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"""Base class for sparse matrice with a .data attribute
subclasses must provide a _with_data() method that
creates a new matrix with the same sparsity pattern
as self but with a different data array
"""
from __future__ import division, print_function, absolute_import
import numpy as np
from .base import spmatrix, _ufuncs_with_fixed_point_at_zero
from .sputils import isscalarlike, validateaxis
__all__ = []
# TODO implement all relevant operations
# use .data.__methods__() instead of /=, *=, etc.
class _data_matrix(spmatrix):
def __init__(self):
spmatrix.__init__(self)
def _get_dtype(self):
return self.data.dtype
def _set_dtype(self, newtype):
self.data.dtype = newtype
dtype = property(fget=_get_dtype, fset=_set_dtype)
def _deduped_data(self):
if hasattr(self, 'sum_duplicates'):
self.sum_duplicates()
return self.data
def __abs__(self):
return self._with_data(abs(self._deduped_data()))
def _real(self):
return self._with_data(self.data.real)
def _imag(self):
return self._with_data(self.data.imag)
def __neg__(self):
return self._with_data(-self.data)
def __imul__(self, other): # self *= other
if isscalarlike(other):
self.data *= other
return self
else:
return NotImplemented
def __itruediv__(self, other): # self /= other
if isscalarlike(other):
recip = 1.0 / other
self.data *= recip
return self
else:
return NotImplemented
def astype(self, t):
return self._with_data(self._deduped_data().astype(t))
def conj(self):
return self._with_data(self.data.conj())
def copy(self):
return self._with_data(self.data.copy(), copy=True)
def count_nonzero(self):
return np.count_nonzero(self._deduped_data())
count_nonzero.__doc__ = spmatrix.count_nonzero.__doc__
def power(self, n, dtype=None):
"""
This function performs element-wise power.
Parameters
----------
n : n is a scalar
dtype : If dtype is not specified, the current dtype will be preserved.
"""
if not isscalarlike(n):
raise NotImplementedError("input is not scalar")
data = self._deduped_data()
if dtype is not None:
data = data.astype(dtype)
return self._with_data(data ** n)
###########################
# Multiplication handlers #
###########################
def _mul_scalar(self, other):
return self._with_data(self.data * other)
# Add the numpy unary ufuncs for which func(0) = 0 to _data_matrix.
for npfunc in _ufuncs_with_fixed_point_at_zero:
name = npfunc.__name__
def _create_method(op):
def method(self):
result = op(self.data)
x = self._with_data(result, copy=True)
return x
method.__doc__ = ("Element-wise %s.\n\n"
"See numpy.%s for more information." % (name, name))
method.__name__ = name
return method
setattr(_data_matrix, name, _create_method(npfunc))
class _minmax_mixin(object):
"""Mixin for min and max methods.
These are not implemented for dia_matrix, hence the separate class.
"""
def _min_or_max_axis(self, axis, min_or_max):
N = self.shape[axis]
if N == 0:
raise ValueError("zero-size array to reduction operation")
M = self.shape[1 - axis]
mat = self.tocsc() if axis == 0 else self.tocsr()
mat.sum_duplicates()
major_index, value = mat._minor_reduce(min_or_max)
not_full = np.diff(mat.indptr)[major_index] < N
value[not_full] = min_or_max(value[not_full], 0)
mask = value != 0
major_index = np.compress(mask, major_index)
value = np.compress(mask, value)
from . import coo_matrix
if axis == 0:
return coo_matrix((value, (np.zeros(len(value)), major_index)),
dtype=self.dtype, shape=(1, M))
else:
return coo_matrix((value, (major_index, np.zeros(len(value)))),
dtype=self.dtype, shape=(M, 1))
def _min_or_max(self, axis, out, min_or_max):
if out is not None:
raise ValueError(("Sparse matrices do not support "
"an 'out' parameter."))
validateaxis(axis)
if axis is None:
if 0 in self.shape:
raise ValueError("zero-size array to reduction operation")
zero = self.dtype.type(0)
if self.nnz == 0:
return zero
m = min_or_max.reduce(self._deduped_data().ravel())
if self.nnz != np.product(self.shape):
m = min_or_max(zero, m)
return m
if axis < 0:
axis += 2
if (axis == 0) or (axis == 1):
return self._min_or_max_axis(axis, min_or_max)
else:
raise ValueError("axis out of range")
def max(self, axis=None, out=None):
"""
Return the maximum of the matrix or maximum along an axis.
This takes all elements into account, not just the non-zero ones.
Parameters
----------
axis : {-2, -1, 0, 1, None} optional
Axis along which the sum is computed. The default is to
compute the maximum over all the matrix elements, returning
a scalar (i.e. `axis` = `None`).
out : None, optional
This argument is in the signature *solely* for NumPy
compatibility reasons. Do not pass in anything except
for the default value, as this argument is not used.
Returns
-------
amax : coo_matrix or scalar
Maximum of `a`. If `axis` is None, the result is a scalar value.
If `axis` is given, the result is a sparse.coo_matrix of dimension
``a.ndim - 1``.
See Also
--------
min : The minimum value of a sparse matrix along a given axis.
np.matrix.max : NumPy's implementation of 'max' for matrices
"""
return self._min_or_max(axis, out, np.maximum)
def min(self, axis=None, out=None):
"""
Return the minimum of the matrix or maximum along an axis.
This takes all elements into account, not just the non-zero ones.
Parameters
----------
axis : {-2, -1, 0, 1, None} optional
Axis along which the sum is computed. The default is to
compute the minimum over all the matrix elements, returning
a scalar (i.e. `axis` = `None`).
out : None, optional
This argument is in the signature *solely* for NumPy
compatibility reasons. Do not pass in anything except for
the default value, as this argument is not used.
Returns
-------
amin : coo_matrix or scalar
Minimum of `a`. If `axis` is None, the result is a scalar value.
If `axis` is given, the result is a sparse.coo_matrix of dimension
``a.ndim - 1``.
See Also
--------
max : The maximum value of a sparse matrix along a given axis.
np.matrix.min : NumPy's implementation of 'min' for matrices
"""
return self._min_or_max(axis, out, np.minimum)
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