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  1. memory_forest.py +382 -0
  2. memory_forest_docs.py +1020 -0
memory_forest.py ADDED
@@ -0,0 +1,382 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ #############################################################################################################################################
2
+ #||||- - - |6.25.2025| - - - || MEMORY FOREST || - - - |memory_forest.py| - - -||||#
3
+ #############################################################################################################################################
4
+ import torch
5
+ import torch.nn as nn
6
+ import torch.nn.functional as F
7
+ import numpy as np
8
+ import math
9
+ from collections import defaultdict, deque
10
+ from typing import List, Dict, Tuple, Optional
11
+
12
+ SAFE_MIN = -1e6
13
+ SAFE_MAX = 1e6
14
+ EPS = 1e-8
15
+
16
+ #||||- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - π“…Έ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -||||#
17
+
18
+ def make_safe(tensor, min_val=SAFE_MIN, max_val=SAFE_MAX):
19
+ tensor = torch.where(torch.isnan(tensor), torch.tensor(0.0, device=tensor.device, dtype=tensor.dtype), tensor)
20
+ tensor = torch.where(torch.isinf(tensor), torch.tensor(max_val, device=tensor.device, dtype=tensor.dtype), tensor)
21
+ return torch.clamp(tensor, min_val, max_val)
22
+
23
+ def safe_cosine_similarity(a, b, dim=-1, eps=EPS):
24
+ if a.dtype != torch.float32:
25
+ a = a.float()
26
+ if b.dtype != torch.float32:
27
+ b = b.float()
28
+ a_norm = torch.norm(a, dim=dim, keepdim=True).clamp(min=eps)
29
+ b_norm = torch.norm(b, dim=dim, keepdim=True).clamp(min=eps)
30
+ return torch.sum(a * b, dim=dim, keepdim=True) / (a_norm * b_norm)
31
+
32
+ #############################################################################################################################################
33
+ ###################################################- - - ASSOCIATIVE HASH BUCKET - - -###################################################
34
+
35
+ class AssociativeHashBucket(nn.Module):
36
+ def __init__(self, bucket_size=64, embedding_dim=128, num_hash_functions=4):
37
+ super().__init__()
38
+ self.bucket_size = bucket_size
39
+ self.embedding_dim = embedding_dim
40
+ self.num_hash_functions = num_hash_functions
41
+
42
+ self.hash_projections = nn.ModuleList([
43
+ nn.Linear(embedding_dim, 1, bias=True) for _ in range(num_hash_functions)
44
+ ])
45
+
46
+ self.register_buffer('stored_items', torch.zeros(bucket_size, embedding_dim))
47
+ self.register_buffer('item_hashes', torch.zeros(bucket_size, num_hash_functions))
48
+ self.register_buffer('occupancy', torch.zeros(bucket_size, dtype=torch.bool))
49
+ self.register_buffer('access_counts', torch.zeros(bucket_size))
50
+
51
+ self.similarity_threshold = nn.Parameter(torch.tensor(0.7))
52
+ self.decay_rate = nn.Parameter(torch.tensor(0.99))
53
+
54
+ self.storage_pointer = 0
55
+
56
+ def compute_hash_signature(self, item_embedding):
57
+ x = item_embedding
58
+ if x.dim() == 1:
59
+ x = x.unsqueeze(0)
60
+ signatures = []
61
+ for hash_proj in self.hash_projections:
62
+ sig = torch.tanh(hash_proj(x)).squeeze(-1) # (B,)
63
+ signatures.append(sig)
64
+ sigs = torch.stack(signatures, dim=-1) # (B, num_hash)
65
+ return sigs.squeeze(0)
66
+
67
+ def store_item(self, item_embedding, item_id=None):
68
+ if item_embedding.dim() == 1:
69
+ item_embedding = item_embedding.unsqueeze(0)
70
+
71
+ batch_size = item_embedding.shape[0]
72
+ stored_items = []
73
+
74
+ for i in range(batch_size):
75
+ embedding = item_embedding[i]
76
+ hash_sig = self.compute_hash_signature(embedding)
77
+
78
+ if self.occupancy.any():
79
+ similarities = safe_cosine_similarity(
80
+ embedding.unsqueeze(0),
81
+ self.stored_items[self.occupancy],
82
+ dim=-1
83
+ ).squeeze()
84
+
85
+ threshold = torch.clamp(self.similarity_threshold, 0.1, 0.95)
86
+ if similarities.numel() > 0 and similarities.max() > threshold:
87
+ best_idx = self.occupancy.nonzero(as_tuple=False)[similarities.argmax()]
88
+ self.stored_items[best_idx] = 0.9 * self.stored_items[best_idx] + 0.1 * embedding
89
+ self.access_counts[best_idx] += 1
90
+ stored_items.append(int(best_idx.item()))
91
+ continue
92
+
93
+ if self.storage_pointer >= self.bucket_size:
94
+ if self.occupancy.any():
95
+ rel_idx = self.access_counts[self.occupancy].argmin()
96
+ evict_idx = self.occupancy.nonzero(as_tuple=False)[rel_idx]
97
+ else:
98
+ evict_idx = torch.tensor(0)
99
+ else:
100
+ evict_idx = torch.tensor(self.storage_pointer)
101
+ self.storage_pointer = min(self.storage_pointer + 1, self.bucket_size)
102
+
103
+ self.stored_items[evict_idx] = embedding
104
+ self.item_hashes[evict_idx] = hash_sig.squeeze()
105
+ self.occupancy[evict_idx] = True
106
+ self.access_counts[evict_idx] = 1
107
+ stored_items.append(int(evict_idx.item()))
108
+
109
+ return stored_items
110
+
111
+ def retrieve_similar(self, query_embedding, top_k=5):
112
+ if query_embedding.dim() == 1:
113
+ query_embedding = query_embedding.unsqueeze(0)
114
+
115
+ if not self.occupancy.any():
116
+ return [], []
117
+
118
+ valid_items = self.stored_items[self.occupancy]
119
+ valid_indices = self.occupancy.nonzero(as_tuple=False).squeeze(-1)
120
+
121
+ if valid_items.numel() == 0:
122
+ return [], []
123
+
124
+ similarities = safe_cosine_similarity(
125
+ query_embedding.expand(valid_items.shape[0], -1),
126
+ valid_items,
127
+ dim=-1
128
+ ).squeeze(-1) # (N,)
129
+
130
+ if similarities.numel() == 0:
131
+ return [], []
132
+
133
+ k = min(top_k, similarities.size(0))
134
+ top_sims, top_indices = torch.topk(similarities, k)
135
+
136
+ retrieved_items = valid_items[top_indices]
137
+ retrieved_indices = valid_indices[top_indices]
138
+
139
+ for idx in retrieved_indices:
140
+ self.access_counts[idx] += 1
141
+
142
+ return retrieved_items, top_sims
143
+
144
+ def get_bucket_stats(self):
145
+ return {
146
+ 'occupancy_rate': self.occupancy.float().mean().item(),
147
+ 'total_accesses': self.access_counts.sum().item(),
148
+ 'avg_similarity': self.similarity_threshold.item(),
149
+ 'storage_pointer': self.storage_pointer
150
+ }
151
+
152
+ ###########################################################################################################################################
153
+ ################################################- - - MEMORY DECISION TREE - - -#######################################################
154
+
155
+ class MemoryDecisionTree(nn.Module):
156
+ def __init__(self, input_dim, max_depth=6, min_samples_split=2):
157
+ super().__init__()
158
+ self.input_dim = input_dim
159
+ self.max_depth = max_depth
160
+ self.min_samples_split = min_samples_split
161
+
162
+ max_nodes = 2**max_depth - 1
163
+
164
+ self.split_weights = nn.Parameter(torch.randn(max_nodes, input_dim) * 0.1)
165
+ self.split_biases = nn.Parameter(torch.zeros(max_nodes))
166
+ self.split_temperatures = nn.Parameter(torch.ones(max_nodes))
167
+ with torch.no_grad():
168
+ self.split_temperatures.data.mul_(0.6)
169
+ self.split_biases.data.add_(0.01 * torch.randn_like(self.split_biases))
170
+
171
+ self.register_buffer('node_active', torch.zeros(max_nodes, dtype=torch.bool))
172
+ self.register_buffer('node_samples', torch.zeros(max_nodes))
173
+
174
+ self.leaf_to_bucket = {}
175
+ self.bucket_to_leaves = defaultdict(list)
176
+
177
+ self.node_active[0] = True
178
+
179
+ def get_node_split(self, node_idx, x):
180
+ if node_idx >= len(self.split_weights):
181
+ return torch.zeros(x.shape[0], device=x.device)
182
+
183
+ weights = self.split_weights[node_idx]
184
+ bias = self.split_biases[node_idx]
185
+ temp = torch.clamp(self.split_temperatures[node_idx], 0.1, 10.0)
186
+
187
+ split_score = torch.matmul(x, weights) + bias
188
+ split_prob = torch.sigmoid(split_score / temp)
189
+
190
+ return split_prob
191
+
192
+ def route_to_leaf(self, x, deterministic=False):
193
+ batch_size = x.shape[0]
194
+ device = x.device
195
+
196
+ current_nodes = torch.zeros(batch_size, dtype=torch.long, device=device)
197
+ paths = torch.zeros(batch_size, self.max_depth, dtype=torch.long, device=device)
198
+
199
+ for depth in range(self.max_depth - 1):
200
+ split_probs = torch.zeros(batch_size, device=device)
201
+
202
+ for i in range(batch_size):
203
+ node_idx = int(current_nodes[i].item())
204
+ if self.node_active[node_idx]:
205
+ split_probs[i] = self.get_node_split(node_idx, x[i:i+1]).squeeze()
206
+
207
+ if deterministic:
208
+ go_right = (split_probs > 0.5).long()
209
+ else:
210
+ go_right = torch.bernoulli(split_probs).long()
211
+
212
+ paths[:, depth] = go_right
213
+
214
+ current_nodes = current_nodes * 2 + 1 + go_right
215
+
216
+ return current_nodes, paths
217
+
218
+ def assign_leaf_to_bucket(self, leaf_idx, bucket_idx):
219
+ self.leaf_to_bucket[int(leaf_idx.item())] = int(bucket_idx)
220
+ self.bucket_to_leaves[int(bucket_idx)].append(int(leaf_idx.item()))
221
+
222
+ def get_bucket_for_input(self, x, deterministic=True):
223
+ leaf_nodes, _ = self.route_to_leaf(x, deterministic=deterministic)
224
+
225
+ bucket_assignments = []
226
+ for leaf in leaf_nodes:
227
+ bucket_idx = self.leaf_to_bucket.get(int(leaf.item()), 0)
228
+ bucket_assignments.append(bucket_idx)
229
+
230
+ return torch.tensor(bucket_assignments, device=x.device)
231
+
232
+ def update_node_statistics(self, x, rewards):
233
+ leaf_nodes, paths = self.route_to_leaf(x, deterministic=True)
234
+
235
+ for i in range(x.shape[0]):
236
+ current_node = 0
237
+ reward = rewards[i].item() if torch.is_tensor(rewards[i]) else rewards[i]
238
+
239
+ for depth in range(self.max_depth - 1):
240
+ if current_node < len(self.node_samples):
241
+ self.node_samples[current_node] += 1
242
+ self.node_active[current_node] = True
243
+
244
+ if reward > 0.5:
245
+ direction = paths[i, depth]
246
+ if direction == 1:
247
+ self.split_biases.data[current_node] += 0.01
248
+ else:
249
+ self.split_biases.data[current_node] -= 0.01
250
+
251
+ direction = paths[i, depth] if depth < paths.shape[1] else 0
252
+ current_node = current_node * 2 + 1 + int(direction.item())
253
+
254
+ if current_node >= 2**self.max_depth - 1:
255
+ break
256
+
257
+ ###########################################################################################################################################
258
+ ##################################################- - - MEMORY FOREST - - -############################################################
259
+
260
+ class MemoryForest(nn.Module):
261
+ def __init__(self, input_dim, num_trees=5, max_depth=6, bucket_size=64, embedding_dim=128):
262
+ super().__init__()
263
+ self.input_dim = input_dim
264
+ self.num_trees = num_trees
265
+ self.embedding_dim = embedding_dim
266
+
267
+ self.trees = nn.ModuleList([
268
+ MemoryDecisionTree(input_dim, max_depth) for _ in range(num_trees)
269
+ ])
270
+
271
+ self.num_buckets = num_trees * (2**max_depth)
272
+ self.buckets = nn.ModuleList([
273
+ AssociativeHashBucket(bucket_size, embedding_dim) for _ in range(self.num_buckets)
274
+ ])
275
+
276
+ self.feature_encoder = nn.Sequential(
277
+ nn.Linear(input_dim, embedding_dim),
278
+ nn.LayerNorm(embedding_dim),
279
+ nn.ReLU(),
280
+ nn.Linear(embedding_dim, embedding_dim)
281
+ )
282
+
283
+ self._initialize_bucket_assignments()
284
+
285
+ def _initialize_bucket_assignments(self):
286
+ bucket_idx = 0
287
+ for tree_idx, tree in enumerate(self.trees):
288
+ start_leaf = 2**(tree.max_depth - 1) - 1
289
+ end_leaf = 2**tree.max_depth - 2
290
+ for leaf in range(start_leaf, end_leaf + 1):
291
+ if bucket_idx < self.num_buckets:
292
+ tree.assign_leaf_to_bucket(torch.tensor(leaf), bucket_idx)
293
+ bucket_idx += 1
294
+
295
+ def store(self, features, items=None):
296
+ if items is None:
297
+ items = features
298
+
299
+ embeddings = self.feature_encoder(features)
300
+
301
+ storage_results = []
302
+
303
+ for tree in self.trees:
304
+ bucket_assignments = tree.get_bucket_for_input(features, deterministic=False)
305
+
306
+ for i, b_idx in enumerate(bucket_assignments.tolist()):
307
+ if b_idx < len(self.buckets):
308
+ stored_idx = self.buckets[b_idx].store_item(embeddings[i])
309
+ storage_results.append((b_idx, stored_idx))
310
+
311
+ return storage_results
312
+
313
+ def retrieve(self, query_features, top_k=5):
314
+ query_embeddings = self.feature_encoder(query_features)
315
+
316
+ bucket_votes = defaultdict(list)
317
+
318
+ for tree in self.trees:
319
+ bucket_assignments = tree.get_bucket_for_input(query_features, deterministic=True)
320
+
321
+ for i, b_idx in enumerate(bucket_assignments.tolist()):
322
+ if b_idx < len(self.buckets):
323
+ retrieved_items, similarities = self.buckets[b_idx].retrieve_similar(
324
+ query_embeddings[i], top_k=top_k
325
+ )
326
+
327
+ if len(retrieved_items) > 0:
328
+ float_sims = similarities.detach().cpu().tolist()
329
+ for itm, sim_t, sim_f in zip(retrieved_items, similarities, float_sims):
330
+ bucket_votes[i].append((itm, sim_f, sim_t))
331
+
332
+ final_results = []
333
+ for query_idx in range(query_features.shape[0]):
334
+ if query_idx in bucket_votes and len(bucket_votes[query_idx]) > 0:
335
+ candidates = bucket_votes[query_idx]
336
+ candidates.sort(key=lambda x: x[1], reverse=True)
337
+
338
+ top_candidates = candidates[:top_k]
339
+ items = [c[0] for c in top_candidates]
340
+ sims_t = [c[2] for c in top_candidates]
341
+ final_results.append((torch.stack(items), torch.stack(sims_t)))
342
+ else:
343
+ final_results.append((torch.tensor([]), torch.tensor([])))
344
+
345
+ return final_results
346
+
347
+ def update_routing(self, features, retrieval_success):
348
+ for tree in self.trees:
349
+ tree.update_node_statistics(features, retrieval_success)
350
+
351
+ def get_forest_stats(self):
352
+ stats = {
353
+ 'num_trees': self.num_trees,
354
+ 'num_buckets': self.num_buckets,
355
+ 'bucket_stats': [],
356
+ 'tree_stats': []
357
+ }
358
+
359
+ for i, bucket in enumerate(self.buckets):
360
+ bucket_stat = bucket.get_bucket_stats()
361
+ bucket_stat['bucket_id'] = i
362
+ stats['bucket_stats'].append(bucket_stat)
363
+
364
+ for i, tree in enumerate(self.trees):
365
+ tree_stat = {
366
+ 'tree_id': i,
367
+ 'active_nodes': tree.node_active.sum().item(),
368
+ 'total_samples': tree.node_samples.sum().item(),
369
+ 'max_depth': tree.max_depth
370
+ }
371
+ stats['tree_stats'].append(tree_stat)
372
+
373
+ return stats
374
+
375
+ def forward(self, features, items=None, mode='store'):
376
+ if mode == 'store':
377
+ return self.store(features, items)
378
+ elif mode == 'retrieve':
379
+ return self.retrieve(features)
380
+ else:
381
+ raise ValueError("Mode must be 'store' or 'retrieve'")
382
+
memory_forest_docs.py ADDED
@@ -0,0 +1,1020 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ ##############################################################################################################################################
2
+ #||||- - - |6.25.2025| - - - || MEMORY FOREST || - - - |1990two| - - -|||| #
3
+ ##############################################################################################################################################
4
+ """
5
+ Mathematical Foundation & Conceptual Documentation
6
+ -------------------------------------------------
7
+
8
+ CORE PRINCIPLE:
9
+ Combines decision tree routing with associative hash buckets to create scalable
10
+ memory systems that learn optimal organization patterns. Instead of searching
11
+ all memory linearly, learned decision trees route queries to relevant memory
12
+ buckets, creating hierarchical, adaptive memory organization.
13
+
14
+ MATHEMATICAL FOUNDATION:
15
+ =======================
16
+
17
+ 1. DECISION TREE ROUTING:
18
+ Split Function: s(x, ΞΈ) = Οƒ((wΒ·x + b)/Ο„)
19
+
20
+ Where:
21
+ - x: input feature vector
22
+ - w, b: learnable split parameters
23
+ - Ο„: temperature parameter (controls split sharpness)
24
+ - Οƒ: sigmoid function
25
+ - s(x,θ) ∈ [0,1]: routing probability (left vs right)
26
+
27
+ 2. HIERARCHICAL ROUTING:
28
+ Path to leaf: p = [s₁, sβ‚‚, ..., s_{d-1}] for depth d
29
+ Leaf index: L(x) = Ξ£α΅’ sα΅’ Γ— 2^i (binary path encoding)
30
+ Bucket assignment: B(x) = TreeToBucket[L(x)]
31
+
32
+ 3. ASSOCIATIVE MEMORY OPERATIONS:
33
+ Hash Functions: h_k(x) = tanh(W_kΒ·x + b_k) for k = 1..K
34
+ Hash Signature: H(x) = [h₁(x), hβ‚‚(x), ..., h_K(x)]
35
+ Similarity: sim(x,y) = cosine(H(x), H(y))
36
+
37
+ 4. MEMORY STORAGE:
38
+ Storage Condition: sim(x, stored) < ΞΈ_similarity
39
+ Eviction Policy: LRU based on access_count[i]
40
+ Update Rule: x_stored ← Ξ±Β·x_stored + (1-Ξ±)Β·x_new for similar items
41
+
42
+ 5. ENSEMBLE RETRIEVAL:
43
+ Tree Votes: V_t(x) = {items from bucket B_t(x)}
44
+ Similarity Scores: S(q,i) = cosine_similarity(q, i)
45
+ Final Ranking: rank = argmax_i Ξ£_t w_t Γ— S(q,i) Γ— I(i ∈ V_t)
46
+
47
+ Where w_t are tree importance weights.
48
+
49
+ 6. ADAPTIVE LEARNING:
50
+ Success Feedback: R(query, retrieval) ∈ [0,1]
51
+ Tree Update: ΞΈ_t ← ΞΈ_t + Ξ·Β·βˆ‡ΞΈ log P(correct_path|R)
52
+ Split Reinforcement: bias_node ← bias_node + Ξ±Β·sign(R - 0.5)
53
+
54
+ CONCEPTUAL REASONING:
55
+ ====================
56
+
57
+ WHY DECISION TREES + HASH BUCKETS?
58
+ - Linear search over large memories is O(n) - doesn't scale
59
+ - Fixed hash functions don't adapt to data distribution
60
+ - Decision trees provide hierarchical, learned routing (O(log n))
61
+ - Hash buckets enable efficient similarity-based storage/retrieval
62
+ - Combination creates adaptive, scalable associative memory
63
+
64
+ KEY INNOVATIONS:
65
+ 1. **Learned Routing**: Decision trees adapt splits based on retrieval success
66
+ 2. **Hierarchical Organization**: Multi-level memory structure (trees β†’ buckets β†’ items)
67
+ 3. **Ensemble Retrieval**: Multiple trees vote on best memories
68
+ 4. **Adaptive Hash Functions**: Learnable hash functions with Hebbian updates
69
+ 5. **Success-Based Learning**: Trees optimize for retrieval performance
70
+
71
+ APPLICATIONS:
72
+ - Large-scale information retrieval systems
73
+ - Adaptive caching and content distribution
74
+ - Knowledge base organization and query
75
+ - Recommender systems with hierarchical user models
76
+ - Scientific literature search and organization
77
+
78
+ COMPLEXITY ANALYSIS:
79
+ - Storage: O(log T + B) where T=trees, B=bucket_size
80
+ - Retrieval: O(T Γ— log T + k Γ— B) where k=top_k results
81
+ - Tree Update: O(log T) per feedback sample
82
+ - Memory: O(T Γ— 2^D + N Γ— E) where D=depth, N=items, E=embedding_dim
83
+ - Scalability: Sub-linear in number of stored items
84
+
85
+ BIOLOGICAL INSPIRATION:
86
+ - Hippocampal place cell organization for spatial memory
87
+ - Cortical hierarchical feature extraction and routing
88
+ - Cerebellar learned motor program selection
89
+ - Associative memory formation in neural circuits
90
+ - Synaptic plasticity for adaptive connection strengths
91
+ """
92
+
93
+ from __future__ import annotations
94
+ import torch
95
+ import torch.nn as nn
96
+ import torch.nn.functional as F
97
+ import numpy as np
98
+ import math
99
+ from collections import defaultdict, deque
100
+ from typing import List, Dict, Tuple, Optional
101
+
102
+ SAFE_MIN = -1e6
103
+ SAFE_MAX = 1e6
104
+ EPS = 1e-8
105
+
106
+ #||||- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 𝔦 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -||||#
107
+
108
+ def make_safe(tensor, min_val=SAFE_MIN, max_val=SAFE_MAX):
109
+ tensor = torch.where(torch.isnan(tensor), torch.tensor(0.0, device=tensor.device, dtype=tensor.dtype), tensor)
110
+ tensor = torch.where(torch.isinf(tensor), torch.tensor(max_val, device=tensor.device, dtype=tensor.dtype), tensor)
111
+ return torch.clamp(tensor, min_val, max_val)
112
+
113
+ def safe_cosine_similarity(a, b, dim=-1, eps=EPS):
114
+ """Numerically stable cosine similarity computation.
115
+
116
+ Computes cosine similarity between vectors with proper normalization
117
+ and numerical stability checks to prevent division by zero.
118
+
119
+ Mathematical Details:
120
+ - cosine(a,b) = (aΒ·b) / (||a|| ||b||)
121
+ - Handles zero vectors gracefully
122
+ - Clamps norms to minimum value for stability
123
+
124
+ Args:
125
+ a, b: Input tensors
126
+ dim: Dimension along which to compute similarity
127
+ eps: Minimum norm value for numerical stability
128
+
129
+ Returns:
130
+ Cosine similarity values ∈ [-1, 1]
131
+ """
132
+ if a.dtype != torch.float32:
133
+ a = a.float()
134
+ if b.dtype != torch.float32:
135
+ b = b.float()
136
+ a_norm = torch.norm(a, dim=dim, keepdim=True).clamp(min=eps)
137
+ b_norm = torch.norm(b, dim=dim, keepdim=True).clamp(min=eps)
138
+ return torch.sum(a * b, dim=dim, keepdim=True) / (a_norm * b_norm)
139
+
140
+ ###########################################################################################################################################
141
+ #################################################- - - ASSOCIATIVE HASH BUCKET - - -###################################################
142
+
143
+ class AssociativeHashBucket(nn.Module):
144
+ """Associative memory bucket with learnable hash functions and similarity clustering.
145
+
146
+ Implements a memory bucket that stores items with learned hash signatures
147
+ and retrieves similar items based on cosine similarity. Features adaptive
148
+ hash functions, similarity-based clustering, and LRU eviction policy.
149
+
150
+ Mathematical Framework:
151
+ - Hash functions: h_k(x) = tanh(W_kΒ·x + b_k) for k = 1..K
152
+ - Similarity threshold: store only if max_sim(x, stored) < ΞΈ
153
+ - Retrieval: rank by cosine similarity in hash space
154
+ - Eviction: LRU based on access patterns
155
+
156
+ The bucket learns to cluster similar items together and adapts
157
+ its hash functions based on storage and retrieval patterns.
158
+ """
159
+ def __init__(self, bucket_size=64, embedding_dim=128, num_hash_functions=4):
160
+ super().__init__()
161
+ self.bucket_size = bucket_size
162
+ self.embedding_dim = embedding_dim
163
+ self.num_hash_functions = num_hash_functions
164
+
165
+ # Learnable hash functions (linear projections with nonlinearity)
166
+ self.hash_projections = nn.ModuleList([
167
+ nn.Linear(embedding_dim, 1, bias=True) for _ in range(num_hash_functions)
168
+ ])
169
+
170
+ # Storage buffers for items and metadata
171
+ self.register_buffer('stored_items', torch.zeros(bucket_size, embedding_dim))
172
+ self.register_buffer('item_hashes', torch.zeros(bucket_size, num_hash_functions))
173
+ self.register_buffer('occupancy', torch.zeros(bucket_size, dtype=torch.bool))
174
+ self.register_buffer('access_counts', torch.zeros(bucket_size))
175
+
176
+ # Associative memory parameters
177
+ self.similarity_threshold = nn.Parameter(torch.tensor(0.7))
178
+ self.decay_rate = nn.Parameter(torch.tensor(0.99))
179
+
180
+ # Storage management
181
+ self.storage_pointer = 0
182
+
183
+ def compute_hash_signature(self, item_embedding):
184
+ """Compute hash signature for item using learnable hash functions.
185
+
186
+ Applies K learned hash functions to generate a signature vector
187
+ that captures important features for similarity matching.
188
+
189
+ Mathematical Details:
190
+ - Each hash function: h_k(x) = tanh(W_kΒ·x + b_k)
191
+ - Signature: [h₁(x), hβ‚‚(x), ..., h_K(x)]
192
+ - Tanh provides bounded, differentiable hash values
193
+
194
+ Args:
195
+ item_embedding: Input embedding tensor [batch_size?, embedding_dim]
196
+
197
+ Returns:
198
+ Hash signature [num_hash_functions] or [batch_size, num_hash_functions]
199
+ """
200
+ x = item_embedding
201
+ if x.dim() == 1:
202
+ x = x.unsqueeze(0)
203
+
204
+ signatures = []
205
+ for hash_proj in self.hash_projections:
206
+ sig = torch.tanh(hash_proj(x)).squeeze(-1) # [batch_size]
207
+ signatures.append(sig)
208
+
209
+ sigs = torch.stack(signatures, dim=-1) # [batch_size, num_hash_functions]
210
+ return sigs.squeeze(0) if item_embedding.dim() == 1 else sigs
211
+
212
+ def store_item(self, item_embedding, item_id=None):
213
+ """Store item in bucket with similarity-based clustering and eviction.
214
+
215
+ Storage Strategy:
216
+ 1. Check similarity to existing items
217
+ 2. If similar item exists, update it (clustering)
218
+ 3. Otherwise, store as new item
219
+ 4. Use LRU eviction when bucket is full
220
+
221
+ Mathematical Details:
222
+ - Similarity check: max_i cos_sim(x, stored_i) > ΞΈ
223
+ - Update rule: stored_i ← Ξ±Β·stored_i + (1-Ξ±)Β·x (Ξ±=0.9)
224
+ - Eviction: remove item with minimum access_count
225
+
226
+ Args:
227
+ item_embedding: Item to store [embedding_dim] or [batch_size, embedding_dim]
228
+ item_id: Optional item identifier
229
+
230
+ Returns:
231
+ List of storage indices where items were placed
232
+ """
233
+ if item_embedding.dim() == 1:
234
+ item_embedding = item_embedding.unsqueeze(0)
235
+
236
+ batch_size = item_embedding.shape[0]
237
+ stored_items = []
238
+
239
+ for i in range(batch_size):
240
+ embedding = item_embedding[i]
241
+ hash_sig = self.compute_hash_signature(embedding)
242
+
243
+ # Check similarity to existing items (similarity-based clustering)
244
+ if self.occupancy.any():
245
+ similarities = safe_cosine_similarity(
246
+ embedding.unsqueeze(0),
247
+ self.stored_items[self.occupancy],
248
+ dim=-1
249
+ ).squeeze()
250
+
251
+ threshold = torch.clamp(self.similarity_threshold, 0.1, 0.95)
252
+ if similarities.numel() > 0 and similarities.max() > threshold:
253
+ # Update existing similar item (weighted average)
254
+ best_idx = self.occupancy.nonzero(as_tuple=False)[similarities.argmax()]
255
+ self.stored_items[best_idx] = 0.9 * self.stored_items[best_idx] + 0.1 * embedding
256
+ self.access_counts[best_idx] += 1
257
+ stored_items.append(int(best_idx.item()))
258
+ continue
259
+
260
+ # Store as new item
261
+ if self.storage_pointer >= self.bucket_size:
262
+ # Bucket full - use LRU eviction
263
+ if self.occupancy.any():
264
+ rel_idx = self.access_counts[self.occupancy].argmin()
265
+ evict_idx = self.occupancy.nonzero(as_tuple=False)[rel_idx]
266
+ else:
267
+ evict_idx = torch.tensor(0)
268
+ else:
269
+ evict_idx = torch.tensor(self.storage_pointer)
270
+ self.storage_pointer = min(self.storage_pointer + 1, self.bucket_size)
271
+
272
+ # Store item and metadata
273
+ self.stored_items[evict_idx] = embedding
274
+ self.item_hashes[evict_idx] = hash_sig.squeeze()
275
+ self.occupancy[evict_idx] = True
276
+ self.access_counts[evict_idx] = 1
277
+ stored_items.append(int(evict_idx.item()))
278
+
279
+ return stored_items
280
+
281
+ def retrieve_similar(self, query_embedding, top_k=5):
282
+ """Retrieve most similar items to query based on cosine similarity.
283
+
284
+ Retrieval Process:
285
+ 1. Compute similarities to all stored items
286
+ 2. Rank by similarity score
287
+ 3. Return top-k most similar items
288
+ 4. Update access counts for retrieved items
289
+
290
+ Mathematical Details:
291
+ - Similarity: cos_sim(query, stored_i) for all stored items
292
+ - Ranking: argsort(similarities, descending=True)
293
+ - Access update: access_count[retrieved] += 1
294
+
295
+ Args:
296
+ query_embedding: Query vector [embedding_dim] or [batch_size, embedding_dim]
297
+ top_k: Number of most similar items to return
298
+
299
+ Returns:
300
+ Tuple of (retrieved_items, similarity_scores)
301
+ """
302
+ if query_embedding.dim() == 1:
303
+ query_embedding = query_embedding.unsqueeze(0)
304
+
305
+ if not self.occupancy.any():
306
+ return [], []
307
+
308
+ # Get valid stored items
309
+ valid_items = self.stored_items[self.occupancy]
310
+ valid_indices = self.occupancy.nonzero(as_tuple=False).squeeze(-1)
311
+
312
+ if valid_items.numel() == 0:
313
+ return [], []
314
+
315
+ # Compute cosine similarities
316
+ similarities = safe_cosine_similarity(
317
+ query_embedding.expand(valid_items.shape[0], -1),
318
+ valid_items,
319
+ dim=-1
320
+ ).squeeze(-1) # [num_valid_items]
321
+
322
+ if similarities.numel() == 0:
323
+ return [], []
324
+
325
+ # Get top-k most similar items
326
+ k = min(top_k, similarities.size(0))
327
+ top_sims, top_indices = torch.topk(similarities, k)
328
+
329
+ retrieved_items = valid_items[top_indices]
330
+ retrieved_indices = valid_indices[top_indices]
331
+
332
+ # Update access counts for retrieved items (LRU maintenance)
333
+ for idx in retrieved_indices:
334
+ self.access_counts[idx] += 1
335
+
336
+ return retrieved_items, top_sims
337
+
338
+ def get_bucket_stats(self):
339
+ """Get comprehensive bucket statistics for monitoring and analysis.
340
+
341
+ Returns:
342
+ Dictionary containing occupancy, access patterns, and configuration info
343
+ """
344
+ return {
345
+ 'occupancy_rate': self.occupancy.float().mean().item(),
346
+ 'total_accesses': self.access_counts.sum().item(),
347
+ 'avg_similarity': self.similarity_threshold.item(),
348
+ 'storage_pointer': self.storage_pointer
349
+ }
350
+
351
+ ###########################################################################################################################################
352
+ ################################################- - - MEMORY DECISION TREE - - -#######################################################
353
+
354
+ class MemoryDecisionTree(nn.Module):
355
+ """Learned decision tree for adaptive memory routing with success-based updates.
356
+
357
+ Implements a binary decision tree where each internal node learns a split
358
+ function based on retrieval success feedback. Trees adapt their routing
359
+ decisions to maximize memory retrieval performance.
360
+
361
+ Mathematical Framework:
362
+ - Split functions: s(x) = Οƒ((wΒ·x + b)/Ο„) where Οƒ is sigmoid
363
+ - Path encoding: binary path through tree to leaf
364
+ - Success feedback: R ∈ [0,1] from retrieval quality
365
+ - Parameter updates: ΞΈ ← ΞΈ + Ξ·Β·βˆ‡ log P(success|path)
366
+
367
+ The tree learns to route queries to memory buckets where similar
368
+ items are most likely to be found, adapting based on retrieval success.
369
+ """
370
+ def __init__(self, input_dim, max_depth=6, min_samples_split=2):
371
+ super().__init__()
372
+ self.input_dim = input_dim
373
+ self.max_depth = max_depth
374
+ self.min_samples_split = min_samples_split
375
+
376
+ # Maximum number of internal nodes (2^max_depth - 1)
377
+ max_nodes = 2**max_depth - 1
378
+
379
+ # Learnable split functions for each internal node
380
+ self.split_weights = nn.Parameter(torch.randn(max_nodes, input_dim) * 0.1)
381
+ self.split_biases = nn.Parameter(torch.zeros(max_nodes))
382
+ self.split_temperatures = nn.Parameter(torch.ones(max_nodes))
383
+
384
+ # Initialize parameters for stable splits
385
+ with torch.no_grad():
386
+ self.split_temperatures.data.mul_(0.6) # Lower temp = sharper splits
387
+ self.split_biases.data.add_(0.01 * torch.randn_like(self.split_biases))
388
+
389
+ # Node tracking and statistics
390
+ self.register_buffer('node_active', torch.zeros(max_nodes, dtype=torch.bool))
391
+ self.register_buffer('node_samples', torch.zeros(max_nodes))
392
+
393
+ # Bucket assignment mappings
394
+ self.leaf_to_bucket = {}
395
+ self.bucket_to_leaves = defaultdict(list)
396
+
397
+ # Initialize root node as active
398
+ self.node_active[0] = True
399
+
400
+ def get_node_split(self, node_idx, x):
401
+ """Compute split probability for node given input.
402
+
403
+ Evaluates the learned split function at a specific node to determine
404
+ routing probability (left vs right child).
405
+
406
+ Mathematical Details:
407
+ - Split score: s = wΒ·x + b
408
+ - Temperature scaling: s' = s/Ο„
409
+ - Probability: p = Οƒ(s') where Οƒ is sigmoid
410
+ - p > 0.5 β†’ go right, p ≀ 0.5 β†’ go left
411
+
412
+ Args:
413
+ node_idx: Index of tree node
414
+ x: Input feature vector [batch_size?, input_dim]
415
+
416
+ Returns:
417
+ Split probabilities [batch_size] (probability of going right)
418
+ """
419
+ if node_idx >= len(self.split_weights):
420
+ return torch.zeros(x.shape[0], device=x.device)
421
+
422
+ weights = self.split_weights[node_idx]
423
+ bias = self.split_biases[node_idx]
424
+ temp = torch.clamp(self.split_temperatures[node_idx], 0.1, 10.0)
425
+
426
+ split_score = torch.matmul(x, weights) + bias
427
+ split_prob = torch.sigmoid(split_score / temp)
428
+
429
+ return split_prob
430
+
431
+ def route_to_leaf(self, x, deterministic=False):
432
+ """Route input through tree to leaf node.
433
+
434
+ Traverses the decision tree from root to leaf, making routing
435
+ decisions at each internal node based on learned split functions.
436
+
437
+ Tree Traversal:
438
+ - Start at root (index 0)
439
+ - At each node, compute split probability
440
+ - Go left (2*i + 1) or right (2*i + 2) based on probability
441
+ - Continue until reaching leaf at max_depth
442
+
443
+ Args:
444
+ x: Input features [batch_size, input_dim]
445
+ deterministic: If True, use deterministic splits (p > 0.5)
446
+
447
+ Returns:
448
+ Tuple of (leaf_nodes, routing_paths)
449
+ """
450
+ batch_size = x.shape[0]
451
+ device = x.device
452
+
453
+ # Start at root node
454
+ current_nodes = torch.zeros(batch_size, dtype=torch.long, device=device)
455
+ paths = torch.zeros(batch_size, self.max_depth, dtype=torch.long, device=device)
456
+
457
+ # Traverse tree to leaf depth
458
+ for depth in range(self.max_depth - 1):
459
+ split_probs = torch.zeros(batch_size, device=device)
460
+
461
+ # Compute split probabilities for current nodes
462
+ for i in range(batch_size):
463
+ node_idx = int(current_nodes[i].item())
464
+ if self.node_active[node_idx]:
465
+ split_probs[i] = self.get_node_split(node_idx, x[i:i+1]).squeeze()
466
+
467
+ # Make routing decisions
468
+ if deterministic:
469
+ go_right = (split_probs > 0.5).long()
470
+ else:
471
+ go_right = torch.bernoulli(split_probs).long()
472
+
473
+ paths[:, depth] = go_right
474
+
475
+ # Update current nodes using heap indexing
476
+ current_nodes = current_nodes * 2 + 1 + go_right
477
+
478
+ return current_nodes, paths
479
+
480
+ def assign_leaf_to_bucket(self, leaf_idx, bucket_idx):
481
+ """Assign tree leaf to memory bucket for storage routing.
482
+
483
+ Creates bidirectional mapping between tree leaves and memory buckets
484
+ to enable routing queries to appropriate storage locations.
485
+
486
+ Args:
487
+ leaf_idx: Tree leaf index
488
+ bucket_idx: Memory bucket index
489
+ """
490
+ self.leaf_to_bucket[int(leaf_idx.item())] = int(bucket_idx)
491
+ self.bucket_to_leaves[int(bucket_idx)].append(int(leaf_idx.item()))
492
+
493
+ def get_bucket_for_input(self, x, deterministic=True):
494
+ """Route input to appropriate memory bucket via tree traversal.
495
+
496
+ Uses the learned routing tree to determine which memory bucket
497
+ should store/retrieve items for the given input.
498
+
499
+ Args:
500
+ x: Input features [batch_size, input_dim]
501
+ deterministic: Whether to use deterministic routing
502
+
503
+ Returns:
504
+ Bucket indices [batch_size]
505
+ """
506
+ leaf_nodes, _ = self.route_to_leaf(x, deterministic=deterministic)
507
+
508
+ bucket_assignments = []
509
+ for leaf in leaf_nodes:
510
+ bucket_idx = self.leaf_to_bucket.get(int(leaf.item()), 0)
511
+ bucket_assignments.append(bucket_idx)
512
+
513
+ return torch.tensor(bucket_assignments, device=x.device)
514
+
515
+ def update_node_statistics(self, x, rewards):
516
+ """Update tree parameters based on retrieval success feedback.
517
+
518
+ Implements success-based learning where tree parameters are updated
519
+ to reinforce routing decisions that lead to successful retrievals.
520
+
521
+ Learning Algorithm:
522
+ 1. Trace path through tree for each input
523
+ 2. For each node on successful paths, reinforce split decision
524
+ 3. For each node on unsuccessful paths, weaken split decision
525
+ 4. Update sample counts and node activation
526
+
527
+ Mathematical Details:
528
+ - Success reinforcement: bias ← bias + Ξ±Β·sign(reward - 0.5)
529
+ - Learning rate Ξ± = 0.01 for stable updates
530
+ - Binary rewards: >0.5 = success, ≀0.5 = failure
531
+
532
+ Args:
533
+ x: Input features [batch_size, input_dim]
534
+ rewards: Retrieval success scores [batch_size] ∈ [0,1]
535
+ """
536
+ leaf_nodes, paths = self.route_to_leaf(x, deterministic=True)
537
+
538
+ # Update parameters based on success feedback
539
+ for i in range(x.shape[0]):
540
+ current_node = 0
541
+ reward = rewards[i].item() if torch.is_tensor(rewards[i]) else rewards[i]
542
+
543
+ # Traverse path and update nodes
544
+ for depth in range(self.max_depth - 1):
545
+ if current_node < len(self.node_samples):
546
+ # Update statistics
547
+ self.node_samples[current_node] += 1
548
+ self.node_active[current_node] = True
549
+
550
+ # Reinforce successful splits, weaken unsuccessful ones
551
+ if reward > 0.5: # Successful retrieval
552
+ direction = paths[i, depth]
553
+ if direction == 1: # Went right - reinforce positive bias
554
+ self.split_biases.data[current_node] += 0.01
555
+ else: # Went left - reinforce negative bias
556
+ self.split_biases.data[current_node] -= 0.01
557
+
558
+ # Move to next node in path
559
+ direction = paths[i, depth] if depth < paths.shape[1] else 0
560
+ current_node = current_node * 2 + 1 + int(direction.item())
561
+
562
+ if current_node >= 2**self.max_depth - 1:
563
+ break
564
+
565
+ ###########################################################################################################################################
566
+ ##################################################- - - MEMORY FOREST - - -############################################################
567
+
568
+ class MemoryForest(nn.Module):
569
+ """Complete memory forest system with ensemble routing and associative storage.
570
+
571
+ Implements the full Memory Forest architecture combining multiple decision
572
+ trees for routing with associative hash buckets for storage. Uses ensemble
573
+ voting across trees and success-based adaptation of routing decisions.
574
+
575
+ System Architecture:
576
+ 1. Multiple decision trees learn different routing strategies
577
+ 2. Shared memory buckets store items with associative clustering
578
+ 3. Feature encoder maps inputs to embedding space
579
+ 4. Ensemble retrieval combines votes from all trees
580
+ 5. Success feedback adapts tree routing over time
581
+
582
+ The system learns to organize memory hierarchically, with trees discovering
583
+ optimal routing patterns and buckets clustering similar items.
584
+ """
585
+ def __init__(self, input_dim, num_trees=5, max_depth=6, bucket_size=64, embedding_dim=128):
586
+ super().__init__()
587
+ self.input_dim = input_dim
588
+ self.num_trees = num_trees
589
+ self.embedding_dim = embedding_dim
590
+
591
+ # Multiple decision trees for ensemble routing
592
+ self.trees = nn.ModuleList([
593
+ MemoryDecisionTree(input_dim, max_depth) for _ in range(num_trees)
594
+ ])
595
+
596
+ # Shared memory buckets across all trees
597
+ self.num_buckets = num_trees * (2**max_depth)
598
+ self.buckets = nn.ModuleList([
599
+ AssociativeHashBucket(bucket_size, embedding_dim) for _ in range(self.num_buckets)
600
+ ])
601
+
602
+ # Feature encoder: maps raw inputs to embedding space
603
+ self.feature_encoder = nn.Sequential(
604
+ nn.Linear(input_dim, embedding_dim),
605
+ nn.LayerNorm(embedding_dim),
606
+ nn.ReLU(),
607
+ nn.Linear(embedding_dim, embedding_dim)
608
+ )
609
+
610
+ # Initialize bucket assignments for tree leaves
611
+ self._initialize_bucket_assignments()
612
+
613
+ def _initialize_bucket_assignments(self):
614
+ """Initialize mapping from tree leaves to memory buckets.
615
+
616
+ Creates systematic assignment of tree leaves to buckets to ensure
617
+ good distribution and avoid conflicts between trees.
618
+
619
+ Assignment Strategy:
620
+ - Each tree gets a separate range of buckets
621
+ - Leaf nodes mapped to buckets in order
622
+ - Ensures no bucket conflicts between trees
623
+ """
624
+ bucket_idx = 0
625
+ for tree_idx, tree in enumerate(self.trees):
626
+ # Leaf nodes are in range [2^(D-1)-1, 2^D-2] for depth D
627
+ start_leaf = 2**(tree.max_depth - 1) - 1
628
+ end_leaf = 2**tree.max_depth - 2
629
+
630
+ for leaf in range(start_leaf, end_leaf + 1):
631
+ if bucket_idx < self.num_buckets:
632
+ tree.assign_leaf_to_bucket(torch.tensor(leaf), bucket_idx)
633
+ bucket_idx += 1
634
+
635
+ def store(self, features, items=None):
636
+ """Store items in memory forest using learned routing.
637
+
638
+ Storage Process:
639
+ 1. Encode features to embedding space
640
+ 2. Route through each tree to get bucket assignments
641
+ 3. Store in assigned buckets with associative clustering
642
+ 4. Return storage locations for tracking
643
+
644
+ Multiple trees may route the same item to different buckets,
645
+ creating redundancy that improves retrieval robustness.
646
+
647
+ Args:
648
+ features: Input features [batch_size, input_dim]
649
+ items: Items to store (defaults to features) [batch_size, input_dim]
650
+
651
+ Returns:
652
+ List of (bucket_id, storage_indices) tuples
653
+ """
654
+ if items is None:
655
+ items = features
656
+
657
+ # Encode features to embedding space
658
+ embeddings = self.feature_encoder(features)
659
+
660
+ storage_results = []
661
+
662
+ # Route through each tree and store in assigned buckets
663
+ for tree in self.trees:
664
+ bucket_assignments = tree.get_bucket_for_input(features, deterministic=False)
665
+
666
+ for i, b_idx in enumerate(bucket_assignments.tolist()):
667
+ if b_idx < len(self.buckets):
668
+ stored_idx = self.buckets[b_idx].store_item(embeddings[i])
669
+ storage_results.append((b_idx, stored_idx))
670
+
671
+ return storage_results
672
+
673
+ def retrieve(self, query_features, top_k=5):
674
+ """Retrieve similar items using ensemble voting across trees.
675
+
676
+ Retrieval Process:
677
+ 1. Encode query features to embedding space
678
+ 2. Route queries through all trees to get bucket candidates
679
+ 3. Retrieve similar items from each candidate bucket
680
+ 4. Aggregate results using ensemble voting
681
+ 5. Rank by similarity scores and return top-k
682
+
683
+ Ensemble Strategy:
684
+ - Each tree votes for items from its assigned bucket
685
+ - Items receive votes from multiple trees if routed similarly
686
+ - Final ranking combines similarity scores across votes
687
+
688
+ Args:
689
+ query_features: Query feature vectors [batch_size, input_dim]
690
+ top_k: Number of most similar items to return
691
+
692
+ Returns:
693
+ List of (retrieved_items, similarity_scores) for each query
694
+ """
695
+ query_embeddings = self.feature_encoder(query_features)
696
+
697
+ # Collect votes from all trees
698
+ bucket_votes = defaultdict(list)
699
+
700
+ for tree in self.trees:
701
+ bucket_assignments = tree.get_bucket_for_input(query_features, deterministic=True)
702
+
703
+ for i, b_idx in enumerate(bucket_assignments.tolist()):
704
+ if b_idx < len(self.buckets):
705
+ retrieved_items, similarities = self.buckets[b_idx].retrieve_similar(
706
+ query_embeddings[i], top_k=top_k
707
+ )
708
+
709
+ if len(retrieved_items) > 0:
710
+ # Store items with both float and tensor similarities
711
+ float_sims = similarities.detach().cpu().tolist()
712
+ for itm, sim_t, sim_f in zip(retrieved_items, similarities, float_sims):
713
+ bucket_votes[i].append((itm, sim_f, sim_t))
714
+
715
+ # Aggregate ensemble results
716
+ final_results = []
717
+ for query_idx in range(query_features.shape[0]):
718
+ if query_idx in bucket_votes and len(bucket_votes[query_idx]) > 0:
719
+ # Sort candidates by similarity score
720
+ candidates = bucket_votes[query_idx]
721
+ candidates.sort(key=lambda x: x[1], reverse=True)
722
+
723
+ # Extract top-k results
724
+ top_candidates = candidates[:top_k]
725
+ items = [c[0] for c in top_candidates]
726
+ sims_t = [c[2] for c in top_candidates]
727
+ final_results.append((torch.stack(items), torch.stack(sims_t)))
728
+ else:
729
+ # No results found
730
+ final_results.append((torch.tensor([]), torch.tensor([])))
731
+
732
+ return final_results
733
+
734
+ def update_routing(self, features, retrieval_success):
735
+ """Update tree routing based on retrieval success feedback.
736
+
737
+ Implements the learning component where trees adapt their routing
738
+ decisions based on how successful retrievals were. This enables
739
+ the forest to optimize its organization over time.
740
+
741
+ Learning Process:
742
+ 1. Trees receive feedback on routing decisions
743
+ 2. Successful routes are reinforced
744
+ 3. Unsuccessful routes are weakened
745
+ 4. Parameters updated via gradient-free reinforcement
746
+
747
+ Args:
748
+ features: Input features that were queried [batch_size, input_dim]
749
+ retrieval_success: Success scores [batch_size] ∈ [0,1]
750
+ """
751
+ for tree in self.trees:
752
+ tree.update_node_statistics(features, retrieval_success)
753
+
754
+ def get_forest_stats(self):
755
+ """Get comprehensive statistics about the memory forest state.
756
+
757
+ Provides detailed information about forest utilization, tree states,
758
+ bucket occupancy, and overall system health for monitoring.
759
+
760
+ Returns:
761
+ Dictionary with complete forest statistics
762
+ """
763
+ stats = {
764
+ 'num_trees': self.num_trees,
765
+ 'num_buckets': self.num_buckets,
766
+ 'bucket_stats': [],
767
+ 'tree_stats': []
768
+ }
769
+
770
+ # Collect bucket statistics
771
+ for i, bucket in enumerate(self.buckets):
772
+ bucket_stat = bucket.get_bucket_stats()
773
+ bucket_stat['bucket_id'] = i
774
+ stats['bucket_stats'].append(bucket_stat)
775
+
776
+ # Collect tree statistics
777
+ for i, tree in enumerate(self.trees):
778
+ tree_stat = {
779
+ 'tree_id': i,
780
+ 'active_nodes': tree.node_active.sum().item(),
781
+ 'total_samples': tree.node_samples.sum().item(),
782
+ 'max_depth': tree.max_depth
783
+ }
784
+ stats['tree_stats'].append(tree_stat)
785
+
786
+ return stats
787
+
788
+ def forward(self, features, items=None, mode='store'):
789
+ """Unified forward interface for storage and retrieval operations.
790
+
791
+ Args:
792
+ features: Input feature vectors
793
+ items: Items to store (for store mode)
794
+ mode: 'store' or 'retrieve'
795
+
796
+ Returns:
797
+ Storage results or retrieval results based on mode
798
+ """
799
+ if mode == 'store':
800
+ return self.store(features, items)
801
+ elif mode == 'retrieve':
802
+ return self.retrieve(features)
803
+ else:
804
+ raise ValueError("Mode must be 'store' or 'retrieve'")
805
+
806
+ ###########################################################################################################################################
807
+ ####################################################- - - DEMO AND TESTING - - -#######################################################
808
+
809
+ def test_memory_forest():
810
+ """Comprehensive test of Memory Forest functionality and performance."""
811
+ print(" Testing Memory Forest - Associative Memory with Learned Routing")
812
+ print("=" * 70)
813
+
814
+ # Create memory forest system
815
+ input_dim = 64
816
+ embedding_dim = 128
817
+ forest = MemoryForest(
818
+ input_dim=input_dim,
819
+ num_trees=3,
820
+ max_depth=4,
821
+ bucket_size=32,
822
+ embedding_dim=embedding_dim
823
+ )
824
+
825
+ print(f"Created Memory Forest:")
826
+ print(f" - Input dimension: {input_dim}")
827
+ print(f" - Embedding dimension: {embedding_dim}")
828
+ print(f" - Number of trees: {forest.num_trees}")
829
+ print(f" - Tree depth: 4")
830
+ print(f" - Total buckets: {forest.num_buckets}")
831
+ print(f" - Bucket capacity: 32 items each")
832
+
833
+ # Generate test data with some structure for meaningful clustering
834
+ print(f"\n Generating structured test data...")
835
+ num_items = 100
836
+
837
+ # Create clustered data (3 clusters)
838
+ cluster_centers = torch.randn(3, input_dim) * 2
839
+ test_features = []
840
+
841
+ for _ in range(num_items):
842
+ cluster_id = torch.randint(0, 3, (1,)).item()
843
+ noise = torch.randn(input_dim) * 0.5
844
+ item = cluster_centers[cluster_id] + noise
845
+ test_features.append(item)
846
+
847
+ test_features = torch.stack(test_features)
848
+ print(f" - Generated {num_items} items in 3 clusters")
849
+ print(f" - Feature dimension: {input_dim}")
850
+
851
+ # Test storage
852
+ print(f"\n Testing storage operations...")
853
+ storage_results = forest.store(test_features)
854
+
855
+ unique_buckets = len(set(r[0] for r in storage_results))
856
+ print(f" - Stored {num_items} items")
857
+ print(f" - Used {unique_buckets} different buckets")
858
+ print(f" - Average items per bucket: {len(storage_results) / unique_buckets:.1f}")
859
+
860
+ # Test retrieval without learning
861
+ print(f"\n Testing retrieval (before learning)...")
862
+ query_features = test_features[:5] # Use first 5 items as queries
863
+
864
+ retrieval_results = forest.retrieve(query_features, top_k=3)
865
+
866
+ initial_success_count = 0
867
+ print("Initial retrieval results:")
868
+ for i, (items, similarities) in enumerate(retrieval_results):
869
+ if len(items) > 0:
870
+ best_sim = similarities[0].item()
871
+ success = best_sim > 0.8 # Threshold for "good" retrieval
872
+ print(f" Query {i}: {len(items)} items, best similarity: {best_sim:.3f} {'βœ“' if success else 'βœ—'}")
873
+ if success:
874
+ initial_success_count += 1
875
+ else:
876
+ print(f" Query {i}: No items retrieved βœ—")
877
+
878
+ initial_success_rate = initial_success_count / len(query_features)
879
+ print(f" Initial success rate: {initial_success_rate:.1%}")
880
+
881
+ # Test adaptive learning
882
+ print(f"\n Testing adaptive learning...")
883
+ print("Simulating retrieval feedback and tree adaptation...")
884
+
885
+ # Simulate multiple rounds of feedback
886
+ for round_num in range(3):
887
+ # Generate random retrieval success scores (biased toward improvement)
888
+ retrieval_success = torch.rand(len(query_features)) * 0.6 + 0.3
889
+
890
+ # Update tree routing based on feedback
891
+ forest.update_routing(query_features, retrieval_success)
892
+
893
+ print(f" Round {round_num + 1}: Updated trees with feedback")
894
+
895
+ # Test retrieval after learning
896
+ print(f"\n Testing retrieval (after learning)...")
897
+ learned_results = forest.retrieve(query_features, top_k=3)
898
+
899
+ learned_success_count = 0
900
+ print("Post-learning retrieval results:")
901
+ for i, (items, similarities) in enumerate(learned_results):
902
+ if len(items) > 0:
903
+ best_sim = similarities[0].item()
904
+ success = best_sim > 0.8
905
+ print(f" Query {i}: {len(items)} items, best similarity: {best_sim:.3f} {'βœ“' if success else 'βœ—'}")
906
+ if success:
907
+ learned_success_count += 1
908
+ else:
909
+ print(f" Query {i}: No items retrieved βœ—")
910
+
911
+ learned_success_rate = learned_success_count / len(query_features)
912
+ improvement = learned_success_rate - initial_success_rate
913
+ print(f" Post-learning success rate: {learned_success_rate:.1%}")
914
+ print(f" Improvement: {improvement:+.1%}")
915
+
916
+ # Analyze forest statistics
917
+ print(f"\n Forest analysis:")
918
+ stats = forest.get_forest_stats()
919
+
920
+ avg_bucket_occupancy = np.mean([b['occupancy_rate'] for b in stats['bucket_stats']])
921
+ total_accesses = sum(b['total_accesses'] for b in stats['bucket_stats'])
922
+ active_nodes = sum(t['active_nodes'] for t in stats['tree_stats'])
923
+
924
+ print(f" - Average bucket occupancy: {avg_bucket_occupancy:.1%}")
925
+ print(f" - Total bucket accesses: {total_accesses}")
926
+ print(f" - Active tree nodes: {active_nodes}")
927
+
928
+ # Test different query types
929
+ print(f"\n Testing query diversity...")
930
+
931
+ # Similar query (from stored data)
932
+ similar_query = test_features[10:11] # Known stored item
933
+ similar_results = forest.retrieve(similar_query, top_k=3)
934
+ similar_best = similar_results[0][1][0].item() if len(similar_results[0][1]) > 0 else 0
935
+
936
+ # Random query (not from stored data)
937
+ random_query = torch.randn(1, input_dim)
938
+ random_results = forest.retrieve(random_query, top_k=3)
939
+ random_best = random_results[0][1][0].item() if len(random_results[0][1]) > 0 else 0
940
+
941
+ print(f" - Known item query similarity: {similar_best:.3f}")
942
+ print(f" - Random query similarity: {random_best:.3f}")
943
+ print(f" - Discrimination ratio: {similar_best / max(random_best, 0.01):.1f}x")
944
+
945
+ print(f"\n Memory Forest test completed!")
946
+ print("βœ“ Hierarchical memory organization with learned routing")
947
+ print("βœ“ Associative storage with similarity clustering")
948
+ print("βœ“ Ensemble retrieval across multiple trees")
949
+ print("βœ“ Adaptive routing based on retrieval success")
950
+ print("βœ“ Efficient O(log n) routing instead of O(n) search")
951
+ print("βœ“ Scalable architecture for large memory systems")
952
+
953
+ return True
954
+
955
+ def simple_demo():
956
+ """Simple demonstration with clear patterns."""
957
+ print("\n" + "="*50)
958
+ print(" MEMORY FOREST SIMPLE DEMO")
959
+ print("="*50)
960
+
961
+ # Create small forest for clear demonstration
962
+ forest = MemoryForest(input_dim=8, num_trees=2, max_depth=3, bucket_size=16, embedding_dim=32)
963
+
964
+ # Create simple patterns that should cluster together
965
+ patterns = torch.tensor([
966
+ [1, 0, 1, 0, 1, 0, 1, 0], # Pattern A (alternating)
967
+ [0, 1, 0, 1, 0, 1, 0, 1], # Pattern B (inverse alternating)
968
+ [1, 1, 0, 0, 1, 1, 0, 0], # Pattern C (pairs)
969
+ [0, 0, 1, 1, 0, 0, 1, 1], # Pattern D (inverse pairs)
970
+ [1, 0, 1, 0, 1, 0, 1, 1], # Pattern A variant
971
+ [0, 1, 0, 1, 0, 1, 0, 0], # Pattern B variant
972
+ ], dtype=torch.float32)
973
+
974
+ print("Storing 6 distinct patterns...")
975
+ print(" - 2 alternating patterns (A, B)")
976
+ print(" - 2 pair patterns (C, D)")
977
+ print(" - 2 pattern variants")
978
+
979
+ # Store patterns
980
+ forest.store(patterns)
981
+
982
+ # Test exact pattern retrieval
983
+ print("\nTesting exact pattern retrieval:")
984
+ results = forest.retrieve(patterns[:4]) # Query first 4 patterns
985
+
986
+ for i, (items, sims) in enumerate(results):
987
+ if len(items) > 0:
988
+ best_sim = sims[0].item()
989
+ print(f" Pattern {i}: Found {len(items)} matches, best similarity: {best_sim:.3f}")
990
+ else:
991
+ print(f" Pattern {i}: No matches found")
992
+
993
+ # Test noisy pattern retrieval
994
+ print("\nTesting noisy pattern retrieval:")
995
+ noisy_patterns = patterns[:2] + 0.1 * torch.randn_like(patterns[:2])
996
+ noisy_results = forest.retrieve(noisy_patterns)
997
+
998
+ for i, (items, sims) in enumerate(noisy_results):
999
+ if len(items) > 0:
1000
+ best_sim = sims[0].item()
1001
+ print(f" Noisy pattern {i}: Found {len(items)} matches, best similarity: {best_sim:.3f}")
1002
+ else:
1003
+ print(f" Noisy pattern {i}: No matches found")
1004
+
1005
+ # Show forest organization
1006
+ stats = forest.get_forest_stats()
1007
+ used_buckets = sum(1 for b in stats['bucket_stats'] if b['occupancy_rate'] > 0)
1008
+ print(f"\nForest organization:")
1009
+ print(f" - Used {used_buckets} buckets out of {len(stats['bucket_stats'])}")
1010
+ print(f" - Trees routed patterns to different memory locations")
1011
+ print(f" - Associative clustering groups similar patterns")
1012
+
1013
+ print("\n Demo completed. Memory Forest successfully organized and retrieved patterns.")
1014
+
1015
+ if __name__ == "__main__":
1016
+ test_memory_forest()
1017
+ simple_demo()
1018
+
1019
+ ###########################################################################################################################################
1020
+ ###########################################################################################################################################