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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.
# ==============================================================================
"""Tests for tensorflow.ops.tf.Cholesky."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import unittest
import numpy as np
from six.moves import xrange # pylint: disable=redefined-builtin
from tensorflow.compiler.tests.xla_test import XLATestCase
from tensorflow.python.framework import constant_op
from tensorflow.python.framework import dtypes
from tensorflow.python.ops import array_ops
from tensorflow.python.ops import linalg_ops
from tensorflow.python.ops import math_ops
from tensorflow.python.platform import test
class CholeskyOpTest(XLATestCase):
# Cholesky defined for float64, float32, complex64, complex128
# (https://www.tensorflow.org/api_docs/python/tf/cholesky)
@property
def float_types(self):
return set(super(CholeskyOpTest, self).float_types).intersection(
(np.float64, np.float32, np.complex64, np.complex128))
def _verifyCholeskyBase(self, sess, placeholder, x, chol, verification, atol):
chol_np, verification_np = sess.run([chol, verification], {placeholder: x})
self.assertAllClose(x, verification_np, atol=atol)
self.assertShapeEqual(x, chol)
# Check that the cholesky is lower triangular, and has positive diagonal
# elements.
if chol_np.shape[-1] > 0:
chol_reshaped = np.reshape(chol_np, (-1, chol_np.shape[-2],
chol_np.shape[-1]))
for chol_matrix in chol_reshaped:
self.assertAllClose(chol_matrix, np.tril(chol_matrix), atol=atol)
self.assertTrue((np.diag(chol_matrix) > 0.0).all())
def _verifyCholesky(self, x, atol=1e-6):
# Verify that LL^T == x.
with self.test_session() as sess:
placeholder = array_ops.placeholder(
dtypes.as_dtype(x.dtype), shape=x.shape)
with self.test_scope():
chol = linalg_ops.cholesky(placeholder)
verification = math_ops.matmul(chol, chol, adjoint_b=True)
self._verifyCholeskyBase(sess, placeholder, x, chol, verification, atol)
def testBasic(self):
data = np.array([[4., -1., 2.], [-1., 6., 0], [2., 0., 5.]])
for dtype in self.float_types:
self._verifyCholesky(data.astype(dtype))
def testBatch(self):
for dtype in self.float_types:
simple_array = np.array(
[[[1., 0.], [0., 5.]]], dtype=dtype) # shape (1, 2, 2)
self._verifyCholesky(simple_array)
self._verifyCholesky(np.vstack((simple_array, simple_array)))
odd_sized_array = np.array(
[[[4., -1., 2.], [-1., 6., 0], [2., 0., 5.]]], dtype=dtype)
self._verifyCholesky(np.vstack((odd_sized_array, odd_sized_array)))
# Generate random positive-definite matrices.
matrices = np.random.rand(10, 5, 5).astype(dtype)
for i in xrange(10):
matrices[i] = np.dot(matrices[i].T, matrices[i])
self._verifyCholesky(matrices, atol=1e-4)
def testNonSquareMatrix(self):
for dtype in self.float_types:
with self.assertRaises(ValueError):
linalg_ops.cholesky(np.array([[1., 2., 3.], [3., 4., 5.]], dtype=dtype))
with self.assertRaises(ValueError):
linalg_ops.cholesky(
np.array(
[[[1., 2., 3.], [3., 4., 5.]], [[1., 2., 3.], [3., 4., 5.]]],
dtype=dtype))
def testWrongDimensions(self):
for dtype in self.float_types:
tensor3 = constant_op.constant([1., 2.], dtype=dtype)
with self.assertRaises(ValueError):
linalg_ops.cholesky(tensor3)
with self.assertRaises(ValueError):
linalg_ops.cholesky(tensor3)
@unittest.skip("Test is slow")
def testLarge(self):
n = 200
shape = (n, n)
data = np.ones(shape).astype(np.float32) / (2.0 * n) + np.diag(
np.ones(n).astype(np.float32))
self._verifyCholesky(data, atol=1e-4)
def testMatrixConditionNumbers(self):
for dtype in self.float_types:
condition_number = 1000
size = 20
# Generate random positive-definite symmetric matrices, and take their
# Eigendecomposition.
matrix = np.random.rand(size, size)
matrix = np.dot(matrix.T, matrix)
_, w = np.linalg.eigh(matrix)
# Build new Eigenvalues exponentially distributed between 1 and
# 1/condition_number
v = np.exp(-np.log(condition_number) * np.linspace(0, size, size) / size)
matrix = np.dot(np.dot(w, np.diag(v)), w.T).astype(dtype)
self._verifyCholesky(matrix, atol=1e-4)
if __name__ == "__main__":
test.main()
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