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# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Operations for linear algebra."""
from
__future__
import
absolute_import
from
__future__
import
division
from
__future__
import
print_function
import
numpy
as
np
from
tensorflow
.
python
.
framework
import
dtypes
from
tensorflow
.
python
.
framework
import
ops
from
tensorflow
.
python
.
ops
import
array_ops
from
tensorflow
.
python
.
ops
import
control_flow_ops
from
tensorflow
.
python
.
ops
import
functional_ops
from
tensorflow
.
python
.
ops
import
gen_linalg_ops
from
tensorflow
.
python
.
ops
import
linalg_ops_impl
from
tensorflow
.
python
.
ops
import
math_ops
# pylint: disable=wildcard-import
from
tensorflow
.
python
.
ops
.
gen_linalg_ops
import
*
# pylint: enable=wildcard-import
from
tensorflow
.
python
.
util
import
deprecation
from
tensorflow
.
python
.
util
.
tf_export
import
tf_export
# Names below are lower_case.
# pylint: disable=invalid-name
def
_RegularizedGramianCholesky
(
matrix
,
l2_regularizer
,
first_kind
):
r"""Computes Cholesky factorization of regularized gramian matrix.
Below we will use the following notation for each pair of matrix and
right-hand sides in the batch:
`matrix`=\\(A \in \Re^{m \times n}\\),
`output`=\\(C \in \Re^{\min(m, n) \times \min(m,n)}\\),
`l2_regularizer`=\\(\lambda\\).
If `first_kind` is True, returns the Cholesky factorization \\(L\\) such that
\\(L L^H = A^H A + \lambda I\\).
If `first_kind` is False, returns the Cholesky factorization \\(L\\) such that
\\(L L^H = A A^H + \lambda I\\).
Args:
matrix: `Tensor` of shape `[..., M, N]`.
l2_regularizer: 0-D `double` `Tensor`. Ignored if `fast=False`.
first_kind: bool. Controls what gramian matrix to factor.
Returns:
output: `Tensor` of shape `[..., min(M,N), min(M,N)]` whose inner-most 2
dimensions contain the Cholesky factors \\(L\\) described above.
"""
gramian
=
math_ops
.
matmul
(
matrix
,
matrix
,
adjoint_a
=
first_kind
,
adjoint_b
=
not
first_kind
)
if
isinstance
(
l2_regularizer
,
ops
.
Tensor
)
or
l2_regularizer
!=
0
:
matrix_shape
=
array_ops
.
shape
(
matrix
)
batch_shape
=
matrix_shape
[:
-
2
]
if
first_kind
:
small_dim
=
matrix_shape
[
-
1
]
else
:
small_dim
=
matrix_shape
[
-
2
]
identity
=
eye
(
small_dim
,
batch_shape
=
batch_shape
,
dtype
=
matrix
.
dtype
)
small_dim_static
=
matrix
.
shape
[
-
1
if
first_kind
else
-
2
]
identity
.
set_shape
(
matrix
.
shape
[:
-
2
].
concatenate
([
small_dim_static
,
small_dim_static
]))
gramian
+=
l2_regularizer
*
identity
return
gen_linalg_ops
.
cholesky
(
gramian
)
@
tf_export
(
'cholesky_solve'
,
'linalg.cholesky_solve'
)
def
cholesky_solve
(
chol
,
rhs
,
name
=
None
):
"""Solves systems of linear eqns `A X = RHS`, given Cholesky factorizations.
```python
# Solve 10 separate 2x2 linear systems:
A = ... # shape 10 x 2 x 2
RHS = ... # shape 10 x 2 x 1
chol = tf.cholesky(A) # shape 10 x 2 x 2
X = tf.cholesky_solve(chol, RHS) # shape 10 x 2 x 1
# tf.matmul(A, X) ~ RHS
X[3, :, 0] # Solution to the linear system A[3, :, :] x = RHS[3, :, 0]
# Solve five linear systems (K = 5) for every member of the length 10 batch.
A = ... # shape 10 x 2 x 2
RHS = ... # shape 10 x 2 x 5
...
X[3, :, 2] # Solution to the linear system A[3, :, :] x = RHS[3, :, 2]
```
Args:
chol: A `Tensor`. Must be `float32` or `float64`, shape is `[..., M, M]`.
Cholesky factorization of `A`, e.g. `chol = tf.cholesky(A)`.
For that reason, only the lower triangular parts (including the diagonal)
of the last two dimensions of `chol` are used. The strictly upper part is
assumed to be zero and not accessed.
rhs: A `Tensor`, same type as `chol`, shape is `[..., M, K]`.
name: A name to give this `Op`. Defaults to `cholesky_solve`.
Returns:
Solution to `A x = rhs`, shape `[..., M, K]`.
"""
# To solve C C^* x = rhs, we
# 1. Solve C y = rhs for y, thus y = C^* x
# 2. Solve C^* x = y for x
with
ops
.
name_scope
(
name
,
'cholesky_solve'
, [
chol
,
rhs
]):
y
=
gen_linalg_ops
.
matrix_triangular_solve
(
chol
,
rhs
,
adjoint
=
False
,
lower
=
True
)
x
=
gen_linalg_ops
.
matrix_triangular_solve
(
chol
,
y
,
adjoint
=
True
,
lower
=
True
)
return
x
@
tf_export
(
'eye'
,
'linalg.eye'
)
def
eye
(
num_rows
,
num_columns
=
None
,
batch_shape
=
None
,
dtype
=
dtypes
.
float32
,
name
=
None
):
"""Construct an identity matrix, or a batch of matrices.
```python
# Construct one identity matrix.
tf.eye(2)
==> [[1., 0.],
[0., 1.]]
# Construct a batch of 3 identity matricies, each 2 x 2.
# batch_identity[i, :, :] is a 2 x 2 identity matrix, i = 0, 1, 2.
batch_identity = tf.eye(2, batch_shape=[3])
# Construct one 2 x 3 "identity" matrix
tf.eye(2, num_columns=3)
==> [[ 1., 0., 0.],
[ 0., 1., 0.]]
```
Args:
num_rows: Non-negative `int32` scalar `Tensor` giving the number of rows
in each batch matrix.
num_columns: Optional non-negative `int32` scalar `Tensor` giving the number
of columns in each batch matrix. Defaults to `num_rows`.
batch_shape: A list or tuple of Python integers or a 1-D `int32` `Tensor`.
If provided, the returned `Tensor` will have leading batch dimensions of
this shape.
dtype: The type of an element in the resulting `Tensor`
name: A name for this `Op`. Defaults to "eye".
Returns:
A `Tensor` of shape `batch_shape + [num_rows, num_columns]`
"""
return
linalg_ops_impl
.
eye
(
num_rows
,
num_columns
=
num_columns
,
batch_shape
=
batch_shape
,
dtype
=
dtype
,
name
=
name
)
@
tf_export
(
'matrix_solve_ls'
,
'linalg.lstsq'
)
def
matrix_solve_ls
(
matrix
,
rhs
,
l2_regularizer
=
0.0
,
fast
=
True
,
name
=
None
):
r"""Solves one or more linear least-squares problems.
`matrix` is a tensor of shape `[..., M, N]` whose inner-most 2 dimensions
form `M`-by-`N` matrices. Rhs is a tensor of shape `[..., M, K]` whose
inner-most 2 dimensions form `M`-by-`K` matrices. The computed output is a
`Tensor` of shape `[..., N, K]` whose inner-most 2 dimensions form `M`-by-`K`
matrices that solve the equations
`matrix[..., :, :] * output[..., :, :] = rhs[..., :, :]` in the least squares
sense.
Below we will use the following notation for each pair of matrix and
right-hand sides in the batch:
`matrix`=\\(A \in \Re^{m \times n}\\),
`rhs`=\\(B \in \Re^{m \times k}\\),
`output`=\\(X \in \Re^{n \times k}\\),
`l2_regularizer`=\\(\lambda\\).
If `fast` is `True`, then the solution is computed by solving the normal
equations using Cholesky decomposition. Specifically, if \\(m \ge n\\) then
\\(X = (A^T A + \lambda I)^{-1} A^T B\\), which solves the least-squares
problem \\(X = \mathrm{argmin}_{Z \in \Re^{n \times k}} ||A Z - B||_F^2 +
\lambda ||Z||_F^2\\). If \\(m \lt n\\) then `output` is computed as
\\(X = A^T (A A^T + \lambda I)^{-1} B\\), which (for \\(\lambda = 0\\)) is
the minimum-norm solution to the under-determined linear system, i.e.
\\(X = \mathrm{argmin}_{Z \in \Re^{n \times k}} ||Z||_F^2 \\), subject to
\\(A Z = B\\). Notice that the fast path is only numerically stable when
\\(A\\) is numerically full rank and has a condition number
\\(\mathrm{cond}(A) \lt \frac{1}{\sqrt{\epsilon_{mach}}}\\) or\\(\lambda\\)
is sufficiently large.
If `fast` is `False` an algorithm based on the numerically robust complete
orthogonal decomposition is used. This computes the minimum-norm
least-squares solution, even when \\(A\\) is rank deficient. This path is
typically 6-7 times slower than the fast path. If `fast` is `False` then
`l2_regularizer` is ignored.
Args:
matrix: `Tensor` of shape `[..., M, N]`.
rhs: `Tensor` of shape `[..., M, K]`.
l2_regularizer: 0-D `double` `Tensor`. Ignored if `fast=False`.
fast: bool. Defaults to `True`.
name: string, optional name of the operation.
Returns:
output: `Tensor` of shape `[..., N, K]` whose inner-most 2 dimensions form
`M`-by-`K` matrices that solve the equations
`matrix[..., :, :] * output[..., :, :] = rhs[..., :, :]` in the least
squares sense.
Raises:
NotImplementedError: matrix_solve_ls is currently disabled for complex128
and l2_regularizer != 0 due to poor accuracy.
"""
# pylint: disable=long-lambda
def
_use_composite_impl
(
fast
,
tensor_shape
):
"""Determines whether to use the composite or specialized CPU kernel.
When the total size of the tensor is larger than the cache size and the
batch size is large compared to the smallest matrix dimension, then the
composite implementation is inefficient since it has to read the entire
tensor from memory multiple times. In this case we fall back to the
original CPU kernel, which does all the computational steps on each
matrix separately.
Only fast mode is supported by the composite impl, so `False` is returned
if `fast` is `False`.
Args:
fast: bool indicating if fast mode in the solver was requested.
tensor_shape: The shape of the tensor.
Returns:
True if the composite impl should be used. False otherwise.
"""
if
fast
is
False
:
return
False
batch_shape
=
tensor_shape
[:
-
2
]
matrix_shape
=
tensor_shape
[
-
2
:]
if
not
tensor_shape
.
is_fully_defined
():
return
True
tensor_size
=
tensor_shape
.
num_elements
()
*
matrix
.
dtype
.
size
is_io_bound
=
batch_shape
.
num_elements
()
>
np
.
min
(
matrix_shape
)
L2_CACHE_SIZE_GUESSTIMATE
=
256000
if
tensor_size
>
L2_CACHE_SIZE_GUESSTIMATE
and
is_io_bound
:
return
False
else
:
return
True
def
_overdetermined
(
matrix
,
rhs
,
l2_regularizer
):
"""Computes (A^H*A + l2_regularizer)^{-1} * A^H * rhs."""
chol
=
_RegularizedGramianCholesky
(
matrix
,
l2_regularizer
=
l2_regularizer
,
first_kind
=
True
)
return
cholesky_solve
(
chol
,
math_ops
.
matmul
(
matrix
,
rhs
,
adjoint_a
=
True
))
def
_underdetermined
(
matrix
,
rhs
,
l2_regularizer
):
"""Computes A^H * (A*A^H + l2_regularizer)^{-1} * rhs."""
chol
=
_RegularizedGramianCholesky
(
matrix
,
l2_regularizer
=
l2_regularizer
,
first_kind
=
False
)
return
math_ops
.
matmul
(
matrix
,
cholesky_solve
(
chol
,
rhs
),
adjoint_a
=
True
)
def
_composite_impl
(
matrix
,
rhs
,
l2_regularizer
):
"""Composite implementation of matrix_solve_ls that supports GPU."""
with
ops
.
name_scope
(
name
,
'matrix_solve_ls'
, [
matrix
,
rhs
,
l2_regularizer
]):
matrix_shape
=
matrix
.
get_shape
()[
-
2
:]
if
matrix_shape
.
is_fully_defined
():
if
matrix_shape
[
-
2
]
>=
matrix_shape
[
-
1
]:
return
_overdetermined
(
matrix
,
rhs
,
l2_regularizer
)
else
:
return
_underdetermined
(
matrix
,
rhs
,
l2_regularizer
)
else
:
# We have to defer determining the shape to runtime and use
# conditional execution of the appropriate graph.
matrix_shape
=
array_ops
.
shape
(
matrix
)[
-
2
:]
return
control_flow_ops
.
cond
(
matrix_shape
[
-
2
]
>=
matrix_shape
[
-
1
],
lambda
:
_overdetermined
(
matrix
,
rhs
,
l2_regularizer
),
lambda
:
_underdetermined
(
matrix
,
rhs
,
l2_regularizer
))
matrix
=
ops
.
convert_to_tensor
(
matrix
,
name
=
'matrix'
)
if
matrix
.
dtype
==
dtypes
.
complex128
and
l2_regularizer
!=
0
:
# TODO(rmlarsen): Investigate and fix accuracy bug.
raise
NotImplementedError
(
'matrix_solve_ls is currently disabled for '
'complex128 and l2_regularizer != 0 due to '
'poor accuracy.'
)
tensor_shape
=
matrix
.
get_shape
()
if
_use_composite_impl
(
fast
,
tensor_shape
):
return
_composite_impl
(
matrix
,
rhs
,
l2_regularizer
)
else
:
return
gen_linalg_ops
.
matrix_solve_ls
(
matrix
,
rhs
,
l2_regularizer
,
fast
=
fast
,
name
=
name
)
@
tf_export
(
'self_adjoint_eig'
,
'linalg.eigh'
)
def
self_adjoint_eig
(
tensor
,
name
=
None
):
"""Computes the eigen decomposition of a batch of self-adjoint matrices.
Computes the eigenvalues and eigenvectors of the innermost N-by-N matrices
in `tensor` such that
`tensor[...,:,:] * v[..., :,i] = e[..., i] * v[...,:,i]`, for i=0...N-1.
Args:
tensor: `Tensor` of shape `[..., N, N]`. Only the lower triangular part of
each inner inner matrix is referenced.
name: string, optional name of the operation.
Returns:
e: Eigenvalues. Shape is `[..., N]`. Sorted in non-decreasing order.
v: Eigenvectors. Shape is `[..., N, N]`. The columns of the inner most
matrices contain eigenvectors of the corresponding matrices in `tensor`
"""
e
,
v
=
gen_linalg_ops
.
self_adjoint_eig_v2
(
tensor
,
compute_v
=
True
,
name
=
name
)
return
e
,
v
@
tf_export
(
'self_adjoint_eigvals'
,
'linalg.eigvalsh'
)
def
self_adjoint_eigvals
(
tensor
,
name
=
None
):
"""Computes the eigenvalues of one or more self-adjoint matrices.
Note: If your program backpropagates through this function, you should replace
it with a call to tf.self_adjoint_eig (possibly ignoring the second output) to
avoid computing the eigen decomposition twice. This is because the
eigenvectors are used to compute the gradient w.r.t. the eigenvalues. See
_SelfAdjointEigV2Grad in linalg_grad.py.
Args:
tensor: `Tensor` of shape `[..., N, N]`.
name: string, optional name of the operation.
Returns:
e: Eigenvalues. Shape is `[..., N]`. The vector `e[..., :]` contains the `N`
eigenvalues of `tensor[..., :, :]`.
"""
e
,
_
=
gen_linalg_ops
.
self_adjoint_eig_v2
(
tensor
,
compute_v
=
False
,
name
=
name
)
return
e
@
tf_export
(
'svd'
,
'linalg.svd'
)
def
svd
(
tensor
,
full_matrices
=
False
,
compute_uv
=
True
,
name
=
None
):
r"""Computes the singular value decompositions of one or more matrices.
Computes the SVD of each inner matrix in `tensor` such that
`tensor[..., :, :] = u[..., :, :] * diag(s[..., :, :]) *
transpose(conj(v[..., :, :]))`
```python
# a is a tensor.
# s is a tensor of singular values.
# u is a tensor of left singular vectors.
# v is a tensor of right singular vectors.
s, u, v = svd(a)
s = svd(a, compute_uv=False)
```
Args:
tensor: `Tensor` of shape `[..., M, N]`. Let `P` be the minimum of `M` and
`N`.
full_matrices: If true, compute full-sized `u` and `v`. If false
(the default), compute only the leading `P` singular vectors.
Ignored if `compute_uv` is `False`.
compute_uv: If `True` then left and right singular vectors will be
computed and returned in `u` and `v`, respectively. Otherwise, only the
singular values will be computed, which can be significantly faster.
name: string, optional name of the operation.
Returns:
s: Singular values. Shape is `[..., P]`. The values are sorted in reverse
order of magnitude, so s[..., 0] is the largest value, s[..., 1] is the
second largest, etc.
u: Left singular vectors. If `full_matrices` is `False` (default) then
shape is `[..., M, P]`; if `full_matrices` is `True` then shape is
`[..., M, M]`. Not returned if `compute_uv` is `False`.
v: Right singular vectors. If `full_matrices` is `False` (default) then
shape is `[..., N, P]`. If `full_matrices` is `True` then shape is
`[..., N, N]`. Not returned if `compute_uv` is `False`.
@compatibility(numpy)
Mostly equivalent to numpy.linalg.svd, except that
* The order of output arguments here is `s`, `u`, `v` when `compute_uv` is
`True`, as opposed to `u`, `s`, `v` for numpy.linalg.svd.
* full_matrices is `False` by default as opposed to `True` for
numpy.linalg.svd.
* tf.linalg.svd uses the standard definition of the SVD
\\(A = U \Sigma V^H\\), such that the left singular vectors of `a` are
the columns of `u`, while the right singular vectors of `a` are the
columns of `v`. On the other hand, numpy.linalg.svd returns the adjoint
\\(V^H\\) as the third output argument.
```python
import tensorflow as tf
import numpy as np
s, u, v = tf.linalg.svd(a)
tf_a_approx = tf.matmul(u, tf.matmul(tf.linalg.diag(s), v, adjoint_v=True))
u, s, v_adj = np.linalg.svd(a, full_matrices=False)
np_a_approx = np.dot(u, np.dot(np.diag(s), v_adj))
# tf_a_approx and np_a_approx should be numerically close.
```
@end_compatibility
"""
s
,
u
,
v
=
gen_linalg_ops
.
svd
(
tensor
,
compute_uv
=
compute_uv
,
full_matrices
=
full_matrices
,
name
=
name
)
if
compute_uv
:
return
math_ops
.
real
(
s
),
u
,
v
else
:
return
math_ops
.
real
(
s
)
# pylint: disable=redefined-builtin
@
tf_export
(
'norm'
,
'linalg.norm'
)
@
deprecation
.
deprecated_args
(
None
,
'keep_dims is deprecated, use keepdims instead'
,
'keep_dims'
)
def
norm
(
tensor
,
ord
=
'euclidean'
,
axis
=
None
,
keepdims
=
None
,
name
=
None
,
keep_dims
=
None
):
r"""Computes the norm of vectors, matrices, and tensors.
This function can compute several different vector norms (the 1-norm, the
Euclidean or 2-norm, the inf-norm, and in general the p-norm for p > 0) and
matrix norms (Frobenius, 1-norm, 2-norm and inf-norm).
Args:
tensor: `Tensor` of types `float32`, `float64`, `complex64`, `complex128`
ord: Order of the norm. Supported values are 'fro', 'euclidean',
`1`, `2`, `np.inf` and any positive real number yielding the corresponding
p-norm. Default is 'euclidean' which is equivalent to Frobenius norm if
`tensor` is a matrix and equivalent to 2-norm for vectors.
Some restrictions apply:
a) The Frobenius norm `fro` is not defined for vectors,
b) If axis is a 2-tuple (matrix norm), only 'euclidean', 'fro', `1`,
`2`, `np.inf` are supported.
See the description of `axis` on how to compute norms for a batch of
vectors or matrices stored in a tensor.
axis: If `axis` is `None` (the default), the input is considered a vector
and a single vector norm is computed over the entire set of values in the
tensor, i.e. `norm(tensor, ord=ord)` is equivalent to
`norm(reshape(tensor, [-1]), ord=ord)`.
If `axis` is a Python integer, the input is considered a batch of vectors,
and `axis` determines the axis in `tensor` over which to compute vector
norms.
If `axis` is a 2-tuple of Python integers it is considered a batch of
matrices and `axis` determines the axes in `tensor` over which to compute
a matrix norm.
Negative indices are supported. Example: If you are passing a tensor that
can be either a matrix or a batch of matrices at runtime, pass
`axis=[-2,-1]` instead of `axis=None` to make sure that matrix norms are
computed.
keepdims: If True, the axis indicated in `axis` are kept with size 1.
Otherwise, the dimensions in `axis` are removed from the output shape.
name: The name of the op.
keep_dims: Deprecated alias for `keepdims`.
Returns:
output: A `Tensor` of the same type as tensor, containing the vector or
matrix norms. If `keepdims` is True then the rank of output is equal to
the rank of `tensor`. Otherwise, if `axis` is none the output is a scalar,
if `axis` is an integer, the rank of `output` is one less than the rank
of `tensor`, if `axis` is a 2-tuple the rank of `output` is two less
than the rank of `tensor`.
Raises:
ValueError: If `ord` or `axis` is invalid.
@compatibility(numpy)
Mostly equivalent to numpy.linalg.norm.
Not supported: ord <= 0, 2-norm for matrices, nuclear norm.
Other differences:
a) If axis is `None`, treats the flattened `tensor` as a vector
regardless of rank.
b) Explicitly supports 'euclidean' norm as the default, including for
higher order tensors.
@end_compatibility
"""
keepdims
=
deprecation
.
deprecated_argument_lookup
(
'keepdims'
,
keepdims
,
'keep_dims'
,
keep_dims
)
if
keepdims
is
None
:
keepdims
=
False
is_matrix_norm
=
((
isinstance
(
axis
,
tuple
)
or
isinstance
(
axis
,
list
))
and
len
(
axis
)
==
2
)
if
is_matrix_norm
:
axis
=
tuple
(
axis
)
if
(
not
isinstance
(
axis
[
0
],
int
)
or
not
isinstance
(
axis
[
1
],
int
)
or
axis
[
0
]
==
axis
[
1
]):
raise
ValueError
(
"'axis' must be None, an integer, or a tuple of 2 unique integers"
)
supported_matrix_norms
=
[
'euclidean'
,
'fro'
,
1
,
2
,
np
.
inf
]
if
ord
not
in
supported_matrix_norms
:
raise
ValueError
(
"'ord' must be a supported matrix norm in %s, got %s"
%
(
supported_matrix_norms
,
ord
))
else
:
if
not
(
isinstance
(
axis
,
int
)
or
axis
is
None
):
raise
ValueError
(
"'axis' must be None, an integer, or a tuple of 2 unique integers"
)
supported_vector_norms
=
[
'euclidean'
,
1
,
2
,
np
.
inf
]
if
(
not
np
.
isreal
(
ord
)
or
ord
<=
0
)
and
ord
not
in
supported_vector_norms
:
raise
ValueError
(
"'ord' must be a supported vector norm, got %s"
%
ord
)
if
axis
is
not
None
:
axis
=
(
axis
,)
with
ops
.
name_scope
(
name
,
'norm'
, [
tensor
]):
tensor
=
ops
.
convert_to_tensor
(
tensor
)
if
ord
in
[
'fro'
,
'euclidean'
,
2
,
2.0
]:
if
is_matrix_norm
and
ord
in
[
2
,
2.0
]:
rank
=
array_ops
.
rank
(
tensor
)
positive_axis
=
functional_ops
.
map_fn
(
lambda
i
:
control_flow_ops
.
cond
(
i
>=
0
,
lambda
:
i
,
lambda
:
i
+
rank
),
ops
.
convert_to_tensor
(
axis
))
axes
=
math_ops
.
range
(
rank
)
perm_before
=
array_ops
.
concat
(
[
array_ops
.
setdiff1d
(
axes
,
positive_axis
)[
0
],
positive_axis
],
axis
=
0
)
perm_after
=
functional_ops
.
map_fn
(
lambda
i
:
math_ops
.
cast
(
array_ops
.
squeeze
(
array_ops
.
where
(
math_ops
.
equal
(
perm_before
,
i
))),
dtype
=
dtypes
.
int32
),
axes
)
permed
=
array_ops
.
transpose
(
tensor
,
perm
=
perm_before
)
matrix_2_norm
=
array_ops
.
expand_dims
(
math_ops
.
reduce_max
(
math_ops
.
abs
(
gen_linalg_ops
.
svd
(
permed
,
compute_uv
=
False
)[
0
]),
axis
=
-
1
,
keepdims
=
True
),
axis
=
-
1
)
result
=
array_ops
.
transpose
(
matrix_2_norm
,
perm
=
perm_after
)
else
:
result
=
math_ops
.
sqrt
(
math_ops
.
reduce_sum
(
tensor
*
math_ops
.
conj
(
tensor
),
axis
,
keepdims
=
True
))
else
:
result
=
math_ops
.
abs
(
tensor
)
if
ord
==
1
:
sum_axis
=
None
if
axis
is
None
else
axis
[
0
]
result
=
math_ops
.
reduce_sum
(
result
,
sum_axis
,
keepdims
=
True
)
if
is_matrix_norm
:
result
=
math_ops
.
reduce_max
(
result
,
axis
[
-
1
],
keepdims
=
True
)
elif
ord
==
np
.
inf
:
if
is_matrix_norm
:
result
=
math_ops
.
reduce_sum
(
result
,
axis
[
1
],
keepdims
=
True
)
max_axis
=
None
if
axis
is
None
else
axis
[
0
]
result
=
math_ops
.
reduce_max
(
result
,
max_axis
,
keepdims
=
True
)
else
:
# General p-norms (positive p only)
result
=
math_ops
.
pow
(
math_ops
.
reduce_sum
(
math_ops
.
pow
(
result
,
ord
),
axis
,
keepdims
=
True
),
1.0
/
ord
)
if
not
keepdims
:
result
=
array_ops
.
squeeze
(
result
,
axis
)
return
result
# pylint: enable=invalid-name,redefined-builtin
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