92 lines
3.6 KiB
Cython
92 lines
3.6 KiB
Cython
|
# Authors: Gilles Louppe <g.louppe@gmail.com>
|
||
|
|
# Peter Prettenhofer <peter.prettenhofer@gmail.com>
|
||
|
|
# Brian Holt <bdholt1@gmail.com>
|
||
|
|
# Joel Nothman <joel.nothman@gmail.com>
|
||
|
|
# Arnaud Joly <arnaud.v.joly@gmail.com>
|
||
|
|
# Jacob Schreiber <jmschreiber91@gmail.com>
|
||
|
|
#
|
||
|
|
# License: BSD 3 clause
|
||
|
|
|
||
|
|
# See _criterion.pyx for implementation details.
|
||
|
|
|
||
|
|
from ._tree cimport DTYPE_t # Type of X
|
||
|
|
from ._tree cimport DOUBLE_t # Type of y, sample_weight
|
||
|
|
from ._tree cimport SIZE_t # Type for indices and counters
|
||
|
|
from ._tree cimport INT32_t # Signed 32 bit integer
|
||
|
|
from ._tree cimport UINT32_t # Unsigned 32 bit integer
|
||
|
|
|
||
|
|
cdef class Criterion:
|
||
|
|
# The criterion computes the impurity of a node and the reduction of
|
||
|
|
# impurity of a split on that node. It also computes the output statistics
|
||
|
|
# such as the mean in regression and class probabilities in classification.
|
||
|
|
|
||
|
|
# Internal structures
|
||
|
|
cdef const DOUBLE_t[:, ::1] y # Values of y
|
||
|
|
cdef const DOUBLE_t[:] sample_weight # Sample weights
|
||
|
|
|
||
|
|
cdef SIZE_t* samples # Sample indices in X, y
|
||
|
|
cdef SIZE_t start # samples[start:pos] are the samples in the left node
|
||
|
|
cdef SIZE_t pos # samples[pos:end] are the samples in the right node
|
||
|
|
cdef SIZE_t end
|
||
|
|
|
||
|
|
cdef SIZE_t n_outputs # Number of outputs
|
||
|
|
cdef SIZE_t n_samples # Number of samples
|
||
|
|
cdef SIZE_t n_node_samples # Number of samples in the node (end-start)
|
||
|
|
cdef double weighted_n_samples # Weighted number of samples (in total)
|
||
|
|
cdef double weighted_n_node_samples # Weighted number of samples in the node
|
||
|
|
cdef double weighted_n_left # Weighted number of samples in the left node
|
||
|
|
cdef double weighted_n_right # Weighted number of samples in the right node
|
||
|
|
|
||
|
|
# The criterion object is maintained such that left and right collected
|
||
|
|
# statistics correspond to samples[start:pos] and samples[pos:end].
|
||
|
|
|
||
|
|
# Methods
|
||
|
|
cdef int init(
|
||
|
|
self,
|
||
|
|
const DOUBLE_t[:, ::1] y,
|
||
|
|
const DOUBLE_t[:] sample_weight,
|
||
|
|
double weighted_n_samples,
|
||
|
|
SIZE_t* samples,
|
||
|
|
SIZE_t start,
|
||
|
|
SIZE_t end
|
||
|
|
) nogil except -1
|
||
|
|
cdef int reset(self) nogil except -1
|
||
|
|
cdef int reverse_reset(self) nogil except -1
|
||
|
|
cdef int update(self, SIZE_t new_pos) nogil except -1
|
||
|
|
cdef double node_impurity(self) nogil
|
||
|
|
cdef void children_impurity(
|
||
|
|
self,
|
||
|
|
double* impurity_left,
|
||
|
|
double* impurity_right
|
||
|
|
) nogil
|
||
|
|
cdef void node_value(
|
||
|
|
self,
|
||
|
|
double* dest
|
||
|
|
) nogil
|
||
|
|
cdef double impurity_improvement(
|
||
|
|
self,
|
||
|
|
double impurity_parent,
|
||
|
|
double impurity_left,
|
||
|
|
double impurity_right
|
||
|
|
) nogil
|
||
|
|
cdef double proxy_impurity_improvement(self) nogil
|
||
|
|
|
||
|
|
cdef class ClassificationCriterion(Criterion):
|
||
|
|
"""Abstract criterion for classification."""
|
||
|
|
|
||
|
|
cdef SIZE_t[::1] n_classes
|
||
|
|
cdef SIZE_t max_n_classes
|
||
|
|
|
||
|
|
cdef double[:, ::1] sum_total # The sum of the weighted count of each label.
|
||
|
|
cdef double[:, ::1] sum_left # Same as above, but for the left side of the split
|
||
|
|
cdef double[:, ::1] sum_right # Same as above, but for the right side of the split
|
||
|
|
|
||
|
|
cdef class RegressionCriterion(Criterion):
|
||
|
|
"""Abstract regression criterion."""
|
||
|
|
|
||
|
|
cdef double sq_sum_total
|
||
|
|
|
||
|
|
cdef double[::1] sum_total # The sum of w*y.
|
||
|
|
cdef double[::1] sum_left # Same as above, but for the left side of the split
|
||
|
|
cdef double[::1] sum_right # Same as above, but for the right side of the split
|