116 lines
4.6 KiB
Cython
116 lines
4.6 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 ..utils._typedefs cimport float64_t, int8_t, intp_t
|
|
|
|
|
|
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 float64_t[:, ::1] y # Values of y
|
|
cdef const float64_t[:] sample_weight # Sample weights
|
|
|
|
cdef const intp_t[:] sample_indices # Sample indices in X, y
|
|
cdef intp_t start # samples[start:pos] are the samples in the left node
|
|
cdef intp_t pos # samples[pos:end] are the samples in the right node
|
|
cdef intp_t end
|
|
cdef intp_t n_missing # Number of missing values for the feature being evaluated
|
|
cdef bint missing_go_to_left # Whether missing values go to the left node
|
|
|
|
cdef intp_t n_outputs # Number of outputs
|
|
cdef intp_t n_samples # Number of samples
|
|
cdef intp_t n_node_samples # Number of samples in the node (end-start)
|
|
cdef float64_t weighted_n_samples # Weighted number of samples (in total)
|
|
cdef float64_t weighted_n_node_samples # Weighted number of samples in the node
|
|
cdef float64_t weighted_n_left # Weighted number of samples in the left node
|
|
cdef float64_t weighted_n_right # Weighted number of samples in the right node
|
|
cdef float64_t weighted_n_missing # Weighted number of samples that are missing
|
|
|
|
# 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 float64_t[:, ::1] y,
|
|
const float64_t[:] sample_weight,
|
|
float64_t weighted_n_samples,
|
|
const intp_t[:] sample_indices,
|
|
intp_t start,
|
|
intp_t end
|
|
) except -1 nogil
|
|
cdef void init_sum_missing(self)
|
|
cdef void init_missing(self, intp_t n_missing) noexcept nogil
|
|
cdef int reset(self) except -1 nogil
|
|
cdef int reverse_reset(self) except -1 nogil
|
|
cdef int update(self, intp_t new_pos) except -1 nogil
|
|
cdef float64_t node_impurity(self) noexcept nogil
|
|
cdef void children_impurity(
|
|
self,
|
|
float64_t* impurity_left,
|
|
float64_t* impurity_right
|
|
) noexcept nogil
|
|
cdef void node_value(
|
|
self,
|
|
float64_t* dest
|
|
) noexcept nogil
|
|
cdef void clip_node_value(
|
|
self,
|
|
float64_t* dest,
|
|
float64_t lower_bound,
|
|
float64_t upper_bound
|
|
) noexcept nogil
|
|
cdef float64_t middle_value(self) noexcept nogil
|
|
cdef float64_t impurity_improvement(
|
|
self,
|
|
float64_t impurity_parent,
|
|
float64_t impurity_left,
|
|
float64_t impurity_right
|
|
) noexcept nogil
|
|
cdef float64_t proxy_impurity_improvement(self) noexcept nogil
|
|
cdef bint check_monotonicity(
|
|
self,
|
|
int8_t monotonic_cst,
|
|
float64_t lower_bound,
|
|
float64_t upper_bound,
|
|
) noexcept nogil
|
|
cdef inline bint _check_monotonicity(
|
|
self,
|
|
int8_t monotonic_cst,
|
|
float64_t lower_bound,
|
|
float64_t upper_bound,
|
|
float64_t sum_left,
|
|
float64_t sum_right,
|
|
) noexcept nogil
|
|
|
|
cdef class ClassificationCriterion(Criterion):
|
|
"""Abstract criterion for classification."""
|
|
|
|
cdef intp_t[::1] n_classes
|
|
cdef intp_t max_n_classes
|
|
|
|
cdef float64_t[:, ::1] sum_total # The sum of the weighted count of each label.
|
|
cdef float64_t[:, ::1] sum_left # Same as above, but for the left side of the split
|
|
cdef float64_t[:, ::1] sum_right # Same as above, but for the right side of the split
|
|
cdef float64_t[:, ::1] sum_missing # Same as above, but for missing values in X
|
|
|
|
cdef class RegressionCriterion(Criterion):
|
|
"""Abstract regression criterion."""
|
|
|
|
cdef float64_t sq_sum_total
|
|
|
|
cdef float64_t[::1] sum_total # The sum of w*y.
|
|
cdef float64_t[::1] sum_left # Same as above, but for the left side of the split
|
|
cdef float64_t[::1] sum_right # Same as above, but for the right side of the split
|
|
cdef float64_t[::1] sum_missing # Same as above, but for missing values in X
|