a node not in A is defined by the
|
| 115 |
+
# of edges connecting it to nodes in A.
|
| 116 |
+
h = heap() # min-heap emulating a max-heap
|
| 117 |
+
for v, e in G[u].items():
|
| 118 |
+
h.insert(v, -e["weight"])
|
| 119 |
+
# Repeat until all but one node has been added to A.
|
| 120 |
+
for j in range(n - i - 2):
|
| 121 |
+
u = h.pop()[0]
|
| 122 |
+
A.add(u)
|
| 123 |
+
for v, e in G[u].items():
|
| 124 |
+
if v not in A:
|
| 125 |
+
h.insert(v, h.get(v, 0) - e["weight"])
|
| 126 |
+
# A and the remaining node v define a "cut of the phase". There is a
|
| 127 |
+
# minimum cut of the original graph that is also a cut of the phase.
|
| 128 |
+
# Due to contractions in earlier phases, v may in fact represent
|
| 129 |
+
# multiple nodes in the original graph.
|
| 130 |
+
v, w = h.min()
|
| 131 |
+
w = -w
|
| 132 |
+
if w < cut_value:
|
| 133 |
+
cut_value = w
|
| 134 |
+
best_phase = i
|
| 135 |
+
# Contract v and the last node added to A.
|
| 136 |
+
contractions.append((u, v))
|
| 137 |
+
for w, e in G[v].items():
|
| 138 |
+
if w != u:
|
| 139 |
+
if w not in G[u]:
|
| 140 |
+
G.add_edge(u, w, weight=e["weight"])
|
| 141 |
+
else:
|
| 142 |
+
G[u][w]["weight"] += e["weight"]
|
| 143 |
+
G.remove_node(v)
|
| 144 |
+
|
| 145 |
+
# Recover the optimal partitioning from the contractions.
|
| 146 |
+
G = nx.Graph(islice(contractions, best_phase))
|
| 147 |
+
v = contractions[best_phase][1]
|
| 148 |
+
G.add_node(v)
|
| 149 |
+
reachable = set(nx.single_source_shortest_path_length(G, v))
|
| 150 |
+
partition = (list(reachable), list(nodes - reachable))
|
| 151 |
+
|
| 152 |
+
return cut_value, partition
|
evalkit_tf446/lib/python3.10/site-packages/networkx/algorithms/connectivity/utils.py
ADDED
|
@@ -0,0 +1,88 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
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|
|
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|
|
| 1 |
+
"""
|
| 2 |
+
Utilities for connectivity package
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
import networkx as nx
|
| 6 |
+
|
| 7 |
+
__all__ = ["build_auxiliary_node_connectivity", "build_auxiliary_edge_connectivity"]
|
| 8 |
+
|
| 9 |
+
|
| 10 |
+
@nx._dispatchable(returns_graph=True)
|
| 11 |
+
def build_auxiliary_node_connectivity(G):
|
| 12 |
+
r"""Creates a directed graph D from an undirected graph G to compute flow
|
| 13 |
+
based node connectivity.
|
| 14 |
+
|
| 15 |
+
For an undirected graph G having `n` nodes and `m` edges we derive a
|
| 16 |
+
directed graph D with `2n` nodes and `2m+n` arcs by replacing each
|
| 17 |
+
original node `v` with two nodes `vA`, `vB` linked by an (internal)
|
| 18 |
+
arc in D. Then for each edge (`u`, `v`) in G we add two arcs (`uB`, `vA`)
|
| 19 |
+
and (`vB`, `uA`) in D. Finally we set the attribute capacity = 1 for each
|
| 20 |
+
arc in D [1]_.
|
| 21 |
+
|
| 22 |
+
For a directed graph having `n` nodes and `m` arcs we derive a
|
| 23 |
+
directed graph D with `2n` nodes and `m+n` arcs by replacing each
|
| 24 |
+
original node `v` with two nodes `vA`, `vB` linked by an (internal)
|
| 25 |
+
arc (`vA`, `vB`) in D. Then for each arc (`u`, `v`) in G we add one
|
| 26 |
+
arc (`uB`, `vA`) in D. Finally we set the attribute capacity = 1 for
|
| 27 |
+
each arc in D.
|
| 28 |
+
|
| 29 |
+
A dictionary with a mapping between nodes in the original graph and the
|
| 30 |
+
auxiliary digraph is stored as a graph attribute: D.graph['mapping'].
|
| 31 |
+
|
| 32 |
+
References
|
| 33 |
+
----------
|
| 34 |
+
.. [1] Kammer, Frank and Hanjo Taubig. Graph Connectivity. in Brandes and
|
| 35 |
+
Erlebach, 'Network Analysis: Methodological Foundations', Lecture
|
| 36 |
+
Notes in Computer Science, Volume 3418, Springer-Verlag, 2005.
|
| 37 |
+
https://doi.org/10.1007/978-3-540-31955-9_7
|
| 38 |
+
|
| 39 |
+
"""
|
| 40 |
+
directed = G.is_directed()
|
| 41 |
+
|
| 42 |
+
mapping = {}
|
| 43 |
+
H = nx.DiGraph()
|
| 44 |
+
|
| 45 |
+
for i, node in enumerate(G):
|
| 46 |
+
mapping[node] = i
|
| 47 |
+
H.add_node(f"{i}A", id=node)
|
| 48 |
+
H.add_node(f"{i}B", id=node)
|
| 49 |
+
H.add_edge(f"{i}A", f"{i}B", capacity=1)
|
| 50 |
+
|
| 51 |
+
edges = []
|
| 52 |
+
for source, target in G.edges():
|
| 53 |
+
edges.append((f"{mapping[source]}B", f"{mapping[target]}A"))
|
| 54 |
+
if not directed:
|
| 55 |
+
edges.append((f"{mapping[target]}B", f"{mapping[source]}A"))
|
| 56 |
+
H.add_edges_from(edges, capacity=1)
|
| 57 |
+
|
| 58 |
+
# Store mapping as graph attribute
|
| 59 |
+
H.graph["mapping"] = mapping
|
| 60 |
+
return H
|
| 61 |
+
|
| 62 |
+
|
| 63 |
+
@nx._dispatchable(returns_graph=True)
|
| 64 |
+
def build_auxiliary_edge_connectivity(G):
|
| 65 |
+
"""Auxiliary digraph for computing flow based edge connectivity
|
| 66 |
+
|
| 67 |
+
If the input graph is undirected, we replace each edge (`u`,`v`) with
|
| 68 |
+
two reciprocal arcs (`u`, `v`) and (`v`, `u`) and then we set the attribute
|
| 69 |
+
'capacity' for each arc to 1. If the input graph is directed we simply
|
| 70 |
+
add the 'capacity' attribute. Part of algorithm 1 in [1]_ .
|
| 71 |
+
|
| 72 |
+
References
|
| 73 |
+
----------
|
| 74 |
+
.. [1] Abdol-Hossein Esfahanian. Connectivity Algorithms. (this is a
|
| 75 |
+
chapter, look for the reference of the book).
|
| 76 |
+
http://www.cse.msu.edu/~cse835/Papers/Graph_connectivity_revised.pdf
|
| 77 |
+
"""
|
| 78 |
+
if G.is_directed():
|
| 79 |
+
H = nx.DiGraph()
|
| 80 |
+
H.add_nodes_from(G.nodes())
|
| 81 |
+
H.add_edges_from(G.edges(), capacity=1)
|
| 82 |
+
return H
|
| 83 |
+
else:
|
| 84 |
+
H = nx.DiGraph()
|
| 85 |
+
H.add_nodes_from(G.nodes())
|
| 86 |
+
for source, target in G.edges():
|
| 87 |
+
H.add_edges_from([(source, target), (target, source)], capacity=1)
|
| 88 |
+
return H
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/classic.cpython-310.pyc
ADDED
|
Binary file (29.9 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/degree_seq.cpython-310.pyc
ADDED
|
Binary file (25.6 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/directed.cpython-310.pyc
ADDED
|
Binary file (15 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/ego.cpython-310.pyc
ADDED
|
Binary file (1.81 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/geometric.cpython-310.pyc
ADDED
|
Binary file (38.9 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/intersection.cpython-310.pyc
ADDED
|
Binary file (4.26 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/mycielski.cpython-310.pyc
ADDED
|
Binary file (3.85 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/random_clustered.cpython-310.pyc
ADDED
|
Binary file (4.13 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/random_graphs.cpython-310.pyc
ADDED
|
Binary file (40.2 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/__pycache__/small.cpython-310.pyc
ADDED
|
Binary file (26.4 kB). View file
|
|
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/atlas.dat.gz
ADDED
|
@@ -0,0 +1,3 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
version https://git-lfs.github.com/spec/v1
|
| 2 |
+
oid sha256:73fc416df0164923607751cb759f4ae81deb5f6550bf25be59c86de3b747e41d
|
| 3 |
+
size 8887
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/classic.py
ADDED
|
@@ -0,0 +1,1068 @@
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|
|
| 1 |
+
"""Generators for some classic graphs.
|
| 2 |
+
|
| 3 |
+
The typical graph builder function is called as follows:
|
| 4 |
+
|
| 5 |
+
>>> G = nx.complete_graph(100)
|
| 6 |
+
|
| 7 |
+
returning the complete graph on n nodes labeled 0, .., 99
|
| 8 |
+
as a simple graph. Except for `empty_graph`, all the functions
|
| 9 |
+
in this module return a Graph class (i.e. a simple, undirected graph).
|
| 10 |
+
|
| 11 |
+
"""
|
| 12 |
+
|
| 13 |
+
import itertools
|
| 14 |
+
import numbers
|
| 15 |
+
|
| 16 |
+
import networkx as nx
|
| 17 |
+
from networkx.classes import Graph
|
| 18 |
+
from networkx.exception import NetworkXError
|
| 19 |
+
from networkx.utils import nodes_or_number, pairwise
|
| 20 |
+
|
| 21 |
+
__all__ = [
|
| 22 |
+
"balanced_tree",
|
| 23 |
+
"barbell_graph",
|
| 24 |
+
"binomial_tree",
|
| 25 |
+
"complete_graph",
|
| 26 |
+
"complete_multipartite_graph",
|
| 27 |
+
"circular_ladder_graph",
|
| 28 |
+
"circulant_graph",
|
| 29 |
+
"cycle_graph",
|
| 30 |
+
"dorogovtsev_goltsev_mendes_graph",
|
| 31 |
+
"empty_graph",
|
| 32 |
+
"full_rary_tree",
|
| 33 |
+
"kneser_graph",
|
| 34 |
+
"ladder_graph",
|
| 35 |
+
"lollipop_graph",
|
| 36 |
+
"null_graph",
|
| 37 |
+
"path_graph",
|
| 38 |
+
"star_graph",
|
| 39 |
+
"tadpole_graph",
|
| 40 |
+
"trivial_graph",
|
| 41 |
+
"turan_graph",
|
| 42 |
+
"wheel_graph",
|
| 43 |
+
]
|
| 44 |
+
|
| 45 |
+
|
| 46 |
+
# -------------------------------------------------------------------
|
| 47 |
+
# Some Classic Graphs
|
| 48 |
+
# -------------------------------------------------------------------
|
| 49 |
+
|
| 50 |
+
|
| 51 |
+
def _tree_edges(n, r):
|
| 52 |
+
if n == 0:
|
| 53 |
+
return
|
| 54 |
+
# helper function for trees
|
| 55 |
+
# yields edges in rooted tree at 0 with n nodes and branching ratio r
|
| 56 |
+
nodes = iter(range(n))
|
| 57 |
+
parents = [next(nodes)] # stack of max length r
|
| 58 |
+
while parents:
|
| 59 |
+
source = parents.pop(0)
|
| 60 |
+
for i in range(r):
|
| 61 |
+
try:
|
| 62 |
+
target = next(nodes)
|
| 63 |
+
parents.append(target)
|
| 64 |
+
yield source, target
|
| 65 |
+
except StopIteration:
|
| 66 |
+
break
|
| 67 |
+
|
| 68 |
+
|
| 69 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 70 |
+
def full_rary_tree(r, n, create_using=None):
|
| 71 |
+
"""Creates a full r-ary tree of `n` nodes.
|
| 72 |
+
|
| 73 |
+
Sometimes called a k-ary, n-ary, or m-ary tree.
|
| 74 |
+
"... all non-leaf nodes have exactly r children and all levels
|
| 75 |
+
are full except for some rightmost position of the bottom level
|
| 76 |
+
(if a leaf at the bottom level is missing, then so are all of the
|
| 77 |
+
leaves to its right." [1]_
|
| 78 |
+
|
| 79 |
+
.. plot::
|
| 80 |
+
|
| 81 |
+
>>> nx.draw(nx.full_rary_tree(2, 10))
|
| 82 |
+
|
| 83 |
+
Parameters
|
| 84 |
+
----------
|
| 85 |
+
r : int
|
| 86 |
+
branching factor of the tree
|
| 87 |
+
n : int
|
| 88 |
+
Number of nodes in the tree
|
| 89 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 90 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 91 |
+
|
| 92 |
+
Returns
|
| 93 |
+
-------
|
| 94 |
+
G : networkx Graph
|
| 95 |
+
An r-ary tree with n nodes
|
| 96 |
+
|
| 97 |
+
References
|
| 98 |
+
----------
|
| 99 |
+
.. [1] An introduction to data structures and algorithms,
|
| 100 |
+
James Andrew Storer, Birkhauser Boston 2001, (page 225).
|
| 101 |
+
"""
|
| 102 |
+
G = empty_graph(n, create_using)
|
| 103 |
+
G.add_edges_from(_tree_edges(n, r))
|
| 104 |
+
return G
|
| 105 |
+
|
| 106 |
+
|
| 107 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 108 |
+
def kneser_graph(n, k):
|
| 109 |
+
"""Returns the Kneser Graph with parameters `n` and `k`.
|
| 110 |
+
|
| 111 |
+
The Kneser Graph has nodes that are k-tuples (subsets) of the integers
|
| 112 |
+
between 0 and ``n-1``. Nodes are adjacent if their corresponding sets are disjoint.
|
| 113 |
+
|
| 114 |
+
Parameters
|
| 115 |
+
----------
|
| 116 |
+
n: int
|
| 117 |
+
Number of integers from which to make node subsets.
|
| 118 |
+
Subsets are drawn from ``set(range(n))``.
|
| 119 |
+
k: int
|
| 120 |
+
Size of the subsets.
|
| 121 |
+
|
| 122 |
+
Returns
|
| 123 |
+
-------
|
| 124 |
+
G : NetworkX Graph
|
| 125 |
+
|
| 126 |
+
Examples
|
| 127 |
+
--------
|
| 128 |
+
>>> G = nx.kneser_graph(5, 2)
|
| 129 |
+
>>> G.number_of_nodes()
|
| 130 |
+
10
|
| 131 |
+
>>> G.number_of_edges()
|
| 132 |
+
15
|
| 133 |
+
>>> nx.is_isomorphic(G, nx.petersen_graph())
|
| 134 |
+
True
|
| 135 |
+
"""
|
| 136 |
+
if n <= 0:
|
| 137 |
+
raise NetworkXError("n should be greater than zero")
|
| 138 |
+
if k <= 0 or k > n:
|
| 139 |
+
raise NetworkXError("k should be greater than zero and smaller than n")
|
| 140 |
+
|
| 141 |
+
G = nx.Graph()
|
| 142 |
+
# Create all k-subsets of [0, 1, ..., n-1]
|
| 143 |
+
subsets = list(itertools.combinations(range(n), k))
|
| 144 |
+
|
| 145 |
+
if 2 * k > n:
|
| 146 |
+
G.add_nodes_from(subsets)
|
| 147 |
+
|
| 148 |
+
universe = set(range(n))
|
| 149 |
+
comb = itertools.combinations # only to make it all fit on one line
|
| 150 |
+
G.add_edges_from((s, t) for s in subsets for t in comb(universe - set(s), k))
|
| 151 |
+
return G
|
| 152 |
+
|
| 153 |
+
|
| 154 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 155 |
+
def balanced_tree(r, h, create_using=None):
|
| 156 |
+
"""Returns the perfectly balanced `r`-ary tree of height `h`.
|
| 157 |
+
|
| 158 |
+
.. plot::
|
| 159 |
+
|
| 160 |
+
>>> nx.draw(nx.balanced_tree(2, 3))
|
| 161 |
+
|
| 162 |
+
Parameters
|
| 163 |
+
----------
|
| 164 |
+
r : int
|
| 165 |
+
Branching factor of the tree; each node will have `r`
|
| 166 |
+
children.
|
| 167 |
+
|
| 168 |
+
h : int
|
| 169 |
+
Height of the tree.
|
| 170 |
+
|
| 171 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 172 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 173 |
+
|
| 174 |
+
Returns
|
| 175 |
+
-------
|
| 176 |
+
G : NetworkX graph
|
| 177 |
+
A balanced `r`-ary tree of height `h`.
|
| 178 |
+
|
| 179 |
+
Notes
|
| 180 |
+
-----
|
| 181 |
+
This is the rooted tree where all leaves are at distance `h` from
|
| 182 |
+
the root. The root has degree `r` and all other internal nodes
|
| 183 |
+
have degree `r + 1`.
|
| 184 |
+
|
| 185 |
+
Node labels are integers, starting from zero.
|
| 186 |
+
|
| 187 |
+
A balanced tree is also known as a *complete r-ary tree*.
|
| 188 |
+
|
| 189 |
+
"""
|
| 190 |
+
# The number of nodes in the balanced tree is `1 + r + ... + r^h`,
|
| 191 |
+
# which is computed by using the closed-form formula for a geometric
|
| 192 |
+
# sum with ratio `r`. In the special case that `r` is 1, the number
|
| 193 |
+
# of nodes is simply `h + 1` (since the tree is actually a path
|
| 194 |
+
# graph).
|
| 195 |
+
if r == 1:
|
| 196 |
+
n = h + 1
|
| 197 |
+
else:
|
| 198 |
+
# This must be an integer if both `r` and `h` are integers. If
|
| 199 |
+
# they are not, we force integer division anyway.
|
| 200 |
+
n = (1 - r ** (h + 1)) // (1 - r)
|
| 201 |
+
return full_rary_tree(r, n, create_using=create_using)
|
| 202 |
+
|
| 203 |
+
|
| 204 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 205 |
+
def barbell_graph(m1, m2, create_using=None):
|
| 206 |
+
"""Returns the Barbell Graph: two complete graphs connected by a path.
|
| 207 |
+
|
| 208 |
+
.. plot::
|
| 209 |
+
|
| 210 |
+
>>> nx.draw(nx.barbell_graph(4, 2))
|
| 211 |
+
|
| 212 |
+
Parameters
|
| 213 |
+
----------
|
| 214 |
+
m1 : int
|
| 215 |
+
Size of the left and right barbells, must be greater than 2.
|
| 216 |
+
|
| 217 |
+
m2 : int
|
| 218 |
+
Length of the path connecting the barbells.
|
| 219 |
+
|
| 220 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 221 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 222 |
+
Only undirected Graphs are supported.
|
| 223 |
+
|
| 224 |
+
Returns
|
| 225 |
+
-------
|
| 226 |
+
G : NetworkX graph
|
| 227 |
+
A barbell graph.
|
| 228 |
+
|
| 229 |
+
Notes
|
| 230 |
+
-----
|
| 231 |
+
|
| 232 |
+
|
| 233 |
+
Two identical complete graphs $K_{m1}$ form the left and right bells,
|
| 234 |
+
and are connected by a path $P_{m2}$.
|
| 235 |
+
|
| 236 |
+
The `2*m1+m2` nodes are numbered
|
| 237 |
+
`0, ..., m1-1` for the left barbell,
|
| 238 |
+
`m1, ..., m1+m2-1` for the path,
|
| 239 |
+
and `m1+m2, ..., 2*m1+m2-1` for the right barbell.
|
| 240 |
+
|
| 241 |
+
The 3 subgraphs are joined via the edges `(m1-1, m1)` and
|
| 242 |
+
`(m1+m2-1, m1+m2)`. If `m2=0`, this is merely two complete
|
| 243 |
+
graphs joined together.
|
| 244 |
+
|
| 245 |
+
This graph is an extremal example in David Aldous
|
| 246 |
+
and Jim Fill's e-text on Random Walks on Graphs.
|
| 247 |
+
|
| 248 |
+
"""
|
| 249 |
+
if m1 < 2:
|
| 250 |
+
raise NetworkXError("Invalid graph description, m1 should be >=2")
|
| 251 |
+
if m2 < 0:
|
| 252 |
+
raise NetworkXError("Invalid graph description, m2 should be >=0")
|
| 253 |
+
|
| 254 |
+
# left barbell
|
| 255 |
+
G = complete_graph(m1, create_using)
|
| 256 |
+
if G.is_directed():
|
| 257 |
+
raise NetworkXError("Directed Graph not supported")
|
| 258 |
+
|
| 259 |
+
# connecting path
|
| 260 |
+
G.add_nodes_from(range(m1, m1 + m2 - 1))
|
| 261 |
+
if m2 > 1:
|
| 262 |
+
G.add_edges_from(pairwise(range(m1, m1 + m2)))
|
| 263 |
+
|
| 264 |
+
# right barbell
|
| 265 |
+
G.add_edges_from(
|
| 266 |
+
(u, v) for u in range(m1 + m2, 2 * m1 + m2) for v in range(u + 1, 2 * m1 + m2)
|
| 267 |
+
)
|
| 268 |
+
|
| 269 |
+
# connect it up
|
| 270 |
+
G.add_edge(m1 - 1, m1)
|
| 271 |
+
if m2 > 0:
|
| 272 |
+
G.add_edge(m1 + m2 - 1, m1 + m2)
|
| 273 |
+
|
| 274 |
+
return G
|
| 275 |
+
|
| 276 |
+
|
| 277 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 278 |
+
def binomial_tree(n, create_using=None):
|
| 279 |
+
"""Returns the Binomial Tree of order n.
|
| 280 |
+
|
| 281 |
+
The binomial tree of order 0 consists of a single node. A binomial tree of order k
|
| 282 |
+
is defined recursively by linking two binomial trees of order k-1: the root of one is
|
| 283 |
+
the leftmost child of the root of the other.
|
| 284 |
+
|
| 285 |
+
.. plot::
|
| 286 |
+
|
| 287 |
+
>>> nx.draw(nx.binomial_tree(3))
|
| 288 |
+
|
| 289 |
+
Parameters
|
| 290 |
+
----------
|
| 291 |
+
n : int
|
| 292 |
+
Order of the binomial tree.
|
| 293 |
+
|
| 294 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 295 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 296 |
+
|
| 297 |
+
Returns
|
| 298 |
+
-------
|
| 299 |
+
G : NetworkX graph
|
| 300 |
+
A binomial tree of $2^n$ nodes and $2^n - 1$ edges.
|
| 301 |
+
|
| 302 |
+
"""
|
| 303 |
+
G = nx.empty_graph(1, create_using)
|
| 304 |
+
|
| 305 |
+
N = 1
|
| 306 |
+
for i in range(n):
|
| 307 |
+
# Use G.edges() to ensure 2-tuples. G.edges is 3-tuple for MultiGraph
|
| 308 |
+
edges = [(u + N, v + N) for (u, v) in G.edges()]
|
| 309 |
+
G.add_edges_from(edges)
|
| 310 |
+
G.add_edge(0, N)
|
| 311 |
+
N *= 2
|
| 312 |
+
return G
|
| 313 |
+
|
| 314 |
+
|
| 315 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 316 |
+
@nodes_or_number(0)
|
| 317 |
+
def complete_graph(n, create_using=None):
|
| 318 |
+
"""Return the complete graph `K_n` with n nodes.
|
| 319 |
+
|
| 320 |
+
A complete graph on `n` nodes means that all pairs
|
| 321 |
+
of distinct nodes have an edge connecting them.
|
| 322 |
+
|
| 323 |
+
.. plot::
|
| 324 |
+
|
| 325 |
+
>>> nx.draw(nx.complete_graph(5))
|
| 326 |
+
|
| 327 |
+
Parameters
|
| 328 |
+
----------
|
| 329 |
+
n : int or iterable container of nodes
|
| 330 |
+
If n is an integer, nodes are from range(n).
|
| 331 |
+
If n is a container of nodes, those nodes appear in the graph.
|
| 332 |
+
Warning: n is not checked for duplicates and if present the
|
| 333 |
+
resulting graph may not be as desired. Make sure you have no duplicates.
|
| 334 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 335 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 336 |
+
|
| 337 |
+
Examples
|
| 338 |
+
--------
|
| 339 |
+
>>> G = nx.complete_graph(9)
|
| 340 |
+
>>> len(G)
|
| 341 |
+
9
|
| 342 |
+
>>> G.size()
|
| 343 |
+
36
|
| 344 |
+
>>> G = nx.complete_graph(range(11, 14))
|
| 345 |
+
>>> list(G.nodes())
|
| 346 |
+
[11, 12, 13]
|
| 347 |
+
>>> G = nx.complete_graph(4, nx.DiGraph())
|
| 348 |
+
>>> G.is_directed()
|
| 349 |
+
True
|
| 350 |
+
|
| 351 |
+
"""
|
| 352 |
+
_, nodes = n
|
| 353 |
+
G = empty_graph(nodes, create_using)
|
| 354 |
+
if len(nodes) > 1:
|
| 355 |
+
if G.is_directed():
|
| 356 |
+
edges = itertools.permutations(nodes, 2)
|
| 357 |
+
else:
|
| 358 |
+
edges = itertools.combinations(nodes, 2)
|
| 359 |
+
G.add_edges_from(edges)
|
| 360 |
+
return G
|
| 361 |
+
|
| 362 |
+
|
| 363 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 364 |
+
def circular_ladder_graph(n, create_using=None):
|
| 365 |
+
"""Returns the circular ladder graph $CL_n$ of length n.
|
| 366 |
+
|
| 367 |
+
$CL_n$ consists of two concentric n-cycles in which
|
| 368 |
+
each of the n pairs of concentric nodes are joined by an edge.
|
| 369 |
+
|
| 370 |
+
Node labels are the integers 0 to n-1
|
| 371 |
+
|
| 372 |
+
.. plot::
|
| 373 |
+
|
| 374 |
+
>>> nx.draw(nx.circular_ladder_graph(5))
|
| 375 |
+
|
| 376 |
+
"""
|
| 377 |
+
G = ladder_graph(n, create_using)
|
| 378 |
+
G.add_edge(0, n - 1)
|
| 379 |
+
G.add_edge(n, 2 * n - 1)
|
| 380 |
+
return G
|
| 381 |
+
|
| 382 |
+
|
| 383 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 384 |
+
def circulant_graph(n, offsets, create_using=None):
|
| 385 |
+
r"""Returns the circulant graph $Ci_n(x_1, x_2, ..., x_m)$ with $n$ nodes.
|
| 386 |
+
|
| 387 |
+
The circulant graph $Ci_n(x_1, ..., x_m)$ consists of $n$ nodes $0, ..., n-1$
|
| 388 |
+
such that node $i$ is connected to nodes $(i + x) \mod n$ and $(i - x) \mod n$
|
| 389 |
+
for all $x$ in $x_1, ..., x_m$. Thus $Ci_n(1)$ is a cycle graph.
|
| 390 |
+
|
| 391 |
+
.. plot::
|
| 392 |
+
|
| 393 |
+
>>> nx.draw(nx.circulant_graph(10, [1]))
|
| 394 |
+
|
| 395 |
+
Parameters
|
| 396 |
+
----------
|
| 397 |
+
n : integer
|
| 398 |
+
The number of nodes in the graph.
|
| 399 |
+
offsets : list of integers
|
| 400 |
+
A list of node offsets, $x_1$ up to $x_m$, as described above.
|
| 401 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 402 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 403 |
+
|
| 404 |
+
Returns
|
| 405 |
+
-------
|
| 406 |
+
NetworkX Graph of type create_using
|
| 407 |
+
|
| 408 |
+
Examples
|
| 409 |
+
--------
|
| 410 |
+
Many well-known graph families are subfamilies of the circulant graphs;
|
| 411 |
+
for example, to create the cycle graph on n points, we connect every
|
| 412 |
+
node to nodes on either side (with offset plus or minus one). For n = 10,
|
| 413 |
+
|
| 414 |
+
>>> G = nx.circulant_graph(10, [1])
|
| 415 |
+
>>> edges = [
|
| 416 |
+
... (0, 9),
|
| 417 |
+
... (0, 1),
|
| 418 |
+
... (1, 2),
|
| 419 |
+
... (2, 3),
|
| 420 |
+
... (3, 4),
|
| 421 |
+
... (4, 5),
|
| 422 |
+
... (5, 6),
|
| 423 |
+
... (6, 7),
|
| 424 |
+
... (7, 8),
|
| 425 |
+
... (8, 9),
|
| 426 |
+
... ]
|
| 427 |
+
>>> sorted(edges) == sorted(G.edges())
|
| 428 |
+
True
|
| 429 |
+
|
| 430 |
+
Similarly, we can create the complete graph
|
| 431 |
+
on 5 points with the set of offsets [1, 2]:
|
| 432 |
+
|
| 433 |
+
>>> G = nx.circulant_graph(5, [1, 2])
|
| 434 |
+
>>> edges = [
|
| 435 |
+
... (0, 1),
|
| 436 |
+
... (0, 2),
|
| 437 |
+
... (0, 3),
|
| 438 |
+
... (0, 4),
|
| 439 |
+
... (1, 2),
|
| 440 |
+
... (1, 3),
|
| 441 |
+
... (1, 4),
|
| 442 |
+
... (2, 3),
|
| 443 |
+
... (2, 4),
|
| 444 |
+
... (3, 4),
|
| 445 |
+
... ]
|
| 446 |
+
>>> sorted(edges) == sorted(G.edges())
|
| 447 |
+
True
|
| 448 |
+
|
| 449 |
+
"""
|
| 450 |
+
G = empty_graph(n, create_using)
|
| 451 |
+
for i in range(n):
|
| 452 |
+
for j in offsets:
|
| 453 |
+
G.add_edge(i, (i - j) % n)
|
| 454 |
+
G.add_edge(i, (i + j) % n)
|
| 455 |
+
return G
|
| 456 |
+
|
| 457 |
+
|
| 458 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 459 |
+
@nodes_or_number(0)
|
| 460 |
+
def cycle_graph(n, create_using=None):
|
| 461 |
+
"""Returns the cycle graph $C_n$ of cyclically connected nodes.
|
| 462 |
+
|
| 463 |
+
$C_n$ is a path with its two end-nodes connected.
|
| 464 |
+
|
| 465 |
+
.. plot::
|
| 466 |
+
|
| 467 |
+
>>> nx.draw(nx.cycle_graph(5))
|
| 468 |
+
|
| 469 |
+
Parameters
|
| 470 |
+
----------
|
| 471 |
+
n : int or iterable container of nodes
|
| 472 |
+
If n is an integer, nodes are from `range(n)`.
|
| 473 |
+
If n is a container of nodes, those nodes appear in the graph.
|
| 474 |
+
Warning: n is not checked for duplicates and if present the
|
| 475 |
+
resulting graph may not be as desired. Make sure you have no duplicates.
|
| 476 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 477 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 478 |
+
|
| 479 |
+
Notes
|
| 480 |
+
-----
|
| 481 |
+
If create_using is directed, the direction is in increasing order.
|
| 482 |
+
|
| 483 |
+
"""
|
| 484 |
+
_, nodes = n
|
| 485 |
+
G = empty_graph(nodes, create_using)
|
| 486 |
+
G.add_edges_from(pairwise(nodes, cyclic=True))
|
| 487 |
+
return G
|
| 488 |
+
|
| 489 |
+
|
| 490 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 491 |
+
def dorogovtsev_goltsev_mendes_graph(n, create_using=None):
|
| 492 |
+
"""Returns the hierarchically constructed Dorogovtsev--Goltsev--Mendes graph.
|
| 493 |
+
|
| 494 |
+
The Dorogovtsev--Goltsev--Mendes [1]_ procedure deterministically produces a
|
| 495 |
+
scale-free graph with ``3/2 * (3**(n-1) + 1)`` nodes
|
| 496 |
+
and ``3**n`` edges for a given `n`.
|
| 497 |
+
|
| 498 |
+
Note that `n` denotes the number of times the state transition is applied,
|
| 499 |
+
starting from the base graph with ``n = 0`` (no transitions), as in [2]_.
|
| 500 |
+
This is different from the parameter ``t = n - 1`` in [1]_.
|
| 501 |
+
|
| 502 |
+
.. plot::
|
| 503 |
+
|
| 504 |
+
>>> nx.draw(nx.dorogovtsev_goltsev_mendes_graph(3))
|
| 505 |
+
|
| 506 |
+
Parameters
|
| 507 |
+
----------
|
| 508 |
+
n : integer
|
| 509 |
+
The generation number.
|
| 510 |
+
|
| 511 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 512 |
+
Graph type to create. Directed graphs and multigraphs are not supported.
|
| 513 |
+
|
| 514 |
+
Returns
|
| 515 |
+
-------
|
| 516 |
+
G : NetworkX `Graph`
|
| 517 |
+
|
| 518 |
+
Raises
|
| 519 |
+
------
|
| 520 |
+
NetworkXError
|
| 521 |
+
If `n` is less than zero.
|
| 522 |
+
|
| 523 |
+
If `create_using` is a directed graph or multigraph.
|
| 524 |
+
|
| 525 |
+
Examples
|
| 526 |
+
--------
|
| 527 |
+
>>> G = nx.dorogovtsev_goltsev_mendes_graph(3)
|
| 528 |
+
>>> G.number_of_nodes()
|
| 529 |
+
15
|
| 530 |
+
>>> G.number_of_edges()
|
| 531 |
+
27
|
| 532 |
+
>>> nx.is_planar(G)
|
| 533 |
+
True
|
| 534 |
+
|
| 535 |
+
References
|
| 536 |
+
----------
|
| 537 |
+
.. [1] S. N. Dorogovtsev, A. V. Goltsev and J. F. F. Mendes,
|
| 538 |
+
"Pseudofractal scale-free web", Physical Review E 65, 066122, 2002.
|
| 539 |
+
https://arxiv.org/pdf/cond-mat/0112143.pdf
|
| 540 |
+
.. [2] Weisstein, Eric W. "Dorogovtsev--Goltsev--Mendes Graph".
|
| 541 |
+
From MathWorld--A Wolfram Web Resource.
|
| 542 |
+
https://mathworld.wolfram.com/Dorogovtsev-Goltsev-MendesGraph.html
|
| 543 |
+
"""
|
| 544 |
+
if n < 0:
|
| 545 |
+
raise NetworkXError("n must be greater than or equal to 0")
|
| 546 |
+
|
| 547 |
+
G = empty_graph(0, create_using)
|
| 548 |
+
if G.is_directed():
|
| 549 |
+
raise NetworkXError("directed graph not supported")
|
| 550 |
+
if G.is_multigraph():
|
| 551 |
+
raise NetworkXError("multigraph not supported")
|
| 552 |
+
|
| 553 |
+
G.add_edge(0, 1)
|
| 554 |
+
new_node = 2 # next node to be added
|
| 555 |
+
for _ in range(n): # iterate over number of generations.
|
| 556 |
+
new_edges = []
|
| 557 |
+
for u, v in G.edges():
|
| 558 |
+
new_edges.append((u, new_node))
|
| 559 |
+
new_edges.append((v, new_node))
|
| 560 |
+
new_node += 1
|
| 561 |
+
|
| 562 |
+
G.add_edges_from(new_edges)
|
| 563 |
+
return G
|
| 564 |
+
|
| 565 |
+
|
| 566 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 567 |
+
@nodes_or_number(0)
|
| 568 |
+
def empty_graph(n=0, create_using=None, default=Graph):
|
| 569 |
+
"""Returns the empty graph with n nodes and zero edges.
|
| 570 |
+
|
| 571 |
+
.. plot::
|
| 572 |
+
|
| 573 |
+
>>> nx.draw(nx.empty_graph(5))
|
| 574 |
+
|
| 575 |
+
Parameters
|
| 576 |
+
----------
|
| 577 |
+
n : int or iterable container of nodes (default = 0)
|
| 578 |
+
If n is an integer, nodes are from `range(n)`.
|
| 579 |
+
If n is a container of nodes, those nodes appear in the graph.
|
| 580 |
+
create_using : Graph Instance, Constructor or None
|
| 581 |
+
Indicator of type of graph to return.
|
| 582 |
+
If a Graph-type instance, then clear and use it.
|
| 583 |
+
If None, use the `default` constructor.
|
| 584 |
+
If a constructor, call it to create an empty graph.
|
| 585 |
+
default : Graph constructor (optional, default = nx.Graph)
|
| 586 |
+
The constructor to use if create_using is None.
|
| 587 |
+
If None, then nx.Graph is used.
|
| 588 |
+
This is used when passing an unknown `create_using` value
|
| 589 |
+
through your home-grown function to `empty_graph` and
|
| 590 |
+
you want a default constructor other than nx.Graph.
|
| 591 |
+
|
| 592 |
+
Examples
|
| 593 |
+
--------
|
| 594 |
+
>>> G = nx.empty_graph(10)
|
| 595 |
+
>>> G.number_of_nodes()
|
| 596 |
+
10
|
| 597 |
+
>>> G.number_of_edges()
|
| 598 |
+
0
|
| 599 |
+
>>> G = nx.empty_graph("ABC")
|
| 600 |
+
>>> G.number_of_nodes()
|
| 601 |
+
3
|
| 602 |
+
>>> sorted(G)
|
| 603 |
+
['A', 'B', 'C']
|
| 604 |
+
|
| 605 |
+
Notes
|
| 606 |
+
-----
|
| 607 |
+
The variable create_using should be a Graph Constructor or a
|
| 608 |
+
"graph"-like object. Constructors, e.g. `nx.Graph` or `nx.MultiGraph`
|
| 609 |
+
will be used to create the returned graph. "graph"-like objects
|
| 610 |
+
will be cleared (nodes and edges will be removed) and refitted as
|
| 611 |
+
an empty "graph" with nodes specified in n. This capability
|
| 612 |
+
is useful for specifying the class-nature of the resulting empty
|
| 613 |
+
"graph" (i.e. Graph, DiGraph, MyWeirdGraphClass, etc.).
|
| 614 |
+
|
| 615 |
+
The variable create_using has three main uses:
|
| 616 |
+
Firstly, the variable create_using can be used to create an
|
| 617 |
+
empty digraph, multigraph, etc. For example,
|
| 618 |
+
|
| 619 |
+
>>> n = 10
|
| 620 |
+
>>> G = nx.empty_graph(n, create_using=nx.DiGraph)
|
| 621 |
+
|
| 622 |
+
will create an empty digraph on n nodes.
|
| 623 |
+
|
| 624 |
+
Secondly, one can pass an existing graph (digraph, multigraph,
|
| 625 |
+
etc.) via create_using. For example, if G is an existing graph
|
| 626 |
+
(resp. digraph, multigraph, etc.), then empty_graph(n, create_using=G)
|
| 627 |
+
will empty G (i.e. delete all nodes and edges using G.clear())
|
| 628 |
+
and then add n nodes and zero edges, and return the modified graph.
|
| 629 |
+
|
| 630 |
+
Thirdly, when constructing your home-grown graph creation function
|
| 631 |
+
you can use empty_graph to construct the graph by passing a user
|
| 632 |
+
defined create_using to empty_graph. In this case, if you want the
|
| 633 |
+
default constructor to be other than nx.Graph, specify `default`.
|
| 634 |
+
|
| 635 |
+
>>> def mygraph(n, create_using=None):
|
| 636 |
+
... G = nx.empty_graph(n, create_using, nx.MultiGraph)
|
| 637 |
+
... G.add_edges_from([(0, 1), (0, 1)])
|
| 638 |
+
... return G
|
| 639 |
+
>>> G = mygraph(3)
|
| 640 |
+
>>> G.is_multigraph()
|
| 641 |
+
True
|
| 642 |
+
>>> G = mygraph(3, nx.Graph)
|
| 643 |
+
>>> G.is_multigraph()
|
| 644 |
+
False
|
| 645 |
+
|
| 646 |
+
See also create_empty_copy(G).
|
| 647 |
+
|
| 648 |
+
"""
|
| 649 |
+
if create_using is None:
|
| 650 |
+
G = default()
|
| 651 |
+
elif isinstance(create_using, type):
|
| 652 |
+
G = create_using()
|
| 653 |
+
elif not hasattr(create_using, "adj"):
|
| 654 |
+
raise TypeError("create_using is not a valid NetworkX graph type or instance")
|
| 655 |
+
else:
|
| 656 |
+
# create_using is a NetworkX style Graph
|
| 657 |
+
create_using.clear()
|
| 658 |
+
G = create_using
|
| 659 |
+
|
| 660 |
+
_, nodes = n
|
| 661 |
+
G.add_nodes_from(nodes)
|
| 662 |
+
return G
|
| 663 |
+
|
| 664 |
+
|
| 665 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 666 |
+
def ladder_graph(n, create_using=None):
|
| 667 |
+
"""Returns the Ladder graph of length n.
|
| 668 |
+
|
| 669 |
+
This is two paths of n nodes, with
|
| 670 |
+
each pair connected by a single edge.
|
| 671 |
+
|
| 672 |
+
Node labels are the integers 0 to 2*n - 1.
|
| 673 |
+
|
| 674 |
+
.. plot::
|
| 675 |
+
|
| 676 |
+
>>> nx.draw(nx.ladder_graph(5))
|
| 677 |
+
|
| 678 |
+
"""
|
| 679 |
+
G = empty_graph(2 * n, create_using)
|
| 680 |
+
if G.is_directed():
|
| 681 |
+
raise NetworkXError("Directed Graph not supported")
|
| 682 |
+
G.add_edges_from(pairwise(range(n)))
|
| 683 |
+
G.add_edges_from(pairwise(range(n, 2 * n)))
|
| 684 |
+
G.add_edges_from((v, v + n) for v in range(n))
|
| 685 |
+
return G
|
| 686 |
+
|
| 687 |
+
|
| 688 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 689 |
+
@nodes_or_number([0, 1])
|
| 690 |
+
def lollipop_graph(m, n, create_using=None):
|
| 691 |
+
"""Returns the Lollipop Graph; ``K_m`` connected to ``P_n``.
|
| 692 |
+
|
| 693 |
+
This is the Barbell Graph without the right barbell.
|
| 694 |
+
|
| 695 |
+
.. plot::
|
| 696 |
+
|
| 697 |
+
>>> nx.draw(nx.lollipop_graph(3, 4))
|
| 698 |
+
|
| 699 |
+
Parameters
|
| 700 |
+
----------
|
| 701 |
+
m, n : int or iterable container of nodes
|
| 702 |
+
If an integer, nodes are from ``range(m)`` and ``range(m, m+n)``.
|
| 703 |
+
If a container of nodes, those nodes appear in the graph.
|
| 704 |
+
Warning: `m` and `n` are not checked for duplicates and if present the
|
| 705 |
+
resulting graph may not be as desired. Make sure you have no duplicates.
|
| 706 |
+
|
| 707 |
+
The nodes for `m` appear in the complete graph $K_m$ and the nodes
|
| 708 |
+
for `n` appear in the path $P_n$
|
| 709 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 710 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 711 |
+
|
| 712 |
+
Returns
|
| 713 |
+
-------
|
| 714 |
+
Networkx graph
|
| 715 |
+
A complete graph with `m` nodes connected to a path of length `n`.
|
| 716 |
+
|
| 717 |
+
Notes
|
| 718 |
+
-----
|
| 719 |
+
The 2 subgraphs are joined via an edge ``(m-1, m)``.
|
| 720 |
+
If ``n=0``, this is merely a complete graph.
|
| 721 |
+
|
| 722 |
+
(This graph is an extremal example in David Aldous and Jim
|
| 723 |
+
Fill's etext on Random Walks on Graphs.)
|
| 724 |
+
|
| 725 |
+
"""
|
| 726 |
+
m, m_nodes = m
|
| 727 |
+
M = len(m_nodes)
|
| 728 |
+
if M < 2:
|
| 729 |
+
raise NetworkXError("Invalid description: m should indicate at least 2 nodes")
|
| 730 |
+
|
| 731 |
+
n, n_nodes = n
|
| 732 |
+
if isinstance(m, numbers.Integral) and isinstance(n, numbers.Integral):
|
| 733 |
+
n_nodes = list(range(M, M + n))
|
| 734 |
+
N = len(n_nodes)
|
| 735 |
+
|
| 736 |
+
# the ball
|
| 737 |
+
G = complete_graph(m_nodes, create_using)
|
| 738 |
+
if G.is_directed():
|
| 739 |
+
raise NetworkXError("Directed Graph not supported")
|
| 740 |
+
|
| 741 |
+
# the stick
|
| 742 |
+
G.add_nodes_from(n_nodes)
|
| 743 |
+
if N > 1:
|
| 744 |
+
G.add_edges_from(pairwise(n_nodes))
|
| 745 |
+
|
| 746 |
+
if len(G) != M + N:
|
| 747 |
+
raise NetworkXError("Nodes must be distinct in containers m and n")
|
| 748 |
+
|
| 749 |
+
# connect ball to stick
|
| 750 |
+
if M > 0 and N > 0:
|
| 751 |
+
G.add_edge(m_nodes[-1], n_nodes[0])
|
| 752 |
+
return G
|
| 753 |
+
|
| 754 |
+
|
| 755 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 756 |
+
def null_graph(create_using=None):
|
| 757 |
+
"""Returns the Null graph with no nodes or edges.
|
| 758 |
+
|
| 759 |
+
See empty_graph for the use of create_using.
|
| 760 |
+
|
| 761 |
+
"""
|
| 762 |
+
G = empty_graph(0, create_using)
|
| 763 |
+
return G
|
| 764 |
+
|
| 765 |
+
|
| 766 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 767 |
+
@nodes_or_number(0)
|
| 768 |
+
def path_graph(n, create_using=None):
|
| 769 |
+
"""Returns the Path graph `P_n` of linearly connected nodes.
|
| 770 |
+
|
| 771 |
+
.. plot::
|
| 772 |
+
|
| 773 |
+
>>> nx.draw(nx.path_graph(5))
|
| 774 |
+
|
| 775 |
+
Parameters
|
| 776 |
+
----------
|
| 777 |
+
n : int or iterable
|
| 778 |
+
If an integer, nodes are 0 to n - 1.
|
| 779 |
+
If an iterable of nodes, in the order they appear in the path.
|
| 780 |
+
Warning: n is not checked for duplicates and if present the
|
| 781 |
+
resulting graph may not be as desired. Make sure you have no duplicates.
|
| 782 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 783 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 784 |
+
|
| 785 |
+
"""
|
| 786 |
+
_, nodes = n
|
| 787 |
+
G = empty_graph(nodes, create_using)
|
| 788 |
+
G.add_edges_from(pairwise(nodes))
|
| 789 |
+
return G
|
| 790 |
+
|
| 791 |
+
|
| 792 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 793 |
+
@nodes_or_number(0)
|
| 794 |
+
def star_graph(n, create_using=None):
|
| 795 |
+
"""Return the star graph
|
| 796 |
+
|
| 797 |
+
The star graph consists of one center node connected to n outer nodes.
|
| 798 |
+
|
| 799 |
+
.. plot::
|
| 800 |
+
|
| 801 |
+
>>> nx.draw(nx.star_graph(6))
|
| 802 |
+
|
| 803 |
+
Parameters
|
| 804 |
+
----------
|
| 805 |
+
n : int or iterable
|
| 806 |
+
If an integer, node labels are 0 to n with center 0.
|
| 807 |
+
If an iterable of nodes, the center is the first.
|
| 808 |
+
Warning: n is not checked for duplicates and if present the
|
| 809 |
+
resulting graph may not be as desired. Make sure you have no duplicates.
|
| 810 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 811 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 812 |
+
|
| 813 |
+
Notes
|
| 814 |
+
-----
|
| 815 |
+
The graph has n+1 nodes for integer n.
|
| 816 |
+
So star_graph(3) is the same as star_graph(range(4)).
|
| 817 |
+
"""
|
| 818 |
+
n, nodes = n
|
| 819 |
+
if isinstance(n, numbers.Integral):
|
| 820 |
+
nodes.append(int(n)) # there should be n+1 nodes
|
| 821 |
+
G = empty_graph(nodes, create_using)
|
| 822 |
+
if G.is_directed():
|
| 823 |
+
raise NetworkXError("Directed Graph not supported")
|
| 824 |
+
|
| 825 |
+
if len(nodes) > 1:
|
| 826 |
+
hub, *spokes = nodes
|
| 827 |
+
G.add_edges_from((hub, node) for node in spokes)
|
| 828 |
+
return G
|
| 829 |
+
|
| 830 |
+
|
| 831 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 832 |
+
@nodes_or_number([0, 1])
|
| 833 |
+
def tadpole_graph(m, n, create_using=None):
|
| 834 |
+
"""Returns the (m,n)-tadpole graph; ``C_m`` connected to ``P_n``.
|
| 835 |
+
|
| 836 |
+
This graph on m+n nodes connects a cycle of size `m` to a path of length `n`.
|
| 837 |
+
It looks like a tadpole. It is also called a kite graph or a dragon graph.
|
| 838 |
+
|
| 839 |
+
.. plot::
|
| 840 |
+
|
| 841 |
+
>>> nx.draw(nx.tadpole_graph(3, 5))
|
| 842 |
+
|
| 843 |
+
Parameters
|
| 844 |
+
----------
|
| 845 |
+
m, n : int or iterable container of nodes
|
| 846 |
+
If an integer, nodes are from ``range(m)`` and ``range(m,m+n)``.
|
| 847 |
+
If a container of nodes, those nodes appear in the graph.
|
| 848 |
+
Warning: `m` and `n` are not checked for duplicates and if present the
|
| 849 |
+
resulting graph may not be as desired.
|
| 850 |
+
|
| 851 |
+
The nodes for `m` appear in the cycle graph $C_m$ and the nodes
|
| 852 |
+
for `n` appear in the path $P_n$.
|
| 853 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 854 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 855 |
+
|
| 856 |
+
Returns
|
| 857 |
+
-------
|
| 858 |
+
Networkx graph
|
| 859 |
+
A cycle of size `m` connected to a path of length `n`.
|
| 860 |
+
|
| 861 |
+
Raises
|
| 862 |
+
------
|
| 863 |
+
NetworkXError
|
| 864 |
+
If ``m < 2``. The tadpole graph is undefined for ``m<2``.
|
| 865 |
+
|
| 866 |
+
Notes
|
| 867 |
+
-----
|
| 868 |
+
The 2 subgraphs are joined via an edge ``(m-1, m)``.
|
| 869 |
+
If ``n=0``, this is a cycle graph.
|
| 870 |
+
`m` and/or `n` can be a container of nodes instead of an integer.
|
| 871 |
+
|
| 872 |
+
"""
|
| 873 |
+
m, m_nodes = m
|
| 874 |
+
M = len(m_nodes)
|
| 875 |
+
if M < 2:
|
| 876 |
+
raise NetworkXError("Invalid description: m should indicate at least 2 nodes")
|
| 877 |
+
|
| 878 |
+
n, n_nodes = n
|
| 879 |
+
if isinstance(m, numbers.Integral) and isinstance(n, numbers.Integral):
|
| 880 |
+
n_nodes = list(range(M, M + n))
|
| 881 |
+
|
| 882 |
+
# the circle
|
| 883 |
+
G = cycle_graph(m_nodes, create_using)
|
| 884 |
+
if G.is_directed():
|
| 885 |
+
raise NetworkXError("Directed Graph not supported")
|
| 886 |
+
|
| 887 |
+
# the stick
|
| 888 |
+
nx.add_path(G, [m_nodes[-1]] + list(n_nodes))
|
| 889 |
+
|
| 890 |
+
return G
|
| 891 |
+
|
| 892 |
+
|
| 893 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 894 |
+
def trivial_graph(create_using=None):
|
| 895 |
+
"""Return the Trivial graph with one node (with label 0) and no edges.
|
| 896 |
+
|
| 897 |
+
.. plot::
|
| 898 |
+
|
| 899 |
+
>>> nx.draw(nx.trivial_graph(), with_labels=True)
|
| 900 |
+
|
| 901 |
+
"""
|
| 902 |
+
G = empty_graph(1, create_using)
|
| 903 |
+
return G
|
| 904 |
+
|
| 905 |
+
|
| 906 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 907 |
+
def turan_graph(n, r):
|
| 908 |
+
r"""Return the Turan Graph
|
| 909 |
+
|
| 910 |
+
The Turan Graph is a complete multipartite graph on $n$ nodes
|
| 911 |
+
with $r$ disjoint subsets. That is, edges connect each node to
|
| 912 |
+
every node not in its subset.
|
| 913 |
+
|
| 914 |
+
Given $n$ and $r$, we create a complete multipartite graph with
|
| 915 |
+
$r-(n \mod r)$ partitions of size $n/r$, rounded down, and
|
| 916 |
+
$n \mod r$ partitions of size $n/r+1$, rounded down.
|
| 917 |
+
|
| 918 |
+
.. plot::
|
| 919 |
+
|
| 920 |
+
>>> nx.draw(nx.turan_graph(6, 2))
|
| 921 |
+
|
| 922 |
+
Parameters
|
| 923 |
+
----------
|
| 924 |
+
n : int
|
| 925 |
+
The number of nodes.
|
| 926 |
+
r : int
|
| 927 |
+
The number of partitions.
|
| 928 |
+
Must be less than or equal to n.
|
| 929 |
+
|
| 930 |
+
Notes
|
| 931 |
+
-----
|
| 932 |
+
Must satisfy $1 <= r <= n$.
|
| 933 |
+
The graph has $(r-1)(n^2)/(2r)$ edges, rounded down.
|
| 934 |
+
"""
|
| 935 |
+
|
| 936 |
+
if not 1 <= r <= n:
|
| 937 |
+
raise NetworkXError("Must satisfy 1 <= r <= n")
|
| 938 |
+
|
| 939 |
+
partitions = [n // r] * (r - (n % r)) + [n // r + 1] * (n % r)
|
| 940 |
+
G = complete_multipartite_graph(*partitions)
|
| 941 |
+
return G
|
| 942 |
+
|
| 943 |
+
|
| 944 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 945 |
+
@nodes_or_number(0)
|
| 946 |
+
def wheel_graph(n, create_using=None):
|
| 947 |
+
"""Return the wheel graph
|
| 948 |
+
|
| 949 |
+
The wheel graph consists of a hub node connected to a cycle of (n-1) nodes.
|
| 950 |
+
|
| 951 |
+
.. plot::
|
| 952 |
+
|
| 953 |
+
>>> nx.draw(nx.wheel_graph(5))
|
| 954 |
+
|
| 955 |
+
Parameters
|
| 956 |
+
----------
|
| 957 |
+
n : int or iterable
|
| 958 |
+
If an integer, node labels are 0 to n with center 0.
|
| 959 |
+
If an iterable of nodes, the center is the first.
|
| 960 |
+
Warning: n is not checked for duplicates and if present the
|
| 961 |
+
resulting graph may not be as desired. Make sure you have no duplicates.
|
| 962 |
+
create_using : NetworkX graph constructor, optional (default=nx.Graph)
|
| 963 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 964 |
+
|
| 965 |
+
Node labels are the integers 0 to n - 1.
|
| 966 |
+
"""
|
| 967 |
+
_, nodes = n
|
| 968 |
+
G = empty_graph(nodes, create_using)
|
| 969 |
+
if G.is_directed():
|
| 970 |
+
raise NetworkXError("Directed Graph not supported")
|
| 971 |
+
|
| 972 |
+
if len(nodes) > 1:
|
| 973 |
+
hub, *rim = nodes
|
| 974 |
+
G.add_edges_from((hub, node) for node in rim)
|
| 975 |
+
if len(rim) > 1:
|
| 976 |
+
G.add_edges_from(pairwise(rim, cyclic=True))
|
| 977 |
+
return G
|
| 978 |
+
|
| 979 |
+
|
| 980 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 981 |
+
def complete_multipartite_graph(*subset_sizes):
|
| 982 |
+
"""Returns the complete multipartite graph with the specified subset sizes.
|
| 983 |
+
|
| 984 |
+
.. plot::
|
| 985 |
+
|
| 986 |
+
>>> nx.draw(nx.complete_multipartite_graph(1, 2, 3))
|
| 987 |
+
|
| 988 |
+
Parameters
|
| 989 |
+
----------
|
| 990 |
+
subset_sizes : tuple of integers or tuple of node iterables
|
| 991 |
+
The arguments can either all be integer number of nodes or they
|
| 992 |
+
can all be iterables of nodes. If integers, they represent the
|
| 993 |
+
number of nodes in each subset of the multipartite graph.
|
| 994 |
+
If iterables, each is used to create the nodes for that subset.
|
| 995 |
+
The length of subset_sizes is the number of subsets.
|
| 996 |
+
|
| 997 |
+
Returns
|
| 998 |
+
-------
|
| 999 |
+
G : NetworkX Graph
|
| 1000 |
+
Returns the complete multipartite graph with the specified subsets.
|
| 1001 |
+
|
| 1002 |
+
For each node, the node attribute 'subset' is an integer
|
| 1003 |
+
indicating which subset contains the node.
|
| 1004 |
+
|
| 1005 |
+
Examples
|
| 1006 |
+
--------
|
| 1007 |
+
Creating a complete tripartite graph, with subsets of one, two, and three
|
| 1008 |
+
nodes, respectively.
|
| 1009 |
+
|
| 1010 |
+
>>> G = nx.complete_multipartite_graph(1, 2, 3)
|
| 1011 |
+
>>> [G.nodes[u]["subset"] for u in G]
|
| 1012 |
+
[0, 1, 1, 2, 2, 2]
|
| 1013 |
+
>>> list(G.edges(0))
|
| 1014 |
+
[(0, 1), (0, 2), (0, 3), (0, 4), (0, 5)]
|
| 1015 |
+
>>> list(G.edges(2))
|
| 1016 |
+
[(2, 0), (2, 3), (2, 4), (2, 5)]
|
| 1017 |
+
>>> list(G.edges(4))
|
| 1018 |
+
[(4, 0), (4, 1), (4, 2)]
|
| 1019 |
+
|
| 1020 |
+
>>> G = nx.complete_multipartite_graph("a", "bc", "def")
|
| 1021 |
+
>>> [G.nodes[u]["subset"] for u in sorted(G)]
|
| 1022 |
+
[0, 1, 1, 2, 2, 2]
|
| 1023 |
+
|
| 1024 |
+
Notes
|
| 1025 |
+
-----
|
| 1026 |
+
This function generalizes several other graph builder functions.
|
| 1027 |
+
|
| 1028 |
+
- If no subset sizes are given, this returns the null graph.
|
| 1029 |
+
- If a single subset size `n` is given, this returns the empty graph on
|
| 1030 |
+
`n` nodes.
|
| 1031 |
+
- If two subset sizes `m` and `n` are given, this returns the complete
|
| 1032 |
+
bipartite graph on `m + n` nodes.
|
| 1033 |
+
- If subset sizes `1` and `n` are given, this returns the star graph on
|
| 1034 |
+
`n + 1` nodes.
|
| 1035 |
+
|
| 1036 |
+
See also
|
| 1037 |
+
--------
|
| 1038 |
+
complete_bipartite_graph
|
| 1039 |
+
"""
|
| 1040 |
+
# The complete multipartite graph is an undirected simple graph.
|
| 1041 |
+
G = Graph()
|
| 1042 |
+
|
| 1043 |
+
if len(subset_sizes) == 0:
|
| 1044 |
+
return G
|
| 1045 |
+
|
| 1046 |
+
# set up subsets of nodes
|
| 1047 |
+
try:
|
| 1048 |
+
extents = pairwise(itertools.accumulate((0,) + subset_sizes))
|
| 1049 |
+
subsets = [range(start, end) for start, end in extents]
|
| 1050 |
+
except TypeError:
|
| 1051 |
+
subsets = subset_sizes
|
| 1052 |
+
else:
|
| 1053 |
+
if any(size < 0 for size in subset_sizes):
|
| 1054 |
+
raise NetworkXError(f"Negative number of nodes not valid: {subset_sizes}")
|
| 1055 |
+
|
| 1056 |
+
# add nodes with subset attribute
|
| 1057 |
+
# while checking that ints are not mixed with iterables
|
| 1058 |
+
try:
|
| 1059 |
+
for i, subset in enumerate(subsets):
|
| 1060 |
+
G.add_nodes_from(subset, subset=i)
|
| 1061 |
+
except TypeError as err:
|
| 1062 |
+
raise NetworkXError("Arguments must be all ints or all iterables") from err
|
| 1063 |
+
|
| 1064 |
+
# Across subsets, all nodes should be adjacent.
|
| 1065 |
+
# We can use itertools.combinations() because undirected.
|
| 1066 |
+
for subset1, subset2 in itertools.combinations(subsets, 2):
|
| 1067 |
+
G.add_edges_from(itertools.product(subset1, subset2))
|
| 1068 |
+
return G
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/directed.py
ADDED
|
@@ -0,0 +1,501 @@
|
|
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|
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|
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|
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|
|
|
|
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|
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|
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|
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|
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|
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|
|
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|
|
|
|
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|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Generators for some directed graphs, including growing network (GN) graphs and
|
| 3 |
+
scale-free graphs.
|
| 4 |
+
|
| 5 |
+
"""
|
| 6 |
+
|
| 7 |
+
import numbers
|
| 8 |
+
from collections import Counter
|
| 9 |
+
|
| 10 |
+
import networkx as nx
|
| 11 |
+
from networkx.generators.classic import empty_graph
|
| 12 |
+
from networkx.utils import discrete_sequence, py_random_state, weighted_choice
|
| 13 |
+
|
| 14 |
+
__all__ = [
|
| 15 |
+
"gn_graph",
|
| 16 |
+
"gnc_graph",
|
| 17 |
+
"gnr_graph",
|
| 18 |
+
"random_k_out_graph",
|
| 19 |
+
"scale_free_graph",
|
| 20 |
+
]
|
| 21 |
+
|
| 22 |
+
|
| 23 |
+
@py_random_state(3)
|
| 24 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 25 |
+
def gn_graph(n, kernel=None, create_using=None, seed=None):
|
| 26 |
+
"""Returns the growing network (GN) digraph with `n` nodes.
|
| 27 |
+
|
| 28 |
+
The GN graph is built by adding nodes one at a time with a link to one
|
| 29 |
+
previously added node. The target node for the link is chosen with
|
| 30 |
+
probability based on degree. The default attachment kernel is a linear
|
| 31 |
+
function of the degree of a node.
|
| 32 |
+
|
| 33 |
+
The graph is always a (directed) tree.
|
| 34 |
+
|
| 35 |
+
Parameters
|
| 36 |
+
----------
|
| 37 |
+
n : int
|
| 38 |
+
The number of nodes for the generated graph.
|
| 39 |
+
kernel : function
|
| 40 |
+
The attachment kernel.
|
| 41 |
+
create_using : NetworkX graph constructor, optional (default DiGraph)
|
| 42 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 43 |
+
seed : integer, random_state, or None (default)
|
| 44 |
+
Indicator of random number generation state.
|
| 45 |
+
See :ref:`Randomness<randomness>`.
|
| 46 |
+
|
| 47 |
+
Examples
|
| 48 |
+
--------
|
| 49 |
+
To create the undirected GN graph, use the :meth:`~DiGraph.to_directed`
|
| 50 |
+
method::
|
| 51 |
+
|
| 52 |
+
>>> D = nx.gn_graph(10) # the GN graph
|
| 53 |
+
>>> G = D.to_undirected() # the undirected version
|
| 54 |
+
|
| 55 |
+
To specify an attachment kernel, use the `kernel` keyword argument::
|
| 56 |
+
|
| 57 |
+
>>> D = nx.gn_graph(10, kernel=lambda x: x**1.5) # A_k = k^1.5
|
| 58 |
+
|
| 59 |
+
References
|
| 60 |
+
----------
|
| 61 |
+
.. [1] P. L. Krapivsky and S. Redner,
|
| 62 |
+
Organization of Growing Random Networks,
|
| 63 |
+
Phys. Rev. E, 63, 066123, 2001.
|
| 64 |
+
"""
|
| 65 |
+
G = empty_graph(1, create_using, default=nx.DiGraph)
|
| 66 |
+
if not G.is_directed():
|
| 67 |
+
raise nx.NetworkXError("create_using must indicate a Directed Graph")
|
| 68 |
+
|
| 69 |
+
if kernel is None:
|
| 70 |
+
|
| 71 |
+
def kernel(x):
|
| 72 |
+
return x
|
| 73 |
+
|
| 74 |
+
if n == 1:
|
| 75 |
+
return G
|
| 76 |
+
|
| 77 |
+
G.add_edge(1, 0) # get started
|
| 78 |
+
ds = [1, 1] # degree sequence
|
| 79 |
+
|
| 80 |
+
for source in range(2, n):
|
| 81 |
+
# compute distribution from kernel and degree
|
| 82 |
+
dist = [kernel(d) for d in ds]
|
| 83 |
+
# choose target from discrete distribution
|
| 84 |
+
target = discrete_sequence(1, distribution=dist, seed=seed)[0]
|
| 85 |
+
G.add_edge(source, target)
|
| 86 |
+
ds.append(1) # the source has only one link (degree one)
|
| 87 |
+
ds[target] += 1 # add one to the target link degree
|
| 88 |
+
return G
|
| 89 |
+
|
| 90 |
+
|
| 91 |
+
@py_random_state(3)
|
| 92 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 93 |
+
def gnr_graph(n, p, create_using=None, seed=None):
|
| 94 |
+
"""Returns the growing network with redirection (GNR) digraph with `n`
|
| 95 |
+
nodes and redirection probability `p`.
|
| 96 |
+
|
| 97 |
+
The GNR graph is built by adding nodes one at a time with a link to one
|
| 98 |
+
previously added node. The previous target node is chosen uniformly at
|
| 99 |
+
random. With probability `p` the link is instead "redirected" to the
|
| 100 |
+
successor node of the target.
|
| 101 |
+
|
| 102 |
+
The graph is always a (directed) tree.
|
| 103 |
+
|
| 104 |
+
Parameters
|
| 105 |
+
----------
|
| 106 |
+
n : int
|
| 107 |
+
The number of nodes for the generated graph.
|
| 108 |
+
p : float
|
| 109 |
+
The redirection probability.
|
| 110 |
+
create_using : NetworkX graph constructor, optional (default DiGraph)
|
| 111 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 112 |
+
seed : integer, random_state, or None (default)
|
| 113 |
+
Indicator of random number generation state.
|
| 114 |
+
See :ref:`Randomness<randomness>`.
|
| 115 |
+
|
| 116 |
+
Examples
|
| 117 |
+
--------
|
| 118 |
+
To create the undirected GNR graph, use the :meth:`~DiGraph.to_directed`
|
| 119 |
+
method::
|
| 120 |
+
|
| 121 |
+
>>> D = nx.gnr_graph(10, 0.5) # the GNR graph
|
| 122 |
+
>>> G = D.to_undirected() # the undirected version
|
| 123 |
+
|
| 124 |
+
References
|
| 125 |
+
----------
|
| 126 |
+
.. [1] P. L. Krapivsky and S. Redner,
|
| 127 |
+
Organization of Growing Random Networks,
|
| 128 |
+
Phys. Rev. E, 63, 066123, 2001.
|
| 129 |
+
"""
|
| 130 |
+
G = empty_graph(1, create_using, default=nx.DiGraph)
|
| 131 |
+
if not G.is_directed():
|
| 132 |
+
raise nx.NetworkXError("create_using must indicate a Directed Graph")
|
| 133 |
+
|
| 134 |
+
if n == 1:
|
| 135 |
+
return G
|
| 136 |
+
|
| 137 |
+
for source in range(1, n):
|
| 138 |
+
target = seed.randrange(0, source)
|
| 139 |
+
if seed.random() < p and target != 0:
|
| 140 |
+
target = next(G.successors(target))
|
| 141 |
+
G.add_edge(source, target)
|
| 142 |
+
return G
|
| 143 |
+
|
| 144 |
+
|
| 145 |
+
@py_random_state(2)
|
| 146 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 147 |
+
def gnc_graph(n, create_using=None, seed=None):
|
| 148 |
+
"""Returns the growing network with copying (GNC) digraph with `n` nodes.
|
| 149 |
+
|
| 150 |
+
The GNC graph is built by adding nodes one at a time with a link to one
|
| 151 |
+
previously added node (chosen uniformly at random) and to all of that
|
| 152 |
+
node's successors.
|
| 153 |
+
|
| 154 |
+
Parameters
|
| 155 |
+
----------
|
| 156 |
+
n : int
|
| 157 |
+
The number of nodes for the generated graph.
|
| 158 |
+
create_using : NetworkX graph constructor, optional (default DiGraph)
|
| 159 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 160 |
+
seed : integer, random_state, or None (default)
|
| 161 |
+
Indicator of random number generation state.
|
| 162 |
+
See :ref:`Randomness<randomness>`.
|
| 163 |
+
|
| 164 |
+
References
|
| 165 |
+
----------
|
| 166 |
+
.. [1] P. L. Krapivsky and S. Redner,
|
| 167 |
+
Network Growth by Copying,
|
| 168 |
+
Phys. Rev. E, 71, 036118, 2005k.},
|
| 169 |
+
"""
|
| 170 |
+
G = empty_graph(1, create_using, default=nx.DiGraph)
|
| 171 |
+
if not G.is_directed():
|
| 172 |
+
raise nx.NetworkXError("create_using must indicate a Directed Graph")
|
| 173 |
+
|
| 174 |
+
if n == 1:
|
| 175 |
+
return G
|
| 176 |
+
|
| 177 |
+
for source in range(1, n):
|
| 178 |
+
target = seed.randrange(0, source)
|
| 179 |
+
for succ in G.successors(target):
|
| 180 |
+
G.add_edge(source, succ)
|
| 181 |
+
G.add_edge(source, target)
|
| 182 |
+
return G
|
| 183 |
+
|
| 184 |
+
|
| 185 |
+
@py_random_state(6)
|
| 186 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 187 |
+
def scale_free_graph(
|
| 188 |
+
n,
|
| 189 |
+
alpha=0.41,
|
| 190 |
+
beta=0.54,
|
| 191 |
+
gamma=0.05,
|
| 192 |
+
delta_in=0.2,
|
| 193 |
+
delta_out=0,
|
| 194 |
+
seed=None,
|
| 195 |
+
initial_graph=None,
|
| 196 |
+
):
|
| 197 |
+
"""Returns a scale-free directed graph.
|
| 198 |
+
|
| 199 |
+
Parameters
|
| 200 |
+
----------
|
| 201 |
+
n : integer
|
| 202 |
+
Number of nodes in graph
|
| 203 |
+
alpha : float
|
| 204 |
+
Probability for adding a new node connected to an existing node
|
| 205 |
+
chosen randomly according to the in-degree distribution.
|
| 206 |
+
beta : float
|
| 207 |
+
Probability for adding an edge between two existing nodes.
|
| 208 |
+
One existing node is chosen randomly according the in-degree
|
| 209 |
+
distribution and the other chosen randomly according to the out-degree
|
| 210 |
+
distribution.
|
| 211 |
+
gamma : float
|
| 212 |
+
Probability for adding a new node connected to an existing node
|
| 213 |
+
chosen randomly according to the out-degree distribution.
|
| 214 |
+
delta_in : float
|
| 215 |
+
Bias for choosing nodes from in-degree distribution.
|
| 216 |
+
delta_out : float
|
| 217 |
+
Bias for choosing nodes from out-degree distribution.
|
| 218 |
+
seed : integer, random_state, or None (default)
|
| 219 |
+
Indicator of random number generation state.
|
| 220 |
+
See :ref:`Randomness<randomness>`.
|
| 221 |
+
initial_graph : MultiDiGraph instance, optional
|
| 222 |
+
Build the scale-free graph starting from this initial MultiDiGraph,
|
| 223 |
+
if provided.
|
| 224 |
+
|
| 225 |
+
Returns
|
| 226 |
+
-------
|
| 227 |
+
MultiDiGraph
|
| 228 |
+
|
| 229 |
+
Examples
|
| 230 |
+
--------
|
| 231 |
+
Create a scale-free graph on one hundred nodes::
|
| 232 |
+
|
| 233 |
+
>>> G = nx.scale_free_graph(100)
|
| 234 |
+
|
| 235 |
+
Notes
|
| 236 |
+
-----
|
| 237 |
+
The sum of `alpha`, `beta`, and `gamma` must be 1.
|
| 238 |
+
|
| 239 |
+
References
|
| 240 |
+
----------
|
| 241 |
+
.. [1] B. Bollobás, C. Borgs, J. Chayes, and O. Riordan,
|
| 242 |
+
Directed scale-free graphs,
|
| 243 |
+
Proceedings of the fourteenth annual ACM-SIAM Symposium on
|
| 244 |
+
Discrete Algorithms, 132--139, 2003.
|
| 245 |
+
"""
|
| 246 |
+
|
| 247 |
+
def _choose_node(candidates, node_list, delta):
|
| 248 |
+
if delta > 0:
|
| 249 |
+
bias_sum = len(node_list) * delta
|
| 250 |
+
p_delta = bias_sum / (bias_sum + len(candidates))
|
| 251 |
+
if seed.random() < p_delta:
|
| 252 |
+
return seed.choice(node_list)
|
| 253 |
+
return seed.choice(candidates)
|
| 254 |
+
|
| 255 |
+
if initial_graph is not None and hasattr(initial_graph, "_adj"):
|
| 256 |
+
if not isinstance(initial_graph, nx.MultiDiGraph):
|
| 257 |
+
raise nx.NetworkXError("initial_graph must be a MultiDiGraph.")
|
| 258 |
+
G = initial_graph
|
| 259 |
+
else:
|
| 260 |
+
# Start with 3-cycle
|
| 261 |
+
G = nx.MultiDiGraph([(0, 1), (1, 2), (2, 0)])
|
| 262 |
+
|
| 263 |
+
if alpha <= 0:
|
| 264 |
+
raise ValueError("alpha must be > 0.")
|
| 265 |
+
if beta <= 0:
|
| 266 |
+
raise ValueError("beta must be > 0.")
|
| 267 |
+
if gamma <= 0:
|
| 268 |
+
raise ValueError("gamma must be > 0.")
|
| 269 |
+
|
| 270 |
+
if abs(alpha + beta + gamma - 1.0) >= 1e-9:
|
| 271 |
+
raise ValueError("alpha+beta+gamma must equal 1.")
|
| 272 |
+
|
| 273 |
+
if delta_in < 0:
|
| 274 |
+
raise ValueError("delta_in must be >= 0.")
|
| 275 |
+
|
| 276 |
+
if delta_out < 0:
|
| 277 |
+
raise ValueError("delta_out must be >= 0.")
|
| 278 |
+
|
| 279 |
+
# pre-populate degree states
|
| 280 |
+
vs = sum((count * [idx] for idx, count in G.out_degree()), [])
|
| 281 |
+
ws = sum((count * [idx] for idx, count in G.in_degree()), [])
|
| 282 |
+
|
| 283 |
+
# pre-populate node state
|
| 284 |
+
node_list = list(G.nodes())
|
| 285 |
+
|
| 286 |
+
# see if there already are number-based nodes
|
| 287 |
+
numeric_nodes = [n for n in node_list if isinstance(n, numbers.Number)]
|
| 288 |
+
if len(numeric_nodes) > 0:
|
| 289 |
+
# set cursor for new nodes appropriately
|
| 290 |
+
cursor = max(int(n.real) for n in numeric_nodes) + 1
|
| 291 |
+
else:
|
| 292 |
+
# or start at zero
|
| 293 |
+
cursor = 0
|
| 294 |
+
|
| 295 |
+
while len(G) < n:
|
| 296 |
+
r = seed.random()
|
| 297 |
+
|
| 298 |
+
# random choice in alpha,beta,gamma ranges
|
| 299 |
+
if r < alpha:
|
| 300 |
+
# alpha
|
| 301 |
+
# add new node v
|
| 302 |
+
v = cursor
|
| 303 |
+
cursor += 1
|
| 304 |
+
# also add to node state
|
| 305 |
+
node_list.append(v)
|
| 306 |
+
# choose w according to in-degree and delta_in
|
| 307 |
+
w = _choose_node(ws, node_list, delta_in)
|
| 308 |
+
|
| 309 |
+
elif r < alpha + beta:
|
| 310 |
+
# beta
|
| 311 |
+
# choose v according to out-degree and delta_out
|
| 312 |
+
v = _choose_node(vs, node_list, delta_out)
|
| 313 |
+
# choose w according to in-degree and delta_in
|
| 314 |
+
w = _choose_node(ws, node_list, delta_in)
|
| 315 |
+
|
| 316 |
+
else:
|
| 317 |
+
# gamma
|
| 318 |
+
# choose v according to out-degree and delta_out
|
| 319 |
+
v = _choose_node(vs, node_list, delta_out)
|
| 320 |
+
# add new node w
|
| 321 |
+
w = cursor
|
| 322 |
+
cursor += 1
|
| 323 |
+
# also add to node state
|
| 324 |
+
node_list.append(w)
|
| 325 |
+
|
| 326 |
+
# add edge to graph
|
| 327 |
+
G.add_edge(v, w)
|
| 328 |
+
|
| 329 |
+
# update degree states
|
| 330 |
+
vs.append(v)
|
| 331 |
+
ws.append(w)
|
| 332 |
+
|
| 333 |
+
return G
|
| 334 |
+
|
| 335 |
+
|
| 336 |
+
@py_random_state(4)
|
| 337 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 338 |
+
def random_uniform_k_out_graph(n, k, self_loops=True, with_replacement=True, seed=None):
|
| 339 |
+
"""Returns a random `k`-out graph with uniform attachment.
|
| 340 |
+
|
| 341 |
+
A random `k`-out graph with uniform attachment is a multidigraph
|
| 342 |
+
generated by the following algorithm. For each node *u*, choose
|
| 343 |
+
`k` nodes *v* uniformly at random (with replacement). Add a
|
| 344 |
+
directed edge joining *u* to *v*.
|
| 345 |
+
|
| 346 |
+
Parameters
|
| 347 |
+
----------
|
| 348 |
+
n : int
|
| 349 |
+
The number of nodes in the returned graph.
|
| 350 |
+
|
| 351 |
+
k : int
|
| 352 |
+
The out-degree of each node in the returned graph.
|
| 353 |
+
|
| 354 |
+
self_loops : bool
|
| 355 |
+
If True, self-loops are allowed when generating the graph.
|
| 356 |
+
|
| 357 |
+
with_replacement : bool
|
| 358 |
+
If True, neighbors are chosen with replacement and the
|
| 359 |
+
returned graph will be a directed multigraph. Otherwise,
|
| 360 |
+
neighbors are chosen without replacement and the returned graph
|
| 361 |
+
will be a directed graph.
|
| 362 |
+
|
| 363 |
+
seed : integer, random_state, or None (default)
|
| 364 |
+
Indicator of random number generation state.
|
| 365 |
+
See :ref:`Randomness<randomness>`.
|
| 366 |
+
|
| 367 |
+
Returns
|
| 368 |
+
-------
|
| 369 |
+
NetworkX graph
|
| 370 |
+
A `k`-out-regular directed graph generated according to the
|
| 371 |
+
above algorithm. It will be a multigraph if and only if
|
| 372 |
+
`with_replacement` is True.
|
| 373 |
+
|
| 374 |
+
Raises
|
| 375 |
+
------
|
| 376 |
+
ValueError
|
| 377 |
+
If `with_replacement` is False and `k` is greater than
|
| 378 |
+
`n`.
|
| 379 |
+
|
| 380 |
+
See also
|
| 381 |
+
--------
|
| 382 |
+
random_k_out_graph
|
| 383 |
+
|
| 384 |
+
Notes
|
| 385 |
+
-----
|
| 386 |
+
The return digraph or multidigraph may not be strongly connected, or
|
| 387 |
+
even weakly connected.
|
| 388 |
+
|
| 389 |
+
If `with_replacement` is True, this function is similar to
|
| 390 |
+
:func:`random_k_out_graph`, if that function had parameter `alpha`
|
| 391 |
+
set to positive infinity.
|
| 392 |
+
|
| 393 |
+
"""
|
| 394 |
+
if with_replacement:
|
| 395 |
+
create_using = nx.MultiDiGraph()
|
| 396 |
+
|
| 397 |
+
def sample(v, nodes):
|
| 398 |
+
if not self_loops:
|
| 399 |
+
nodes = nodes - {v}
|
| 400 |
+
return (seed.choice(list(nodes)) for i in range(k))
|
| 401 |
+
|
| 402 |
+
else:
|
| 403 |
+
create_using = nx.DiGraph()
|
| 404 |
+
|
| 405 |
+
def sample(v, nodes):
|
| 406 |
+
if not self_loops:
|
| 407 |
+
nodes = nodes - {v}
|
| 408 |
+
return seed.sample(list(nodes), k)
|
| 409 |
+
|
| 410 |
+
G = nx.empty_graph(n, create_using)
|
| 411 |
+
nodes = set(G)
|
| 412 |
+
for u in G:
|
| 413 |
+
G.add_edges_from((u, v) for v in sample(u, nodes))
|
| 414 |
+
return G
|
| 415 |
+
|
| 416 |
+
|
| 417 |
+
@py_random_state(4)
|
| 418 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 419 |
+
def random_k_out_graph(n, k, alpha, self_loops=True, seed=None):
|
| 420 |
+
"""Returns a random `k`-out graph with preferential attachment.
|
| 421 |
+
|
| 422 |
+
A random `k`-out graph with preferential attachment is a
|
| 423 |
+
multidigraph generated by the following algorithm.
|
| 424 |
+
|
| 425 |
+
1. Begin with an empty digraph, and initially set each node to have
|
| 426 |
+
weight `alpha`.
|
| 427 |
+
2. Choose a node `u` with out-degree less than `k` uniformly at
|
| 428 |
+
random.
|
| 429 |
+
3. Choose a node `v` from with probability proportional to its
|
| 430 |
+
weight.
|
| 431 |
+
4. Add a directed edge from `u` to `v`, and increase the weight
|
| 432 |
+
of `v` by one.
|
| 433 |
+
5. If each node has out-degree `k`, halt, otherwise repeat from
|
| 434 |
+
step 2.
|
| 435 |
+
|
| 436 |
+
For more information on this model of random graph, see [1].
|
| 437 |
+
|
| 438 |
+
Parameters
|
| 439 |
+
----------
|
| 440 |
+
n : int
|
| 441 |
+
The number of nodes in the returned graph.
|
| 442 |
+
|
| 443 |
+
k : int
|
| 444 |
+
The out-degree of each node in the returned graph.
|
| 445 |
+
|
| 446 |
+
alpha : float
|
| 447 |
+
A positive :class:`float` representing the initial weight of
|
| 448 |
+
each vertex. A higher number means that in step 3 above, nodes
|
| 449 |
+
will be chosen more like a true uniformly random sample, and a
|
| 450 |
+
lower number means that nodes are more likely to be chosen as
|
| 451 |
+
their in-degree increases. If this parameter is not positive, a
|
| 452 |
+
:exc:`ValueError` is raised.
|
| 453 |
+
|
| 454 |
+
self_loops : bool
|
| 455 |
+
If True, self-loops are allowed when generating the graph.
|
| 456 |
+
|
| 457 |
+
seed : integer, random_state, or None (default)
|
| 458 |
+
Indicator of random number generation state.
|
| 459 |
+
See :ref:`Randomness<randomness>`.
|
| 460 |
+
|
| 461 |
+
Returns
|
| 462 |
+
-------
|
| 463 |
+
:class:`~networkx.classes.MultiDiGraph`
|
| 464 |
+
A `k`-out-regular multidigraph generated according to the above
|
| 465 |
+
algorithm.
|
| 466 |
+
|
| 467 |
+
Raises
|
| 468 |
+
------
|
| 469 |
+
ValueError
|
| 470 |
+
If `alpha` is not positive.
|
| 471 |
+
|
| 472 |
+
Notes
|
| 473 |
+
-----
|
| 474 |
+
The returned multidigraph may not be strongly connected, or even
|
| 475 |
+
weakly connected.
|
| 476 |
+
|
| 477 |
+
References
|
| 478 |
+
----------
|
| 479 |
+
[1]: Peterson, Nicholas R., and Boris Pittel.
|
| 480 |
+
"Distance between two random `k`-out digraphs, with and without
|
| 481 |
+
preferential attachment."
|
| 482 |
+
arXiv preprint arXiv:1311.5961 (2013).
|
| 483 |
+
<https://arxiv.org/abs/1311.5961>
|
| 484 |
+
|
| 485 |
+
"""
|
| 486 |
+
if alpha < 0:
|
| 487 |
+
raise ValueError("alpha must be positive")
|
| 488 |
+
G = nx.empty_graph(n, create_using=nx.MultiDiGraph)
|
| 489 |
+
weights = Counter({v: alpha for v in G})
|
| 490 |
+
for i in range(k * n):
|
| 491 |
+
u = seed.choice([v for v, d in G.out_degree() if d < k])
|
| 492 |
+
# If self-loops are not allowed, make the source node `u` have
|
| 493 |
+
# weight zero.
|
| 494 |
+
if not self_loops:
|
| 495 |
+
adjustment = Counter({u: weights[u]})
|
| 496 |
+
else:
|
| 497 |
+
adjustment = Counter()
|
| 498 |
+
v = weighted_choice(weights - adjustment, seed=seed)
|
| 499 |
+
G.add_edge(u, v)
|
| 500 |
+
weights[v] += 1
|
| 501 |
+
return G
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/duplication.py
ADDED
|
@@ -0,0 +1,174 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""Functions for generating graphs based on the "duplication" method.
|
| 2 |
+
|
| 3 |
+
These graph generators start with a small initial graph then duplicate
|
| 4 |
+
nodes and (partially) duplicate their edges. These functions are
|
| 5 |
+
generally inspired by biological networks.
|
| 6 |
+
|
| 7 |
+
"""
|
| 8 |
+
|
| 9 |
+
import networkx as nx
|
| 10 |
+
from networkx.exception import NetworkXError
|
| 11 |
+
from networkx.utils import py_random_state
|
| 12 |
+
from networkx.utils.misc import check_create_using
|
| 13 |
+
|
| 14 |
+
__all__ = ["partial_duplication_graph", "duplication_divergence_graph"]
|
| 15 |
+
|
| 16 |
+
|
| 17 |
+
@py_random_state(4)
|
| 18 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 19 |
+
def partial_duplication_graph(N, n, p, q, seed=None, *, create_using=None):
|
| 20 |
+
"""Returns a random graph using the partial duplication model.
|
| 21 |
+
|
| 22 |
+
Parameters
|
| 23 |
+
----------
|
| 24 |
+
N : int
|
| 25 |
+
The total number of nodes in the final graph.
|
| 26 |
+
|
| 27 |
+
n : int
|
| 28 |
+
The number of nodes in the initial clique.
|
| 29 |
+
|
| 30 |
+
p : float
|
| 31 |
+
The probability of joining each neighbor of a node to the
|
| 32 |
+
duplicate node. Must be a number in the between zero and one,
|
| 33 |
+
inclusive.
|
| 34 |
+
|
| 35 |
+
q : float
|
| 36 |
+
The probability of joining the source node to the duplicate
|
| 37 |
+
node. Must be a number in the between zero and one, inclusive.
|
| 38 |
+
|
| 39 |
+
seed : integer, random_state, or None (default)
|
| 40 |
+
Indicator of random number generation state.
|
| 41 |
+
See :ref:`Randomness<randomness>`.
|
| 42 |
+
|
| 43 |
+
create_using : Graph constructor, optional (default=nx.Graph)
|
| 44 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 45 |
+
Multigraph and directed types are not supported and raise a ``NetworkXError``.
|
| 46 |
+
|
| 47 |
+
Notes
|
| 48 |
+
-----
|
| 49 |
+
A graph of nodes is grown by creating a fully connected graph
|
| 50 |
+
of size `n`. The following procedure is then repeated until
|
| 51 |
+
a total of `N` nodes have been reached.
|
| 52 |
+
|
| 53 |
+
1. A random node, *u*, is picked and a new node, *v*, is created.
|
| 54 |
+
2. For each neighbor of *u* an edge from the neighbor to *v* is created
|
| 55 |
+
with probability `p`.
|
| 56 |
+
3. An edge from *u* to *v* is created with probability `q`.
|
| 57 |
+
|
| 58 |
+
This algorithm appears in [1].
|
| 59 |
+
|
| 60 |
+
This implementation allows the possibility of generating
|
| 61 |
+
disconnected graphs.
|
| 62 |
+
|
| 63 |
+
References
|
| 64 |
+
----------
|
| 65 |
+
.. [1] Knudsen Michael, and Carsten Wiuf. "A Markov chain approach to
|
| 66 |
+
randomly grown graphs." Journal of Applied Mathematics 2008.
|
| 67 |
+
<https://doi.org/10.1155/2008/190836>
|
| 68 |
+
|
| 69 |
+
"""
|
| 70 |
+
create_using = check_create_using(create_using, directed=False, multigraph=False)
|
| 71 |
+
if p < 0 or p > 1 or q < 0 or q > 1:
|
| 72 |
+
msg = "partial duplication graph must have 0 <= p, q <= 1."
|
| 73 |
+
raise NetworkXError(msg)
|
| 74 |
+
if n > N:
|
| 75 |
+
raise NetworkXError("partial duplication graph must have n <= N.")
|
| 76 |
+
|
| 77 |
+
G = nx.complete_graph(n, create_using)
|
| 78 |
+
for new_node in range(n, N):
|
| 79 |
+
# Pick a random vertex, u, already in the graph.
|
| 80 |
+
src_node = seed.randint(0, new_node - 1)
|
| 81 |
+
|
| 82 |
+
# Add a new vertex, v, to the graph.
|
| 83 |
+
G.add_node(new_node)
|
| 84 |
+
|
| 85 |
+
# For each neighbor of u...
|
| 86 |
+
for nbr_node in list(nx.all_neighbors(G, src_node)):
|
| 87 |
+
# Add the neighbor to v with probability p.
|
| 88 |
+
if seed.random() < p:
|
| 89 |
+
G.add_edge(new_node, nbr_node)
|
| 90 |
+
|
| 91 |
+
# Join v and u with probability q.
|
| 92 |
+
if seed.random() < q:
|
| 93 |
+
G.add_edge(new_node, src_node)
|
| 94 |
+
return G
|
| 95 |
+
|
| 96 |
+
|
| 97 |
+
@py_random_state(2)
|
| 98 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 99 |
+
def duplication_divergence_graph(n, p, seed=None, *, create_using=None):
|
| 100 |
+
"""Returns an undirected graph using the duplication-divergence model.
|
| 101 |
+
|
| 102 |
+
A graph of `n` nodes is created by duplicating the initial nodes
|
| 103 |
+
and retaining edges incident to the original nodes with a retention
|
| 104 |
+
probability `p`.
|
| 105 |
+
|
| 106 |
+
Parameters
|
| 107 |
+
----------
|
| 108 |
+
n : int
|
| 109 |
+
The desired number of nodes in the graph.
|
| 110 |
+
p : float
|
| 111 |
+
The probability for retaining the edge of the replicated node.
|
| 112 |
+
seed : integer, random_state, or None (default)
|
| 113 |
+
Indicator of random number generation state.
|
| 114 |
+
See :ref:`Randomness<randomness>`.
|
| 115 |
+
create_using : Graph constructor, optional (default=nx.Graph)
|
| 116 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 117 |
+
Multigraph and directed types are not supported and raise a ``NetworkXError``.
|
| 118 |
+
|
| 119 |
+
Returns
|
| 120 |
+
-------
|
| 121 |
+
G : Graph
|
| 122 |
+
|
| 123 |
+
Raises
|
| 124 |
+
------
|
| 125 |
+
NetworkXError
|
| 126 |
+
If `p` is not a valid probability.
|
| 127 |
+
If `n` is less than 2.
|
| 128 |
+
|
| 129 |
+
Notes
|
| 130 |
+
-----
|
| 131 |
+
This algorithm appears in [1].
|
| 132 |
+
|
| 133 |
+
This implementation disallows the possibility of generating
|
| 134 |
+
disconnected graphs.
|
| 135 |
+
|
| 136 |
+
References
|
| 137 |
+
----------
|
| 138 |
+
.. [1] I. Ispolatov, P. L. Krapivsky, A. Yuryev,
|
| 139 |
+
"Duplication-divergence model of protein interaction network",
|
| 140 |
+
Phys. Rev. E, 71, 061911, 2005.
|
| 141 |
+
|
| 142 |
+
"""
|
| 143 |
+
if p > 1 or p < 0:
|
| 144 |
+
msg = f"NetworkXError p={p} is not in [0,1]."
|
| 145 |
+
raise nx.NetworkXError(msg)
|
| 146 |
+
if n < 2:
|
| 147 |
+
msg = "n must be greater than or equal to 2"
|
| 148 |
+
raise nx.NetworkXError(msg)
|
| 149 |
+
|
| 150 |
+
create_using = check_create_using(create_using, directed=False, multigraph=False)
|
| 151 |
+
G = nx.empty_graph(create_using=create_using)
|
| 152 |
+
|
| 153 |
+
# Initialize the graph with two connected nodes.
|
| 154 |
+
G.add_edge(0, 1)
|
| 155 |
+
i = 2
|
| 156 |
+
while i < n:
|
| 157 |
+
# Choose a random node from current graph to duplicate.
|
| 158 |
+
random_node = seed.choice(list(G))
|
| 159 |
+
# Make the replica.
|
| 160 |
+
G.add_node(i)
|
| 161 |
+
# flag indicates whether at least one edge is connected on the replica.
|
| 162 |
+
flag = False
|
| 163 |
+
for nbr in G.neighbors(random_node):
|
| 164 |
+
if seed.random() < p:
|
| 165 |
+
# Link retention step.
|
| 166 |
+
G.add_edge(i, nbr)
|
| 167 |
+
flag = True
|
| 168 |
+
if not flag:
|
| 169 |
+
# Delete replica if no edges retained.
|
| 170 |
+
G.remove_node(i)
|
| 171 |
+
else:
|
| 172 |
+
# Successful duplication.
|
| 173 |
+
i += 1
|
| 174 |
+
return G
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/harary_graph.py
ADDED
|
@@ -0,0 +1,199 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""Generators for Harary graphs
|
| 2 |
+
|
| 3 |
+
This module gives two generators for the Harary graph, which was
|
| 4 |
+
introduced by the famous mathematician Frank Harary in his 1962 work [H]_.
|
| 5 |
+
The first generator gives the Harary graph that maximizes the node
|
| 6 |
+
connectivity with given number of nodes and given number of edges.
|
| 7 |
+
The second generator gives the Harary graph that minimizes
|
| 8 |
+
the number of edges in the graph with given node connectivity and
|
| 9 |
+
number of nodes.
|
| 10 |
+
|
| 11 |
+
References
|
| 12 |
+
----------
|
| 13 |
+
.. [H] Harary, F. "The Maximum Connectivity of a Graph."
|
| 14 |
+
Proc. Nat. Acad. Sci. USA 48, 1142-1146, 1962.
|
| 15 |
+
|
| 16 |
+
"""
|
| 17 |
+
|
| 18 |
+
import networkx as nx
|
| 19 |
+
from networkx.exception import NetworkXError
|
| 20 |
+
|
| 21 |
+
__all__ = ["hnm_harary_graph", "hkn_harary_graph"]
|
| 22 |
+
|
| 23 |
+
|
| 24 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 25 |
+
def hnm_harary_graph(n, m, create_using=None):
|
| 26 |
+
"""Returns the Harary graph with given numbers of nodes and edges.
|
| 27 |
+
|
| 28 |
+
The Harary graph $H_{n,m}$ is the graph that maximizes node connectivity
|
| 29 |
+
with $n$ nodes and $m$ edges.
|
| 30 |
+
|
| 31 |
+
This maximum node connectivity is known to be floor($2m/n$). [1]_
|
| 32 |
+
|
| 33 |
+
Parameters
|
| 34 |
+
----------
|
| 35 |
+
n: integer
|
| 36 |
+
The number of nodes the generated graph is to contain
|
| 37 |
+
|
| 38 |
+
m: integer
|
| 39 |
+
The number of edges the generated graph is to contain
|
| 40 |
+
|
| 41 |
+
create_using : NetworkX graph constructor, optional Graph type
|
| 42 |
+
to create (default=nx.Graph). If graph instance, then cleared
|
| 43 |
+
before populated.
|
| 44 |
+
|
| 45 |
+
Returns
|
| 46 |
+
-------
|
| 47 |
+
NetworkX graph
|
| 48 |
+
The Harary graph $H_{n,m}$.
|
| 49 |
+
|
| 50 |
+
See Also
|
| 51 |
+
--------
|
| 52 |
+
hkn_harary_graph
|
| 53 |
+
|
| 54 |
+
Notes
|
| 55 |
+
-----
|
| 56 |
+
This algorithm runs in $O(m)$ time.
|
| 57 |
+
It is implemented by following the Reference [2]_.
|
| 58 |
+
|
| 59 |
+
References
|
| 60 |
+
----------
|
| 61 |
+
.. [1] F. T. Boesch, A. Satyanarayana, and C. L. Suffel,
|
| 62 |
+
"A Survey of Some Network Reliability Analysis and Synthesis Results,"
|
| 63 |
+
Networks, pp. 99-107, 2009.
|
| 64 |
+
|
| 65 |
+
.. [2] Harary, F. "The Maximum Connectivity of a Graph."
|
| 66 |
+
Proc. Nat. Acad. Sci. USA 48, 1142-1146, 1962.
|
| 67 |
+
"""
|
| 68 |
+
|
| 69 |
+
if n < 1:
|
| 70 |
+
raise NetworkXError("The number of nodes must be >= 1!")
|
| 71 |
+
if m < n - 1:
|
| 72 |
+
raise NetworkXError("The number of edges must be >= n - 1 !")
|
| 73 |
+
if m > n * (n - 1) // 2:
|
| 74 |
+
raise NetworkXError("The number of edges must be <= n(n-1)/2")
|
| 75 |
+
|
| 76 |
+
# Construct an empty graph with n nodes first
|
| 77 |
+
H = nx.empty_graph(n, create_using)
|
| 78 |
+
# Get the floor of average node degree
|
| 79 |
+
d = 2 * m // n
|
| 80 |
+
|
| 81 |
+
# Test the parity of n and d
|
| 82 |
+
if (n % 2 == 0) or (d % 2 == 0):
|
| 83 |
+
# Start with a regular graph of d degrees
|
| 84 |
+
offset = d // 2
|
| 85 |
+
for i in range(n):
|
| 86 |
+
for j in range(1, offset + 1):
|
| 87 |
+
H.add_edge(i, (i - j) % n)
|
| 88 |
+
H.add_edge(i, (i + j) % n)
|
| 89 |
+
if d & 1:
|
| 90 |
+
# in case d is odd; n must be even in this case
|
| 91 |
+
half = n // 2
|
| 92 |
+
for i in range(half):
|
| 93 |
+
# add edges diagonally
|
| 94 |
+
H.add_edge(i, i + half)
|
| 95 |
+
# Get the remainder of 2*m modulo n
|
| 96 |
+
r = 2 * m % n
|
| 97 |
+
if r > 0:
|
| 98 |
+
# add remaining edges at offset+1
|
| 99 |
+
for i in range(r // 2):
|
| 100 |
+
H.add_edge(i, i + offset + 1)
|
| 101 |
+
else:
|
| 102 |
+
# Start with a regular graph of (d - 1) degrees
|
| 103 |
+
offset = (d - 1) // 2
|
| 104 |
+
for i in range(n):
|
| 105 |
+
for j in range(1, offset + 1):
|
| 106 |
+
H.add_edge(i, (i - j) % n)
|
| 107 |
+
H.add_edge(i, (i + j) % n)
|
| 108 |
+
half = n // 2
|
| 109 |
+
for i in range(m - n * offset):
|
| 110 |
+
# add the remaining m - n*offset edges between i and i+half
|
| 111 |
+
H.add_edge(i, (i + half) % n)
|
| 112 |
+
|
| 113 |
+
return H
|
| 114 |
+
|
| 115 |
+
|
| 116 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 117 |
+
def hkn_harary_graph(k, n, create_using=None):
|
| 118 |
+
"""Returns the Harary graph with given node connectivity and node number.
|
| 119 |
+
|
| 120 |
+
The Harary graph $H_{k,n}$ is the graph that minimizes the number of
|
| 121 |
+
edges needed with given node connectivity $k$ and node number $n$.
|
| 122 |
+
|
| 123 |
+
This smallest number of edges is known to be ceil($kn/2$) [1]_.
|
| 124 |
+
|
| 125 |
+
Parameters
|
| 126 |
+
----------
|
| 127 |
+
k: integer
|
| 128 |
+
The node connectivity of the generated graph
|
| 129 |
+
|
| 130 |
+
n: integer
|
| 131 |
+
The number of nodes the generated graph is to contain
|
| 132 |
+
|
| 133 |
+
create_using : NetworkX graph constructor, optional Graph type
|
| 134 |
+
to create (default=nx.Graph). If graph instance, then cleared
|
| 135 |
+
before populated.
|
| 136 |
+
|
| 137 |
+
Returns
|
| 138 |
+
-------
|
| 139 |
+
NetworkX graph
|
| 140 |
+
The Harary graph $H_{k,n}$.
|
| 141 |
+
|
| 142 |
+
See Also
|
| 143 |
+
--------
|
| 144 |
+
hnm_harary_graph
|
| 145 |
+
|
| 146 |
+
Notes
|
| 147 |
+
-----
|
| 148 |
+
This algorithm runs in $O(kn)$ time.
|
| 149 |
+
It is implemented by following the Reference [2]_.
|
| 150 |
+
|
| 151 |
+
References
|
| 152 |
+
----------
|
| 153 |
+
.. [1] Weisstein, Eric W. "Harary Graph." From MathWorld--A Wolfram Web
|
| 154 |
+
Resource. http://mathworld.wolfram.com/HararyGraph.html.
|
| 155 |
+
|
| 156 |
+
.. [2] Harary, F. "The Maximum Connectivity of a Graph."
|
| 157 |
+
Proc. Nat. Acad. Sci. USA 48, 1142-1146, 1962.
|
| 158 |
+
"""
|
| 159 |
+
|
| 160 |
+
if k < 1:
|
| 161 |
+
raise NetworkXError("The node connectivity must be >= 1!")
|
| 162 |
+
if n < k + 1:
|
| 163 |
+
raise NetworkXError("The number of nodes must be >= k+1 !")
|
| 164 |
+
|
| 165 |
+
# in case of connectivity 1, simply return the path graph
|
| 166 |
+
if k == 1:
|
| 167 |
+
H = nx.path_graph(n, create_using)
|
| 168 |
+
return H
|
| 169 |
+
|
| 170 |
+
# Construct an empty graph with n nodes first
|
| 171 |
+
H = nx.empty_graph(n, create_using)
|
| 172 |
+
|
| 173 |
+
# Test the parity of k and n
|
| 174 |
+
if (k % 2 == 0) or (n % 2 == 0):
|
| 175 |
+
# Construct a regular graph with k degrees
|
| 176 |
+
offset = k // 2
|
| 177 |
+
for i in range(n):
|
| 178 |
+
for j in range(1, offset + 1):
|
| 179 |
+
H.add_edge(i, (i - j) % n)
|
| 180 |
+
H.add_edge(i, (i + j) % n)
|
| 181 |
+
if k & 1:
|
| 182 |
+
# odd degree; n must be even in this case
|
| 183 |
+
half = n // 2
|
| 184 |
+
for i in range(half):
|
| 185 |
+
# add edges diagonally
|
| 186 |
+
H.add_edge(i, i + half)
|
| 187 |
+
else:
|
| 188 |
+
# Construct a regular graph with (k - 1) degrees
|
| 189 |
+
offset = (k - 1) // 2
|
| 190 |
+
for i in range(n):
|
| 191 |
+
for j in range(1, offset + 1):
|
| 192 |
+
H.add_edge(i, (i - j) % n)
|
| 193 |
+
H.add_edge(i, (i + j) % n)
|
| 194 |
+
half = n // 2
|
| 195 |
+
for i in range(half + 1):
|
| 196 |
+
# add half+1 edges between i and i+half
|
| 197 |
+
H.add_edge(i, (i + half) % n)
|
| 198 |
+
|
| 199 |
+
return H
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/interval_graph.py
ADDED
|
@@ -0,0 +1,70 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Generators for interval graph.
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
from collections.abc import Sequence
|
| 6 |
+
|
| 7 |
+
import networkx as nx
|
| 8 |
+
|
| 9 |
+
__all__ = ["interval_graph"]
|
| 10 |
+
|
| 11 |
+
|
| 12 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 13 |
+
def interval_graph(intervals):
|
| 14 |
+
"""Generates an interval graph for a list of intervals given.
|
| 15 |
+
|
| 16 |
+
In graph theory, an interval graph is an undirected graph formed from a set
|
| 17 |
+
of closed intervals on the real line, with a vertex for each interval
|
| 18 |
+
and an edge between vertices whose intervals intersect.
|
| 19 |
+
It is the intersection graph of the intervals.
|
| 20 |
+
|
| 21 |
+
More information can be found at:
|
| 22 |
+
https://en.wikipedia.org/wiki/Interval_graph
|
| 23 |
+
|
| 24 |
+
Parameters
|
| 25 |
+
----------
|
| 26 |
+
intervals : a sequence of intervals, say (l, r) where l is the left end,
|
| 27 |
+
and r is the right end of the closed interval.
|
| 28 |
+
|
| 29 |
+
Returns
|
| 30 |
+
-------
|
| 31 |
+
G : networkx graph
|
| 32 |
+
|
| 33 |
+
Examples
|
| 34 |
+
--------
|
| 35 |
+
>>> intervals = [(-2, 3), [1, 4], (2, 3), (4, 6)]
|
| 36 |
+
>>> G = nx.interval_graph(intervals)
|
| 37 |
+
>>> sorted(G.edges)
|
| 38 |
+
[((-2, 3), (1, 4)), ((-2, 3), (2, 3)), ((1, 4), (2, 3)), ((1, 4), (4, 6))]
|
| 39 |
+
|
| 40 |
+
Raises
|
| 41 |
+
------
|
| 42 |
+
:exc:`TypeError`
|
| 43 |
+
if `intervals` contains None or an element which is not
|
| 44 |
+
collections.abc.Sequence or not a length of 2.
|
| 45 |
+
:exc:`ValueError`
|
| 46 |
+
if `intervals` contains an interval such that min1 > max1
|
| 47 |
+
where min1,max1 = interval
|
| 48 |
+
"""
|
| 49 |
+
intervals = list(intervals)
|
| 50 |
+
for interval in intervals:
|
| 51 |
+
if not (isinstance(interval, Sequence) and len(interval) == 2):
|
| 52 |
+
raise TypeError(
|
| 53 |
+
"Each interval must have length 2, and be a "
|
| 54 |
+
"collections.abc.Sequence such as tuple or list."
|
| 55 |
+
)
|
| 56 |
+
if interval[0] > interval[1]:
|
| 57 |
+
raise ValueError(f"Interval must have lower value first. Got {interval}")
|
| 58 |
+
|
| 59 |
+
graph = nx.Graph()
|
| 60 |
+
|
| 61 |
+
tupled_intervals = [tuple(interval) for interval in intervals]
|
| 62 |
+
graph.add_nodes_from(tupled_intervals)
|
| 63 |
+
|
| 64 |
+
while tupled_intervals:
|
| 65 |
+
min1, max1 = interval1 = tupled_intervals.pop()
|
| 66 |
+
for interval2 in tupled_intervals:
|
| 67 |
+
min2, max2 = interval2
|
| 68 |
+
if max1 >= min2 and max2 >= min1:
|
| 69 |
+
graph.add_edge(interval1, interval2)
|
| 70 |
+
return graph
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/nonisomorphic_trees.py
ADDED
|
@@ -0,0 +1,212 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""
|
| 2 |
+
Implementation of the Wright, Richmond, Odlyzko and McKay (WROM)
|
| 3 |
+
algorithm for the enumeration of all non-isomorphic free trees of a
|
| 4 |
+
given order. Rooted trees are represented by level sequences, i.e.,
|
| 5 |
+
lists in which the i-th element specifies the distance of vertex i to
|
| 6 |
+
the root.
|
| 7 |
+
|
| 8 |
+
"""
|
| 9 |
+
|
| 10 |
+
__all__ = ["nonisomorphic_trees", "number_of_nonisomorphic_trees"]
|
| 11 |
+
|
| 12 |
+
import networkx as nx
|
| 13 |
+
|
| 14 |
+
|
| 15 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 16 |
+
def nonisomorphic_trees(order, create="graph"):
|
| 17 |
+
"""Generates lists of nonisomorphic trees
|
| 18 |
+
|
| 19 |
+
Parameters
|
| 20 |
+
----------
|
| 21 |
+
order : int
|
| 22 |
+
order of the desired tree(s)
|
| 23 |
+
|
| 24 |
+
create : one of {"graph", "matrix"} (default="graph")
|
| 25 |
+
If ``"graph"`` is selected a list of ``Graph`` instances will be returned,
|
| 26 |
+
if matrix is selected a list of adjacency matrices will be returned.
|
| 27 |
+
|
| 28 |
+
.. deprecated:: 3.3
|
| 29 |
+
|
| 30 |
+
The `create` argument is deprecated and will be removed in NetworkX
|
| 31 |
+
version 3.5. In the future, `nonisomorphic_trees` will yield graph
|
| 32 |
+
instances by default. To generate adjacency matrices, call
|
| 33 |
+
``nx.to_numpy_array`` on the output, e.g.::
|
| 34 |
+
|
| 35 |
+
[nx.to_numpy_array(G) for G in nx.nonisomorphic_trees(N)]
|
| 36 |
+
|
| 37 |
+
Yields
|
| 38 |
+
------
|
| 39 |
+
list
|
| 40 |
+
A list of nonisomorphic trees, in one of two formats depending on the
|
| 41 |
+
value of the `create` parameter:
|
| 42 |
+
- ``create="graph"``: yields a list of `networkx.Graph` instances
|
| 43 |
+
- ``create="matrix"``: yields a list of list-of-lists representing adjacency matrices
|
| 44 |
+
"""
|
| 45 |
+
|
| 46 |
+
if order < 2:
|
| 47 |
+
raise ValueError
|
| 48 |
+
# start at the path graph rooted at its center
|
| 49 |
+
layout = list(range(order // 2 + 1)) + list(range(1, (order + 1) // 2))
|
| 50 |
+
|
| 51 |
+
while layout is not None:
|
| 52 |
+
layout = _next_tree(layout)
|
| 53 |
+
if layout is not None:
|
| 54 |
+
if create == "graph":
|
| 55 |
+
yield _layout_to_graph(layout)
|
| 56 |
+
elif create == "matrix":
|
| 57 |
+
import warnings
|
| 58 |
+
|
| 59 |
+
warnings.warn(
|
| 60 |
+
(
|
| 61 |
+
"\n\nThe 'create=matrix' argument of nonisomorphic_trees\n"
|
| 62 |
+
"is deprecated and will be removed in version 3.5.\n"
|
| 63 |
+
"Use ``nx.to_numpy_array`` to convert graphs to adjacency "
|
| 64 |
+
"matrices, e.g.::\n\n"
|
| 65 |
+
" [nx.to_numpy_array(G) for G in nx.nonisomorphic_trees(N)]"
|
| 66 |
+
),
|
| 67 |
+
category=DeprecationWarning,
|
| 68 |
+
stacklevel=2,
|
| 69 |
+
)
|
| 70 |
+
|
| 71 |
+
yield _layout_to_matrix(layout)
|
| 72 |
+
layout = _next_rooted_tree(layout)
|
| 73 |
+
|
| 74 |
+
|
| 75 |
+
@nx._dispatchable(graphs=None)
|
| 76 |
+
def number_of_nonisomorphic_trees(order):
|
| 77 |
+
"""Returns the number of nonisomorphic trees
|
| 78 |
+
|
| 79 |
+
Parameters
|
| 80 |
+
----------
|
| 81 |
+
order : int
|
| 82 |
+
order of the desired tree(s)
|
| 83 |
+
|
| 84 |
+
Returns
|
| 85 |
+
-------
|
| 86 |
+
length : Number of nonisomorphic graphs for the given order
|
| 87 |
+
|
| 88 |
+
References
|
| 89 |
+
----------
|
| 90 |
+
|
| 91 |
+
"""
|
| 92 |
+
return sum(1 for _ in nonisomorphic_trees(order))
|
| 93 |
+
|
| 94 |
+
|
| 95 |
+
def _next_rooted_tree(predecessor, p=None):
|
| 96 |
+
"""One iteration of the Beyer-Hedetniemi algorithm."""
|
| 97 |
+
|
| 98 |
+
if p is None:
|
| 99 |
+
p = len(predecessor) - 1
|
| 100 |
+
while predecessor[p] == 1:
|
| 101 |
+
p -= 1
|
| 102 |
+
if p == 0:
|
| 103 |
+
return None
|
| 104 |
+
|
| 105 |
+
q = p - 1
|
| 106 |
+
while predecessor[q] != predecessor[p] - 1:
|
| 107 |
+
q -= 1
|
| 108 |
+
result = list(predecessor)
|
| 109 |
+
for i in range(p, len(result)):
|
| 110 |
+
result[i] = result[i - p + q]
|
| 111 |
+
return result
|
| 112 |
+
|
| 113 |
+
|
| 114 |
+
def _next_tree(candidate):
|
| 115 |
+
"""One iteration of the Wright, Richmond, Odlyzko and McKay
|
| 116 |
+
algorithm."""
|
| 117 |
+
|
| 118 |
+
# valid representation of a free tree if:
|
| 119 |
+
# there are at least two vertices at layer 1
|
| 120 |
+
# (this is always the case because we start at the path graph)
|
| 121 |
+
left, rest = _split_tree(candidate)
|
| 122 |
+
|
| 123 |
+
# and the left subtree of the root
|
| 124 |
+
# is less high than the tree with the left subtree removed
|
| 125 |
+
left_height = max(left)
|
| 126 |
+
rest_height = max(rest)
|
| 127 |
+
valid = rest_height >= left_height
|
| 128 |
+
|
| 129 |
+
if valid and rest_height == left_height:
|
| 130 |
+
# and, if left and rest are of the same height,
|
| 131 |
+
# if left does not encompass more vertices
|
| 132 |
+
if len(left) > len(rest):
|
| 133 |
+
valid = False
|
| 134 |
+
# and, if they have the same number or vertices,
|
| 135 |
+
# if left does not come after rest lexicographically
|
| 136 |
+
elif len(left) == len(rest) and left > rest:
|
| 137 |
+
valid = False
|
| 138 |
+
|
| 139 |
+
if valid:
|
| 140 |
+
return candidate
|
| 141 |
+
else:
|
| 142 |
+
# jump to the next valid free tree
|
| 143 |
+
p = len(left)
|
| 144 |
+
new_candidate = _next_rooted_tree(candidate, p)
|
| 145 |
+
if candidate[p] > 2:
|
| 146 |
+
new_left, new_rest = _split_tree(new_candidate)
|
| 147 |
+
new_left_height = max(new_left)
|
| 148 |
+
suffix = range(1, new_left_height + 2)
|
| 149 |
+
new_candidate[-len(suffix) :] = suffix
|
| 150 |
+
return new_candidate
|
| 151 |
+
|
| 152 |
+
|
| 153 |
+
def _split_tree(layout):
|
| 154 |
+
"""Returns a tuple of two layouts, one containing the left
|
| 155 |
+
subtree of the root vertex, and one containing the original tree
|
| 156 |
+
with the left subtree removed."""
|
| 157 |
+
|
| 158 |
+
one_found = False
|
| 159 |
+
m = None
|
| 160 |
+
for i in range(len(layout)):
|
| 161 |
+
if layout[i] == 1:
|
| 162 |
+
if one_found:
|
| 163 |
+
m = i
|
| 164 |
+
break
|
| 165 |
+
else:
|
| 166 |
+
one_found = True
|
| 167 |
+
|
| 168 |
+
if m is None:
|
| 169 |
+
m = len(layout)
|
| 170 |
+
|
| 171 |
+
left = [layout[i] - 1 for i in range(1, m)]
|
| 172 |
+
rest = [0] + [layout[i] for i in range(m, len(layout))]
|
| 173 |
+
return (left, rest)
|
| 174 |
+
|
| 175 |
+
|
| 176 |
+
def _layout_to_matrix(layout):
|
| 177 |
+
"""Create the adjacency matrix for the tree specified by the
|
| 178 |
+
given layout (level sequence)."""
|
| 179 |
+
|
| 180 |
+
result = [[0] * len(layout) for i in range(len(layout))]
|
| 181 |
+
stack = []
|
| 182 |
+
for i in range(len(layout)):
|
| 183 |
+
i_level = layout[i]
|
| 184 |
+
if stack:
|
| 185 |
+
j = stack[-1]
|
| 186 |
+
j_level = layout[j]
|
| 187 |
+
while j_level >= i_level:
|
| 188 |
+
stack.pop()
|
| 189 |
+
j = stack[-1]
|
| 190 |
+
j_level = layout[j]
|
| 191 |
+
result[i][j] = result[j][i] = 1
|
| 192 |
+
stack.append(i)
|
| 193 |
+
return result
|
| 194 |
+
|
| 195 |
+
|
| 196 |
+
def _layout_to_graph(layout):
|
| 197 |
+
"""Create a NetworkX Graph for the tree specified by the
|
| 198 |
+
given layout(level sequence)"""
|
| 199 |
+
G = nx.Graph()
|
| 200 |
+
stack = []
|
| 201 |
+
for i in range(len(layout)):
|
| 202 |
+
i_level = layout[i]
|
| 203 |
+
if stack:
|
| 204 |
+
j = stack[-1]
|
| 205 |
+
j_level = layout[j]
|
| 206 |
+
while j_level >= i_level:
|
| 207 |
+
stack.pop()
|
| 208 |
+
j = stack[-1]
|
| 209 |
+
j_level = layout[j]
|
| 210 |
+
G.add_edge(i, j)
|
| 211 |
+
stack.append(i)
|
| 212 |
+
return G
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/random_clustered.py
ADDED
|
@@ -0,0 +1,117 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""Generate graphs with given degree and triangle sequence."""
|
| 2 |
+
|
| 3 |
+
import networkx as nx
|
| 4 |
+
from networkx.utils import py_random_state
|
| 5 |
+
|
| 6 |
+
__all__ = ["random_clustered_graph"]
|
| 7 |
+
|
| 8 |
+
|
| 9 |
+
@py_random_state(2)
|
| 10 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 11 |
+
def random_clustered_graph(joint_degree_sequence, create_using=None, seed=None):
|
| 12 |
+
r"""Generate a random graph with the given joint independent edge degree and
|
| 13 |
+
triangle degree sequence.
|
| 14 |
+
|
| 15 |
+
This uses a configuration model-like approach to generate a random graph
|
| 16 |
+
(with parallel edges and self-loops) by randomly assigning edges to match
|
| 17 |
+
the given joint degree sequence.
|
| 18 |
+
|
| 19 |
+
The joint degree sequence is a list of pairs of integers of the form
|
| 20 |
+
$[(d_{1,i}, d_{1,t}), \dotsc, (d_{n,i}, d_{n,t})]$. According to this list,
|
| 21 |
+
vertex $u$ is a member of $d_{u,t}$ triangles and has $d_{u, i}$ other
|
| 22 |
+
edges. The number $d_{u,t}$ is the *triangle degree* of $u$ and the number
|
| 23 |
+
$d_{u,i}$ is the *independent edge degree*.
|
| 24 |
+
|
| 25 |
+
Parameters
|
| 26 |
+
----------
|
| 27 |
+
joint_degree_sequence : list of integer pairs
|
| 28 |
+
Each list entry corresponds to the independent edge degree and
|
| 29 |
+
triangle degree of a node.
|
| 30 |
+
create_using : NetworkX graph constructor, optional (default MultiGraph)
|
| 31 |
+
Graph type to create. If graph instance, then cleared before populated.
|
| 32 |
+
seed : integer, random_state, or None (default)
|
| 33 |
+
Indicator of random number generation state.
|
| 34 |
+
See :ref:`Randomness<randomness>`.
|
| 35 |
+
|
| 36 |
+
Returns
|
| 37 |
+
-------
|
| 38 |
+
G : MultiGraph
|
| 39 |
+
A graph with the specified degree sequence. Nodes are labeled
|
| 40 |
+
starting at 0 with an index corresponding to the position in
|
| 41 |
+
deg_sequence.
|
| 42 |
+
|
| 43 |
+
Raises
|
| 44 |
+
------
|
| 45 |
+
NetworkXError
|
| 46 |
+
If the independent edge degree sequence sum is not even
|
| 47 |
+
or the triangle degree sequence sum is not divisible by 3.
|
| 48 |
+
|
| 49 |
+
Notes
|
| 50 |
+
-----
|
| 51 |
+
As described by Miller [1]_ (see also Newman [2]_ for an equivalent
|
| 52 |
+
description).
|
| 53 |
+
|
| 54 |
+
A non-graphical degree sequence (not realizable by some simple
|
| 55 |
+
graph) is allowed since this function returns graphs with self
|
| 56 |
+
loops and parallel edges. An exception is raised if the
|
| 57 |
+
independent degree sequence does not have an even sum or the
|
| 58 |
+
triangle degree sequence sum is not divisible by 3.
|
| 59 |
+
|
| 60 |
+
This configuration model-like construction process can lead to
|
| 61 |
+
duplicate edges and loops. You can remove the self-loops and
|
| 62 |
+
parallel edges (see below) which will likely result in a graph
|
| 63 |
+
that doesn't have the exact degree sequence specified. This
|
| 64 |
+
"finite-size effect" decreases as the size of the graph increases.
|
| 65 |
+
|
| 66 |
+
References
|
| 67 |
+
----------
|
| 68 |
+
.. [1] Joel C. Miller. "Percolation and epidemics in random clustered
|
| 69 |
+
networks". In: Physical review. E, Statistical, nonlinear, and soft
|
| 70 |
+
matter physics 80 (2 Part 1 August 2009).
|
| 71 |
+
.. [2] M. E. J. Newman. "Random Graphs with Clustering".
|
| 72 |
+
In: Physical Review Letters 103 (5 July 2009)
|
| 73 |
+
|
| 74 |
+
Examples
|
| 75 |
+
--------
|
| 76 |
+
>>> deg = [(1, 0), (1, 0), (1, 0), (2, 0), (1, 0), (2, 1), (0, 1), (0, 1)]
|
| 77 |
+
>>> G = nx.random_clustered_graph(deg)
|
| 78 |
+
|
| 79 |
+
To remove parallel edges:
|
| 80 |
+
|
| 81 |
+
>>> G = nx.Graph(G)
|
| 82 |
+
|
| 83 |
+
To remove self loops:
|
| 84 |
+
|
| 85 |
+
>>> G.remove_edges_from(nx.selfloop_edges(G))
|
| 86 |
+
|
| 87 |
+
"""
|
| 88 |
+
# In Python 3, zip() returns an iterator. Make this into a list.
|
| 89 |
+
joint_degree_sequence = list(joint_degree_sequence)
|
| 90 |
+
|
| 91 |
+
N = len(joint_degree_sequence)
|
| 92 |
+
G = nx.empty_graph(N, create_using, default=nx.MultiGraph)
|
| 93 |
+
if G.is_directed():
|
| 94 |
+
raise nx.NetworkXError("Directed Graph not supported")
|
| 95 |
+
|
| 96 |
+
ilist = []
|
| 97 |
+
tlist = []
|
| 98 |
+
for n in G:
|
| 99 |
+
degrees = joint_degree_sequence[n]
|
| 100 |
+
for icount in range(degrees[0]):
|
| 101 |
+
ilist.append(n)
|
| 102 |
+
for tcount in range(degrees[1]):
|
| 103 |
+
tlist.append(n)
|
| 104 |
+
|
| 105 |
+
if len(ilist) % 2 != 0 or len(tlist) % 3 != 0:
|
| 106 |
+
raise nx.NetworkXError("Invalid degree sequence")
|
| 107 |
+
|
| 108 |
+
seed.shuffle(ilist)
|
| 109 |
+
seed.shuffle(tlist)
|
| 110 |
+
while ilist:
|
| 111 |
+
G.add_edge(ilist.pop(), ilist.pop())
|
| 112 |
+
while tlist:
|
| 113 |
+
n1 = tlist.pop()
|
| 114 |
+
n2 = tlist.pop()
|
| 115 |
+
n3 = tlist.pop()
|
| 116 |
+
G.add_edges_from([(n1, n2), (n1, n3), (n2, n3)])
|
| 117 |
+
return G
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/social.py
ADDED
|
@@ -0,0 +1,554 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
|
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|
|
|
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|
|
|
|
|
|
|
|
|
|
|
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|
| 1 |
+
"""
|
| 2 |
+
Famous social networks.
|
| 3 |
+
"""
|
| 4 |
+
|
| 5 |
+
import networkx as nx
|
| 6 |
+
|
| 7 |
+
__all__ = [
|
| 8 |
+
"karate_club_graph",
|
| 9 |
+
"davis_southern_women_graph",
|
| 10 |
+
"florentine_families_graph",
|
| 11 |
+
"les_miserables_graph",
|
| 12 |
+
]
|
| 13 |
+
|
| 14 |
+
|
| 15 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 16 |
+
def karate_club_graph():
|
| 17 |
+
"""Returns Zachary's Karate Club graph.
|
| 18 |
+
|
| 19 |
+
Each node in the returned graph has a node attribute 'club' that
|
| 20 |
+
indicates the name of the club to which the member represented by that node
|
| 21 |
+
belongs, either 'Mr. Hi' or 'Officer'. Each edge has a weight based on the
|
| 22 |
+
number of contexts in which that edge's incident node members interacted.
|
| 23 |
+
|
| 24 |
+
The dataset is derived from the 'Club After Split From Data' column of Table 3 in [1]_.
|
| 25 |
+
This was in turn derived from the 'Club After Fission' column of Table 1 in the
|
| 26 |
+
same paper. Note that the nodes are 0-indexed in NetworkX, but 1-indexed in the
|
| 27 |
+
paper (the 'Individual Number in Matrix C' column of Table 3 starts at 1). This
|
| 28 |
+
means, for example, that ``G.nodes[9]["club"]`` returns 'Officer', which
|
| 29 |
+
corresponds to row 10 of Table 3 in the paper.
|
| 30 |
+
|
| 31 |
+
Examples
|
| 32 |
+
--------
|
| 33 |
+
To get the name of the club to which a node belongs::
|
| 34 |
+
|
| 35 |
+
>>> G = nx.karate_club_graph()
|
| 36 |
+
>>> G.nodes[5]["club"]
|
| 37 |
+
'Mr. Hi'
|
| 38 |
+
>>> G.nodes[9]["club"]
|
| 39 |
+
'Officer'
|
| 40 |
+
|
| 41 |
+
References
|
| 42 |
+
----------
|
| 43 |
+
.. [1] Zachary, Wayne W.
|
| 44 |
+
"An Information Flow Model for Conflict and Fission in Small Groups."
|
| 45 |
+
*Journal of Anthropological Research*, 33, 452--473, (1977).
|
| 46 |
+
"""
|
| 47 |
+
# Create the set of all members, and the members of each club.
|
| 48 |
+
all_members = set(range(34))
|
| 49 |
+
club1 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 16, 17, 19, 21}
|
| 50 |
+
# club2 = all_members - club1
|
| 51 |
+
|
| 52 |
+
G = nx.Graph()
|
| 53 |
+
G.add_nodes_from(all_members)
|
| 54 |
+
G.name = "Zachary's Karate Club"
|
| 55 |
+
|
| 56 |
+
zacharydat = """\
|
| 57 |
+
0 4 5 3 3 3 3 2 2 0 2 3 2 3 0 0 0 2 0 2 0 2 0 0 0 0 0 0 0 0 0 2 0 0
|
| 58 |
+
4 0 6 3 0 0 0 4 0 0 0 0 0 5 0 0 0 1 0 2 0 2 0 0 0 0 0 0 0 0 2 0 0 0
|
| 59 |
+
5 6 0 3 0 0 0 4 5 1 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 0 0 0 3 0
|
| 60 |
+
3 3 3 0 0 0 0 3 0 0 0 0 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 61 |
+
3 0 0 0 0 0 2 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 62 |
+
3 0 0 0 0 0 5 0 0 0 3 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 63 |
+
3 0 0 0 2 5 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 64 |
+
2 4 4 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 65 |
+
2 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 4 3
|
| 66 |
+
0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2
|
| 67 |
+
2 0 0 0 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 68 |
+
3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 69 |
+
1 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 70 |
+
3 5 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3
|
| 71 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 2
|
| 72 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 4
|
| 73 |
+
0 0 0 0 0 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 74 |
+
2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 75 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2
|
| 76 |
+
2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
|
| 77 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 1
|
| 78 |
+
2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
|
| 79 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0
|
| 80 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 4 0 2 0 0 5 4
|
| 81 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 3 0 0 0 2 0 0
|
| 82 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 2 0 0 0 0 0 0 7 0 0
|
| 83 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 2
|
| 84 |
+
0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 3 0 0 0 0 0 0 0 0 4
|
| 85 |
+
0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2
|
| 86 |
+
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 4 0 0 0 0 0 3 2
|
| 87 |
+
0 2 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 3
|
| 88 |
+
2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 7 0 0 2 0 0 0 4 4
|
| 89 |
+
0 0 2 0 0 0 0 0 3 0 0 0 0 0 3 3 0 0 1 0 3 0 2 5 0 0 0 0 0 4 3 4 0 5
|
| 90 |
+
0 0 0 0 0 0 0 0 4 2 0 0 0 3 2 4 0 0 2 1 1 0 3 4 0 0 2 4 2 2 3 4 5 0"""
|
| 91 |
+
|
| 92 |
+
for row, line in enumerate(zacharydat.split("\n")):
|
| 93 |
+
thisrow = [int(b) for b in line.split()]
|
| 94 |
+
for col, entry in enumerate(thisrow):
|
| 95 |
+
if entry >= 1:
|
| 96 |
+
G.add_edge(row, col, weight=entry)
|
| 97 |
+
|
| 98 |
+
# Add the name of each member's club as a node attribute.
|
| 99 |
+
for v in G:
|
| 100 |
+
G.nodes[v]["club"] = "Mr. Hi" if v in club1 else "Officer"
|
| 101 |
+
return G
|
| 102 |
+
|
| 103 |
+
|
| 104 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 105 |
+
def davis_southern_women_graph():
|
| 106 |
+
"""Returns Davis Southern women social network.
|
| 107 |
+
|
| 108 |
+
This is a bipartite graph.
|
| 109 |
+
|
| 110 |
+
References
|
| 111 |
+
----------
|
| 112 |
+
.. [1] A. Davis, Gardner, B. B., Gardner, M. R., 1941. Deep South.
|
| 113 |
+
University of Chicago Press, Chicago, IL.
|
| 114 |
+
"""
|
| 115 |
+
G = nx.Graph()
|
| 116 |
+
# Top nodes
|
| 117 |
+
women = [
|
| 118 |
+
"Evelyn Jefferson",
|
| 119 |
+
"Laura Mandeville",
|
| 120 |
+
"Theresa Anderson",
|
| 121 |
+
"Brenda Rogers",
|
| 122 |
+
"Charlotte McDowd",
|
| 123 |
+
"Frances Anderson",
|
| 124 |
+
"Eleanor Nye",
|
| 125 |
+
"Pearl Oglethorpe",
|
| 126 |
+
"Ruth DeSand",
|
| 127 |
+
"Verne Sanderson",
|
| 128 |
+
"Myra Liddel",
|
| 129 |
+
"Katherina Rogers",
|
| 130 |
+
"Sylvia Avondale",
|
| 131 |
+
"Nora Fayette",
|
| 132 |
+
"Helen Lloyd",
|
| 133 |
+
"Dorothy Murchison",
|
| 134 |
+
"Olivia Carleton",
|
| 135 |
+
"Flora Price",
|
| 136 |
+
]
|
| 137 |
+
G.add_nodes_from(women, bipartite=0)
|
| 138 |
+
# Bottom nodes
|
| 139 |
+
events = [
|
| 140 |
+
"E1",
|
| 141 |
+
"E2",
|
| 142 |
+
"E3",
|
| 143 |
+
"E4",
|
| 144 |
+
"E5",
|
| 145 |
+
"E6",
|
| 146 |
+
"E7",
|
| 147 |
+
"E8",
|
| 148 |
+
"E9",
|
| 149 |
+
"E10",
|
| 150 |
+
"E11",
|
| 151 |
+
"E12",
|
| 152 |
+
"E13",
|
| 153 |
+
"E14",
|
| 154 |
+
]
|
| 155 |
+
G.add_nodes_from(events, bipartite=1)
|
| 156 |
+
|
| 157 |
+
G.add_edges_from(
|
| 158 |
+
[
|
| 159 |
+
("Evelyn Jefferson", "E1"),
|
| 160 |
+
("Evelyn Jefferson", "E2"),
|
| 161 |
+
("Evelyn Jefferson", "E3"),
|
| 162 |
+
("Evelyn Jefferson", "E4"),
|
| 163 |
+
("Evelyn Jefferson", "E5"),
|
| 164 |
+
("Evelyn Jefferson", "E6"),
|
| 165 |
+
("Evelyn Jefferson", "E8"),
|
| 166 |
+
("Evelyn Jefferson", "E9"),
|
| 167 |
+
("Laura Mandeville", "E1"),
|
| 168 |
+
("Laura Mandeville", "E2"),
|
| 169 |
+
("Laura Mandeville", "E3"),
|
| 170 |
+
("Laura Mandeville", "E5"),
|
| 171 |
+
("Laura Mandeville", "E6"),
|
| 172 |
+
("Laura Mandeville", "E7"),
|
| 173 |
+
("Laura Mandeville", "E8"),
|
| 174 |
+
("Theresa Anderson", "E2"),
|
| 175 |
+
("Theresa Anderson", "E3"),
|
| 176 |
+
("Theresa Anderson", "E4"),
|
| 177 |
+
("Theresa Anderson", "E5"),
|
| 178 |
+
("Theresa Anderson", "E6"),
|
| 179 |
+
("Theresa Anderson", "E7"),
|
| 180 |
+
("Theresa Anderson", "E8"),
|
| 181 |
+
("Theresa Anderson", "E9"),
|
| 182 |
+
("Brenda Rogers", "E1"),
|
| 183 |
+
("Brenda Rogers", "E3"),
|
| 184 |
+
("Brenda Rogers", "E4"),
|
| 185 |
+
("Brenda Rogers", "E5"),
|
| 186 |
+
("Brenda Rogers", "E6"),
|
| 187 |
+
("Brenda Rogers", "E7"),
|
| 188 |
+
("Brenda Rogers", "E8"),
|
| 189 |
+
("Charlotte McDowd", "E3"),
|
| 190 |
+
("Charlotte McDowd", "E4"),
|
| 191 |
+
("Charlotte McDowd", "E5"),
|
| 192 |
+
("Charlotte McDowd", "E7"),
|
| 193 |
+
("Frances Anderson", "E3"),
|
| 194 |
+
("Frances Anderson", "E5"),
|
| 195 |
+
("Frances Anderson", "E6"),
|
| 196 |
+
("Frances Anderson", "E8"),
|
| 197 |
+
("Eleanor Nye", "E5"),
|
| 198 |
+
("Eleanor Nye", "E6"),
|
| 199 |
+
("Eleanor Nye", "E7"),
|
| 200 |
+
("Eleanor Nye", "E8"),
|
| 201 |
+
("Pearl Oglethorpe", "E6"),
|
| 202 |
+
("Pearl Oglethorpe", "E8"),
|
| 203 |
+
("Pearl Oglethorpe", "E9"),
|
| 204 |
+
("Ruth DeSand", "E5"),
|
| 205 |
+
("Ruth DeSand", "E7"),
|
| 206 |
+
("Ruth DeSand", "E8"),
|
| 207 |
+
("Ruth DeSand", "E9"),
|
| 208 |
+
("Verne Sanderson", "E7"),
|
| 209 |
+
("Verne Sanderson", "E8"),
|
| 210 |
+
("Verne Sanderson", "E9"),
|
| 211 |
+
("Verne Sanderson", "E12"),
|
| 212 |
+
("Myra Liddel", "E8"),
|
| 213 |
+
("Myra Liddel", "E9"),
|
| 214 |
+
("Myra Liddel", "E10"),
|
| 215 |
+
("Myra Liddel", "E12"),
|
| 216 |
+
("Katherina Rogers", "E8"),
|
| 217 |
+
("Katherina Rogers", "E9"),
|
| 218 |
+
("Katherina Rogers", "E10"),
|
| 219 |
+
("Katherina Rogers", "E12"),
|
| 220 |
+
("Katherina Rogers", "E13"),
|
| 221 |
+
("Katherina Rogers", "E14"),
|
| 222 |
+
("Sylvia Avondale", "E7"),
|
| 223 |
+
("Sylvia Avondale", "E8"),
|
| 224 |
+
("Sylvia Avondale", "E9"),
|
| 225 |
+
("Sylvia Avondale", "E10"),
|
| 226 |
+
("Sylvia Avondale", "E12"),
|
| 227 |
+
("Sylvia Avondale", "E13"),
|
| 228 |
+
("Sylvia Avondale", "E14"),
|
| 229 |
+
("Nora Fayette", "E6"),
|
| 230 |
+
("Nora Fayette", "E7"),
|
| 231 |
+
("Nora Fayette", "E9"),
|
| 232 |
+
("Nora Fayette", "E10"),
|
| 233 |
+
("Nora Fayette", "E11"),
|
| 234 |
+
("Nora Fayette", "E12"),
|
| 235 |
+
("Nora Fayette", "E13"),
|
| 236 |
+
("Nora Fayette", "E14"),
|
| 237 |
+
("Helen Lloyd", "E7"),
|
| 238 |
+
("Helen Lloyd", "E8"),
|
| 239 |
+
("Helen Lloyd", "E10"),
|
| 240 |
+
("Helen Lloyd", "E11"),
|
| 241 |
+
("Helen Lloyd", "E12"),
|
| 242 |
+
("Dorothy Murchison", "E8"),
|
| 243 |
+
("Dorothy Murchison", "E9"),
|
| 244 |
+
("Olivia Carleton", "E9"),
|
| 245 |
+
("Olivia Carleton", "E11"),
|
| 246 |
+
("Flora Price", "E9"),
|
| 247 |
+
("Flora Price", "E11"),
|
| 248 |
+
]
|
| 249 |
+
)
|
| 250 |
+
G.graph["top"] = women
|
| 251 |
+
G.graph["bottom"] = events
|
| 252 |
+
return G
|
| 253 |
+
|
| 254 |
+
|
| 255 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 256 |
+
def florentine_families_graph():
|
| 257 |
+
"""Returns Florentine families graph.
|
| 258 |
+
|
| 259 |
+
References
|
| 260 |
+
----------
|
| 261 |
+
.. [1] Ronald L. Breiger and Philippa E. Pattison
|
| 262 |
+
Cumulated social roles: The duality of persons and their algebras,1
|
| 263 |
+
Social Networks, Volume 8, Issue 3, September 1986, Pages 215-256
|
| 264 |
+
"""
|
| 265 |
+
G = nx.Graph()
|
| 266 |
+
G.add_edge("Acciaiuoli", "Medici")
|
| 267 |
+
G.add_edge("Castellani", "Peruzzi")
|
| 268 |
+
G.add_edge("Castellani", "Strozzi")
|
| 269 |
+
G.add_edge("Castellani", "Barbadori")
|
| 270 |
+
G.add_edge("Medici", "Barbadori")
|
| 271 |
+
G.add_edge("Medici", "Ridolfi")
|
| 272 |
+
G.add_edge("Medici", "Tornabuoni")
|
| 273 |
+
G.add_edge("Medici", "Albizzi")
|
| 274 |
+
G.add_edge("Medici", "Salviati")
|
| 275 |
+
G.add_edge("Salviati", "Pazzi")
|
| 276 |
+
G.add_edge("Peruzzi", "Strozzi")
|
| 277 |
+
G.add_edge("Peruzzi", "Bischeri")
|
| 278 |
+
G.add_edge("Strozzi", "Ridolfi")
|
| 279 |
+
G.add_edge("Strozzi", "Bischeri")
|
| 280 |
+
G.add_edge("Ridolfi", "Tornabuoni")
|
| 281 |
+
G.add_edge("Tornabuoni", "Guadagni")
|
| 282 |
+
G.add_edge("Albizzi", "Ginori")
|
| 283 |
+
G.add_edge("Albizzi", "Guadagni")
|
| 284 |
+
G.add_edge("Bischeri", "Guadagni")
|
| 285 |
+
G.add_edge("Guadagni", "Lamberteschi")
|
| 286 |
+
return G
|
| 287 |
+
|
| 288 |
+
|
| 289 |
+
@nx._dispatchable(graphs=None, returns_graph=True)
|
| 290 |
+
def les_miserables_graph():
|
| 291 |
+
"""Returns coappearance network of characters in the novel Les Miserables.
|
| 292 |
+
|
| 293 |
+
References
|
| 294 |
+
----------
|
| 295 |
+
.. [1] D. E. Knuth, 1993.
|
| 296 |
+
The Stanford GraphBase: a platform for combinatorial computing,
|
| 297 |
+
pp. 74-87. New York: AcM Press.
|
| 298 |
+
"""
|
| 299 |
+
G = nx.Graph()
|
| 300 |
+
G.add_edge("Napoleon", "Myriel", weight=1)
|
| 301 |
+
G.add_edge("MlleBaptistine", "Myriel", weight=8)
|
| 302 |
+
G.add_edge("MmeMagloire", "Myriel", weight=10)
|
| 303 |
+
G.add_edge("MmeMagloire", "MlleBaptistine", weight=6)
|
| 304 |
+
G.add_edge("CountessDeLo", "Myriel", weight=1)
|
| 305 |
+
G.add_edge("Geborand", "Myriel", weight=1)
|
| 306 |
+
G.add_edge("Champtercier", "Myriel", weight=1)
|
| 307 |
+
G.add_edge("Cravatte", "Myriel", weight=1)
|
| 308 |
+
G.add_edge("Count", "Myriel", weight=2)
|
| 309 |
+
G.add_edge("OldMan", "Myriel", weight=1)
|
| 310 |
+
G.add_edge("Valjean", "Labarre", weight=1)
|
| 311 |
+
G.add_edge("Valjean", "MmeMagloire", weight=3)
|
| 312 |
+
G.add_edge("Valjean", "MlleBaptistine", weight=3)
|
| 313 |
+
G.add_edge("Valjean", "Myriel", weight=5)
|
| 314 |
+
G.add_edge("Marguerite", "Valjean", weight=1)
|
| 315 |
+
G.add_edge("MmeDeR", "Valjean", weight=1)
|
| 316 |
+
G.add_edge("Isabeau", "Valjean", weight=1)
|
| 317 |
+
G.add_edge("Gervais", "Valjean", weight=1)
|
| 318 |
+
G.add_edge("Listolier", "Tholomyes", weight=4)
|
| 319 |
+
G.add_edge("Fameuil", "Tholomyes", weight=4)
|
| 320 |
+
G.add_edge("Fameuil", "Listolier", weight=4)
|
| 321 |
+
G.add_edge("Blacheville", "Tholomyes", weight=4)
|
| 322 |
+
G.add_edge("Blacheville", "Listolier", weight=4)
|
| 323 |
+
G.add_edge("Blacheville", "Fameuil", weight=4)
|
| 324 |
+
G.add_edge("Favourite", "Tholomyes", weight=3)
|
| 325 |
+
G.add_edge("Favourite", "Listolier", weight=3)
|
| 326 |
+
G.add_edge("Favourite", "Fameuil", weight=3)
|
| 327 |
+
G.add_edge("Favourite", "Blacheville", weight=4)
|
| 328 |
+
G.add_edge("Dahlia", "Tholomyes", weight=3)
|
| 329 |
+
G.add_edge("Dahlia", "Listolier", weight=3)
|
| 330 |
+
G.add_edge("Dahlia", "Fameuil", weight=3)
|
| 331 |
+
G.add_edge("Dahlia", "Blacheville", weight=3)
|
| 332 |
+
G.add_edge("Dahlia", "Favourite", weight=5)
|
| 333 |
+
G.add_edge("Zephine", "Tholomyes", weight=3)
|
| 334 |
+
G.add_edge("Zephine", "Listolier", weight=3)
|
| 335 |
+
G.add_edge("Zephine", "Fameuil", weight=3)
|
| 336 |
+
G.add_edge("Zephine", "Blacheville", weight=3)
|
| 337 |
+
G.add_edge("Zephine", "Favourite", weight=4)
|
| 338 |
+
G.add_edge("Zephine", "Dahlia", weight=4)
|
| 339 |
+
G.add_edge("Fantine", "Tholomyes", weight=3)
|
| 340 |
+
G.add_edge("Fantine", "Listolier", weight=3)
|
| 341 |
+
G.add_edge("Fantine", "Fameuil", weight=3)
|
| 342 |
+
G.add_edge("Fantine", "Blacheville", weight=3)
|
| 343 |
+
G.add_edge("Fantine", "Favourite", weight=4)
|
| 344 |
+
G.add_edge("Fantine", "Dahlia", weight=4)
|
| 345 |
+
G.add_edge("Fantine", "Zephine", weight=4)
|
| 346 |
+
G.add_edge("Fantine", "Marguerite", weight=2)
|
| 347 |
+
G.add_edge("Fantine", "Valjean", weight=9)
|
| 348 |
+
G.add_edge("MmeThenardier", "Fantine", weight=2)
|
| 349 |
+
G.add_edge("MmeThenardier", "Valjean", weight=7)
|
| 350 |
+
G.add_edge("Thenardier", "MmeThenardier", weight=13)
|
| 351 |
+
G.add_edge("Thenardier", "Fantine", weight=1)
|
| 352 |
+
G.add_edge("Thenardier", "Valjean", weight=12)
|
| 353 |
+
G.add_edge("Cosette", "MmeThenardier", weight=4)
|
| 354 |
+
G.add_edge("Cosette", "Valjean", weight=31)
|
| 355 |
+
G.add_edge("Cosette", "Tholomyes", weight=1)
|
| 356 |
+
G.add_edge("Cosette", "Thenardier", weight=1)
|
| 357 |
+
G.add_edge("Javert", "Valjean", weight=17)
|
| 358 |
+
G.add_edge("Javert", "Fantine", weight=5)
|
| 359 |
+
G.add_edge("Javert", "Thenardier", weight=5)
|
| 360 |
+
G.add_edge("Javert", "MmeThenardier", weight=1)
|
| 361 |
+
G.add_edge("Javert", "Cosette", weight=1)
|
| 362 |
+
G.add_edge("Fauchelevent", "Valjean", weight=8)
|
| 363 |
+
G.add_edge("Fauchelevent", "Javert", weight=1)
|
| 364 |
+
G.add_edge("Bamatabois", "Fantine", weight=1)
|
| 365 |
+
G.add_edge("Bamatabois", "Javert", weight=1)
|
| 366 |
+
G.add_edge("Bamatabois", "Valjean", weight=2)
|
| 367 |
+
G.add_edge("Perpetue", "Fantine", weight=1)
|
| 368 |
+
G.add_edge("Simplice", "Perpetue", weight=2)
|
| 369 |
+
G.add_edge("Simplice", "Valjean", weight=3)
|
| 370 |
+
G.add_edge("Simplice", "Fantine", weight=2)
|
| 371 |
+
G.add_edge("Simplice", "Javert", weight=1)
|
| 372 |
+
G.add_edge("Scaufflaire", "Valjean", weight=1)
|
| 373 |
+
G.add_edge("Woman1", "Valjean", weight=2)
|
| 374 |
+
G.add_edge("Woman1", "Javert", weight=1)
|
| 375 |
+
G.add_edge("Judge", "Valjean", weight=3)
|
| 376 |
+
G.add_edge("Judge", "Bamatabois", weight=2)
|
| 377 |
+
G.add_edge("Champmathieu", "Valjean", weight=3)
|
| 378 |
+
G.add_edge("Champmathieu", "Judge", weight=3)
|
| 379 |
+
G.add_edge("Champmathieu", "Bamatabois", weight=2)
|
| 380 |
+
G.add_edge("Brevet", "Judge", weight=2)
|
| 381 |
+
G.add_edge("Brevet", "Champmathieu", weight=2)
|
| 382 |
+
G.add_edge("Brevet", "Valjean", weight=2)
|
| 383 |
+
G.add_edge("Brevet", "Bamatabois", weight=1)
|
| 384 |
+
G.add_edge("Chenildieu", "Judge", weight=2)
|
| 385 |
+
G.add_edge("Chenildieu", "Champmathieu", weight=2)
|
| 386 |
+
G.add_edge("Chenildieu", "Brevet", weight=2)
|
| 387 |
+
G.add_edge("Chenildieu", "Valjean", weight=2)
|
| 388 |
+
G.add_edge("Chenildieu", "Bamatabois", weight=1)
|
| 389 |
+
G.add_edge("Cochepaille", "Judge", weight=2)
|
| 390 |
+
G.add_edge("Cochepaille", "Champmathieu", weight=2)
|
| 391 |
+
G.add_edge("Cochepaille", "Brevet", weight=2)
|
| 392 |
+
G.add_edge("Cochepaille", "Chenildieu", weight=2)
|
| 393 |
+
G.add_edge("Cochepaille", "Valjean", weight=2)
|
| 394 |
+
G.add_edge("Cochepaille", "Bamatabois", weight=1)
|
| 395 |
+
G.add_edge("Pontmercy", "Thenardier", weight=1)
|
| 396 |
+
G.add_edge("Boulatruelle", "Thenardier", weight=1)
|
| 397 |
+
G.add_edge("Eponine", "MmeThenardier", weight=2)
|
| 398 |
+
G.add_edge("Eponine", "Thenardier", weight=3)
|
| 399 |
+
G.add_edge("Anzelma", "Eponine", weight=2)
|
| 400 |
+
G.add_edge("Anzelma", "Thenardier", weight=2)
|
| 401 |
+
G.add_edge("Anzelma", "MmeThenardier", weight=1)
|
| 402 |
+
G.add_edge("Woman2", "Valjean", weight=3)
|
| 403 |
+
G.add_edge("Woman2", "Cosette", weight=1)
|
| 404 |
+
G.add_edge("Woman2", "Javert", weight=1)
|
| 405 |
+
G.add_edge("MotherInnocent", "Fauchelevent", weight=3)
|
| 406 |
+
G.add_edge("MotherInnocent", "Valjean", weight=1)
|
| 407 |
+
G.add_edge("Gribier", "Fauchelevent", weight=2)
|
| 408 |
+
G.add_edge("MmeBurgon", "Jondrette", weight=1)
|
| 409 |
+
G.add_edge("Gavroche", "MmeBurgon", weight=2)
|
| 410 |
+
G.add_edge("Gavroche", "Thenardier", weight=1)
|
| 411 |
+
G.add_edge("Gavroche", "Javert", weight=1)
|
| 412 |
+
G.add_edge("Gavroche", "Valjean", weight=1)
|
| 413 |
+
G.add_edge("Gillenormand", "Cosette", weight=3)
|
| 414 |
+
G.add_edge("Gillenormand", "Valjean", weight=2)
|
| 415 |
+
G.add_edge("Magnon", "Gillenormand", weight=1)
|
| 416 |
+
G.add_edge("Magnon", "MmeThenardier", weight=1)
|
| 417 |
+
G.add_edge("MlleGillenormand", "Gillenormand", weight=9)
|
| 418 |
+
G.add_edge("MlleGillenormand", "Cosette", weight=2)
|
| 419 |
+
G.add_edge("MlleGillenormand", "Valjean", weight=2)
|
| 420 |
+
G.add_edge("MmePontmercy", "MlleGillenormand", weight=1)
|
| 421 |
+
G.add_edge("MmePontmercy", "Pontmercy", weight=1)
|
| 422 |
+
G.add_edge("MlleVaubois", "MlleGillenormand", weight=1)
|
| 423 |
+
G.add_edge("LtGillenormand", "MlleGillenormand", weight=2)
|
| 424 |
+
G.add_edge("LtGillenormand", "Gillenormand", weight=1)
|
| 425 |
+
G.add_edge("LtGillenormand", "Cosette", weight=1)
|
| 426 |
+
G.add_edge("Marius", "MlleGillenormand", weight=6)
|
| 427 |
+
G.add_edge("Marius", "Gillenormand", weight=12)
|
| 428 |
+
G.add_edge("Marius", "Pontmercy", weight=1)
|
| 429 |
+
G.add_edge("Marius", "LtGillenormand", weight=1)
|
| 430 |
+
G.add_edge("Marius", "Cosette", weight=21)
|
| 431 |
+
G.add_edge("Marius", "Valjean", weight=19)
|
| 432 |
+
G.add_edge("Marius", "Tholomyes", weight=1)
|
| 433 |
+
G.add_edge("Marius", "Thenardier", weight=2)
|
| 434 |
+
G.add_edge("Marius", "Eponine", weight=5)
|
| 435 |
+
G.add_edge("Marius", "Gavroche", weight=4)
|
| 436 |
+
G.add_edge("BaronessT", "Gillenormand", weight=1)
|
| 437 |
+
G.add_edge("BaronessT", "Marius", weight=1)
|
| 438 |
+
G.add_edge("Mabeuf", "Marius", weight=1)
|
| 439 |
+
G.add_edge("Mabeuf", "Eponine", weight=1)
|
| 440 |
+
G.add_edge("Mabeuf", "Gavroche", weight=1)
|
| 441 |
+
G.add_edge("Enjolras", "Marius", weight=7)
|
| 442 |
+
G.add_edge("Enjolras", "Gavroche", weight=7)
|
| 443 |
+
G.add_edge("Enjolras", "Javert", weight=6)
|
| 444 |
+
G.add_edge("Enjolras", "Mabeuf", weight=1)
|
| 445 |
+
G.add_edge("Enjolras", "Valjean", weight=4)
|
| 446 |
+
G.add_edge("Combeferre", "Enjolras", weight=15)
|
| 447 |
+
G.add_edge("Combeferre", "Marius", weight=5)
|
| 448 |
+
G.add_edge("Combeferre", "Gavroche", weight=6)
|
| 449 |
+
G.add_edge("Combeferre", "Mabeuf", weight=2)
|
| 450 |
+
G.add_edge("Prouvaire", "Gavroche", weight=1)
|
| 451 |
+
G.add_edge("Prouvaire", "Enjolras", weight=4)
|
| 452 |
+
G.add_edge("Prouvaire", "Combeferre", weight=2)
|
| 453 |
+
G.add_edge("Feuilly", "Gavroche", weight=2)
|
| 454 |
+
G.add_edge("Feuilly", "Enjolras", weight=6)
|
| 455 |
+
G.add_edge("Feuilly", "Prouvaire", weight=2)
|
| 456 |
+
G.add_edge("Feuilly", "Combeferre", weight=5)
|
| 457 |
+
G.add_edge("Feuilly", "Mabeuf", weight=1)
|
| 458 |
+
G.add_edge("Feuilly", "Marius", weight=1)
|
| 459 |
+
G.add_edge("Courfeyrac", "Marius", weight=9)
|
| 460 |
+
G.add_edge("Courfeyrac", "Enjolras", weight=17)
|
| 461 |
+
G.add_edge("Courfeyrac", "Combeferre", weight=13)
|
| 462 |
+
G.add_edge("Courfeyrac", "Gavroche", weight=7)
|
| 463 |
+
G.add_edge("Courfeyrac", "Mabeuf", weight=2)
|
| 464 |
+
G.add_edge("Courfeyrac", "Eponine", weight=1)
|
| 465 |
+
G.add_edge("Courfeyrac", "Feuilly", weight=6)
|
| 466 |
+
G.add_edge("Courfeyrac", "Prouvaire", weight=3)
|
| 467 |
+
G.add_edge("Bahorel", "Combeferre", weight=5)
|
| 468 |
+
G.add_edge("Bahorel", "Gavroche", weight=5)
|
| 469 |
+
G.add_edge("Bahorel", "Courfeyrac", weight=6)
|
| 470 |
+
G.add_edge("Bahorel", "Mabeuf", weight=2)
|
| 471 |
+
G.add_edge("Bahorel", "Enjolras", weight=4)
|
| 472 |
+
G.add_edge("Bahorel", "Feuilly", weight=3)
|
| 473 |
+
G.add_edge("Bahorel", "Prouvaire", weight=2)
|
| 474 |
+
G.add_edge("Bahorel", "Marius", weight=1)
|
| 475 |
+
G.add_edge("Bossuet", "Marius", weight=5)
|
| 476 |
+
G.add_edge("Bossuet", "Courfeyrac", weight=12)
|
| 477 |
+
G.add_edge("Bossuet", "Gavroche", weight=5)
|
| 478 |
+
G.add_edge("Bossuet", "Bahorel", weight=4)
|
| 479 |
+
G.add_edge("Bossuet", "Enjolras", weight=10)
|
| 480 |
+
G.add_edge("Bossuet", "Feuilly", weight=6)
|
| 481 |
+
G.add_edge("Bossuet", "Prouvaire", weight=2)
|
| 482 |
+
G.add_edge("Bossuet", "Combeferre", weight=9)
|
| 483 |
+
G.add_edge("Bossuet", "Mabeuf", weight=1)
|
| 484 |
+
G.add_edge("Bossuet", "Valjean", weight=1)
|
| 485 |
+
G.add_edge("Joly", "Bahorel", weight=5)
|
| 486 |
+
G.add_edge("Joly", "Bossuet", weight=7)
|
| 487 |
+
G.add_edge("Joly", "Gavroche", weight=3)
|
| 488 |
+
G.add_edge("Joly", "Courfeyrac", weight=5)
|
| 489 |
+
G.add_edge("Joly", "Enjolras", weight=5)
|
| 490 |
+
G.add_edge("Joly", "Feuilly", weight=5)
|
| 491 |
+
G.add_edge("Joly", "Prouvaire", weight=2)
|
| 492 |
+
G.add_edge("Joly", "Combeferre", weight=5)
|
| 493 |
+
G.add_edge("Joly", "Mabeuf", weight=1)
|
| 494 |
+
G.add_edge("Joly", "Marius", weight=2)
|
| 495 |
+
G.add_edge("Grantaire", "Bossuet", weight=3)
|
| 496 |
+
G.add_edge("Grantaire", "Enjolras", weight=3)
|
| 497 |
+
G.add_edge("Grantaire", "Combeferre", weight=1)
|
| 498 |
+
G.add_edge("Grantaire", "Courfeyrac", weight=2)
|
| 499 |
+
G.add_edge("Grantaire", "Joly", weight=2)
|
| 500 |
+
G.add_edge("Grantaire", "Gavroche", weight=1)
|
| 501 |
+
G.add_edge("Grantaire", "Bahorel", weight=1)
|
| 502 |
+
G.add_edge("Grantaire", "Feuilly", weight=1)
|
| 503 |
+
G.add_edge("Grantaire", "Prouvaire", weight=1)
|
| 504 |
+
G.add_edge("MotherPlutarch", "Mabeuf", weight=3)
|
| 505 |
+
G.add_edge("Gueulemer", "Thenardier", weight=5)
|
| 506 |
+
G.add_edge("Gueulemer", "Valjean", weight=1)
|
| 507 |
+
G.add_edge("Gueulemer", "MmeThenardier", weight=1)
|
| 508 |
+
G.add_edge("Gueulemer", "Javert", weight=1)
|
| 509 |
+
G.add_edge("Gueulemer", "Gavroche", weight=1)
|
| 510 |
+
G.add_edge("Gueulemer", "Eponine", weight=1)
|
| 511 |
+
G.add_edge("Babet", "Thenardier", weight=6)
|
| 512 |
+
G.add_edge("Babet", "Gueulemer", weight=6)
|
| 513 |
+
G.add_edge("Babet", "Valjean", weight=1)
|
| 514 |
+
G.add_edge("Babet", "MmeThenardier", weight=1)
|
| 515 |
+
G.add_edge("Babet", "Javert", weight=2)
|
| 516 |
+
G.add_edge("Babet", "Gavroche", weight=1)
|
| 517 |
+
G.add_edge("Babet", "Eponine", weight=1)
|
| 518 |
+
G.add_edge("Claquesous", "Thenardier", weight=4)
|
| 519 |
+
G.add_edge("Claquesous", "Babet", weight=4)
|
| 520 |
+
G.add_edge("Claquesous", "Gueulemer", weight=4)
|
| 521 |
+
G.add_edge("Claquesous", "Valjean", weight=1)
|
| 522 |
+
G.add_edge("Claquesous", "MmeThenardier", weight=1)
|
| 523 |
+
G.add_edge("Claquesous", "Javert", weight=1)
|
| 524 |
+
G.add_edge("Claquesous", "Eponine", weight=1)
|
| 525 |
+
G.add_edge("Claquesous", "Enjolras", weight=1)
|
| 526 |
+
G.add_edge("Montparnasse", "Javert", weight=1)
|
| 527 |
+
G.add_edge("Montparnasse", "Babet", weight=2)
|
| 528 |
+
G.add_edge("Montparnasse", "Gueulemer", weight=2)
|
| 529 |
+
G.add_edge("Montparnasse", "Claquesous", weight=2)
|
| 530 |
+
G.add_edge("Montparnasse", "Valjean", weight=1)
|
| 531 |
+
G.add_edge("Montparnasse", "Gavroche", weight=1)
|
| 532 |
+
G.add_edge("Montparnasse", "Eponine", weight=1)
|
| 533 |
+
G.add_edge("Montparnasse", "Thenardier", weight=1)
|
| 534 |
+
G.add_edge("Toussaint", "Cosette", weight=2)
|
| 535 |
+
G.add_edge("Toussaint", "Javert", weight=1)
|
| 536 |
+
G.add_edge("Toussaint", "Valjean", weight=1)
|
| 537 |
+
G.add_edge("Child1", "Gavroche", weight=2)
|
| 538 |
+
G.add_edge("Child2", "Gavroche", weight=2)
|
| 539 |
+
G.add_edge("Child2", "Child1", weight=3)
|
| 540 |
+
G.add_edge("Brujon", "Babet", weight=3)
|
| 541 |
+
G.add_edge("Brujon", "Gueulemer", weight=3)
|
| 542 |
+
G.add_edge("Brujon", "Thenardier", weight=3)
|
| 543 |
+
G.add_edge("Brujon", "Gavroche", weight=1)
|
| 544 |
+
G.add_edge("Brujon", "Eponine", weight=1)
|
| 545 |
+
G.add_edge("Brujon", "Claquesous", weight=1)
|
| 546 |
+
G.add_edge("Brujon", "Montparnasse", weight=1)
|
| 547 |
+
G.add_edge("MmeHucheloup", "Bossuet", weight=1)
|
| 548 |
+
G.add_edge("MmeHucheloup", "Joly", weight=1)
|
| 549 |
+
G.add_edge("MmeHucheloup", "Grantaire", weight=1)
|
| 550 |
+
G.add_edge("MmeHucheloup", "Bahorel", weight=1)
|
| 551 |
+
G.add_edge("MmeHucheloup", "Courfeyrac", weight=1)
|
| 552 |
+
G.add_edge("MmeHucheloup", "Gavroche", weight=1)
|
| 553 |
+
G.add_edge("MmeHucheloup", "Enjolras", weight=1)
|
| 554 |
+
return G
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/spectral_graph_forge.py
ADDED
|
@@ -0,0 +1,120 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
"""Generates graphs with a given eigenvector structure"""
|
| 2 |
+
|
| 3 |
+
import networkx as nx
|
| 4 |
+
from networkx.utils import np_random_state
|
| 5 |
+
|
| 6 |
+
__all__ = ["spectral_graph_forge"]
|
| 7 |
+
|
| 8 |
+
|
| 9 |
+
@np_random_state(3)
|
| 10 |
+
@nx._dispatchable(returns_graph=True)
|
| 11 |
+
def spectral_graph_forge(G, alpha, transformation="identity", seed=None):
|
| 12 |
+
"""Returns a random simple graph with spectrum resembling that of `G`
|
| 13 |
+
|
| 14 |
+
This algorithm, called Spectral Graph Forge (SGF), computes the
|
| 15 |
+
eigenvectors of a given graph adjacency matrix, filters them and
|
| 16 |
+
builds a random graph with a similar eigenstructure.
|
| 17 |
+
SGF has been proved to be particularly useful for synthesizing
|
| 18 |
+
realistic social networks and it can also be used to anonymize
|
| 19 |
+
graph sensitive data.
|
| 20 |
+
|
| 21 |
+
Parameters
|
| 22 |
+
----------
|
| 23 |
+
G : Graph
|
| 24 |
+
alpha : float
|
| 25 |
+
Ratio representing the percentage of eigenvectors of G to consider,
|
| 26 |
+
values in [0,1].
|
| 27 |
+
transformation : string, optional
|
| 28 |
+
Represents the intended matrix linear transformation, possible values
|
| 29 |
+
are 'identity' and 'modularity'
|
| 30 |
+
seed : integer, random_state, or None (default)
|
| 31 |
+
Indicator of numpy random number generation state.
|
| 32 |
+
See :ref:`Randomness<randomness>`.
|
| 33 |
+
|
| 34 |
+
Returns
|
| 35 |
+
-------
|
| 36 |
+
H : Graph
|
| 37 |
+
A graph with a similar eigenvector structure of the input one.
|
| 38 |
+
|
| 39 |
+
Raises
|
| 40 |
+
------
|
| 41 |
+
NetworkXError
|
| 42 |
+
If transformation has a value different from 'identity' or 'modularity'
|
| 43 |
+
|
| 44 |
+
Notes
|
| 45 |
+
-----
|
| 46 |
+
Spectral Graph Forge (SGF) generates a random simple graph resembling the
|
| 47 |
+
global properties of the given one.
|
| 48 |
+
It leverages the low-rank approximation of the associated adjacency matrix
|
| 49 |
+
driven by the *alpha* precision parameter.
|
| 50 |
+
SGF preserves the number of nodes of the input graph and their ordering.
|
| 51 |
+
This way, nodes of output graphs resemble the properties of the input one
|
| 52 |
+
and attributes can be directly mapped.
|
| 53 |
+
|
| 54 |
+
It considers the graph adjacency matrices which can optionally be
|
| 55 |
+
transformed to other symmetric real matrices (currently transformation
|
| 56 |
+
options include *identity* and *modularity*).
|
| 57 |
+
The *modularity* transformation, in the sense of Newman's modularity matrix
|
| 58 |
+
allows the focusing on community structure related properties of the graph.
|
| 59 |
+
|
| 60 |
+
SGF applies a low-rank approximation whose fixed rank is computed from the
|
| 61 |
+
ratio *alpha* of the input graph adjacency matrix dimension.
|
| 62 |
+
This step performs a filtering on the input eigenvectors similar to the low
|
| 63 |
+
pass filtering common in telecommunications.
|
| 64 |
+
|
| 65 |
+
The filtered values (after truncation) are used as input to a Bernoulli
|
| 66 |
+
sampling for constructing a random adjacency matrix.
|
| 67 |
+
|
| 68 |
+
References
|
| 69 |
+
----------
|
| 70 |
+
.. [1] L. Baldesi, C. T. Butts, A. Markopoulou, "Spectral Graph Forge:
|
| 71 |
+
Graph Generation Targeting Modularity", IEEE Infocom, '18.
|
| 72 |
+
https://arxiv.org/abs/1801.01715
|
| 73 |
+
.. [2] M. Newman, "Networks: an introduction", Oxford university press,
|
| 74 |
+
2010
|
| 75 |
+
|
| 76 |
+
Examples
|
| 77 |
+
--------
|
| 78 |
+
>>> G = nx.karate_club_graph()
|
| 79 |
+
>>> H = nx.spectral_graph_forge(G, 0.3)
|
| 80 |
+
>>>
|
| 81 |
+
"""
|
| 82 |
+
import numpy as np
|
| 83 |
+
import scipy as sp
|
| 84 |
+
|
| 85 |
+
available_transformations = ["identity", "modularity"]
|
| 86 |
+
alpha = np.clip(alpha, 0, 1)
|
| 87 |
+
A = nx.to_numpy_array(G)
|
| 88 |
+
n = A.shape[1]
|
| 89 |
+
level = round(n * alpha)
|
| 90 |
+
|
| 91 |
+
if transformation not in available_transformations:
|
| 92 |
+
msg = f"{transformation!r} is not a valid transformation. "
|
| 93 |
+
msg += f"Transformations: {available_transformations}"
|
| 94 |
+
raise nx.NetworkXError(msg)
|
| 95 |
+
|
| 96 |
+
K = np.ones((1, n)) @ A
|
| 97 |
+
|
| 98 |
+
B = A
|
| 99 |
+
if transformation == "modularity":
|
| 100 |
+
B -= K.T @ K / K.sum()
|
| 101 |
+
|
| 102 |
+
# Compute low-rank approximation of B
|
| 103 |
+
evals, evecs = np.linalg.eigh(B)
|
| 104 |
+
k = np.argsort(np.abs(evals))[::-1] # indices of evals in descending order
|
| 105 |
+
evecs[:, k[np.arange(level, n)]] = 0 # set smallest eigenvectors to 0
|
| 106 |
+
B = evecs @ np.diag(evals) @ evecs.T
|
| 107 |
+
|
| 108 |
+
if transformation == "modularity":
|
| 109 |
+
B += K.T @ K / K.sum()
|
| 110 |
+
|
| 111 |
+
B = np.clip(B, 0, 1)
|
| 112 |
+
np.fill_diagonal(B, 0)
|
| 113 |
+
|
| 114 |
+
for i in range(n - 1):
|
| 115 |
+
B[i, i + 1 :] = sp.stats.bernoulli.rvs(B[i, i + 1 :], random_state=seed)
|
| 116 |
+
B[i + 1 :, i] = np.transpose(B[i, i + 1 :])
|
| 117 |
+
|
| 118 |
+
H = nx.from_numpy_array(B)
|
| 119 |
+
|
| 120 |
+
return H
|
evalkit_tf446/lib/python3.10/site-packages/networkx/generators/sudoku.py
ADDED
|
@@ -0,0 +1,131 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
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|
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|
|
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|
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|
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|
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"""Generator for Sudoku graphs
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This module gives a generator for n-Sudoku graphs. It can be used to develop
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algorithms for solving or generating Sudoku puzzles.
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+
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A completed Sudoku grid is a 9x9 array of integers between 1 and 9, with no
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number appearing twice in the same row, column, or 3x3 box.
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+
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+---------+---------+---------+
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+
| | 8 6 4 | | 3 7 1 | | 2 5 9 |
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+
| | 3 2 5 | | 8 4 9 | | 7 6 1 |
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+
| | 9 7 1 | | 2 6 5 | | 8 4 3 |
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+
+---------+---------+---------+
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+
| | 4 3 6 | | 1 9 2 | | 5 8 7 |
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+
| | 1 9 8 | | 6 5 7 | | 4 3 2 |
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| 16 |
+
| | 2 5 7 | | 4 8 3 | | 9 1 6 |
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+---------+---------+---------+
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+
| | 6 8 9 | | 7 3 4 | | 1 2 5 |
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+
| | 7 1 3 | | 5 2 8 | | 6 9 4 |
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+
| | 5 4 2 | | 9 1 6 | | 3 7 8 |
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+
+---------+---------+---------+
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+
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+
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The Sudoku graph is an undirected graph with 81 vertices, corresponding to
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the cells of a Sudoku grid. It is a regular graph of degree 20. Two distinct
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vertices are adjacent if and only if the corresponding cells belong to the
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same row, column, or box. A completed Sudoku grid corresponds to a vertex
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coloring of the Sudoku graph with nine colors.
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+
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More generally, the n-Sudoku graph is a graph with n^4 vertices, corresponding
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+
to the cells of an n^2 by n^2 grid. Two distinct vertices are adjacent if and
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only if they belong to the same row, column, or n by n box.
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+
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References
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----------
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.. [1] Herzberg, A. M., & Murty, M. R. (2007). Sudoku squares and chromatic
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polynomials. Notices of the AMS, 54(6), 708-717.
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+
.. [2] Sander, Torsten (2009), "Sudoku graphs are integral",
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Electronic Journal of Combinatorics, 16 (1): Note 25, 7pp, MR 2529816
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.. [3] Wikipedia contributors. "Glossary of Sudoku." Wikipedia, The Free
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Encyclopedia, 3 Dec. 2019. Web. 22 Dec. 2019.
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"""
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import networkx as nx
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from networkx.exception import NetworkXError
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+
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__all__ = ["sudoku_graph"]
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+
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+
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@nx._dispatchable(graphs=None, returns_graph=True)
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def sudoku_graph(n=3):
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"""Returns the n-Sudoku graph. The default value of n is 3.
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+
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The n-Sudoku graph is a graph with n^4 vertices, corresponding to the
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cells of an n^2 by n^2 grid. Two distinct vertices are adjacent if and
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only if they belong to the same row, column, or n-by-n box.
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+
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Parameters
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----------
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n: integer
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The order of the Sudoku graph, equal to the square root of the
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number of rows. The default is 3.
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+
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Returns
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-------
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NetworkX graph
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The n-Sudoku graph Sud(n).
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+
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Examples
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--------
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>>> G = nx.sudoku_graph()
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>>> G.number_of_nodes()
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+
81
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>>> G.number_of_edges()
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+
810
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>>> sorted(G.neighbors(42))
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[6, 15, 24, 33, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 51, 52, 53, 60, 69, 78]
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>>> G = nx.sudoku_graph(2)
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>>> G.number_of_nodes()
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16
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>>> G.number_of_edges()
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56
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+
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References
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----------
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+
.. [1] Herzberg, A. M., & Murty, M. R. (2007). Sudoku squares and chromatic
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polynomials. Notices of the AMS, 54(6), 708-717.
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+
.. [2] Sander, Torsten (2009), "Sudoku graphs are integral",
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Electronic Journal of Combinatorics, 16 (1): Note 25, 7pp, MR 2529816
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.. [3] Wikipedia contributors. "Glossary of Sudoku." Wikipedia, The Free
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Encyclopedia, 3 Dec. 2019. Web. 22 Dec. 2019.
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"""
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if n < 0:
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raise NetworkXError("The order must be greater than or equal to zero.")
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n2 = n * n
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n3 = n2 * n
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n4 = n3 * n
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+
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# Construct an empty graph with n^4 nodes
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G = nx.empty_graph(n4)
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+
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# A Sudoku graph of order 0 or 1 has no edges
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if n < 2:
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return G
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+
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# Add edges for cells in the same row
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for row_no in range(n2):
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row_start = row_no * n2
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for j in range(1, n2):
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for i in range(j):
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G.add_edge(row_start + i, row_start + j)
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+
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# Add edges for cells in the same column
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for col_no in range(n2):
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for j in range(col_no, n4, n2):
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for i in range(col_no, j, n2):
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G.add_edge(i, j)
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+
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# Add edges for cells in the same box
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for band_no in range(n):
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for stack_no in range(n):
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box_start = n3 * band_no + n * stack_no
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for j in range(1, n2):
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for i in range(j):
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u = box_start + (i % n) + n2 * (i // n)
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v = box_start + (j % n) + n2 * (j // n)
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G.add_edge(u, v)
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+
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return G
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