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Convert a ctypes int pointer array to a numpy array.
def cint8_array_to_numpy(cptr, length):
"""Convert a ctypes int pointer array to a numpy array."""
if isinstance(cptr, ctypes.POINTER(ctypes.c_int8)):
return np.fromiter(cptr, dtype=np.int8, count=length)
else:
raise RuntimeError('Expected int pointer') |
Convert Python dictionary to string, which is passed to C API.
def param_dict_to_str(data):
"""Convert Python dictionary to string, which is passed to C API."""
if data is None or not data:
return ""
pairs = []
for key, val in data.items():
if isinstance(val, (list, tuple, set)) or is_numpy_1d_array(val):
pairs.append(str(key) + '=' + ','.join(map(str, val)))
elif isinstance(val, string_type) or isinstance(val, numeric_types) or is_numeric(val):
pairs.append(str(key) + '=' + str(val))
elif val is not None:
raise TypeError('Unknown type of parameter:%s, got:%s'
% (key, type(val).__name__))
return ' '.join(pairs) |
Fix the memory of multi-dimensional sliced object.
def convert_from_sliced_object(data):
"""Fix the memory of multi-dimensional sliced object."""
if data.base is not None and isinstance(data, np.ndarray) and isinstance(data.base, np.ndarray):
if not data.flags.c_contiguous:
warnings.warn("Usage of np.ndarray subset (sliced data) is not recommended "
"due to it will double the peak memory cost in LightGBM.")
return np.copy(data)
return data |
Get pointer of float numpy array / list.
def c_float_array(data):
"""Get pointer of float numpy array / list."""
if is_1d_list(data):
data = np.array(data, copy=False)
if is_numpy_1d_array(data):
data = convert_from_sliced_object(data)
assert data.flags.c_contiguous
if data.dtype == np.float32:
ptr_data = data.ctypes.data_as(ctypes.POINTER(ctypes.c_float))
type_data = C_API_DTYPE_FLOAT32
elif data.dtype == np.float64:
ptr_data = data.ctypes.data_as(ctypes.POINTER(ctypes.c_double))
type_data = C_API_DTYPE_FLOAT64
else:
raise TypeError("Expected np.float32 or np.float64, met type({})"
.format(data.dtype))
else:
raise TypeError("Unknown type({})".format(type(data).__name__))
return (ptr_data, type_data, data) |
Get pointer of int numpy array / list.
def c_int_array(data):
"""Get pointer of int numpy array / list."""
if is_1d_list(data):
data = np.array(data, copy=False)
if is_numpy_1d_array(data):
data = convert_from_sliced_object(data)
assert data.flags.c_contiguous
if data.dtype == np.int32:
ptr_data = data.ctypes.data_as(ctypes.POINTER(ctypes.c_int32))
type_data = C_API_DTYPE_INT32
elif data.dtype == np.int64:
ptr_data = data.ctypes.data_as(ctypes.POINTER(ctypes.c_int64))
type_data = C_API_DTYPE_INT64
else:
raise TypeError("Expected np.int32 or np.int64, met type({})"
.format(data.dtype))
else:
raise TypeError("Unknown type({})".format(type(data).__name__))
return (ptr_data, type_data, data) |
Predict logic.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame or scipy.sparse
Data source for prediction.
When data type is string, it represents the path of txt file.
num_iteration : int, optional (default=-1)
Iteration used for prediction.
raw_score : bool, optional (default=False)
Whether to predict raw scores.
pred_leaf : bool, optional (default=False)
Whether to predict leaf index.
pred_contrib : bool, optional (default=False)
Whether to predict feature contributions.
data_has_header : bool, optional (default=False)
Whether data has header.
Used only for txt data.
is_reshape : bool, optional (default=True)
Whether to reshape to (nrow, ncol).
Returns
-------
result : numpy array
Prediction result.
def predict(self, data, num_iteration=-1,
raw_score=False, pred_leaf=False, pred_contrib=False, data_has_header=False,
is_reshape=True):
"""Predict logic.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame or scipy.sparse
Data source for prediction.
When data type is string, it represents the path of txt file.
num_iteration : int, optional (default=-1)
Iteration used for prediction.
raw_score : bool, optional (default=False)
Whether to predict raw scores.
pred_leaf : bool, optional (default=False)
Whether to predict leaf index.
pred_contrib : bool, optional (default=False)
Whether to predict feature contributions.
data_has_header : bool, optional (default=False)
Whether data has header.
Used only for txt data.
is_reshape : bool, optional (default=True)
Whether to reshape to (nrow, ncol).
Returns
-------
result : numpy array
Prediction result.
"""
if isinstance(data, Dataset):
raise TypeError("Cannot use Dataset instance for prediction, please use raw data instead")
data = _data_from_pandas(data, None, None, self.pandas_categorical)[0]
predict_type = C_API_PREDICT_NORMAL
if raw_score:
predict_type = C_API_PREDICT_RAW_SCORE
if pred_leaf:
predict_type = C_API_PREDICT_LEAF_INDEX
if pred_contrib:
predict_type = C_API_PREDICT_CONTRIB
int_data_has_header = 1 if data_has_header else 0
if num_iteration > self.num_total_iteration:
num_iteration = self.num_total_iteration
if isinstance(data, string_type):
with _TempFile() as f:
_safe_call(_LIB.LGBM_BoosterPredictForFile(
self.handle,
c_str(data),
ctypes.c_int(int_data_has_header),
ctypes.c_int(predict_type),
ctypes.c_int(num_iteration),
c_str(self.pred_parameter),
c_str(f.name)))
lines = f.readlines()
nrow = len(lines)
preds = [float(token) for line in lines for token in line.split('\t')]
preds = np.array(preds, dtype=np.float64, copy=False)
elif isinstance(data, scipy.sparse.csr_matrix):
preds, nrow = self.__pred_for_csr(data, num_iteration, predict_type)
elif isinstance(data, scipy.sparse.csc_matrix):
preds, nrow = self.__pred_for_csc(data, num_iteration, predict_type)
elif isinstance(data, np.ndarray):
preds, nrow = self.__pred_for_np2d(data, num_iteration, predict_type)
elif isinstance(data, list):
try:
data = np.array(data)
except BaseException:
raise ValueError('Cannot convert data list to numpy array.')
preds, nrow = self.__pred_for_np2d(data, num_iteration, predict_type)
elif isinstance(data, DataTable):
preds, nrow = self.__pred_for_np2d(data.to_numpy(), num_iteration, predict_type)
else:
try:
warnings.warn('Converting data to scipy sparse matrix.')
csr = scipy.sparse.csr_matrix(data)
except BaseException:
raise TypeError('Cannot predict data for type {}'.format(type(data).__name__))
preds, nrow = self.__pred_for_csr(csr, num_iteration, predict_type)
if pred_leaf:
preds = preds.astype(np.int32)
if is_reshape and preds.size != nrow:
if preds.size % nrow == 0:
preds = preds.reshape(nrow, -1)
else:
raise ValueError('Length of predict result (%d) cannot be divide nrow (%d)'
% (preds.size, nrow))
return preds |
Get size of prediction result.
def __get_num_preds(self, num_iteration, nrow, predict_type):
"""Get size of prediction result."""
if nrow > MAX_INT32:
raise LightGBMError('LightGBM cannot perform prediction for data'
'with number of rows greater than MAX_INT32 (%d).\n'
'You can split your data into chunks'
'and then concatenate predictions for them' % MAX_INT32)
n_preds = ctypes.c_int64(0)
_safe_call(_LIB.LGBM_BoosterCalcNumPredict(
self.handle,
ctypes.c_int(nrow),
ctypes.c_int(predict_type),
ctypes.c_int(num_iteration),
ctypes.byref(n_preds)))
return n_preds.value |
Predict for a 2-D numpy matrix.
def __pred_for_np2d(self, mat, num_iteration, predict_type):
"""Predict for a 2-D numpy matrix."""
if len(mat.shape) != 2:
raise ValueError('Input numpy.ndarray or list must be 2 dimensional')
def inner_predict(mat, num_iteration, predict_type, preds=None):
if mat.dtype == np.float32 or mat.dtype == np.float64:
data = np.array(mat.reshape(mat.size), dtype=mat.dtype, copy=False)
else:
"""change non-float data to float data, need to copy"""
data = np.array(mat.reshape(mat.size), dtype=np.float32)
ptr_data, type_ptr_data, _ = c_float_array(data)
n_preds = self.__get_num_preds(num_iteration, mat.shape[0], predict_type)
if preds is None:
preds = np.zeros(n_preds, dtype=np.float64)
elif len(preds.shape) != 1 or len(preds) != n_preds:
raise ValueError("Wrong length of pre-allocated predict array")
out_num_preds = ctypes.c_int64(0)
_safe_call(_LIB.LGBM_BoosterPredictForMat(
self.handle,
ptr_data,
ctypes.c_int(type_ptr_data),
ctypes.c_int(mat.shape[0]),
ctypes.c_int(mat.shape[1]),
ctypes.c_int(C_API_IS_ROW_MAJOR),
ctypes.c_int(predict_type),
ctypes.c_int(num_iteration),
c_str(self.pred_parameter),
ctypes.byref(out_num_preds),
preds.ctypes.data_as(ctypes.POINTER(ctypes.c_double))))
if n_preds != out_num_preds.value:
raise ValueError("Wrong length for predict results")
return preds, mat.shape[0]
nrow = mat.shape[0]
if nrow > MAX_INT32:
sections = np.arange(start=MAX_INT32, stop=nrow, step=MAX_INT32)
# __get_num_preds() cannot work with nrow > MAX_INT32, so calculate overall number of predictions piecemeal
n_preds = [self.__get_num_preds(num_iteration, i, predict_type) for i in np.diff([0] + list(sections) + [nrow])]
n_preds_sections = np.array([0] + n_preds, dtype=np.intp).cumsum()
preds = np.zeros(sum(n_preds), dtype=np.float64)
for chunk, (start_idx_pred, end_idx_pred) in zip_(np.array_split(mat, sections),
zip_(n_preds_sections, n_preds_sections[1:])):
# avoid memory consumption by arrays concatenation operations
inner_predict(chunk, num_iteration, predict_type, preds[start_idx_pred:end_idx_pred])
return preds, nrow
else:
return inner_predict(mat, num_iteration, predict_type) |
Predict for a CSR data.
def __pred_for_csr(self, csr, num_iteration, predict_type):
"""Predict for a CSR data."""
def inner_predict(csr, num_iteration, predict_type, preds=None):
nrow = len(csr.indptr) - 1
n_preds = self.__get_num_preds(num_iteration, nrow, predict_type)
if preds is None:
preds = np.zeros(n_preds, dtype=np.float64)
elif len(preds.shape) != 1 or len(preds) != n_preds:
raise ValueError("Wrong length of pre-allocated predict array")
out_num_preds = ctypes.c_int64(0)
ptr_indptr, type_ptr_indptr, __ = c_int_array(csr.indptr)
ptr_data, type_ptr_data, _ = c_float_array(csr.data)
assert csr.shape[1] <= MAX_INT32
csr.indices = csr.indices.astype(np.int32, copy=False)
_safe_call(_LIB.LGBM_BoosterPredictForCSR(
self.handle,
ptr_indptr,
ctypes.c_int32(type_ptr_indptr),
csr.indices.ctypes.data_as(ctypes.POINTER(ctypes.c_int32)),
ptr_data,
ctypes.c_int(type_ptr_data),
ctypes.c_int64(len(csr.indptr)),
ctypes.c_int64(len(csr.data)),
ctypes.c_int64(csr.shape[1]),
ctypes.c_int(predict_type),
ctypes.c_int(num_iteration),
c_str(self.pred_parameter),
ctypes.byref(out_num_preds),
preds.ctypes.data_as(ctypes.POINTER(ctypes.c_double))))
if n_preds != out_num_preds.value:
raise ValueError("Wrong length for predict results")
return preds, nrow
nrow = len(csr.indptr) - 1
if nrow > MAX_INT32:
sections = [0] + list(np.arange(start=MAX_INT32, stop=nrow, step=MAX_INT32)) + [nrow]
# __get_num_preds() cannot work with nrow > MAX_INT32, so calculate overall number of predictions piecemeal
n_preds = [self.__get_num_preds(num_iteration, i, predict_type) for i in np.diff(sections)]
n_preds_sections = np.array([0] + n_preds, dtype=np.intp).cumsum()
preds = np.zeros(sum(n_preds), dtype=np.float64)
for (start_idx, end_idx), (start_idx_pred, end_idx_pred) in zip_(zip_(sections, sections[1:]),
zip_(n_preds_sections, n_preds_sections[1:])):
# avoid memory consumption by arrays concatenation operations
inner_predict(csr[start_idx:end_idx], num_iteration, predict_type, preds[start_idx_pred:end_idx_pred])
return preds, nrow
else:
return inner_predict(csr, num_iteration, predict_type) |
Predict for a CSC data.
def __pred_for_csc(self, csc, num_iteration, predict_type):
"""Predict for a CSC data."""
nrow = csc.shape[0]
if nrow > MAX_INT32:
return self.__pred_for_csr(csc.tocsr(), num_iteration, predict_type)
n_preds = self.__get_num_preds(num_iteration, nrow, predict_type)
preds = np.zeros(n_preds, dtype=np.float64)
out_num_preds = ctypes.c_int64(0)
ptr_indptr, type_ptr_indptr, __ = c_int_array(csc.indptr)
ptr_data, type_ptr_data, _ = c_float_array(csc.data)
assert csc.shape[0] <= MAX_INT32
csc.indices = csc.indices.astype(np.int32, copy=False)
_safe_call(_LIB.LGBM_BoosterPredictForCSC(
self.handle,
ptr_indptr,
ctypes.c_int32(type_ptr_indptr),
csc.indices.ctypes.data_as(ctypes.POINTER(ctypes.c_int32)),
ptr_data,
ctypes.c_int(type_ptr_data),
ctypes.c_int64(len(csc.indptr)),
ctypes.c_int64(len(csc.data)),
ctypes.c_int64(csc.shape[0]),
ctypes.c_int(predict_type),
ctypes.c_int(num_iteration),
c_str(self.pred_parameter),
ctypes.byref(out_num_preds),
preds.ctypes.data_as(ctypes.POINTER(ctypes.c_double))))
if n_preds != out_num_preds.value:
raise ValueError("Wrong length for predict results")
return preds, nrow |
Initialize data from a 2-D numpy matrix.
def __init_from_np2d(self, mat, params_str, ref_dataset):
"""Initialize data from a 2-D numpy matrix."""
if len(mat.shape) != 2:
raise ValueError('Input numpy.ndarray must be 2 dimensional')
self.handle = ctypes.c_void_p()
if mat.dtype == np.float32 or mat.dtype == np.float64:
data = np.array(mat.reshape(mat.size), dtype=mat.dtype, copy=False)
else:
# change non-float data to float data, need to copy
data = np.array(mat.reshape(mat.size), dtype=np.float32)
ptr_data, type_ptr_data, _ = c_float_array(data)
_safe_call(_LIB.LGBM_DatasetCreateFromMat(
ptr_data,
ctypes.c_int(type_ptr_data),
ctypes.c_int(mat.shape[0]),
ctypes.c_int(mat.shape[1]),
ctypes.c_int(C_API_IS_ROW_MAJOR),
c_str(params_str),
ref_dataset,
ctypes.byref(self.handle)))
return self |
Initialize data from a list of 2-D numpy matrices.
def __init_from_list_np2d(self, mats, params_str, ref_dataset):
"""Initialize data from a list of 2-D numpy matrices."""
ncol = mats[0].shape[1]
nrow = np.zeros((len(mats),), np.int32)
if mats[0].dtype == np.float64:
ptr_data = (ctypes.POINTER(ctypes.c_double) * len(mats))()
else:
ptr_data = (ctypes.POINTER(ctypes.c_float) * len(mats))()
holders = []
type_ptr_data = None
for i, mat in enumerate(mats):
if len(mat.shape) != 2:
raise ValueError('Input numpy.ndarray must be 2 dimensional')
if mat.shape[1] != ncol:
raise ValueError('Input arrays must have same number of columns')
nrow[i] = mat.shape[0]
if mat.dtype == np.float32 or mat.dtype == np.float64:
mats[i] = np.array(mat.reshape(mat.size), dtype=mat.dtype, copy=False)
else:
# change non-float data to float data, need to copy
mats[i] = np.array(mat.reshape(mat.size), dtype=np.float32)
chunk_ptr_data, chunk_type_ptr_data, holder = c_float_array(mats[i])
if type_ptr_data is not None and chunk_type_ptr_data != type_ptr_data:
raise ValueError('Input chunks must have same type')
ptr_data[i] = chunk_ptr_data
type_ptr_data = chunk_type_ptr_data
holders.append(holder)
self.handle = ctypes.c_void_p()
_safe_call(_LIB.LGBM_DatasetCreateFromMats(
ctypes.c_int(len(mats)),
ctypes.cast(ptr_data, ctypes.POINTER(ctypes.POINTER(ctypes.c_double))),
ctypes.c_int(type_ptr_data),
nrow.ctypes.data_as(ctypes.POINTER(ctypes.c_int32)),
ctypes.c_int(ncol),
ctypes.c_int(C_API_IS_ROW_MAJOR),
c_str(params_str),
ref_dataset,
ctypes.byref(self.handle)))
return self |
Initialize data from a CSR matrix.
def __init_from_csr(self, csr, params_str, ref_dataset):
"""Initialize data from a CSR matrix."""
if len(csr.indices) != len(csr.data):
raise ValueError('Length mismatch: {} vs {}'.format(len(csr.indices), len(csr.data)))
self.handle = ctypes.c_void_p()
ptr_indptr, type_ptr_indptr, __ = c_int_array(csr.indptr)
ptr_data, type_ptr_data, _ = c_float_array(csr.data)
assert csr.shape[1] <= MAX_INT32
csr.indices = csr.indices.astype(np.int32, copy=False)
_safe_call(_LIB.LGBM_DatasetCreateFromCSR(
ptr_indptr,
ctypes.c_int(type_ptr_indptr),
csr.indices.ctypes.data_as(ctypes.POINTER(ctypes.c_int32)),
ptr_data,
ctypes.c_int(type_ptr_data),
ctypes.c_int64(len(csr.indptr)),
ctypes.c_int64(len(csr.data)),
ctypes.c_int64(csr.shape[1]),
c_str(params_str),
ref_dataset,
ctypes.byref(self.handle)))
return self |
Initialize data from a CSC matrix.
def __init_from_csc(self, csc, params_str, ref_dataset):
"""Initialize data from a CSC matrix."""
if len(csc.indices) != len(csc.data):
raise ValueError('Length mismatch: {} vs {}'.format(len(csc.indices), len(csc.data)))
self.handle = ctypes.c_void_p()
ptr_indptr, type_ptr_indptr, __ = c_int_array(csc.indptr)
ptr_data, type_ptr_data, _ = c_float_array(csc.data)
assert csc.shape[0] <= MAX_INT32
csc.indices = csc.indices.astype(np.int32, copy=False)
_safe_call(_LIB.LGBM_DatasetCreateFromCSC(
ptr_indptr,
ctypes.c_int(type_ptr_indptr),
csc.indices.ctypes.data_as(ctypes.POINTER(ctypes.c_int32)),
ptr_data,
ctypes.c_int(type_ptr_data),
ctypes.c_int64(len(csc.indptr)),
ctypes.c_int64(len(csc.data)),
ctypes.c_int64(csc.shape[0]),
c_str(params_str),
ref_dataset,
ctypes.byref(self.handle)))
return self |
Lazy init.
Returns
-------
self : Dataset
Constructed Dataset object.
def construct(self):
"""Lazy init.
Returns
-------
self : Dataset
Constructed Dataset object.
"""
if self.handle is None:
if self.reference is not None:
if self.used_indices is None:
# create valid
self._lazy_init(self.data, label=self.label, reference=self.reference,
weight=self.weight, group=self.group,
init_score=self.init_score, predictor=self._predictor,
silent=self.silent, feature_name=self.feature_name, params=self.params)
else:
# construct subset
used_indices = list_to_1d_numpy(self.used_indices, np.int32, name='used_indices')
assert used_indices.flags.c_contiguous
if self.reference.group is not None:
group_info = np.array(self.reference.group).astype(int)
_, self.group = np.unique(np.repeat(range_(len(group_info)), repeats=group_info)[self.used_indices],
return_counts=True)
self.handle = ctypes.c_void_p()
params_str = param_dict_to_str(self.params)
_safe_call(_LIB.LGBM_DatasetGetSubset(
self.reference.construct().handle,
used_indices.ctypes.data_as(ctypes.POINTER(ctypes.c_int32)),
ctypes.c_int(used_indices.shape[0]),
c_str(params_str),
ctypes.byref(self.handle)))
self.data = self.reference.data
self.get_data()
if self.group is not None:
self.set_group(self.group)
if self.get_label() is None:
raise ValueError("Label should not be None.")
else:
# create train
self._lazy_init(self.data, label=self.label,
weight=self.weight, group=self.group,
init_score=self.init_score, predictor=self._predictor,
silent=self.silent, feature_name=self.feature_name,
categorical_feature=self.categorical_feature, params=self.params)
if self.free_raw_data:
self.data = None
return self |
Create validation data align with current Dataset.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame, scipy.sparse or list of numpy arrays
Data source of Dataset.
If string, it represents the path to txt file.
label : list, numpy 1-D array, pandas Series / one-column DataFrame or None, optional (default=None)
Label of the data.
weight : list, numpy 1-D array, pandas Series or None, optional (default=None)
Weight for each instance.
group : list, numpy 1-D array, pandas Series or None, optional (default=None)
Group/query size for Dataset.
init_score : list, numpy 1-D array, pandas Series or None, optional (default=None)
Init score for Dataset.
silent : bool, optional (default=False)
Whether to print messages during construction.
params : dict or None, optional (default=None)
Other parameters for validation Dataset.
Returns
-------
valid : Dataset
Validation Dataset with reference to self.
def create_valid(self, data, label=None, weight=None, group=None,
init_score=None, silent=False, params=None):
"""Create validation data align with current Dataset.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame, scipy.sparse or list of numpy arrays
Data source of Dataset.
If string, it represents the path to txt file.
label : list, numpy 1-D array, pandas Series / one-column DataFrame or None, optional (default=None)
Label of the data.
weight : list, numpy 1-D array, pandas Series or None, optional (default=None)
Weight for each instance.
group : list, numpy 1-D array, pandas Series or None, optional (default=None)
Group/query size for Dataset.
init_score : list, numpy 1-D array, pandas Series or None, optional (default=None)
Init score for Dataset.
silent : bool, optional (default=False)
Whether to print messages during construction.
params : dict or None, optional (default=None)
Other parameters for validation Dataset.
Returns
-------
valid : Dataset
Validation Dataset with reference to self.
"""
ret = Dataset(data, label=label, reference=self,
weight=weight, group=group, init_score=init_score,
silent=silent, params=params, free_raw_data=self.free_raw_data)
ret._predictor = self._predictor
ret.pandas_categorical = self.pandas_categorical
return ret |
Get subset of current Dataset.
Parameters
----------
used_indices : list of int
Indices used to create the subset.
params : dict or None, optional (default=None)
These parameters will be passed to Dataset constructor.
Returns
-------
subset : Dataset
Subset of the current Dataset.
def subset(self, used_indices, params=None):
"""Get subset of current Dataset.
Parameters
----------
used_indices : list of int
Indices used to create the subset.
params : dict or None, optional (default=None)
These parameters will be passed to Dataset constructor.
Returns
-------
subset : Dataset
Subset of the current Dataset.
"""
if params is None:
params = self.params
ret = Dataset(None, reference=self, feature_name=self.feature_name,
categorical_feature=self.categorical_feature, params=params,
free_raw_data=self.free_raw_data)
ret._predictor = self._predictor
ret.pandas_categorical = self.pandas_categorical
ret.used_indices = used_indices
return ret |
Save Dataset to a binary file.
Parameters
----------
filename : string
Name of the output file.
Returns
-------
self : Dataset
Returns self.
def save_binary(self, filename):
"""Save Dataset to a binary file.
Parameters
----------
filename : string
Name of the output file.
Returns
-------
self : Dataset
Returns self.
"""
_safe_call(_LIB.LGBM_DatasetSaveBinary(
self.construct().handle,
c_str(filename)))
return self |
Set property into the Dataset.
Parameters
----------
field_name : string
The field name of the information.
data : list, numpy 1-D array, pandas Series or None
The array of data to be set.
Returns
-------
self : Dataset
Dataset with set property.
def set_field(self, field_name, data):
"""Set property into the Dataset.
Parameters
----------
field_name : string
The field name of the information.
data : list, numpy 1-D array, pandas Series or None
The array of data to be set.
Returns
-------
self : Dataset
Dataset with set property.
"""
if self.handle is None:
raise Exception("Cannot set %s before construct dataset" % field_name)
if data is None:
# set to None
_safe_call(_LIB.LGBM_DatasetSetField(
self.handle,
c_str(field_name),
None,
ctypes.c_int(0),
ctypes.c_int(FIELD_TYPE_MAPPER[field_name])))
return self
dtype = np.float32
if field_name == 'group':
dtype = np.int32
elif field_name == 'init_score':
dtype = np.float64
data = list_to_1d_numpy(data, dtype, name=field_name)
if data.dtype == np.float32 or data.dtype == np.float64:
ptr_data, type_data, _ = c_float_array(data)
elif data.dtype == np.int32:
ptr_data, type_data, _ = c_int_array(data)
else:
raise TypeError("Excepted np.float32/64 or np.int32, meet type({})".format(data.dtype))
if type_data != FIELD_TYPE_MAPPER[field_name]:
raise TypeError("Input type error for set_field")
_safe_call(_LIB.LGBM_DatasetSetField(
self.handle,
c_str(field_name),
ptr_data,
ctypes.c_int(len(data)),
ctypes.c_int(type_data)))
return self |
Get property from the Dataset.
Parameters
----------
field_name : string
The field name of the information.
Returns
-------
info : numpy array
A numpy array with information from the Dataset.
def get_field(self, field_name):
"""Get property from the Dataset.
Parameters
----------
field_name : string
The field name of the information.
Returns
-------
info : numpy array
A numpy array with information from the Dataset.
"""
if self.handle is None:
raise Exception("Cannot get %s before construct Dataset" % field_name)
tmp_out_len = ctypes.c_int()
out_type = ctypes.c_int()
ret = ctypes.POINTER(ctypes.c_void_p)()
_safe_call(_LIB.LGBM_DatasetGetField(
self.handle,
c_str(field_name),
ctypes.byref(tmp_out_len),
ctypes.byref(ret),
ctypes.byref(out_type)))
if out_type.value != FIELD_TYPE_MAPPER[field_name]:
raise TypeError("Return type error for get_field")
if tmp_out_len.value == 0:
return None
if out_type.value == C_API_DTYPE_INT32:
return cint32_array_to_numpy(ctypes.cast(ret, ctypes.POINTER(ctypes.c_int32)), tmp_out_len.value)
elif out_type.value == C_API_DTYPE_FLOAT32:
return cfloat32_array_to_numpy(ctypes.cast(ret, ctypes.POINTER(ctypes.c_float)), tmp_out_len.value)
elif out_type.value == C_API_DTYPE_FLOAT64:
return cfloat64_array_to_numpy(ctypes.cast(ret, ctypes.POINTER(ctypes.c_double)), tmp_out_len.value)
elif out_type.value == C_API_DTYPE_INT8:
return cint8_array_to_numpy(ctypes.cast(ret, ctypes.POINTER(ctypes.c_int8)), tmp_out_len.value)
else:
raise TypeError("Unknown type") |
Set categorical features.
Parameters
----------
categorical_feature : list of int or strings
Names or indices of categorical features.
Returns
-------
self : Dataset
Dataset with set categorical features.
def set_categorical_feature(self, categorical_feature):
"""Set categorical features.
Parameters
----------
categorical_feature : list of int or strings
Names or indices of categorical features.
Returns
-------
self : Dataset
Dataset with set categorical features.
"""
if self.categorical_feature == categorical_feature:
return self
if self.data is not None:
if self.categorical_feature is None:
self.categorical_feature = categorical_feature
return self._free_handle()
elif categorical_feature == 'auto':
warnings.warn('Using categorical_feature in Dataset.')
return self
else:
warnings.warn('categorical_feature in Dataset is overridden.\n'
'New categorical_feature is {}'.format(sorted(list(categorical_feature))))
self.categorical_feature = categorical_feature
return self._free_handle()
else:
raise LightGBMError("Cannot set categorical feature after freed raw data, "
"set free_raw_data=False when construct Dataset to avoid this.") |
Set predictor for continued training.
It is not recommended for user to call this function.
Please use init_model argument in engine.train() or engine.cv() instead.
def _set_predictor(self, predictor):
"""Set predictor for continued training.
It is not recommended for user to call this function.
Please use init_model argument in engine.train() or engine.cv() instead.
"""
if predictor is self._predictor:
return self
if self.data is not None:
self._predictor = predictor
return self._free_handle()
else:
raise LightGBMError("Cannot set predictor after freed raw data, "
"set free_raw_data=False when construct Dataset to avoid this.") |
Set reference Dataset.
Parameters
----------
reference : Dataset
Reference that is used as a template to construct the current Dataset.
Returns
-------
self : Dataset
Dataset with set reference.
def set_reference(self, reference):
"""Set reference Dataset.
Parameters
----------
reference : Dataset
Reference that is used as a template to construct the current Dataset.
Returns
-------
self : Dataset
Dataset with set reference.
"""
self.set_categorical_feature(reference.categorical_feature) \
.set_feature_name(reference.feature_name) \
._set_predictor(reference._predictor)
# we're done if self and reference share a common upstrem reference
if self.get_ref_chain().intersection(reference.get_ref_chain()):
return self
if self.data is not None:
self.reference = reference
return self._free_handle()
else:
raise LightGBMError("Cannot set reference after freed raw data, "
"set free_raw_data=False when construct Dataset to avoid this.") |
Set feature name.
Parameters
----------
feature_name : list of strings
Feature names.
Returns
-------
self : Dataset
Dataset with set feature name.
def set_feature_name(self, feature_name):
"""Set feature name.
Parameters
----------
feature_name : list of strings
Feature names.
Returns
-------
self : Dataset
Dataset with set feature name.
"""
if feature_name != 'auto':
self.feature_name = feature_name
if self.handle is not None and feature_name is not None and feature_name != 'auto':
if len(feature_name) != self.num_feature():
raise ValueError("Length of feature_name({}) and num_feature({}) don't match"
.format(len(feature_name), self.num_feature()))
c_feature_name = [c_str(name) for name in feature_name]
_safe_call(_LIB.LGBM_DatasetSetFeatureNames(
self.handle,
c_array(ctypes.c_char_p, c_feature_name),
ctypes.c_int(len(feature_name))))
return self |
Set label of Dataset.
Parameters
----------
label : list, numpy 1-D array, pandas Series / one-column DataFrame or None
The label information to be set into Dataset.
Returns
-------
self : Dataset
Dataset with set label.
def set_label(self, label):
"""Set label of Dataset.
Parameters
----------
label : list, numpy 1-D array, pandas Series / one-column DataFrame or None
The label information to be set into Dataset.
Returns
-------
self : Dataset
Dataset with set label.
"""
self.label = label
if self.handle is not None:
label = list_to_1d_numpy(_label_from_pandas(label), name='label')
self.set_field('label', label)
return self |
Set weight of each instance.
Parameters
----------
weight : list, numpy 1-D array, pandas Series or None
Weight to be set for each data point.
Returns
-------
self : Dataset
Dataset with set weight.
def set_weight(self, weight):
"""Set weight of each instance.
Parameters
----------
weight : list, numpy 1-D array, pandas Series or None
Weight to be set for each data point.
Returns
-------
self : Dataset
Dataset with set weight.
"""
if weight is not None and np.all(weight == 1):
weight = None
self.weight = weight
if self.handle is not None and weight is not None:
weight = list_to_1d_numpy(weight, name='weight')
self.set_field('weight', weight)
return self |
Set init score of Booster to start from.
Parameters
----------
init_score : list, numpy 1-D array, pandas Series or None
Init score for Booster.
Returns
-------
self : Dataset
Dataset with set init score.
def set_init_score(self, init_score):
"""Set init score of Booster to start from.
Parameters
----------
init_score : list, numpy 1-D array, pandas Series or None
Init score for Booster.
Returns
-------
self : Dataset
Dataset with set init score.
"""
self.init_score = init_score
if self.handle is not None and init_score is not None:
init_score = list_to_1d_numpy(init_score, np.float64, name='init_score')
self.set_field('init_score', init_score)
return self |
Set group size of Dataset (used for ranking).
Parameters
----------
group : list, numpy 1-D array, pandas Series or None
Group size of each group.
Returns
-------
self : Dataset
Dataset with set group.
def set_group(self, group):
"""Set group size of Dataset (used for ranking).
Parameters
----------
group : list, numpy 1-D array, pandas Series or None
Group size of each group.
Returns
-------
self : Dataset
Dataset with set group.
"""
self.group = group
if self.handle is not None and group is not None:
group = list_to_1d_numpy(group, np.int32, name='group')
self.set_field('group', group)
return self |
Get the label of the Dataset.
Returns
-------
label : numpy array or None
The label information from the Dataset.
def get_label(self):
"""Get the label of the Dataset.
Returns
-------
label : numpy array or None
The label information from the Dataset.
"""
if self.label is None:
self.label = self.get_field('label')
return self.label |
Get the weight of the Dataset.
Returns
-------
weight : numpy array or None
Weight for each data point from the Dataset.
def get_weight(self):
"""Get the weight of the Dataset.
Returns
-------
weight : numpy array or None
Weight for each data point from the Dataset.
"""
if self.weight is None:
self.weight = self.get_field('weight')
return self.weight |
Get the feature penalty of the Dataset.
Returns
-------
feature_penalty : numpy array or None
Feature penalty for each feature in the Dataset.
def get_feature_penalty(self):
"""Get the feature penalty of the Dataset.
Returns
-------
feature_penalty : numpy array or None
Feature penalty for each feature in the Dataset.
"""
if self.feature_penalty is None:
self.feature_penalty = self.get_field('feature_penalty')
return self.feature_penalty |
Get the monotone constraints of the Dataset.
Returns
-------
monotone_constraints : numpy array or None
Monotone constraints: -1, 0 or 1, for each feature in the Dataset.
def get_monotone_constraints(self):
"""Get the monotone constraints of the Dataset.
Returns
-------
monotone_constraints : numpy array or None
Monotone constraints: -1, 0 or 1, for each feature in the Dataset.
"""
if self.monotone_constraints is None:
self.monotone_constraints = self.get_field('monotone_constraints')
return self.monotone_constraints |
Get the initial score of the Dataset.
Returns
-------
init_score : numpy array or None
Init score of Booster.
def get_init_score(self):
"""Get the initial score of the Dataset.
Returns
-------
init_score : numpy array or None
Init score of Booster.
"""
if self.init_score is None:
self.init_score = self.get_field('init_score')
return self.init_score |
Get the raw data of the Dataset.
Returns
-------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame, scipy.sparse, list of numpy arrays or None
Raw data used in the Dataset construction.
def get_data(self):
"""Get the raw data of the Dataset.
Returns
-------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame, scipy.sparse, list of numpy arrays or None
Raw data used in the Dataset construction.
"""
if self.handle is None:
raise Exception("Cannot get data before construct Dataset")
if self.data is not None and self.used_indices is not None and self.need_slice:
if isinstance(self.data, np.ndarray) or scipy.sparse.issparse(self.data):
self.data = self.data[self.used_indices, :]
elif isinstance(self.data, DataFrame):
self.data = self.data.iloc[self.used_indices].copy()
elif isinstance(self.data, DataTable):
self.data = self.data[self.used_indices, :]
else:
warnings.warn("Cannot subset {} type of raw data.\n"
"Returning original raw data".format(type(self.data).__name__))
self.need_slice = False
return self.data |
Get the group of the Dataset.
Returns
-------
group : numpy array or None
Group size of each group.
def get_group(self):
"""Get the group of the Dataset.
Returns
-------
group : numpy array or None
Group size of each group.
"""
if self.group is None:
self.group = self.get_field('group')
if self.group is not None:
# group data from LightGBM is boundaries data, need to convert to group size
self.group = np.diff(self.group)
return self.group |
Get the number of rows in the Dataset.
Returns
-------
number_of_rows : int
The number of rows in the Dataset.
def num_data(self):
"""Get the number of rows in the Dataset.
Returns
-------
number_of_rows : int
The number of rows in the Dataset.
"""
if self.handle is not None:
ret = ctypes.c_int()
_safe_call(_LIB.LGBM_DatasetGetNumData(self.handle,
ctypes.byref(ret)))
return ret.value
else:
raise LightGBMError("Cannot get num_data before construct dataset") |
Get the number of columns (features) in the Dataset.
Returns
-------
number_of_columns : int
The number of columns (features) in the Dataset.
def num_feature(self):
"""Get the number of columns (features) in the Dataset.
Returns
-------
number_of_columns : int
The number of columns (features) in the Dataset.
"""
if self.handle is not None:
ret = ctypes.c_int()
_safe_call(_LIB.LGBM_DatasetGetNumFeature(self.handle,
ctypes.byref(ret)))
return ret.value
else:
raise LightGBMError("Cannot get num_feature before construct dataset") |
Get a chain of Dataset objects.
Starts with r, then goes to r.reference (if exists),
then to r.reference.reference, etc.
until we hit ``ref_limit`` or a reference loop.
Parameters
----------
ref_limit : int, optional (default=100)
The limit number of references.
Returns
-------
ref_chain : set of Dataset
Chain of references of the Datasets.
def get_ref_chain(self, ref_limit=100):
"""Get a chain of Dataset objects.
Starts with r, then goes to r.reference (if exists),
then to r.reference.reference, etc.
until we hit ``ref_limit`` or a reference loop.
Parameters
----------
ref_limit : int, optional (default=100)
The limit number of references.
Returns
-------
ref_chain : set of Dataset
Chain of references of the Datasets.
"""
head = self
ref_chain = set()
while len(ref_chain) < ref_limit:
if isinstance(head, Dataset):
ref_chain.add(head)
if (head.reference is not None) and (head.reference not in ref_chain):
head = head.reference
else:
break
else:
break
return ref_chain |
Add features from other Dataset to the current Dataset.
Both Datasets must be constructed before calling this method.
Parameters
----------
other : Dataset
The Dataset to take features from.
Returns
-------
self : Dataset
Dataset with the new features added.
def add_features_from(self, other):
"""Add features from other Dataset to the current Dataset.
Both Datasets must be constructed before calling this method.
Parameters
----------
other : Dataset
The Dataset to take features from.
Returns
-------
self : Dataset
Dataset with the new features added.
"""
if self.handle is None or other.handle is None:
raise ValueError('Both source and target Datasets must be constructed before adding features')
_safe_call(_LIB.LGBM_DatasetAddFeaturesFrom(self.handle, other.handle))
return self |
Save Dataset to a text file.
This format cannot be loaded back in by LightGBM, but is useful for debugging purposes.
Parameters
----------
filename : string
Name of the output file.
Returns
-------
self : Dataset
Returns self.
def dump_text(self, filename):
"""Save Dataset to a text file.
This format cannot be loaded back in by LightGBM, but is useful for debugging purposes.
Parameters
----------
filename : string
Name of the output file.
Returns
-------
self : Dataset
Returns self.
"""
_safe_call(_LIB.LGBM_DatasetDumpText(
self.construct().handle,
c_str(filename)))
return self |
Free Booster's Datasets.
Returns
-------
self : Booster
Booster without Datasets.
def free_dataset(self):
"""Free Booster's Datasets.
Returns
-------
self : Booster
Booster without Datasets.
"""
self.__dict__.pop('train_set', None)
self.__dict__.pop('valid_sets', None)
self.__num_dataset = 0
return self |
Set the network configuration.
Parameters
----------
machines : list, set or string
Names of machines.
local_listen_port : int, optional (default=12400)
TCP listen port for local machines.
listen_time_out : int, optional (default=120)
Socket time-out in minutes.
num_machines : int, optional (default=1)
The number of machines for parallel learning application.
Returns
-------
self : Booster
Booster with set network.
def set_network(self, machines, local_listen_port=12400,
listen_time_out=120, num_machines=1):
"""Set the network configuration.
Parameters
----------
machines : list, set or string
Names of machines.
local_listen_port : int, optional (default=12400)
TCP listen port for local machines.
listen_time_out : int, optional (default=120)
Socket time-out in minutes.
num_machines : int, optional (default=1)
The number of machines for parallel learning application.
Returns
-------
self : Booster
Booster with set network.
"""
_safe_call(_LIB.LGBM_NetworkInit(c_str(machines),
ctypes.c_int(local_listen_port),
ctypes.c_int(listen_time_out),
ctypes.c_int(num_machines)))
self.network = True
return self |
Add validation data.
Parameters
----------
data : Dataset
Validation data.
name : string
Name of validation data.
Returns
-------
self : Booster
Booster with set validation data.
def add_valid(self, data, name):
"""Add validation data.
Parameters
----------
data : Dataset
Validation data.
name : string
Name of validation data.
Returns
-------
self : Booster
Booster with set validation data.
"""
if not isinstance(data, Dataset):
raise TypeError('Validation data should be Dataset instance, met {}'
.format(type(data).__name__))
if data._predictor is not self.__init_predictor:
raise LightGBMError("Add validation data failed, "
"you should use same predictor for these data")
_safe_call(_LIB.LGBM_BoosterAddValidData(
self.handle,
data.construct().handle))
self.valid_sets.append(data)
self.name_valid_sets.append(name)
self.__num_dataset += 1
self.__inner_predict_buffer.append(None)
self.__is_predicted_cur_iter.append(False)
return self |
Reset parameters of Booster.
Parameters
----------
params : dict
New parameters for Booster.
Returns
-------
self : Booster
Booster with new parameters.
def reset_parameter(self, params):
"""Reset parameters of Booster.
Parameters
----------
params : dict
New parameters for Booster.
Returns
-------
self : Booster
Booster with new parameters.
"""
if any(metric_alias in params for metric_alias in ('metric', 'metrics', 'metric_types')):
self.__need_reload_eval_info = True
params_str = param_dict_to_str(params)
if params_str:
_safe_call(_LIB.LGBM_BoosterResetParameter(
self.handle,
c_str(params_str)))
self.params.update(params)
return self |
Update Booster for one iteration.
Parameters
----------
train_set : Dataset or None, optional (default=None)
Training data.
If None, last training data is used.
fobj : callable or None, optional (default=None)
Customized objective function.
For multi-class task, the score is group by class_id first, then group by row_id.
If you want to get i-th row score in j-th class, the access way is score[j * num_data + i]
and you should group grad and hess in this way as well.
Returns
-------
is_finished : bool
Whether the update was successfully finished.
def update(self, train_set=None, fobj=None):
"""Update Booster for one iteration.
Parameters
----------
train_set : Dataset or None, optional (default=None)
Training data.
If None, last training data is used.
fobj : callable or None, optional (default=None)
Customized objective function.
For multi-class task, the score is group by class_id first, then group by row_id.
If you want to get i-th row score in j-th class, the access way is score[j * num_data + i]
and you should group grad and hess in this way as well.
Returns
-------
is_finished : bool
Whether the update was successfully finished.
"""
# need reset training data
if train_set is not None and train_set is not self.train_set:
if not isinstance(train_set, Dataset):
raise TypeError('Training data should be Dataset instance, met {}'
.format(type(train_set).__name__))
if train_set._predictor is not self.__init_predictor:
raise LightGBMError("Replace training data failed, "
"you should use same predictor for these data")
self.train_set = train_set
_safe_call(_LIB.LGBM_BoosterResetTrainingData(
self.handle,
self.train_set.construct().handle))
self.__inner_predict_buffer[0] = None
is_finished = ctypes.c_int(0)
if fobj is None:
if self.__set_objective_to_none:
raise LightGBMError('Cannot update due to null objective function.')
_safe_call(_LIB.LGBM_BoosterUpdateOneIter(
self.handle,
ctypes.byref(is_finished)))
self.__is_predicted_cur_iter = [False for _ in range_(self.__num_dataset)]
return is_finished.value == 1
else:
if not self.__set_objective_to_none:
self.reset_parameter({"objective": "none"}).__set_objective_to_none = True
grad, hess = fobj(self.__inner_predict(0), self.train_set)
return self.__boost(grad, hess) |
Boost Booster for one iteration with customized gradient statistics.
Note
----
For multi-class task, the score is group by class_id first, then group by row_id.
If you want to get i-th row score in j-th class, the access way is score[j * num_data + i]
and you should group grad and hess in this way as well.
Parameters
----------
grad : 1-D numpy array or 1-D list
The first order derivative (gradient).
hess : 1-D numpy array or 1-D list
The second order derivative (Hessian).
Returns
-------
is_finished : bool
Whether the boost was successfully finished.
def __boost(self, grad, hess):
"""Boost Booster for one iteration with customized gradient statistics.
Note
----
For multi-class task, the score is group by class_id first, then group by row_id.
If you want to get i-th row score in j-th class, the access way is score[j * num_data + i]
and you should group grad and hess in this way as well.
Parameters
----------
grad : 1-D numpy array or 1-D list
The first order derivative (gradient).
hess : 1-D numpy array or 1-D list
The second order derivative (Hessian).
Returns
-------
is_finished : bool
Whether the boost was successfully finished.
"""
grad = list_to_1d_numpy(grad, name='gradient')
hess = list_to_1d_numpy(hess, name='hessian')
assert grad.flags.c_contiguous
assert hess.flags.c_contiguous
if len(grad) != len(hess):
raise ValueError("Lengths of gradient({}) and hessian({}) don't match"
.format(len(grad), len(hess)))
is_finished = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterUpdateOneIterCustom(
self.handle,
grad.ctypes.data_as(ctypes.POINTER(ctypes.c_float)),
hess.ctypes.data_as(ctypes.POINTER(ctypes.c_float)),
ctypes.byref(is_finished)))
self.__is_predicted_cur_iter = [False for _ in range_(self.__num_dataset)]
return is_finished.value == 1 |
Rollback one iteration.
Returns
-------
self : Booster
Booster with rolled back one iteration.
def rollback_one_iter(self):
"""Rollback one iteration.
Returns
-------
self : Booster
Booster with rolled back one iteration.
"""
_safe_call(_LIB.LGBM_BoosterRollbackOneIter(
self.handle))
self.__is_predicted_cur_iter = [False for _ in range_(self.__num_dataset)]
return self |
Get the index of the current iteration.
Returns
-------
cur_iter : int
The index of the current iteration.
def current_iteration(self):
"""Get the index of the current iteration.
Returns
-------
cur_iter : int
The index of the current iteration.
"""
out_cur_iter = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterGetCurrentIteration(
self.handle,
ctypes.byref(out_cur_iter)))
return out_cur_iter.value |
Get number of models per iteration.
Returns
-------
model_per_iter : int
The number of models per iteration.
def num_model_per_iteration(self):
"""Get number of models per iteration.
Returns
-------
model_per_iter : int
The number of models per iteration.
"""
model_per_iter = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterNumModelPerIteration(
self.handle,
ctypes.byref(model_per_iter)))
return model_per_iter.value |
Get number of weak sub-models.
Returns
-------
num_trees : int
The number of weak sub-models.
def num_trees(self):
"""Get number of weak sub-models.
Returns
-------
num_trees : int
The number of weak sub-models.
"""
num_trees = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterNumberOfTotalModel(
self.handle,
ctypes.byref(num_trees)))
return num_trees.value |
Evaluate for data.
Parameters
----------
data : Dataset
Data for the evaluating.
name : string
Name of the data.
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
Returns
-------
result : list
List with evaluation results.
def eval(self, data, name, feval=None):
"""Evaluate for data.
Parameters
----------
data : Dataset
Data for the evaluating.
name : string
Name of the data.
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
Returns
-------
result : list
List with evaluation results.
"""
if not isinstance(data, Dataset):
raise TypeError("Can only eval for Dataset instance")
data_idx = -1
if data is self.train_set:
data_idx = 0
else:
for i in range_(len(self.valid_sets)):
if data is self.valid_sets[i]:
data_idx = i + 1
break
# need to push new valid data
if data_idx == -1:
self.add_valid(data, name)
data_idx = self.__num_dataset - 1
return self.__inner_eval(name, data_idx, feval) |
Evaluate for validation data.
Parameters
----------
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
Returns
-------
result : list
List with evaluation results.
def eval_valid(self, feval=None):
"""Evaluate for validation data.
Parameters
----------
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
Returns
-------
result : list
List with evaluation results.
"""
return [item for i in range_(1, self.__num_dataset)
for item in self.__inner_eval(self.name_valid_sets[i - 1], i, feval)] |
Save Booster to file.
Parameters
----------
filename : string
Filename to save Booster.
num_iteration : int or None, optional (default=None)
Index of the iteration that should be saved.
If None, if the best iteration exists, it is saved; otherwise, all iterations are saved.
If <= 0, all iterations are saved.
start_iteration : int, optional (default=0)
Start index of the iteration that should be saved.
Returns
-------
self : Booster
Returns self.
def save_model(self, filename, num_iteration=None, start_iteration=0):
"""Save Booster to file.
Parameters
----------
filename : string
Filename to save Booster.
num_iteration : int or None, optional (default=None)
Index of the iteration that should be saved.
If None, if the best iteration exists, it is saved; otherwise, all iterations are saved.
If <= 0, all iterations are saved.
start_iteration : int, optional (default=0)
Start index of the iteration that should be saved.
Returns
-------
self : Booster
Returns self.
"""
if num_iteration is None:
num_iteration = self.best_iteration
_safe_call(_LIB.LGBM_BoosterSaveModel(
self.handle,
ctypes.c_int(start_iteration),
ctypes.c_int(num_iteration),
c_str(filename)))
_dump_pandas_categorical(self.pandas_categorical, filename)
return self |
Shuffle models.
Parameters
----------
start_iteration : int, optional (default=0)
The first iteration that will be shuffled.
end_iteration : int, optional (default=-1)
The last iteration that will be shuffled.
If <= 0, means the last available iteration.
Returns
-------
self : Booster
Booster with shuffled models.
def shuffle_models(self, start_iteration=0, end_iteration=-1):
"""Shuffle models.
Parameters
----------
start_iteration : int, optional (default=0)
The first iteration that will be shuffled.
end_iteration : int, optional (default=-1)
The last iteration that will be shuffled.
If <= 0, means the last available iteration.
Returns
-------
self : Booster
Booster with shuffled models.
"""
_safe_call(_LIB.LGBM_BoosterShuffleModels(
self.handle,
ctypes.c_int(start_iteration),
ctypes.c_int(end_iteration)))
return self |
Load Booster from a string.
Parameters
----------
model_str : string
Model will be loaded from this string.
verbose : bool, optional (default=True)
Whether to print messages while loading model.
Returns
-------
self : Booster
Loaded Booster object.
def model_from_string(self, model_str, verbose=True):
"""Load Booster from a string.
Parameters
----------
model_str : string
Model will be loaded from this string.
verbose : bool, optional (default=True)
Whether to print messages while loading model.
Returns
-------
self : Booster
Loaded Booster object.
"""
if self.handle is not None:
_safe_call(_LIB.LGBM_BoosterFree(self.handle))
self._free_buffer()
self.handle = ctypes.c_void_p()
out_num_iterations = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterLoadModelFromString(
c_str(model_str),
ctypes.byref(out_num_iterations),
ctypes.byref(self.handle)))
out_num_class = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterGetNumClasses(
self.handle,
ctypes.byref(out_num_class)))
if verbose:
print('Finished loading model, total used %d iterations' % int(out_num_iterations.value))
self.__num_class = out_num_class.value
self.pandas_categorical = _load_pandas_categorical(model_str=model_str)
return self |
Save Booster to string.
Parameters
----------
num_iteration : int or None, optional (default=None)
Index of the iteration that should be saved.
If None, if the best iteration exists, it is saved; otherwise, all iterations are saved.
If <= 0, all iterations are saved.
start_iteration : int, optional (default=0)
Start index of the iteration that should be saved.
Returns
-------
str_repr : string
String representation of Booster.
def model_to_string(self, num_iteration=None, start_iteration=0):
"""Save Booster to string.
Parameters
----------
num_iteration : int or None, optional (default=None)
Index of the iteration that should be saved.
If None, if the best iteration exists, it is saved; otherwise, all iterations are saved.
If <= 0, all iterations are saved.
start_iteration : int, optional (default=0)
Start index of the iteration that should be saved.
Returns
-------
str_repr : string
String representation of Booster.
"""
if num_iteration is None:
num_iteration = self.best_iteration
buffer_len = 1 << 20
tmp_out_len = ctypes.c_int64(0)
string_buffer = ctypes.create_string_buffer(buffer_len)
ptr_string_buffer = ctypes.c_char_p(*[ctypes.addressof(string_buffer)])
_safe_call(_LIB.LGBM_BoosterSaveModelToString(
self.handle,
ctypes.c_int(start_iteration),
ctypes.c_int(num_iteration),
ctypes.c_int64(buffer_len),
ctypes.byref(tmp_out_len),
ptr_string_buffer))
actual_len = tmp_out_len.value
# if buffer length is not long enough, re-allocate a buffer
if actual_len > buffer_len:
string_buffer = ctypes.create_string_buffer(actual_len)
ptr_string_buffer = ctypes.c_char_p(*[ctypes.addressof(string_buffer)])
_safe_call(_LIB.LGBM_BoosterSaveModelToString(
self.handle,
ctypes.c_int(start_iteration),
ctypes.c_int(num_iteration),
ctypes.c_int64(actual_len),
ctypes.byref(tmp_out_len),
ptr_string_buffer))
ret = string_buffer.value.decode()
ret += _dump_pandas_categorical(self.pandas_categorical)
return ret |
Dump Booster to JSON format.
Parameters
----------
num_iteration : int or None, optional (default=None)
Index of the iteration that should be dumped.
If None, if the best iteration exists, it is dumped; otherwise, all iterations are dumped.
If <= 0, all iterations are dumped.
start_iteration : int, optional (default=0)
Start index of the iteration that should be dumped.
Returns
-------
json_repr : dict
JSON format of Booster.
def dump_model(self, num_iteration=None, start_iteration=0):
"""Dump Booster to JSON format.
Parameters
----------
num_iteration : int or None, optional (default=None)
Index of the iteration that should be dumped.
If None, if the best iteration exists, it is dumped; otherwise, all iterations are dumped.
If <= 0, all iterations are dumped.
start_iteration : int, optional (default=0)
Start index of the iteration that should be dumped.
Returns
-------
json_repr : dict
JSON format of Booster.
"""
if num_iteration is None:
num_iteration = self.best_iteration
buffer_len = 1 << 20
tmp_out_len = ctypes.c_int64(0)
string_buffer = ctypes.create_string_buffer(buffer_len)
ptr_string_buffer = ctypes.c_char_p(*[ctypes.addressof(string_buffer)])
_safe_call(_LIB.LGBM_BoosterDumpModel(
self.handle,
ctypes.c_int(start_iteration),
ctypes.c_int(num_iteration),
ctypes.c_int64(buffer_len),
ctypes.byref(tmp_out_len),
ptr_string_buffer))
actual_len = tmp_out_len.value
# if buffer length is not long enough, reallocate a buffer
if actual_len > buffer_len:
string_buffer = ctypes.create_string_buffer(actual_len)
ptr_string_buffer = ctypes.c_char_p(*[ctypes.addressof(string_buffer)])
_safe_call(_LIB.LGBM_BoosterDumpModel(
self.handle,
ctypes.c_int(start_iteration),
ctypes.c_int(num_iteration),
ctypes.c_int64(actual_len),
ctypes.byref(tmp_out_len),
ptr_string_buffer))
ret = json.loads(string_buffer.value.decode())
ret['pandas_categorical'] = json.loads(json.dumps(self.pandas_categorical,
default=json_default_with_numpy))
return ret |
Make a prediction.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame or scipy.sparse
Data source for prediction.
If string, it represents the path to txt file.
num_iteration : int or None, optional (default=None)
Limit number of iterations in the prediction.
If None, if the best iteration exists, it is used; otherwise, all iterations are used.
If <= 0, all iterations are used (no limits).
raw_score : bool, optional (default=False)
Whether to predict raw scores.
pred_leaf : bool, optional (default=False)
Whether to predict leaf index.
pred_contrib : bool, optional (default=False)
Whether to predict feature contributions.
Note
----
If you want to get more explanations for your model's predictions using SHAP values,
like SHAP interaction values,
you can install the shap package (https://github.com/slundberg/shap).
Note that unlike the shap package, with ``pred_contrib`` we return a matrix with an extra
column, where the last column is the expected value.
data_has_header : bool, optional (default=False)
Whether the data has header.
Used only if data is string.
is_reshape : bool, optional (default=True)
If True, result is reshaped to [nrow, ncol].
**kwargs
Other parameters for the prediction.
Returns
-------
result : numpy array
Prediction result.
def predict(self, data, num_iteration=None,
raw_score=False, pred_leaf=False, pred_contrib=False,
data_has_header=False, is_reshape=True, **kwargs):
"""Make a prediction.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame or scipy.sparse
Data source for prediction.
If string, it represents the path to txt file.
num_iteration : int or None, optional (default=None)
Limit number of iterations in the prediction.
If None, if the best iteration exists, it is used; otherwise, all iterations are used.
If <= 0, all iterations are used (no limits).
raw_score : bool, optional (default=False)
Whether to predict raw scores.
pred_leaf : bool, optional (default=False)
Whether to predict leaf index.
pred_contrib : bool, optional (default=False)
Whether to predict feature contributions.
Note
----
If you want to get more explanations for your model's predictions using SHAP values,
like SHAP interaction values,
you can install the shap package (https://github.com/slundberg/shap).
Note that unlike the shap package, with ``pred_contrib`` we return a matrix with an extra
column, where the last column is the expected value.
data_has_header : bool, optional (default=False)
Whether the data has header.
Used only if data is string.
is_reshape : bool, optional (default=True)
If True, result is reshaped to [nrow, ncol].
**kwargs
Other parameters for the prediction.
Returns
-------
result : numpy array
Prediction result.
"""
predictor = self._to_predictor(copy.deepcopy(kwargs))
if num_iteration is None:
num_iteration = self.best_iteration
return predictor.predict(data, num_iteration,
raw_score, pred_leaf, pred_contrib,
data_has_header, is_reshape) |
Refit the existing Booster by new data.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame or scipy.sparse
Data source for refit.
If string, it represents the path to txt file.
label : list, numpy 1-D array or pandas Series / one-column DataFrame
Label for refit.
decay_rate : float, optional (default=0.9)
Decay rate of refit,
will use ``leaf_output = decay_rate * old_leaf_output + (1.0 - decay_rate) * new_leaf_output`` to refit trees.
**kwargs
Other parameters for refit.
These parameters will be passed to ``predict`` method.
Returns
-------
result : Booster
Refitted Booster.
def refit(self, data, label, decay_rate=0.9, **kwargs):
"""Refit the existing Booster by new data.
Parameters
----------
data : string, numpy array, pandas DataFrame, H2O DataTable's Frame or scipy.sparse
Data source for refit.
If string, it represents the path to txt file.
label : list, numpy 1-D array or pandas Series / one-column DataFrame
Label for refit.
decay_rate : float, optional (default=0.9)
Decay rate of refit,
will use ``leaf_output = decay_rate * old_leaf_output + (1.0 - decay_rate) * new_leaf_output`` to refit trees.
**kwargs
Other parameters for refit.
These parameters will be passed to ``predict`` method.
Returns
-------
result : Booster
Refitted Booster.
"""
if self.__set_objective_to_none:
raise LightGBMError('Cannot refit due to null objective function.')
predictor = self._to_predictor(copy.deepcopy(kwargs))
leaf_preds = predictor.predict(data, -1, pred_leaf=True)
nrow, ncol = leaf_preds.shape
train_set = Dataset(data, label, silent=True)
new_booster = Booster(self.params, train_set, silent=True)
# Copy models
_safe_call(_LIB.LGBM_BoosterMerge(
new_booster.handle,
predictor.handle))
leaf_preds = leaf_preds.reshape(-1)
ptr_data, type_ptr_data, _ = c_int_array(leaf_preds)
_safe_call(_LIB.LGBM_BoosterRefit(
new_booster.handle,
ptr_data,
ctypes.c_int(nrow),
ctypes.c_int(ncol)))
new_booster.network = self.network
new_booster.__attr = self.__attr.copy()
return new_booster |
Get the output of a leaf.
Parameters
----------
tree_id : int
The index of the tree.
leaf_id : int
The index of the leaf in the tree.
Returns
-------
result : float
The output of the leaf.
def get_leaf_output(self, tree_id, leaf_id):
"""Get the output of a leaf.
Parameters
----------
tree_id : int
The index of the tree.
leaf_id : int
The index of the leaf in the tree.
Returns
-------
result : float
The output of the leaf.
"""
ret = ctypes.c_double(0)
_safe_call(_LIB.LGBM_BoosterGetLeafValue(
self.handle,
ctypes.c_int(tree_id),
ctypes.c_int(leaf_id),
ctypes.byref(ret)))
return ret.value |
Convert to predictor.
def _to_predictor(self, pred_parameter=None):
"""Convert to predictor."""
predictor = _InnerPredictor(booster_handle=self.handle, pred_parameter=pred_parameter)
predictor.pandas_categorical = self.pandas_categorical
return predictor |
Get number of features.
Returns
-------
num_feature : int
The number of features.
def num_feature(self):
"""Get number of features.
Returns
-------
num_feature : int
The number of features.
"""
out_num_feature = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterGetNumFeature(
self.handle,
ctypes.byref(out_num_feature)))
return out_num_feature.value |
Get names of features.
Returns
-------
result : list
List with names of features.
def feature_name(self):
"""Get names of features.
Returns
-------
result : list
List with names of features.
"""
num_feature = self.num_feature()
# Get name of features
tmp_out_len = ctypes.c_int(0)
string_buffers = [ctypes.create_string_buffer(255) for i in range_(num_feature)]
ptr_string_buffers = (ctypes.c_char_p * num_feature)(*map(ctypes.addressof, string_buffers))
_safe_call(_LIB.LGBM_BoosterGetFeatureNames(
self.handle,
ctypes.byref(tmp_out_len),
ptr_string_buffers))
if num_feature != tmp_out_len.value:
raise ValueError("Length of feature names doesn't equal with num_feature")
return [string_buffers[i].value.decode() for i in range_(num_feature)] |
Get feature importances.
Parameters
----------
importance_type : string, optional (default="split")
How the importance is calculated.
If "split", result contains numbers of times the feature is used in a model.
If "gain", result contains total gains of splits which use the feature.
iteration : int or None, optional (default=None)
Limit number of iterations in the feature importance calculation.
If None, if the best iteration exists, it is used; otherwise, all trees are used.
If <= 0, all trees are used (no limits).
Returns
-------
result : numpy array
Array with feature importances.
def feature_importance(self, importance_type='split', iteration=None):
"""Get feature importances.
Parameters
----------
importance_type : string, optional (default="split")
How the importance is calculated.
If "split", result contains numbers of times the feature is used in a model.
If "gain", result contains total gains of splits which use the feature.
iteration : int or None, optional (default=None)
Limit number of iterations in the feature importance calculation.
If None, if the best iteration exists, it is used; otherwise, all trees are used.
If <= 0, all trees are used (no limits).
Returns
-------
result : numpy array
Array with feature importances.
"""
if iteration is None:
iteration = self.best_iteration
if importance_type == "split":
importance_type_int = 0
elif importance_type == "gain":
importance_type_int = 1
else:
importance_type_int = -1
result = np.zeros(self.num_feature(), dtype=np.float64)
_safe_call(_LIB.LGBM_BoosterFeatureImportance(
self.handle,
ctypes.c_int(iteration),
ctypes.c_int(importance_type_int),
result.ctypes.data_as(ctypes.POINTER(ctypes.c_double))))
if importance_type_int == 0:
return result.astype(int)
else:
return result |
Get split value histogram for the specified feature.
Parameters
----------
feature : int or string
The feature name or index the histogram is calculated for.
If int, interpreted as index.
If string, interpreted as name.
Note
----
Categorical features are not supported.
bins : int, string or None, optional (default=None)
The maximum number of bins.
If None, or int and > number of unique split values and ``xgboost_style=True``,
the number of bins equals number of unique split values.
If string, it should be one from the list of the supported values by ``numpy.histogram()`` function.
xgboost_style : bool, optional (default=False)
Whether the returned result should be in the same form as it is in XGBoost.
If False, the returned value is tuple of 2 numpy arrays as it is in ``numpy.histogram()`` function.
If True, the returned value is matrix, in which the first column is the right edges of non-empty bins
and the second one is the histogram values.
Returns
-------
result_tuple : tuple of 2 numpy arrays
If ``xgboost_style=False``, the values of the histogram of used splitting values for the specified feature
and the bin edges.
result_array_like : numpy array or pandas DataFrame (if pandas is installed)
If ``xgboost_style=True``, the histogram of used splitting values for the specified feature.
def get_split_value_histogram(self, feature, bins=None, xgboost_style=False):
"""Get split value histogram for the specified feature.
Parameters
----------
feature : int or string
The feature name or index the histogram is calculated for.
If int, interpreted as index.
If string, interpreted as name.
Note
----
Categorical features are not supported.
bins : int, string or None, optional (default=None)
The maximum number of bins.
If None, or int and > number of unique split values and ``xgboost_style=True``,
the number of bins equals number of unique split values.
If string, it should be one from the list of the supported values by ``numpy.histogram()`` function.
xgboost_style : bool, optional (default=False)
Whether the returned result should be in the same form as it is in XGBoost.
If False, the returned value is tuple of 2 numpy arrays as it is in ``numpy.histogram()`` function.
If True, the returned value is matrix, in which the first column is the right edges of non-empty bins
and the second one is the histogram values.
Returns
-------
result_tuple : tuple of 2 numpy arrays
If ``xgboost_style=False``, the values of the histogram of used splitting values for the specified feature
and the bin edges.
result_array_like : numpy array or pandas DataFrame (if pandas is installed)
If ``xgboost_style=True``, the histogram of used splitting values for the specified feature.
"""
def add(root):
"""Recursively add thresholds."""
if 'split_index' in root: # non-leaf
if feature_names is not None and isinstance(feature, string_type):
split_feature = feature_names[root['split_feature']]
else:
split_feature = root['split_feature']
if split_feature == feature:
if isinstance(root['threshold'], string_type):
raise LightGBMError('Cannot compute split value histogram for the categorical feature')
else:
values.append(root['threshold'])
add(root['left_child'])
add(root['right_child'])
model = self.dump_model()
feature_names = model.get('feature_names')
tree_infos = model['tree_info']
values = []
for tree_info in tree_infos:
add(tree_info['tree_structure'])
if bins is None or isinstance(bins, integer_types) and xgboost_style:
n_unique = len(np.unique(values))
bins = max(min(n_unique, bins) if bins is not None else n_unique, 1)
hist, bin_edges = np.histogram(values, bins=bins)
if xgboost_style:
ret = np.column_stack((bin_edges[1:], hist))
ret = ret[ret[:, 1] > 0]
if PANDAS_INSTALLED:
return DataFrame(ret, columns=['SplitValue', 'Count'])
else:
return ret
else:
return hist, bin_edges |
Evaluate training or validation data.
def __inner_eval(self, data_name, data_idx, feval=None):
"""Evaluate training or validation data."""
if data_idx >= self.__num_dataset:
raise ValueError("Data_idx should be smaller than number of dataset")
self.__get_eval_info()
ret = []
if self.__num_inner_eval > 0:
result = np.zeros(self.__num_inner_eval, dtype=np.float64)
tmp_out_len = ctypes.c_int(0)
_safe_call(_LIB.LGBM_BoosterGetEval(
self.handle,
ctypes.c_int(data_idx),
ctypes.byref(tmp_out_len),
result.ctypes.data_as(ctypes.POINTER(ctypes.c_double))))
if tmp_out_len.value != self.__num_inner_eval:
raise ValueError("Wrong length of eval results")
for i in range_(self.__num_inner_eval):
ret.append((data_name, self.__name_inner_eval[i],
result[i], self.__higher_better_inner_eval[i]))
if feval is not None:
if data_idx == 0:
cur_data = self.train_set
else:
cur_data = self.valid_sets[data_idx - 1]
feval_ret = feval(self.__inner_predict(data_idx), cur_data)
if isinstance(feval_ret, list):
for eval_name, val, is_higher_better in feval_ret:
ret.append((data_name, eval_name, val, is_higher_better))
else:
eval_name, val, is_higher_better = feval_ret
ret.append((data_name, eval_name, val, is_higher_better))
return ret |
Predict for training and validation dataset.
def __inner_predict(self, data_idx):
"""Predict for training and validation dataset."""
if data_idx >= self.__num_dataset:
raise ValueError("Data_idx should be smaller than number of dataset")
if self.__inner_predict_buffer[data_idx] is None:
if data_idx == 0:
n_preds = self.train_set.num_data() * self.__num_class
else:
n_preds = self.valid_sets[data_idx - 1].num_data() * self.__num_class
self.__inner_predict_buffer[data_idx] = np.zeros(n_preds, dtype=np.float64)
# avoid to predict many time in one iteration
if not self.__is_predicted_cur_iter[data_idx]:
tmp_out_len = ctypes.c_int64(0)
data_ptr = self.__inner_predict_buffer[data_idx].ctypes.data_as(ctypes.POINTER(ctypes.c_double))
_safe_call(_LIB.LGBM_BoosterGetPredict(
self.handle,
ctypes.c_int(data_idx),
ctypes.byref(tmp_out_len),
data_ptr))
if tmp_out_len.value != len(self.__inner_predict_buffer[data_idx]):
raise ValueError("Wrong length of predict results for data %d" % (data_idx))
self.__is_predicted_cur_iter[data_idx] = True
return self.__inner_predict_buffer[data_idx] |
Get inner evaluation count and names.
def __get_eval_info(self):
"""Get inner evaluation count and names."""
if self.__need_reload_eval_info:
self.__need_reload_eval_info = False
out_num_eval = ctypes.c_int(0)
# Get num of inner evals
_safe_call(_LIB.LGBM_BoosterGetEvalCounts(
self.handle,
ctypes.byref(out_num_eval)))
self.__num_inner_eval = out_num_eval.value
if self.__num_inner_eval > 0:
# Get name of evals
tmp_out_len = ctypes.c_int(0)
string_buffers = [ctypes.create_string_buffer(255) for i in range_(self.__num_inner_eval)]
ptr_string_buffers = (ctypes.c_char_p * self.__num_inner_eval)(*map(ctypes.addressof, string_buffers))
_safe_call(_LIB.LGBM_BoosterGetEvalNames(
self.handle,
ctypes.byref(tmp_out_len),
ptr_string_buffers))
if self.__num_inner_eval != tmp_out_len.value:
raise ValueError("Length of eval names doesn't equal with num_evals")
self.__name_inner_eval = \
[string_buffers[i].value.decode() for i in range_(self.__num_inner_eval)]
self.__higher_better_inner_eval = \
[name.startswith(('auc', 'ndcg@', 'map@')) for name in self.__name_inner_eval] |
Set attributes to the Booster.
Parameters
----------
**kwargs
The attributes to set.
Setting a value to None deletes an attribute.
Returns
-------
self : Booster
Booster with set attributes.
def set_attr(self, **kwargs):
"""Set attributes to the Booster.
Parameters
----------
**kwargs
The attributes to set.
Setting a value to None deletes an attribute.
Returns
-------
self : Booster
Booster with set attributes.
"""
for key, value in kwargs.items():
if value is not None:
if not isinstance(value, string_type):
raise ValueError("Only string values are accepted")
self.__attr[key] = value
else:
self.__attr.pop(key, None)
return self |
Find the path to LightGBM library files.
Returns
-------
lib_path: list of strings
List of all found library paths to LightGBM.
def find_lib_path():
"""Find the path to LightGBM library files.
Returns
-------
lib_path: list of strings
List of all found library paths to LightGBM.
"""
if os.environ.get('LIGHTGBM_BUILD_DOC', False):
# we don't need lib_lightgbm while building docs
return []
curr_path = os.path.dirname(os.path.abspath(os.path.expanduser(__file__)))
dll_path = [curr_path,
os.path.join(curr_path, '../../'),
os.path.join(curr_path, 'compile'),
os.path.join(curr_path, '../compile'),
os.path.join(curr_path, '../../lib/')]
if system() in ('Windows', 'Microsoft'):
dll_path.append(os.path.join(curr_path, '../compile/Release/'))
dll_path.append(os.path.join(curr_path, '../compile/windows/x64/DLL/'))
dll_path.append(os.path.join(curr_path, '../../Release/'))
dll_path.append(os.path.join(curr_path, '../../windows/x64/DLL/'))
dll_path = [os.path.join(p, 'lib_lightgbm.dll') for p in dll_path]
else:
dll_path = [os.path.join(p, 'lib_lightgbm.so') for p in dll_path]
lib_path = [p for p in dll_path if os.path.exists(p) and os.path.isfile(p)]
if not lib_path:
dll_path = [os.path.realpath(p) for p in dll_path]
raise Exception('Cannot find lightgbm library file in following paths:\n' + '\n'.join(dll_path))
return lib_path |
Convert numpy classes to JSON serializable objects.
def json_default_with_numpy(obj):
"""Convert numpy classes to JSON serializable objects."""
if isinstance(obj, (np.integer, np.floating, np.bool_)):
return obj.item()
elif isinstance(obj, np.ndarray):
return obj.tolist()
else:
return obj |
Format metric string.
def _format_eval_result(value, show_stdv=True):
"""Format metric string."""
if len(value) == 4:
return '%s\'s %s: %g' % (value[0], value[1], value[2])
elif len(value) == 5:
if show_stdv:
return '%s\'s %s: %g + %g' % (value[0], value[1], value[2], value[4])
else:
return '%s\'s %s: %g' % (value[0], value[1], value[2])
else:
raise ValueError("Wrong metric value") |
Create a callback that prints the evaluation results.
Parameters
----------
period : int, optional (default=1)
The period to print the evaluation results.
show_stdv : bool, optional (default=True)
Whether to show stdv (if provided).
Returns
-------
callback : function
The callback that prints the evaluation results every ``period`` iteration(s).
def print_evaluation(period=1, show_stdv=True):
"""Create a callback that prints the evaluation results.
Parameters
----------
period : int, optional (default=1)
The period to print the evaluation results.
show_stdv : bool, optional (default=True)
Whether to show stdv (if provided).
Returns
-------
callback : function
The callback that prints the evaluation results every ``period`` iteration(s).
"""
def _callback(env):
if period > 0 and env.evaluation_result_list and (env.iteration + 1) % period == 0:
result = '\t'.join([_format_eval_result(x, show_stdv) for x in env.evaluation_result_list])
print('[%d]\t%s' % (env.iteration + 1, result))
_callback.order = 10
return _callback |
Create a callback that records the evaluation history into ``eval_result``.
Parameters
----------
eval_result : dict
A dictionary to store the evaluation results.
Returns
-------
callback : function
The callback that records the evaluation history into the passed dictionary.
def record_evaluation(eval_result):
"""Create a callback that records the evaluation history into ``eval_result``.
Parameters
----------
eval_result : dict
A dictionary to store the evaluation results.
Returns
-------
callback : function
The callback that records the evaluation history into the passed dictionary.
"""
if not isinstance(eval_result, dict):
raise TypeError('Eval_result should be a dictionary')
eval_result.clear()
def _init(env):
for data_name, _, _, _ in env.evaluation_result_list:
eval_result.setdefault(data_name, collections.defaultdict(list))
def _callback(env):
if not eval_result:
_init(env)
for data_name, eval_name, result, _ in env.evaluation_result_list:
eval_result[data_name][eval_name].append(result)
_callback.order = 20
return _callback |
Create a callback that resets the parameter after the first iteration.
Note
----
The initial parameter will still take in-effect on first iteration.
Parameters
----------
**kwargs : value should be list or function
List of parameters for each boosting round
or a customized function that calculates the parameter in terms of
current number of round (e.g. yields learning rate decay).
If list lst, parameter = lst[current_round].
If function func, parameter = func(current_round).
Returns
-------
callback : function
The callback that resets the parameter after the first iteration.
def reset_parameter(**kwargs):
"""Create a callback that resets the parameter after the first iteration.
Note
----
The initial parameter will still take in-effect on first iteration.
Parameters
----------
**kwargs : value should be list or function
List of parameters for each boosting round
or a customized function that calculates the parameter in terms of
current number of round (e.g. yields learning rate decay).
If list lst, parameter = lst[current_round].
If function func, parameter = func(current_round).
Returns
-------
callback : function
The callback that resets the parameter after the first iteration.
"""
def _callback(env):
new_parameters = {}
for key, value in kwargs.items():
if key in ['num_class', 'num_classes',
'boosting', 'boost', 'boosting_type',
'metric', 'metrics', 'metric_types']:
raise RuntimeError("cannot reset {} during training".format(repr(key)))
if isinstance(value, list):
if len(value) != env.end_iteration - env.begin_iteration:
raise ValueError("Length of list {} has to equal to 'num_boost_round'."
.format(repr(key)))
new_param = value[env.iteration - env.begin_iteration]
else:
new_param = value(env.iteration - env.begin_iteration)
if new_param != env.params.get(key, None):
new_parameters[key] = new_param
if new_parameters:
env.model.reset_parameter(new_parameters)
env.params.update(new_parameters)
_callback.before_iteration = True
_callback.order = 10
return _callback |
Create a callback that activates early stopping.
Note
----
Activates early stopping.
The model will train until the validation score stops improving.
Validation score needs to improve at least every ``early_stopping_rounds`` round(s)
to continue training.
Requires at least one validation data and one metric.
If there's more than one, will check all of them. But the training data is ignored anyway.
To check only the first metric set ``first_metric_only`` to True.
Parameters
----------
stopping_rounds : int
The possible number of rounds without the trend occurrence.
first_metric_only : bool, optional (default=False)
Whether to use only the first metric for early stopping.
verbose : bool, optional (default=True)
Whether to print message with early stopping information.
Returns
-------
callback : function
The callback that activates early stopping.
def early_stopping(stopping_rounds, first_metric_only=False, verbose=True):
"""Create a callback that activates early stopping.
Note
----
Activates early stopping.
The model will train until the validation score stops improving.
Validation score needs to improve at least every ``early_stopping_rounds`` round(s)
to continue training.
Requires at least one validation data and one metric.
If there's more than one, will check all of them. But the training data is ignored anyway.
To check only the first metric set ``first_metric_only`` to True.
Parameters
----------
stopping_rounds : int
The possible number of rounds without the trend occurrence.
first_metric_only : bool, optional (default=False)
Whether to use only the first metric for early stopping.
verbose : bool, optional (default=True)
Whether to print message with early stopping information.
Returns
-------
callback : function
The callback that activates early stopping.
"""
best_score = []
best_iter = []
best_score_list = []
cmp_op = []
enabled = [True]
def _init(env):
enabled[0] = not any((boost_alias in env.params
and env.params[boost_alias] == 'dart') for boost_alias in ('boosting',
'boosting_type',
'boost'))
if not enabled[0]:
warnings.warn('Early stopping is not available in dart mode')
return
if not env.evaluation_result_list:
raise ValueError('For early stopping, '
'at least one dataset and eval metric is required for evaluation')
if verbose:
msg = "Training until validation scores don't improve for {} rounds."
print(msg.format(stopping_rounds))
for eval_ret in env.evaluation_result_list:
best_iter.append(0)
best_score_list.append(None)
if eval_ret[3]:
best_score.append(float('-inf'))
cmp_op.append(gt)
else:
best_score.append(float('inf'))
cmp_op.append(lt)
def _callback(env):
if not cmp_op:
_init(env)
if not enabled[0]:
return
for i in range_(len(env.evaluation_result_list)):
score = env.evaluation_result_list[i][2]
if best_score_list[i] is None or cmp_op[i](score, best_score[i]):
best_score[i] = score
best_iter[i] = env.iteration
best_score_list[i] = env.evaluation_result_list
elif env.iteration - best_iter[i] >= stopping_rounds:
if verbose:
print('Early stopping, best iteration is:\n[%d]\t%s' % (
best_iter[i] + 1, '\t'.join([_format_eval_result(x) for x in best_score_list[i]])))
raise EarlyStopException(best_iter[i], best_score_list[i])
if env.iteration == env.end_iteration - 1:
if verbose:
print('Did not meet early stopping. Best iteration is:\n[%d]\t%s' % (
best_iter[i] + 1, '\t'.join([_format_eval_result(x) for x in best_score_list[i]])))
raise EarlyStopException(best_iter[i], best_score_list[i])
if first_metric_only: # the only first metric is used for early stopping
break
_callback.order = 30
return _callback |
Perform the training with given parameters.
Parameters
----------
params : dict
Parameters for training.
train_set : Dataset
Data to be trained on.
num_boost_round : int, optional (default=100)
Number of boosting iterations.
valid_sets : list of Datasets or None, optional (default=None)
List of data to be evaluated on during training.
valid_names : list of strings or None, optional (default=None)
Names of ``valid_sets``.
fobj : callable or None, optional (default=None)
Customized objective function.
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
To ignore the default metric corresponding to the used objective,
set the ``metric`` parameter to the string ``"None"`` in ``params``.
init_model : string, Booster or None, optional (default=None)
Filename of LightGBM model or Booster instance used for continue training.
feature_name : list of strings or 'auto', optional (default="auto")
Feature names.
If 'auto' and data is pandas DataFrame, data columns names are used.
categorical_feature : list of strings or int, or 'auto', optional (default="auto")
Categorical features.
If list of int, interpreted as indices.
If list of strings, interpreted as feature names (need to specify ``feature_name`` as well).
If 'auto' and data is pandas DataFrame, pandas unordered categorical columns are used.
All values in categorical features should be less than int32 max value (2147483647).
Large values could be memory consuming. Consider using consecutive integers starting from zero.
All negative values in categorical features will be treated as missing values.
early_stopping_rounds : int or None, optional (default=None)
Activates early stopping. The model will train until the validation score stops improving.
Validation score needs to improve at least every ``early_stopping_rounds`` round(s)
to continue training.
Requires at least one validation data and one metric.
If there's more than one, will check all of them. But the training data is ignored anyway.
To check only the first metric you can pass in ``callbacks``
``early_stopping`` callback with ``first_metric_only=True``.
The index of iteration that has the best performance will be saved in the ``best_iteration`` field
if early stopping logic is enabled by setting ``early_stopping_rounds``.
evals_result: dict or None, optional (default=None)
This dictionary used to store all evaluation results of all the items in ``valid_sets``.
Example
-------
With a ``valid_sets`` = [valid_set, train_set],
``valid_names`` = ['eval', 'train']
and a ``params`` = {'metric': 'logloss'}
returns {'train': {'logloss': ['0.48253', '0.35953', ...]},
'eval': {'logloss': ['0.480385', '0.357756', ...]}}.
verbose_eval : bool or int, optional (default=True)
Requires at least one validation data.
If True, the eval metric on the valid set is printed at each boosting stage.
If int, the eval metric on the valid set is printed at every ``verbose_eval`` boosting stage.
The last boosting stage or the boosting stage found by using ``early_stopping_rounds`` is also printed.
Example
-------
With ``verbose_eval`` = 4 and at least one item in ``valid_sets``,
an evaluation metric is printed every 4 (instead of 1) boosting stages.
learning_rates : list, callable or None, optional (default=None)
List of learning rates for each boosting round
or a customized function that calculates ``learning_rate``
in terms of current number of round (e.g. yields learning rate decay).
keep_training_booster : bool, optional (default=False)
Whether the returned Booster will be used to keep training.
If False, the returned value will be converted into _InnerPredictor before returning.
You can still use _InnerPredictor as ``init_model`` for future continue training.
callbacks : list of callables or None, optional (default=None)
List of callback functions that are applied at each iteration.
See Callbacks in Python API for more information.
Returns
-------
booster : Booster
The trained Booster model.
def train(params, train_set, num_boost_round=100,
valid_sets=None, valid_names=None,
fobj=None, feval=None, init_model=None,
feature_name='auto', categorical_feature='auto',
early_stopping_rounds=None, evals_result=None,
verbose_eval=True, learning_rates=None,
keep_training_booster=False, callbacks=None):
"""Perform the training with given parameters.
Parameters
----------
params : dict
Parameters for training.
train_set : Dataset
Data to be trained on.
num_boost_round : int, optional (default=100)
Number of boosting iterations.
valid_sets : list of Datasets or None, optional (default=None)
List of data to be evaluated on during training.
valid_names : list of strings or None, optional (default=None)
Names of ``valid_sets``.
fobj : callable or None, optional (default=None)
Customized objective function.
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
To ignore the default metric corresponding to the used objective,
set the ``metric`` parameter to the string ``"None"`` in ``params``.
init_model : string, Booster or None, optional (default=None)
Filename of LightGBM model or Booster instance used for continue training.
feature_name : list of strings or 'auto', optional (default="auto")
Feature names.
If 'auto' and data is pandas DataFrame, data columns names are used.
categorical_feature : list of strings or int, or 'auto', optional (default="auto")
Categorical features.
If list of int, interpreted as indices.
If list of strings, interpreted as feature names (need to specify ``feature_name`` as well).
If 'auto' and data is pandas DataFrame, pandas unordered categorical columns are used.
All values in categorical features should be less than int32 max value (2147483647).
Large values could be memory consuming. Consider using consecutive integers starting from zero.
All negative values in categorical features will be treated as missing values.
early_stopping_rounds : int or None, optional (default=None)
Activates early stopping. The model will train until the validation score stops improving.
Validation score needs to improve at least every ``early_stopping_rounds`` round(s)
to continue training.
Requires at least one validation data and one metric.
If there's more than one, will check all of them. But the training data is ignored anyway.
To check only the first metric you can pass in ``callbacks``
``early_stopping`` callback with ``first_metric_only=True``.
The index of iteration that has the best performance will be saved in the ``best_iteration`` field
if early stopping logic is enabled by setting ``early_stopping_rounds``.
evals_result: dict or None, optional (default=None)
This dictionary used to store all evaluation results of all the items in ``valid_sets``.
Example
-------
With a ``valid_sets`` = [valid_set, train_set],
``valid_names`` = ['eval', 'train']
and a ``params`` = {'metric': 'logloss'}
returns {'train': {'logloss': ['0.48253', '0.35953', ...]},
'eval': {'logloss': ['0.480385', '0.357756', ...]}}.
verbose_eval : bool or int, optional (default=True)
Requires at least one validation data.
If True, the eval metric on the valid set is printed at each boosting stage.
If int, the eval metric on the valid set is printed at every ``verbose_eval`` boosting stage.
The last boosting stage or the boosting stage found by using ``early_stopping_rounds`` is also printed.
Example
-------
With ``verbose_eval`` = 4 and at least one item in ``valid_sets``,
an evaluation metric is printed every 4 (instead of 1) boosting stages.
learning_rates : list, callable or None, optional (default=None)
List of learning rates for each boosting round
or a customized function that calculates ``learning_rate``
in terms of current number of round (e.g. yields learning rate decay).
keep_training_booster : bool, optional (default=False)
Whether the returned Booster will be used to keep training.
If False, the returned value will be converted into _InnerPredictor before returning.
You can still use _InnerPredictor as ``init_model`` for future continue training.
callbacks : list of callables or None, optional (default=None)
List of callback functions that are applied at each iteration.
See Callbacks in Python API for more information.
Returns
-------
booster : Booster
The trained Booster model.
"""
# create predictor first
params = copy.deepcopy(params)
if fobj is not None:
params['objective'] = 'none'
for alias in ["num_iterations", "num_iteration", "n_iter", "num_tree", "num_trees",
"num_round", "num_rounds", "num_boost_round", "n_estimators"]:
if alias in params:
num_boost_round = int(params.pop(alias))
warnings.warn("Found `{}` in params. Will use it instead of argument".format(alias))
break
for alias in ["early_stopping_round", "early_stopping_rounds", "early_stopping"]:
if alias in params and params[alias] is not None:
early_stopping_rounds = int(params.pop(alias))
warnings.warn("Found `{}` in params. Will use it instead of argument".format(alias))
break
if num_boost_round <= 0:
raise ValueError("num_boost_round should be greater than zero.")
if isinstance(init_model, string_type):
predictor = _InnerPredictor(model_file=init_model, pred_parameter=params)
elif isinstance(init_model, Booster):
predictor = init_model._to_predictor(dict(init_model.params, **params))
else:
predictor = None
init_iteration = predictor.num_total_iteration if predictor is not None else 0
# check dataset
if not isinstance(train_set, Dataset):
raise TypeError("Training only accepts Dataset object")
train_set._update_params(params) \
._set_predictor(predictor) \
.set_feature_name(feature_name) \
.set_categorical_feature(categorical_feature)
is_valid_contain_train = False
train_data_name = "training"
reduced_valid_sets = []
name_valid_sets = []
if valid_sets is not None:
if isinstance(valid_sets, Dataset):
valid_sets = [valid_sets]
if isinstance(valid_names, string_type):
valid_names = [valid_names]
for i, valid_data in enumerate(valid_sets):
# reduce cost for prediction training data
if valid_data is train_set:
is_valid_contain_train = True
if valid_names is not None:
train_data_name = valid_names[i]
continue
if not isinstance(valid_data, Dataset):
raise TypeError("Traninig only accepts Dataset object")
reduced_valid_sets.append(valid_data._update_params(params).set_reference(train_set))
if valid_names is not None and len(valid_names) > i:
name_valid_sets.append(valid_names[i])
else:
name_valid_sets.append('valid_' + str(i))
# process callbacks
if callbacks is None:
callbacks = set()
else:
for i, cb in enumerate(callbacks):
cb.__dict__.setdefault('order', i - len(callbacks))
callbacks = set(callbacks)
# Most of legacy advanced options becomes callbacks
if verbose_eval is True:
callbacks.add(callback.print_evaluation())
elif isinstance(verbose_eval, integer_types):
callbacks.add(callback.print_evaluation(verbose_eval))
if early_stopping_rounds is not None:
callbacks.add(callback.early_stopping(early_stopping_rounds, verbose=bool(verbose_eval)))
if learning_rates is not None:
callbacks.add(callback.reset_parameter(learning_rate=learning_rates))
if evals_result is not None:
callbacks.add(callback.record_evaluation(evals_result))
callbacks_before_iter = {cb for cb in callbacks if getattr(cb, 'before_iteration', False)}
callbacks_after_iter = callbacks - callbacks_before_iter
callbacks_before_iter = sorted(callbacks_before_iter, key=attrgetter('order'))
callbacks_after_iter = sorted(callbacks_after_iter, key=attrgetter('order'))
# construct booster
try:
booster = Booster(params=params, train_set=train_set)
if is_valid_contain_train:
booster.set_train_data_name(train_data_name)
for valid_set, name_valid_set in zip_(reduced_valid_sets, name_valid_sets):
booster.add_valid(valid_set, name_valid_set)
finally:
train_set._reverse_update_params()
for valid_set in reduced_valid_sets:
valid_set._reverse_update_params()
booster.best_iteration = 0
# start training
for i in range_(init_iteration, init_iteration + num_boost_round):
for cb in callbacks_before_iter:
cb(callback.CallbackEnv(model=booster,
params=params,
iteration=i,
begin_iteration=init_iteration,
end_iteration=init_iteration + num_boost_round,
evaluation_result_list=None))
booster.update(fobj=fobj)
evaluation_result_list = []
# check evaluation result.
if valid_sets is not None:
if is_valid_contain_train:
evaluation_result_list.extend(booster.eval_train(feval))
evaluation_result_list.extend(booster.eval_valid(feval))
try:
for cb in callbacks_after_iter:
cb(callback.CallbackEnv(model=booster,
params=params,
iteration=i,
begin_iteration=init_iteration,
end_iteration=init_iteration + num_boost_round,
evaluation_result_list=evaluation_result_list))
except callback.EarlyStopException as earlyStopException:
booster.best_iteration = earlyStopException.best_iteration + 1
evaluation_result_list = earlyStopException.best_score
break
booster.best_score = collections.defaultdict(dict)
for dataset_name, eval_name, score, _ in evaluation_result_list:
booster.best_score[dataset_name][eval_name] = score
if not keep_training_booster:
booster.model_from_string(booster.model_to_string(), False).free_dataset()
return booster |
Make a n-fold list of Booster from random indices.
def _make_n_folds(full_data, folds, nfold, params, seed, fpreproc=None, stratified=True,
shuffle=True, eval_train_metric=False):
"""Make a n-fold list of Booster from random indices."""
full_data = full_data.construct()
num_data = full_data.num_data()
if folds is not None:
if not hasattr(folds, '__iter__') and not hasattr(folds, 'split'):
raise AttributeError("folds should be a generator or iterator of (train_idx, test_idx) tuples "
"or scikit-learn splitter object with split method")
if hasattr(folds, 'split'):
group_info = full_data.get_group()
if group_info is not None:
group_info = group_info.astype(int)
flatted_group = np.repeat(range_(len(group_info)), repeats=group_info)
else:
flatted_group = np.zeros(num_data, dtype=int)
folds = folds.split(X=np.zeros(num_data), y=full_data.get_label(), groups=flatted_group)
else:
if 'objective' in params and params['objective'] == 'lambdarank':
if not SKLEARN_INSTALLED:
raise LightGBMError('Scikit-learn is required for lambdarank cv.')
# lambdarank task, split according to groups
group_info = full_data.get_group().astype(int)
flatted_group = np.repeat(range_(len(group_info)), repeats=group_info)
group_kfold = _LGBMGroupKFold(n_splits=nfold)
folds = group_kfold.split(X=np.zeros(num_data), groups=flatted_group)
elif stratified:
if not SKLEARN_INSTALLED:
raise LightGBMError('Scikit-learn is required for stratified cv.')
skf = _LGBMStratifiedKFold(n_splits=nfold, shuffle=shuffle, random_state=seed)
folds = skf.split(X=np.zeros(num_data), y=full_data.get_label())
else:
if shuffle:
randidx = np.random.RandomState(seed).permutation(num_data)
else:
randidx = np.arange(num_data)
kstep = int(num_data / nfold)
test_id = [randidx[i: i + kstep] for i in range_(0, num_data, kstep)]
train_id = [np.concatenate([test_id[i] for i in range_(nfold) if k != i]) for k in range_(nfold)]
folds = zip_(train_id, test_id)
ret = _CVBooster()
for train_idx, test_idx in folds:
train_set = full_data.subset(train_idx)
valid_set = full_data.subset(test_idx)
# run preprocessing on the data set if needed
if fpreproc is not None:
train_set, valid_set, tparam = fpreproc(train_set, valid_set, params.copy())
else:
tparam = params
cvbooster = Booster(tparam, train_set)
if eval_train_metric:
cvbooster.add_valid(train_set, 'train')
cvbooster.add_valid(valid_set, 'valid')
ret.append(cvbooster)
return ret |
Aggregate cross-validation results.
def _agg_cv_result(raw_results, eval_train_metric=False):
"""Aggregate cross-validation results."""
cvmap = collections.defaultdict(list)
metric_type = {}
for one_result in raw_results:
for one_line in one_result:
if eval_train_metric:
key = "{} {}".format(one_line[0], one_line[1])
else:
key = one_line[1]
metric_type[key] = one_line[3]
cvmap[key].append(one_line[2])
return [('cv_agg', k, np.mean(v), metric_type[k], np.std(v)) for k, v in cvmap.items()] |
Perform the cross-validation with given paramaters.
Parameters
----------
params : dict
Parameters for Booster.
train_set : Dataset
Data to be trained on.
num_boost_round : int, optional (default=100)
Number of boosting iterations.
folds : generator or iterator of (train_idx, test_idx) tuples, scikit-learn splitter object or None, optional (default=None)
If generator or iterator, it should yield the train and test indices for each fold.
If object, it should be one of the scikit-learn splitter classes
(https://scikit-learn.org/stable/modules/classes.html#splitter-classes)
and have ``split`` method.
This argument has highest priority over other data split arguments.
nfold : int, optional (default=5)
Number of folds in CV.
stratified : bool, optional (default=True)
Whether to perform stratified sampling.
shuffle : bool, optional (default=True)
Whether to shuffle before splitting data.
metrics : string, list of strings or None, optional (default=None)
Evaluation metrics to be monitored while CV.
If not None, the metric in ``params`` will be overridden.
fobj : callable or None, optional (default=None)
Custom objective function.
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
To ignore the default metric corresponding to the used objective,
set ``metrics`` to the string ``"None"``.
init_model : string, Booster or None, optional (default=None)
Filename of LightGBM model or Booster instance used for continue training.
feature_name : list of strings or 'auto', optional (default="auto")
Feature names.
If 'auto' and data is pandas DataFrame, data columns names are used.
categorical_feature : list of strings or int, or 'auto', optional (default="auto")
Categorical features.
If list of int, interpreted as indices.
If list of strings, interpreted as feature names (need to specify ``feature_name`` as well).
If 'auto' and data is pandas DataFrame, pandas unordered categorical columns are used.
All values in categorical features should be less than int32 max value (2147483647).
Large values could be memory consuming. Consider using consecutive integers starting from zero.
All negative values in categorical features will be treated as missing values.
early_stopping_rounds : int or None, optional (default=None)
Activates early stopping.
CV score needs to improve at least every ``early_stopping_rounds`` round(s)
to continue.
Requires at least one metric. If there's more than one, will check all of them.
To check only the first metric you can pass in ``callbacks``
``early_stopping`` callback with ``first_metric_only=True``.
Last entry in evaluation history is the one from the best iteration.
fpreproc : callable or None, optional (default=None)
Preprocessing function that takes (dtrain, dtest, params)
and returns transformed versions of those.
verbose_eval : bool, int, or None, optional (default=None)
Whether to display the progress.
If None, progress will be displayed when np.ndarray is returned.
If True, progress will be displayed at every boosting stage.
If int, progress will be displayed at every given ``verbose_eval`` boosting stage.
show_stdv : bool, optional (default=True)
Whether to display the standard deviation in progress.
Results are not affected by this parameter, and always contain std.
seed : int, optional (default=0)
Seed used to generate the folds (passed to numpy.random.seed).
callbacks : list of callables or None, optional (default=None)
List of callback functions that are applied at each iteration.
See Callbacks in Python API for more information.
eval_train_metric : bool, optional (default=False)
Whether to display the train metric in progress.
The score of the metric is calculated again after each training step, so there is some impact on performance.
Returns
-------
eval_hist : dict
Evaluation history.
The dictionary has the following format:
{'metric1-mean': [values], 'metric1-stdv': [values],
'metric2-mean': [values], 'metric2-stdv': [values],
...}.
def cv(params, train_set, num_boost_round=100,
folds=None, nfold=5, stratified=True, shuffle=True,
metrics=None, fobj=None, feval=None, init_model=None,
feature_name='auto', categorical_feature='auto',
early_stopping_rounds=None, fpreproc=None,
verbose_eval=None, show_stdv=True, seed=0,
callbacks=None, eval_train_metric=False):
"""Perform the cross-validation with given paramaters.
Parameters
----------
params : dict
Parameters for Booster.
train_set : Dataset
Data to be trained on.
num_boost_round : int, optional (default=100)
Number of boosting iterations.
folds : generator or iterator of (train_idx, test_idx) tuples, scikit-learn splitter object or None, optional (default=None)
If generator or iterator, it should yield the train and test indices for each fold.
If object, it should be one of the scikit-learn splitter classes
(https://scikit-learn.org/stable/modules/classes.html#splitter-classes)
and have ``split`` method.
This argument has highest priority over other data split arguments.
nfold : int, optional (default=5)
Number of folds in CV.
stratified : bool, optional (default=True)
Whether to perform stratified sampling.
shuffle : bool, optional (default=True)
Whether to shuffle before splitting data.
metrics : string, list of strings or None, optional (default=None)
Evaluation metrics to be monitored while CV.
If not None, the metric in ``params`` will be overridden.
fobj : callable or None, optional (default=None)
Custom objective function.
feval : callable or None, optional (default=None)
Customized evaluation function.
Should accept two parameters: preds, train_data,
and return (eval_name, eval_result, is_higher_better) or list of such tuples.
For multi-class task, the preds is group by class_id first, then group by row_id.
If you want to get i-th row preds in j-th class, the access way is preds[j * num_data + i].
To ignore the default metric corresponding to the used objective,
set ``metrics`` to the string ``"None"``.
init_model : string, Booster or None, optional (default=None)
Filename of LightGBM model or Booster instance used for continue training.
feature_name : list of strings or 'auto', optional (default="auto")
Feature names.
If 'auto' and data is pandas DataFrame, data columns names are used.
categorical_feature : list of strings or int, or 'auto', optional (default="auto")
Categorical features.
If list of int, interpreted as indices.
If list of strings, interpreted as feature names (need to specify ``feature_name`` as well).
If 'auto' and data is pandas DataFrame, pandas unordered categorical columns are used.
All values in categorical features should be less than int32 max value (2147483647).
Large values could be memory consuming. Consider using consecutive integers starting from zero.
All negative values in categorical features will be treated as missing values.
early_stopping_rounds : int or None, optional (default=None)
Activates early stopping.
CV score needs to improve at least every ``early_stopping_rounds`` round(s)
to continue.
Requires at least one metric. If there's more than one, will check all of them.
To check only the first metric you can pass in ``callbacks``
``early_stopping`` callback with ``first_metric_only=True``.
Last entry in evaluation history is the one from the best iteration.
fpreproc : callable or None, optional (default=None)
Preprocessing function that takes (dtrain, dtest, params)
and returns transformed versions of those.
verbose_eval : bool, int, or None, optional (default=None)
Whether to display the progress.
If None, progress will be displayed when np.ndarray is returned.
If True, progress will be displayed at every boosting stage.
If int, progress will be displayed at every given ``verbose_eval`` boosting stage.
show_stdv : bool, optional (default=True)
Whether to display the standard deviation in progress.
Results are not affected by this parameter, and always contain std.
seed : int, optional (default=0)
Seed used to generate the folds (passed to numpy.random.seed).
callbacks : list of callables or None, optional (default=None)
List of callback functions that are applied at each iteration.
See Callbacks in Python API for more information.
eval_train_metric : bool, optional (default=False)
Whether to display the train metric in progress.
The score of the metric is calculated again after each training step, so there is some impact on performance.
Returns
-------
eval_hist : dict
Evaluation history.
The dictionary has the following format:
{'metric1-mean': [values], 'metric1-stdv': [values],
'metric2-mean': [values], 'metric2-stdv': [values],
...}.
"""
if not isinstance(train_set, Dataset):
raise TypeError("Traninig only accepts Dataset object")
params = copy.deepcopy(params)
if fobj is not None:
params['objective'] = 'none'
for alias in ["num_iterations", "num_iteration", "n_iter", "num_tree", "num_trees",
"num_round", "num_rounds", "num_boost_round", "n_estimators"]:
if alias in params:
warnings.warn("Found `{}` in params. Will use it instead of argument".format(alias))
num_boost_round = params.pop(alias)
break
for alias in ["early_stopping_round", "early_stopping_rounds", "early_stopping"]:
if alias in params:
warnings.warn("Found `{}` in params. Will use it instead of argument".format(alias))
early_stopping_rounds = params.pop(alias)
break
if num_boost_round <= 0:
raise ValueError("num_boost_round should be greater than zero.")
if isinstance(init_model, string_type):
predictor = _InnerPredictor(model_file=init_model, pred_parameter=params)
elif isinstance(init_model, Booster):
predictor = init_model._to_predictor(dict(init_model.params, **params))
else:
predictor = None
train_set._update_params(params) \
._set_predictor(predictor) \
.set_feature_name(feature_name) \
.set_categorical_feature(categorical_feature)
if metrics is not None:
params['metric'] = metrics
results = collections.defaultdict(list)
cvfolds = _make_n_folds(train_set, folds=folds, nfold=nfold,
params=params, seed=seed, fpreproc=fpreproc,
stratified=stratified, shuffle=shuffle,
eval_train_metric=eval_train_metric)
# setup callbacks
if callbacks is None:
callbacks = set()
else:
for i, cb in enumerate(callbacks):
cb.__dict__.setdefault('order', i - len(callbacks))
callbacks = set(callbacks)
if early_stopping_rounds is not None:
callbacks.add(callback.early_stopping(early_stopping_rounds, verbose=False))
if verbose_eval is True:
callbacks.add(callback.print_evaluation(show_stdv=show_stdv))
elif isinstance(verbose_eval, integer_types):
callbacks.add(callback.print_evaluation(verbose_eval, show_stdv=show_stdv))
callbacks_before_iter = {cb for cb in callbacks if getattr(cb, 'before_iteration', False)}
callbacks_after_iter = callbacks - callbacks_before_iter
callbacks_before_iter = sorted(callbacks_before_iter, key=attrgetter('order'))
callbacks_after_iter = sorted(callbacks_after_iter, key=attrgetter('order'))
for i in range_(num_boost_round):
for cb in callbacks_before_iter:
cb(callback.CallbackEnv(model=cvfolds,
params=params,
iteration=i,
begin_iteration=0,
end_iteration=num_boost_round,
evaluation_result_list=None))
cvfolds.update(fobj=fobj)
res = _agg_cv_result(cvfolds.eval_valid(feval), eval_train_metric)
for _, key, mean, _, std in res:
results[key + '-mean'].append(mean)
results[key + '-stdv'].append(std)
try:
for cb in callbacks_after_iter:
cb(callback.CallbackEnv(model=cvfolds,
params=params,
iteration=i,
begin_iteration=0,
end_iteration=num_boost_round,
evaluation_result_list=res))
except callback.EarlyStopException as earlyStopException:
cvfolds.best_iteration = earlyStopException.best_iteration + 1
for k in results:
results[k] = results[k][:cvfolds.best_iteration]
break
return dict(results) |
Logarithmic loss with non-necessarily-binary labels.
def log_loss(preds, labels):
"""Logarithmic loss with non-necessarily-binary labels."""
log_likelihood = np.sum(labels * np.log(preds)) / len(preds)
return -log_likelihood |
Measure performance of an objective.
Parameters
----------
objective : string 'binary' or 'xentropy'
Objective function.
label_type : string 'binary' or 'probability'
Type of the label.
data : dict
Data for training.
Returns
-------
result : dict
Experiment summary stats.
def experiment(objective, label_type, data):
"""Measure performance of an objective.
Parameters
----------
objective : string 'binary' or 'xentropy'
Objective function.
label_type : string 'binary' or 'probability'
Type of the label.
data : dict
Data for training.
Returns
-------
result : dict
Experiment summary stats.
"""
np.random.seed(0)
nrounds = 5
lgb_data = data['lgb_with_' + label_type + '_labels']
params = {
'objective': objective,
'feature_fraction': 1,
'bagging_fraction': 1,
'verbose': -1
}
time_zero = time.time()
gbm = lgb.train(params, lgb_data, num_boost_round=nrounds)
y_fitted = gbm.predict(data['X'])
y_true = data[label_type + '_labels']
duration = time.time() - time_zero
return {
'time': duration,
'correlation': np.corrcoef(y_fitted, y_true)[0, 1],
'logloss': log_loss(y_fitted, y_true)
} |
Check object is not tuple or does not have 2 elements.
def _check_not_tuple_of_2_elements(obj, obj_name='obj'):
"""Check object is not tuple or does not have 2 elements."""
if not isinstance(obj, tuple) or len(obj) != 2:
raise TypeError('%s must be a tuple of 2 elements.' % obj_name) |
Plot model's feature importances.
Parameters
----------
booster : Booster or LGBMModel
Booster or LGBMModel instance which feature importance should be plotted.
ax : matplotlib.axes.Axes or None, optional (default=None)
Target axes instance.
If None, new figure and axes will be created.
height : float, optional (default=0.2)
Bar height, passed to ``ax.barh()``.
xlim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.xlim()``.
ylim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.ylim()``.
title : string or None, optional (default="Feature importance")
Axes title.
If None, title is disabled.
xlabel : string or None, optional (default="Feature importance")
X-axis title label.
If None, title is disabled.
ylabel : string or None, optional (default="Features")
Y-axis title label.
If None, title is disabled.
importance_type : string, optional (default="split")
How the importance is calculated.
If "split", result contains numbers of times the feature is used in a model.
If "gain", result contains total gains of splits which use the feature.
max_num_features : int or None, optional (default=None)
Max number of top features displayed on plot.
If None or <1, all features will be displayed.
ignore_zero : bool, optional (default=True)
Whether to ignore features with zero importance.
figsize : tuple of 2 elements or None, optional (default=None)
Figure size.
grid : bool, optional (default=True)
Whether to add a grid for axes.
precision : int or None, optional (default=None)
Used to restrict the display of floating point values to a certain precision.
**kwargs
Other parameters passed to ``ax.barh()``.
Returns
-------
ax : matplotlib.axes.Axes
The plot with model's feature importances.
def plot_importance(booster, ax=None, height=0.2,
xlim=None, ylim=None, title='Feature importance',
xlabel='Feature importance', ylabel='Features',
importance_type='split', max_num_features=None,
ignore_zero=True, figsize=None, grid=True,
precision=None, **kwargs):
"""Plot model's feature importances.
Parameters
----------
booster : Booster or LGBMModel
Booster or LGBMModel instance which feature importance should be plotted.
ax : matplotlib.axes.Axes or None, optional (default=None)
Target axes instance.
If None, new figure and axes will be created.
height : float, optional (default=0.2)
Bar height, passed to ``ax.barh()``.
xlim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.xlim()``.
ylim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.ylim()``.
title : string or None, optional (default="Feature importance")
Axes title.
If None, title is disabled.
xlabel : string or None, optional (default="Feature importance")
X-axis title label.
If None, title is disabled.
ylabel : string or None, optional (default="Features")
Y-axis title label.
If None, title is disabled.
importance_type : string, optional (default="split")
How the importance is calculated.
If "split", result contains numbers of times the feature is used in a model.
If "gain", result contains total gains of splits which use the feature.
max_num_features : int or None, optional (default=None)
Max number of top features displayed on plot.
If None or <1, all features will be displayed.
ignore_zero : bool, optional (default=True)
Whether to ignore features with zero importance.
figsize : tuple of 2 elements or None, optional (default=None)
Figure size.
grid : bool, optional (default=True)
Whether to add a grid for axes.
precision : int or None, optional (default=None)
Used to restrict the display of floating point values to a certain precision.
**kwargs
Other parameters passed to ``ax.barh()``.
Returns
-------
ax : matplotlib.axes.Axes
The plot with model's feature importances.
"""
if MATPLOTLIB_INSTALLED:
import matplotlib.pyplot as plt
else:
raise ImportError('You must install matplotlib to plot importance.')
if isinstance(booster, LGBMModel):
booster = booster.booster_
elif not isinstance(booster, Booster):
raise TypeError('booster must be Booster or LGBMModel.')
importance = booster.feature_importance(importance_type=importance_type)
feature_name = booster.feature_name()
if not len(importance):
raise ValueError("Booster's feature_importance is empty.")
tuples = sorted(zip_(feature_name, importance), key=lambda x: x[1])
if ignore_zero:
tuples = [x for x in tuples if x[1] > 0]
if max_num_features is not None and max_num_features > 0:
tuples = tuples[-max_num_features:]
labels, values = zip_(*tuples)
if ax is None:
if figsize is not None:
_check_not_tuple_of_2_elements(figsize, 'figsize')
_, ax = plt.subplots(1, 1, figsize=figsize)
ylocs = np.arange(len(values))
ax.barh(ylocs, values, align='center', height=height, **kwargs)
for x, y in zip_(values, ylocs):
ax.text(x + 1, y,
_float2str(x, precision) if importance_type == 'gain' else x,
va='center')
ax.set_yticks(ylocs)
ax.set_yticklabels(labels)
if xlim is not None:
_check_not_tuple_of_2_elements(xlim, 'xlim')
else:
xlim = (0, max(values) * 1.1)
ax.set_xlim(xlim)
if ylim is not None:
_check_not_tuple_of_2_elements(ylim, 'ylim')
else:
ylim = (-1, len(values))
ax.set_ylim(ylim)
if title is not None:
ax.set_title(title)
if xlabel is not None:
ax.set_xlabel(xlabel)
if ylabel is not None:
ax.set_ylabel(ylabel)
ax.grid(grid)
return ax |
Plot one metric during training.
Parameters
----------
booster : dict or LGBMModel
Dictionary returned from ``lightgbm.train()`` or LGBMModel instance.
metric : string or None, optional (default=None)
The metric name to plot.
Only one metric supported because different metrics have various scales.
If None, first metric picked from dictionary (according to hashcode).
dataset_names : list of strings or None, optional (default=None)
List of the dataset names which are used to calculate metric to plot.
If None, all datasets are used.
ax : matplotlib.axes.Axes or None, optional (default=None)
Target axes instance.
If None, new figure and axes will be created.
xlim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.xlim()``.
ylim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.ylim()``.
title : string or None, optional (default="Metric during training")
Axes title.
If None, title is disabled.
xlabel : string or None, optional (default="Iterations")
X-axis title label.
If None, title is disabled.
ylabel : string or None, optional (default="auto")
Y-axis title label.
If 'auto', metric name is used.
If None, title is disabled.
figsize : tuple of 2 elements or None, optional (default=None)
Figure size.
grid : bool, optional (default=True)
Whether to add a grid for axes.
Returns
-------
ax : matplotlib.axes.Axes
The plot with metric's history over the training.
def plot_metric(booster, metric=None, dataset_names=None,
ax=None, xlim=None, ylim=None,
title='Metric during training',
xlabel='Iterations', ylabel='auto',
figsize=None, grid=True):
"""Plot one metric during training.
Parameters
----------
booster : dict or LGBMModel
Dictionary returned from ``lightgbm.train()`` or LGBMModel instance.
metric : string or None, optional (default=None)
The metric name to plot.
Only one metric supported because different metrics have various scales.
If None, first metric picked from dictionary (according to hashcode).
dataset_names : list of strings or None, optional (default=None)
List of the dataset names which are used to calculate metric to plot.
If None, all datasets are used.
ax : matplotlib.axes.Axes or None, optional (default=None)
Target axes instance.
If None, new figure and axes will be created.
xlim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.xlim()``.
ylim : tuple of 2 elements or None, optional (default=None)
Tuple passed to ``ax.ylim()``.
title : string or None, optional (default="Metric during training")
Axes title.
If None, title is disabled.
xlabel : string or None, optional (default="Iterations")
X-axis title label.
If None, title is disabled.
ylabel : string or None, optional (default="auto")
Y-axis title label.
If 'auto', metric name is used.
If None, title is disabled.
figsize : tuple of 2 elements or None, optional (default=None)
Figure size.
grid : bool, optional (default=True)
Whether to add a grid for axes.
Returns
-------
ax : matplotlib.axes.Axes
The plot with metric's history over the training.
"""
if MATPLOTLIB_INSTALLED:
import matplotlib.pyplot as plt
else:
raise ImportError('You must install matplotlib to plot metric.')
if isinstance(booster, LGBMModel):
eval_results = deepcopy(booster.evals_result_)
elif isinstance(booster, dict):
eval_results = deepcopy(booster)
else:
raise TypeError('booster must be dict or LGBMModel.')
num_data = len(eval_results)
if not num_data:
raise ValueError('eval results cannot be empty.')
if ax is None:
if figsize is not None:
_check_not_tuple_of_2_elements(figsize, 'figsize')
_, ax = plt.subplots(1, 1, figsize=figsize)
if dataset_names is None:
dataset_names = iter(eval_results.keys())
elif not isinstance(dataset_names, (list, tuple, set)) or not dataset_names:
raise ValueError('dataset_names should be iterable and cannot be empty')
else:
dataset_names = iter(dataset_names)
name = next(dataset_names) # take one as sample
metrics_for_one = eval_results[name]
num_metric = len(metrics_for_one)
if metric is None:
if num_metric > 1:
msg = """more than one metric available, picking one to plot."""
warnings.warn(msg, stacklevel=2)
metric, results = metrics_for_one.popitem()
else:
if metric not in metrics_for_one:
raise KeyError('No given metric in eval results.')
results = metrics_for_one[metric]
num_iteration, max_result, min_result = len(results), max(results), min(results)
x_ = range_(num_iteration)
ax.plot(x_, results, label=name)
for name in dataset_names:
metrics_for_one = eval_results[name]
results = metrics_for_one[metric]
max_result, min_result = max(max(results), max_result), min(min(results), min_result)
ax.plot(x_, results, label=name)
ax.legend(loc='best')
if xlim is not None:
_check_not_tuple_of_2_elements(xlim, 'xlim')
else:
xlim = (0, num_iteration)
ax.set_xlim(xlim)
if ylim is not None:
_check_not_tuple_of_2_elements(ylim, 'ylim')
else:
range_result = max_result - min_result
ylim = (min_result - range_result * 0.2, max_result + range_result * 0.2)
ax.set_ylim(ylim)
if ylabel == 'auto':
ylabel = metric
if title is not None:
ax.set_title(title)
if xlabel is not None:
ax.set_xlabel(xlabel)
if ylabel is not None:
ax.set_ylabel(ylabel)
ax.grid(grid)
return ax |
Convert specified tree to graphviz instance.
See:
- https://graphviz.readthedocs.io/en/stable/api.html#digraph
def _to_graphviz(tree_info, show_info, feature_names, precision=None, **kwargs):
"""Convert specified tree to graphviz instance.
See:
- https://graphviz.readthedocs.io/en/stable/api.html#digraph
"""
if GRAPHVIZ_INSTALLED:
from graphviz import Digraph
else:
raise ImportError('You must install graphviz to plot tree.')
def add(root, parent=None, decision=None):
"""Recursively add node or edge."""
if 'split_index' in root: # non-leaf
name = 'split{0}'.format(root['split_index'])
if feature_names is not None:
label = 'split_feature_name: {0}'.format(feature_names[root['split_feature']])
else:
label = 'split_feature_index: {0}'.format(root['split_feature'])
label += r'\nthreshold: {0}'.format(_float2str(root['threshold'], precision))
for info in show_info:
if info in {'split_gain', 'internal_value'}:
label += r'\n{0}: {1}'.format(info, _float2str(root[info], precision))
elif info == 'internal_count':
label += r'\n{0}: {1}'.format(info, root[info])
graph.node(name, label=label)
if root['decision_type'] == '<=':
l_dec, r_dec = '<=', '>'
elif root['decision_type'] == '==':
l_dec, r_dec = 'is', "isn't"
else:
raise ValueError('Invalid decision type in tree model.')
add(root['left_child'], name, l_dec)
add(root['right_child'], name, r_dec)
else: # leaf
name = 'leaf{0}'.format(root['leaf_index'])
label = 'leaf_index: {0}'.format(root['leaf_index'])
label += r'\nleaf_value: {0}'.format(_float2str(root['leaf_value'], precision))
if 'leaf_count' in show_info:
label += r'\nleaf_count: {0}'.format(root['leaf_count'])
graph.node(name, label=label)
if parent is not None:
graph.edge(parent, name, decision)
graph = Digraph(**kwargs)
add(tree_info['tree_structure'])
return graph |
Create a digraph representation of specified tree.
Note
----
For more information please visit
https://graphviz.readthedocs.io/en/stable/api.html#digraph.
Parameters
----------
booster : Booster or LGBMModel
Booster or LGBMModel instance to be converted.
tree_index : int, optional (default=0)
The index of a target tree to convert.
show_info : list of strings or None, optional (default=None)
What information should be shown in nodes.
Possible values of list items: 'split_gain', 'internal_value', 'internal_count', 'leaf_count'.
precision : int or None, optional (default=None)
Used to restrict the display of floating point values to a certain precision.
**kwargs
Other parameters passed to ``Digraph`` constructor.
Check https://graphviz.readthedocs.io/en/stable/api.html#digraph for the full list of supported parameters.
Returns
-------
graph : graphviz.Digraph
The digraph representation of specified tree.
def create_tree_digraph(booster, tree_index=0, show_info=None, precision=None,
old_name=None, old_comment=None, old_filename=None, old_directory=None,
old_format=None, old_engine=None, old_encoding=None, old_graph_attr=None,
old_node_attr=None, old_edge_attr=None, old_body=None, old_strict=False, **kwargs):
"""Create a digraph representation of specified tree.
Note
----
For more information please visit
https://graphviz.readthedocs.io/en/stable/api.html#digraph.
Parameters
----------
booster : Booster or LGBMModel
Booster or LGBMModel instance to be converted.
tree_index : int, optional (default=0)
The index of a target tree to convert.
show_info : list of strings or None, optional (default=None)
What information should be shown in nodes.
Possible values of list items: 'split_gain', 'internal_value', 'internal_count', 'leaf_count'.
precision : int or None, optional (default=None)
Used to restrict the display of floating point values to a certain precision.
**kwargs
Other parameters passed to ``Digraph`` constructor.
Check https://graphviz.readthedocs.io/en/stable/api.html#digraph for the full list of supported parameters.
Returns
-------
graph : graphviz.Digraph
The digraph representation of specified tree.
"""
if isinstance(booster, LGBMModel):
booster = booster.booster_
elif not isinstance(booster, Booster):
raise TypeError('booster must be Booster or LGBMModel.')
for param_name in ['old_name', 'old_comment', 'old_filename', 'old_directory',
'old_format', 'old_engine', 'old_encoding', 'old_graph_attr',
'old_node_attr', 'old_edge_attr', 'old_body']:
param = locals().get(param_name)
if param is not None:
warnings.warn('{0} parameter is deprecated and will be removed in 2.4 version.\n'
'Please use **kwargs to pass {1} parameter.'.format(param_name, param_name[4:]),
LGBMDeprecationWarning)
if param_name[4:] not in kwargs:
kwargs[param_name[4:]] = param
if locals().get('strict'):
warnings.warn('old_strict parameter is deprecated and will be removed in 2.4 version.\n'
'Please use **kwargs to pass strict parameter.',
LGBMDeprecationWarning)
if 'strict' not in kwargs:
kwargs['strict'] = True
model = booster.dump_model()
tree_infos = model['tree_info']
if 'feature_names' in model:
feature_names = model['feature_names']
else:
feature_names = None
if tree_index < len(tree_infos):
tree_info = tree_infos[tree_index]
else:
raise IndexError('tree_index is out of range.')
if show_info is None:
show_info = []
graph = _to_graphviz(tree_info, show_info, feature_names, precision, **kwargs)
return graph |
Plot specified tree.
Note
----
It is preferable to use ``create_tree_digraph()`` because of its lossless quality
and returned objects can be also rendered and displayed directly inside a Jupyter notebook.
Parameters
----------
booster : Booster or LGBMModel
Booster or LGBMModel instance to be plotted.
ax : matplotlib.axes.Axes or None, optional (default=None)
Target axes instance.
If None, new figure and axes will be created.
tree_index : int, optional (default=0)
The index of a target tree to plot.
figsize : tuple of 2 elements or None, optional (default=None)
Figure size.
show_info : list of strings or None, optional (default=None)
What information should be shown in nodes.
Possible values of list items: 'split_gain', 'internal_value', 'internal_count', 'leaf_count'.
precision : int or None, optional (default=None)
Used to restrict the display of floating point values to a certain precision.
**kwargs
Other parameters passed to ``Digraph`` constructor.
Check https://graphviz.readthedocs.io/en/stable/api.html#digraph for the full list of supported parameters.
Returns
-------
ax : matplotlib.axes.Axes
The plot with single tree.
def plot_tree(booster, ax=None, tree_index=0, figsize=None,
old_graph_attr=None, old_node_attr=None, old_edge_attr=None,
show_info=None, precision=None, **kwargs):
"""Plot specified tree.
Note
----
It is preferable to use ``create_tree_digraph()`` because of its lossless quality
and returned objects can be also rendered and displayed directly inside a Jupyter notebook.
Parameters
----------
booster : Booster or LGBMModel
Booster or LGBMModel instance to be plotted.
ax : matplotlib.axes.Axes or None, optional (default=None)
Target axes instance.
If None, new figure and axes will be created.
tree_index : int, optional (default=0)
The index of a target tree to plot.
figsize : tuple of 2 elements or None, optional (default=None)
Figure size.
show_info : list of strings or None, optional (default=None)
What information should be shown in nodes.
Possible values of list items: 'split_gain', 'internal_value', 'internal_count', 'leaf_count'.
precision : int or None, optional (default=None)
Used to restrict the display of floating point values to a certain precision.
**kwargs
Other parameters passed to ``Digraph`` constructor.
Check https://graphviz.readthedocs.io/en/stable/api.html#digraph for the full list of supported parameters.
Returns
-------
ax : matplotlib.axes.Axes
The plot with single tree.
"""
if MATPLOTLIB_INSTALLED:
import matplotlib.pyplot as plt
import matplotlib.image as image
else:
raise ImportError('You must install matplotlib to plot tree.')
for param_name in ['old_graph_attr', 'old_node_attr', 'old_edge_attr']:
param = locals().get(param_name)
if param is not None:
warnings.warn('{0} parameter is deprecated and will be removed in 2.4 version.\n'
'Please use **kwargs to pass {1} parameter.'.format(param_name, param_name[4:]),
LGBMDeprecationWarning)
if param_name[4:] not in kwargs:
kwargs[param_name[4:]] = param
if ax is None:
if figsize is not None:
_check_not_tuple_of_2_elements(figsize, 'figsize')
_, ax = plt.subplots(1, 1, figsize=figsize)
graph = create_tree_digraph(booster=booster, tree_index=tree_index,
show_info=show_info, precision=precision, **kwargs)
s = BytesIO()
s.write(graph.pipe(format='png'))
s.seek(0)
img = image.imread(s)
ax.imshow(img)
ax.axis('off')
return ax |
Return the -std=c++[0x/11/14] compiler flag.
The c++14 is preferred over c++0x/11 (when it is available).
def cpp_flag(compiler):
"""Return the -std=c++[0x/11/14] compiler flag.
The c++14 is preferred over c++0x/11 (when it is available).
"""
standards = ['-std=c++14', '-std=c++11', '-std=c++0x']
for standard in standards:
if has_flag(compiler, [standard]):
return standard
raise RuntimeError(
'Unsupported compiler -- at least C++0x support '
'is needed!'
) |
query is a 1d numpy array corresponding to the vector to which you want to
find the closest vector
vectors is a 2d numpy array corresponding to the vectors you want to consider
ban_set is a set of indicies within vectors you want to ignore for nearest match
cossims is a 1d numpy array of size len(vectors), which can be passed for efficiency
returns the index of the closest match to query within vectors
def find_nearest_neighbor(query, vectors, ban_set, cossims=None):
"""
query is a 1d numpy array corresponding to the vector to which you want to
find the closest vector
vectors is a 2d numpy array corresponding to the vectors you want to consider
ban_set is a set of indicies within vectors you want to ignore for nearest match
cossims is a 1d numpy array of size len(vectors), which can be passed for efficiency
returns the index of the closest match to query within vectors
"""
if cossims is None:
cossims = np.matmul(vectors, query, out=cossims)
else:
np.matmul(vectors, query, out=cossims)
rank = len(cossims) - 1
result_i = np.argpartition(cossims, rank)[rank]
while result_i in ban_set:
rank -= 1
result_i = np.argpartition(cossims, rank)[rank]
return result_i |
Train a supervised model and return a model object.
input must be a filepath. The input text does not need to be tokenized
as per the tokenize function, but it must be preprocessed and encoded
as UTF-8. You might want to consult standard preprocessing scripts such
as tokenizer.perl mentioned here: http://www.statmt.org/wmt07/baseline.html
The input file must must contain at least one label per line. For an
example consult the example datasets which are part of the fastText
repository such as the dataset pulled by classification-example.sh.
def train_supervised(
input,
lr=0.1,
dim=100,
ws=5,
epoch=5,
minCount=1,
minCountLabel=0,
minn=0,
maxn=0,
neg=5,
wordNgrams=1,
loss="softmax",
bucket=2000000,
thread=multiprocessing.cpu_count() - 1,
lrUpdateRate=100,
t=1e-4,
label="__label__",
verbose=2,
pretrainedVectors="",
):
"""
Train a supervised model and return a model object.
input must be a filepath. The input text does not need to be tokenized
as per the tokenize function, but it must be preprocessed and encoded
as UTF-8. You might want to consult standard preprocessing scripts such
as tokenizer.perl mentioned here: http://www.statmt.org/wmt07/baseline.html
The input file must must contain at least one label per line. For an
example consult the example datasets which are part of the fastText
repository such as the dataset pulled by classification-example.sh.
"""
model = "supervised"
a = _build_args(locals())
ft = _FastText()
fasttext.train(ft.f, a)
return ft |
Get the vector representation of word.
def get_word_vector(self, word):
"""Get the vector representation of word."""
dim = self.get_dimension()
b = fasttext.Vector(dim)
self.f.getWordVector(b, word)
return np.array(b) |
Given a string, get a single vector represenation. This function
assumes to be given a single line of text. We split words on
whitespace (space, newline, tab, vertical tab) and the control
characters carriage return, formfeed and the null character.
def get_sentence_vector(self, text):
"""
Given a string, get a single vector represenation. This function
assumes to be given a single line of text. We split words on
whitespace (space, newline, tab, vertical tab) and the control
characters carriage return, formfeed and the null character.
"""
if text.find('\n') != -1:
raise ValueError(
"predict processes one line at a time (remove \'\\n\')"
)
text += "\n"
dim = self.get_dimension()
b = fasttext.Vector(dim)
self.f.getSentenceVector(b, text)
return np.array(b) |
Given a word, get the subwords and their indicies.
def get_subwords(self, word, on_unicode_error='strict'):
"""
Given a word, get the subwords and their indicies.
"""
pair = self.f.getSubwords(word, on_unicode_error)
return pair[0], np.array(pair[1]) |
Given an index, get the corresponding vector of the Input Matrix.
def get_input_vector(self, ind):
"""
Given an index, get the corresponding vector of the Input Matrix.
"""
dim = self.get_dimension()
b = fasttext.Vector(dim)
self.f.getInputVector(b, ind)
return np.array(b) |
Given a string, get a list of labels and a list of
corresponding probabilities. k controls the number
of returned labels. A choice of 5, will return the 5
most probable labels. By default this returns only
the most likely label and probability. threshold filters
the returned labels by a threshold on probability. A
choice of 0.5 will return labels with at least 0.5
probability. k and threshold will be applied together to
determine the returned labels.
This function assumes to be given
a single line of text. We split words on whitespace (space,
newline, tab, vertical tab) and the control characters carriage
return, formfeed and the null character.
If the model is not supervised, this function will throw a ValueError.
If given a list of strings, it will return a list of results as usually
received for a single line of text.
def predict(self, text, k=1, threshold=0.0, on_unicode_error='strict'):
"""
Given a string, get a list of labels and a list of
corresponding probabilities. k controls the number
of returned labels. A choice of 5, will return the 5
most probable labels. By default this returns only
the most likely label and probability. threshold filters
the returned labels by a threshold on probability. A
choice of 0.5 will return labels with at least 0.5
probability. k and threshold will be applied together to
determine the returned labels.
This function assumes to be given
a single line of text. We split words on whitespace (space,
newline, tab, vertical tab) and the control characters carriage
return, formfeed and the null character.
If the model is not supervised, this function will throw a ValueError.
If given a list of strings, it will return a list of results as usually
received for a single line of text.
"""
def check(entry):
if entry.find('\n') != -1:
raise ValueError(
"predict processes one line at a time (remove \'\\n\')"
)
entry += "\n"
return entry
if type(text) == list:
text = [check(entry) for entry in text]
predictions = self.f.multilinePredict(text, k, threshold, on_unicode_error)
dt = np.dtype([('probability', 'float64'), ('label', 'object')])
result_as_pair = np.array(predictions, dtype=dt)
return result_as_pair['label'].tolist(), result_as_pair['probability']
else:
text = check(text)
predictions = self.f.predict(text, k, threshold, on_unicode_error)
probs, labels = zip(*predictions)
return labels, np.array(probs, copy=False) |
Get a copy of the full input matrix of a Model. This only
works if the model is not quantized.
def get_input_matrix(self):
"""
Get a copy of the full input matrix of a Model. This only
works if the model is not quantized.
"""
if self.f.isQuant():
raise ValueError("Can't get quantized Matrix")
return np.array(self.f.getInputMatrix()) |
Get a copy of the full output matrix of a Model. This only
works if the model is not quantized.
def get_output_matrix(self):
"""
Get a copy of the full output matrix of a Model. This only
works if the model is not quantized.
"""
if self.f.isQuant():
raise ValueError("Can't get quantized Matrix")
return np.array(self.f.getOutputMatrix()) |
Get the entire list of words of the dictionary optionally
including the frequency of the individual words. This
does not include any subwords. For that please consult
the function get_subwords.
def get_words(self, include_freq=False, on_unicode_error='strict'):
"""
Get the entire list of words of the dictionary optionally
including the frequency of the individual words. This
does not include any subwords. For that please consult
the function get_subwords.
"""
pair = self.f.getVocab(on_unicode_error)
if include_freq:
return (pair[0], np.array(pair[1]))
else:
return pair[0] |
Get the entire list of labels of the dictionary optionally
including the frequency of the individual labels. Unsupervised
models use words as labels, which is why get_labels
will call and return get_words for this type of
model.
def get_labels(self, include_freq=False, on_unicode_error='strict'):
"""
Get the entire list of labels of the dictionary optionally
including the frequency of the individual labels. Unsupervised
models use words as labels, which is why get_labels
will call and return get_words for this type of
model.
"""
a = self.f.getArgs()
if a.model == model_name.supervised:
pair = self.f.getLabels(on_unicode_error)
if include_freq:
return (pair[0], np.array(pair[1]))
else:
return pair[0]
else:
return self.get_words(include_freq) |
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