tf.linalg.LinearOperatorPermutation

LinearOperator acting like a [batch] of permutation matrices.

Inherits From: LinearOperator

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Compat aliases for migration

See Migration guide for more details.

tf.compat.v1.linalg.LinearOperatorPermutation

tf.linalg.LinearOperatorPermutation(
    perm, dtype=tf.dtypes.float32, is_non_singular=None, is_self_adjoint=None,
    is_positive_definite=None, is_square=None, name='LinearOperatorPermutation'
)

This operator acts like a [batch] of permutations with shape [B1,...,Bb, N, N] for some b >= 0. The first b indices index a batch member. For every batch index (i1,...,ib), A[i1,...,ib, : :] is an N x N matrix. This matrix A is not materialized, but for purposes of broadcasting this shape will be relevant.

LinearOperatorPermutation is initialized with a (batch) vector.

A permutation, is defined by an integer vector v whose values are unique and are in the range [0, ... n]. Applying the permutation on an input matrix has the folllowing meaning: the value of v at index i says to move the v[i]-th row of the input matrix to the i-th row. Because all values are unique, this will result in a permutation of the rows the input matrix. Note, that the permutation vector v has the same semantics as tf.transpose.

# Create a 3 x 3 permutation matrix that swaps the last two columns.
vec = [0, 2, 1]
operator = LinearOperatorPermutation(vec)

operator.to_dense()
==> [[1., 0., 0.]
     [0., 0., 1.]
     [0., 1., 0.]]

operator.shape
==> [3, 3]

# This will be zero.
operator.log_abs_determinant()
==> scalar Tensor

x = ... Shape [3, 4] Tensor
operator.matmul(x)
==> Shape [3, 4] Tensor

Shape compatibility

This operator acts on [batch] matrix with compatible shape. x is a batch matrix with compatible shape for matmul and solve if

operator.shape = [B1,...,Bb] + [N, N],  with b >= 0
x.shape =   [C1,...,Cc] + [N, R],
and [C1,...,Cc] broadcasts with [B1,...,Bb] to [D1,...,Dd]

Matrix property hints

This LinearOperator is initialized with boolean flags of the form is_X, for X = non_singular, self_adjoint, positive_definite, square. These have the following meaning:

• If is_X == True, callers should expect the operator to have the property X. This is a promise that should be fulfilled, but is not a runtime assert. For example, finite floating point precision may result in these promises being violated.
• If is_X == False, callers should expect the operator to not have X.
• If is_X == None (the default), callers should have no expectation either way.

Args
perm	Shape [B1,...,Bb, N] Integer Tensor with b >= 0 N >= 0. An integer vector that represents the permutation to apply. Note that this argument is same as tf.transpose. However, this permutation is applied on the rows, while the permutation in tf.transpose is applied on the dimensions of the Tensor. perm is required to have unique entries from {0, 1, ... N-1}.
dtype	The dtype of arguments to this operator. Default: float32. Allowed dtypes: float16, float32, float64, complex64, complex128.
is_non_singular	Expect that this operator is non-singular.
is_self_adjoint	Expect that this operator is equal to its hermitian transpose. This is autoset to true
is_positive_definite	Expect that this operator is positive definite, meaning the quadratic form x^H A x has positive real part for all nonzero x. Note that we do not require the operator to be self-adjoint to be positive-definite. See: https://en.wikipedia.org/wiki/Positive-definite_matrix#Extension_for_non-symmetric_matrices This is autoset to false.
is_square	Expect that this operator acts like square [batch] matrices. This is autoset to true.
name	A name for this LinearOperator.

Raises
ValueError	is_self_adjoint is not True, is_positive_definite is not False or is_square is not True.

Attributes
H	Returns the adjoint of the current LinearOperator. Given A representing this LinearOperator, return A*. Note that calling self.adjoint() and self.H are equivalent.
batch_shape	TensorShape of batch dimensions of this LinearOperator. If this operator acts like the batch matrix A with A.shape = [B1,...,Bb, M, N], then this returns TensorShape([B1,...,Bb]), equivalent to A.shape[:-2]
domain_dimension	Dimension (in the sense of vector spaces) of the domain of this operator. If this operator acts like the batch matrix A with A.shape = [B1,...,Bb, M, N], then this returns N.
dtype	The DType of Tensors handled by this LinearOperator.
graph_parents	List of graph dependencies of this LinearOperator. (deprecated) Warning: THIS FUNCTION IS DEPRECATED. It will be removed in a future version. Instructions for updating: Do not call graph_parents.
is_non_singular
is_positive_definite
is_self_adjoint
is_square	Return True/False depending on if this operator is square.
perm
range_dimension	Dimension (in the sense of vector spaces) of the range of this operator. If this operator acts like the batch matrix A with A.shape = [B1,...,Bb, M, N], then this returns M.
shape	TensorShape of this LinearOperator. If this operator acts like the batch matrix A with A.shape = [B1,...,Bb, M, N], then this returns TensorShape([B1,...,Bb, M, N]), equivalent to A.shape.
tensor_rank	Rank (in the sense of tensors) of matrix corresponding to this operator. If this operator acts like the batch matrix A with A.shape = [B1,...,Bb, M, N], then this returns b + 2.

Methods

add_to_tensor

View source

add_to_tensor(
    x, name='add_to_tensor'
)

Add matrix represented by this operator to x. Equivalent to A + x.

Args
x	Tensor with same dtype and shape broadcastable to self.shape.
name	A name to give this Op.

Returns
A Tensor with broadcast shape and same dtype as self.

adjoint

View source

adjoint(
    name='adjoint'
)

Returns the adjoint of the current LinearOperator.

Given A representing this LinearOperator, return A*. Note that calling self.adjoint() and self.H are equivalent.

Args
name	A name for this Op.

Returns
LinearOperator which represents the adjoint of this LinearOperator.

assert_non_singular

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