403 lines
13 KiB
Python
403 lines
13 KiB
Python
"""Base class for sparse matrice with a .data attribute
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subclasses must provide a _with_data() method that
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creates a new matrix with the same sparsity pattern
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as self but with a different data array
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"""
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import numpy as np
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from ._base import spmatrix, _ufuncs_with_fixed_point_at_zero
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from ._sputils import isscalarlike, validateaxis, matrix
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__all__ = []
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# TODO implement all relevant operations
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# use .data.__methods__() instead of /=, *=, etc.
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class _data_matrix(spmatrix):
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def __init__(self):
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spmatrix.__init__(self)
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def _get_dtype(self):
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return self.data.dtype
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def _set_dtype(self, newtype):
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self.data.dtype = newtype
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dtype = property(fget=_get_dtype, fset=_set_dtype)
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def _deduped_data(self):
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if hasattr(self, 'sum_duplicates'):
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self.sum_duplicates()
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return self.data
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def __abs__(self):
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return self._with_data(abs(self._deduped_data()))
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def __round__(self, ndigits=0):
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return self._with_data(np.around(self._deduped_data(), decimals=ndigits))
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def _real(self):
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return self._with_data(self.data.real)
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def _imag(self):
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return self._with_data(self.data.imag)
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def __neg__(self):
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if self.dtype.kind == 'b':
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raise NotImplementedError('negating a sparse boolean '
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'matrix is not supported')
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return self._with_data(-self.data)
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def __imul__(self, other): # self *= other
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if isscalarlike(other):
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self.data *= other
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return self
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else:
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return NotImplemented
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def __itruediv__(self, other): # self /= other
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if isscalarlike(other):
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recip = 1.0 / other
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self.data *= recip
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return self
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else:
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return NotImplemented
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def astype(self, dtype, casting='unsafe', copy=True):
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dtype = np.dtype(dtype)
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if self.dtype != dtype:
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return self._with_data(
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self._deduped_data().astype(dtype, casting=casting, copy=copy),
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copy=copy)
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elif copy:
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return self.copy()
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else:
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return self
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astype.__doc__ = spmatrix.astype.__doc__
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def conj(self, copy=True):
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if np.issubdtype(self.dtype, np.complexfloating):
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return self._with_data(self.data.conj(), copy=copy)
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elif copy:
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return self.copy()
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else:
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return self
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conj.__doc__ = spmatrix.conj.__doc__
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def copy(self):
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return self._with_data(self.data.copy(), copy=True)
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copy.__doc__ = spmatrix.copy.__doc__
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def count_nonzero(self):
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return np.count_nonzero(self._deduped_data())
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count_nonzero.__doc__ = spmatrix.count_nonzero.__doc__
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def power(self, n, dtype=None):
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"""
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This function performs element-wise power.
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Parameters
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----------
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n : n is a scalar
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dtype : If dtype is not specified, the current dtype will be preserved.
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"""
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if not isscalarlike(n):
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raise NotImplementedError("input is not scalar")
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data = self._deduped_data()
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if dtype is not None:
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data = data.astype(dtype)
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return self._with_data(data ** n)
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###########################
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# Multiplication handlers #
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###########################
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def _mul_scalar(self, other):
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return self._with_data(self.data * other)
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# Add the numpy unary ufuncs for which func(0) = 0 to _data_matrix.
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for npfunc in _ufuncs_with_fixed_point_at_zero:
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name = npfunc.__name__
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def _create_method(op):
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def method(self):
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result = op(self._deduped_data())
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return self._with_data(result, copy=True)
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method.__doc__ = ("Element-wise %s.\n\n"
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"See `numpy.%s` for more information." % (name, name))
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method.__name__ = name
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return method
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setattr(_data_matrix, name, _create_method(npfunc))
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def _find_missing_index(ind, n):
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for k, a in enumerate(ind):
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if k != a:
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return k
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k += 1
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if k < n:
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return k
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else:
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return -1
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class _minmax_mixin:
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"""Mixin for min and max methods.
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These are not implemented for dia_matrix, hence the separate class.
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"""
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def _min_or_max_axis(self, axis, min_or_max):
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N = self.shape[axis]
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if N == 0:
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raise ValueError("zero-size array to reduction operation")
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M = self.shape[1 - axis]
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mat = self.tocsc() if axis == 0 else self.tocsr()
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mat.sum_duplicates()
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major_index, value = mat._minor_reduce(min_or_max)
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not_full = np.diff(mat.indptr)[major_index] < N
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value[not_full] = min_or_max(value[not_full], 0)
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mask = value != 0
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major_index = np.compress(mask, major_index)
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value = np.compress(mask, value)
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if axis == 0:
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return self._coo_container(
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(value, (np.zeros(len(value)), major_index)),
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dtype=self.dtype, shape=(1, M)
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)
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else:
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return self._coo_container(
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(value, (major_index, np.zeros(len(value)))),
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dtype=self.dtype, shape=(M, 1)
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)
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def _min_or_max(self, axis, out, min_or_max):
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if out is not None:
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raise ValueError(("Sparse matrices do not support "
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"an 'out' parameter."))
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validateaxis(axis)
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if axis is None:
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if 0 in self.shape:
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raise ValueError("zero-size array to reduction operation")
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zero = self.dtype.type(0)
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if self.nnz == 0:
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return zero
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m = min_or_max.reduce(self._deduped_data().ravel())
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if self.nnz != np.prod(self.shape):
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m = min_or_max(zero, m)
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return m
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if axis < 0:
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axis += 2
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if (axis == 0) or (axis == 1):
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return self._min_or_max_axis(axis, min_or_max)
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else:
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raise ValueError("axis out of range")
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def _arg_min_or_max_axis(self, axis, op, compare):
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if self.shape[axis] == 0:
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raise ValueError("Can't apply the operation along a zero-sized "
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"dimension.")
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if axis < 0:
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axis += 2
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zero = self.dtype.type(0)
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mat = self.tocsc() if axis == 0 else self.tocsr()
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mat.sum_duplicates()
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ret_size, line_size = mat._swap(mat.shape)
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ret = np.zeros(ret_size, dtype=int)
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nz_lines, = np.nonzero(np.diff(mat.indptr))
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for i in nz_lines:
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p, q = mat.indptr[i:i + 2]
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data = mat.data[p:q]
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indices = mat.indices[p:q]
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am = op(data)
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m = data[am]
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if compare(m, zero) or q - p == line_size:
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ret[i] = indices[am]
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else:
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zero_ind = _find_missing_index(indices, line_size)
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if m == zero:
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ret[i] = min(am, zero_ind)
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else:
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ret[i] = zero_ind
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if axis == 1:
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ret = ret.reshape(-1, 1)
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return matrix(ret)
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def _arg_min_or_max(self, axis, out, op, compare):
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if out is not None:
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raise ValueError("Sparse matrices do not support "
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"an 'out' parameter.")
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validateaxis(axis)
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if axis is None:
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if 0 in self.shape:
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raise ValueError("Can't apply the operation to "
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"an empty matrix.")
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if self.nnz == 0:
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return 0
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else:
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zero = self.dtype.type(0)
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mat = self.tocoo()
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mat.sum_duplicates()
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am = op(mat.data)
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m = mat.data[am]
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if compare(m, zero):
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# cast to Python int to avoid overflow
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# and RuntimeError
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return int(mat.row[am])*mat.shape[1] + int(mat.col[am])
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else:
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size = np.prod(mat.shape)
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if size == mat.nnz:
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return am
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else:
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ind = mat.row * mat.shape[1] + mat.col
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zero_ind = _find_missing_index(ind, size)
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if m == zero:
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return min(zero_ind, am)
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else:
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return zero_ind
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return self._arg_min_or_max_axis(axis, op, compare)
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def max(self, axis=None, out=None):
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"""
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Return the maximum of the matrix or maximum along an axis.
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This takes all elements into account, not just the non-zero ones.
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Parameters
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----------
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axis : {-2, -1, 0, 1, None} optional
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Axis along which the sum is computed. The default is to
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compute the maximum over all the matrix elements, returning
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a scalar (i.e., `axis` = `None`).
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out : None, optional
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This argument is in the signature *solely* for NumPy
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compatibility reasons. Do not pass in anything except
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for the default value, as this argument is not used.
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Returns
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-------
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amax : coo_matrix or scalar
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Maximum of `a`. If `axis` is None, the result is a scalar value.
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If `axis` is given, the result is a sparse.coo_matrix of dimension
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``a.ndim - 1``.
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See Also
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--------
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min : The minimum value of a sparse matrix along a given axis.
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numpy.matrix.max : NumPy's implementation of 'max' for matrices
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"""
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return self._min_or_max(axis, out, np.maximum)
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def min(self, axis=None, out=None):
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"""
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Return the minimum of the matrix or maximum along an axis.
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This takes all elements into account, not just the non-zero ones.
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Parameters
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----------
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axis : {-2, -1, 0, 1, None} optional
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Axis along which the sum is computed. The default is to
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compute the minimum over all the matrix elements, returning
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a scalar (i.e., `axis` = `None`).
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out : None, optional
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This argument is in the signature *solely* for NumPy
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compatibility reasons. Do not pass in anything except for
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the default value, as this argument is not used.
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Returns
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-------
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amin : coo_matrix or scalar
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Minimum of `a`. If `axis` is None, the result is a scalar value.
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If `axis` is given, the result is a sparse.coo_matrix of dimension
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``a.ndim - 1``.
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See Also
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--------
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max : The maximum value of a sparse matrix along a given axis.
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numpy.matrix.min : NumPy's implementation of 'min' for matrices
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"""
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return self._min_or_max(axis, out, np.minimum)
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def argmax(self, axis=None, out=None):
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"""Return indices of maximum elements along an axis.
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Implicit zero elements are also taken into account. If there are
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several maximum values, the index of the first occurrence is returned.
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Parameters
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----------
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axis : {-2, -1, 0, 1, None}, optional
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Axis along which the argmax is computed. If None (default), index
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of the maximum element in the flatten data is returned.
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out : None, optional
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This argument is in the signature *solely* for NumPy
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compatibility reasons. Do not pass in anything except for
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the default value, as this argument is not used.
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Returns
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-------
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ind : numpy.matrix or int
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Indices of maximum elements. If matrix, its size along `axis` is 1.
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"""
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return self._arg_min_or_max(axis, out, np.argmax, np.greater)
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def argmin(self, axis=None, out=None):
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"""Return indices of minimum elements along an axis.
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Implicit zero elements are also taken into account. If there are
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several minimum values, the index of the first occurrence is returned.
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Parameters
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----------
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axis : {-2, -1, 0, 1, None}, optional
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Axis along which the argmin is computed. If None (default), index
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of the minimum element in the flatten data is returned.
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out : None, optional
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This argument is in the signature *solely* for NumPy
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compatibility reasons. Do not pass in anything except for
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the default value, as this argument is not used.
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Returns
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-------
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ind : numpy.matrix or int
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Indices of minimum elements. If matrix, its size along `axis` is 1.
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"""
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return self._arg_min_or_max(axis, out, np.argmin, np.less)
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