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# Copyright 2017 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 BatchNorm Bijector."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import numpy as np
from tensorflow.contrib import distributions
from tensorflow.contrib.distributions.python.ops import test_util
from tensorflow.contrib.distributions.python.ops.bijectors.batch_normalization import BatchNormalization
from tensorflow.contrib.distributions.python.ops.bijectors.invert import Invert
from tensorflow.python.framework import constant_op
from tensorflow.python.framework import ops
from tensorflow.python.layers import normalization
from tensorflow.python.ops import array_ops
from tensorflow.python.ops import math_ops
from tensorflow.python.ops import variables
from tensorflow.python.ops.distributions import normal as normal_lib
from tensorflow.python.ops.distributions import transformed_distribution as transformed_distribution_lib
from tensorflow.python.platform import test
from tensorflow.python.training import adam
class BatchNormTest(test_util.VectorDistributionTestHelpers,
test.TestCase):
def _reduction_axes(self, input_shape, event_dims):
if isinstance(event_dims, int):
event_dims = [event_dims]
ndims = len(input_shape)
# Convert event_dims to non-negative indexing.
event_dims = list(event_dims)
for idx, x in enumerate(event_dims):
if x < 0:
event_dims[idx] = ndims + x
return tuple(i for i in range(ndims) if i not in event_dims)
def testForwardInverse(self):
"""Tests forward and backward passes with different event shapes.
input_shape: Tuple of shapes for input tensor.
event_dims: Tuple of dimension indices that will be normalized.
training: Boolean of whether bijector runs in training or inference mode.
"""
params = [
((5*2, 4), [-1], False),
((5, 2, 4), [-1], False),
((5, 2, 4), [1, 2], False),
((5, 2, 4), [0, 1], False),
((5*2, 4), [-1], True),
((5, 2, 4), [-1], True),
((5, 2, 4), [1, 2], True),
((5, 2, 4), [0, 1], True)
]
for input_shape, event_dims, training in params:
x_ = np.arange(5 * 4 * 2).astype(np.float32).reshape(input_shape)
with self.cached_session() as sess:
x = constant_op.constant(x_)
# When training, memorize the exact mean of the last
# minibatch that it normalized (instead of moving average assignment).
layer = normalization.BatchNormalization(
axis=event_dims, momentum=0., epsilon=0.)
batch_norm = BatchNormalization(
batchnorm_layer=layer, training=training)
# Minibatch statistics are saved only after norm_x has been computed.
norm_x = batch_norm.inverse(x)
with ops.control_dependencies(batch_norm.batchnorm.updates):
moving_mean = array_ops.identity(batch_norm.batchnorm.moving_mean)
moving_var = array_ops.identity(batch_norm.batchnorm.moving_variance)
denorm_x = batch_norm.forward(array_ops.identity(norm_x))
fldj = batch_norm.forward_log_det_jacobian(
x, event_ndims=len(event_dims))
# Use identity to invalidate cache.
ildj = batch_norm.inverse_log_det_jacobian(
array_ops.identity(denorm_x), event_ndims=len(event_dims))
variables.global_variables_initializer().run()
# Update variables.
norm_x_ = sess.run(norm_x)
[
norm_x_,
moving_mean_,
moving_var_,
denorm_x_,
ildj_,
fldj_,
] = sess.run([
norm_x,
moving_mean,
moving_var,
denorm_x,
ildj,
fldj,
])
self.assertEqual("batch_normalization", batch_norm.name)
reduction_axes = self._reduction_axes(input_shape, event_dims)
keepdims = len(event_dims) > 1
expected_batch_mean = np.mean(
x_, axis=reduction_axes, keepdims=keepdims)
expected_batch_var = np.var(x_, axis=reduction_axes, keepdims=keepdims)
if training:
# When training=True, values become normalized across batch dim and
# original values are recovered after de-normalizing.
zeros = np.zeros_like(norm_x_)
self.assertAllClose(np.mean(zeros, axis=reduction_axes),
np.mean(norm_x_, axis=reduction_axes))
self.assertAllClose(expected_batch_mean, moving_mean_)
self.assertAllClose(expected_batch_var, moving_var_)
self.assertAllClose(x_, denorm_x_, atol=1e-5)
# Since moving statistics are set to batch statistics after
# normalization, ildj and -fldj should match.
self.assertAllClose(ildj_, -fldj_)
# ildj is computed with minibatch statistics.
expected_ildj = np.sum(np.log(1.) - .5 * np.log(
expected_batch_var + batch_norm.batchnorm.epsilon))
self.assertAllClose(expected_ildj, ildj_)
else:
# When training=False, moving_mean, moving_var remain at their
# initialized values (0., 1.), resulting in no scale/shift (a small
# shift occurs if epsilon > 0.)
self.assertAllClose(x_, norm_x_)
self.assertAllClose(x_, denorm_x_, atol=1e-5)
# ildj is computed with saved statistics.
expected_ildj = np.sum(
np.log(1.) - .5 * np.log(1. + batch_norm.batchnorm.epsilon))
self.assertAllClose(expected_ildj, ildj_)
def testMaximumLikelihoodTraining(self):
# Test Maximum Likelihood training with default bijector.
with self.cached_session() as sess:
base_dist = distributions.MultivariateNormalDiag(loc=[0., 0.])
batch_norm = BatchNormalization(training=True)
dist = transformed_distribution_lib.TransformedDistribution(
distribution=base_dist,
bijector=batch_norm)
target_dist = distributions.MultivariateNormalDiag(loc=[1., 2.])
target_samples = target_dist.sample(100)
dist_samples = dist.sample(3000)
loss = -math_ops.reduce_mean(dist.log_prob(target_samples))
with ops.control_dependencies(batch_norm.batchnorm.updates):
train_op = adam.AdamOptimizer(1e-2).minimize(loss)
moving_mean = array_ops.identity(batch_norm.batchnorm.moving_mean)
moving_var = array_ops.identity(batch_norm.batchnorm.moving_variance)
variables.global_variables_initializer().run()
for _ in range(3000):
sess.run(train_op)
[
dist_samples_,
moving_mean_,
moving_var_
] = sess.run([
dist_samples,
moving_mean,
moving_var
])
self.assertAllClose([1., 2.], np.mean(dist_samples_, axis=0), atol=5e-2)
self.assertAllClose([1., 2.], moving_mean_, atol=5e-2)
self.assertAllClose([1., 1.], moving_var_, atol=5e-2)
def testLogProb(self):
with self.cached_session() as sess:
layer = normalization.BatchNormalization(epsilon=0.)
batch_norm = BatchNormalization(batchnorm_layer=layer, training=False)
base_dist = distributions.MultivariateNormalDiag(loc=[0., 0.])
dist = transformed_distribution_lib.TransformedDistribution(
distribution=base_dist,
bijector=batch_norm,
validate_args=True)
samples = dist.sample(int(1e5))
# No volume distortion since training=False, bijector is initialized
# to the identity transformation.
base_log_prob = base_dist.log_prob(samples)
dist_log_prob = dist.log_prob(samples)
variables.global_variables_initializer().run()
base_log_prob_, dist_log_prob_ = sess.run([base_log_prob, dist_log_prob])
self.assertAllClose(base_log_prob_, dist_log_prob_)
def testMutuallyConsistent(self):
# BatchNorm bijector is only mutually consistent when training=False.
dims = 4
with self.cached_session() as sess:
layer = normalization.BatchNormalization(epsilon=0.)
batch_norm = BatchNormalization(batchnorm_layer=layer, training=False)
dist = transformed_distribution_lib.TransformedDistribution(
distribution=normal_lib.Normal(loc=0., scale=1.),
bijector=batch_norm,
event_shape=[dims],
validate_args=True)
self.run_test_sample_consistent_log_prob(
sess_run_fn=sess.run,
dist=dist,
num_samples=int(1e5),
radius=2.,
center=0.,
rtol=0.02)
def testInvertMutuallyConsistent(self):
# BatchNorm bijector is only mutually consistent when training=False.
dims = 4
with self.cached_session() as sess:
layer = normalization.BatchNormalization(epsilon=0.)
batch_norm = Invert(
BatchNormalization(batchnorm_layer=layer, training=False))
dist = transformed_distribution_lib.TransformedDistribution(
distribution=normal_lib.Normal(loc=0., scale=1.),
bijector=batch_norm,
event_shape=[dims],
validate_args=True)
self.run_test_sample_consistent_log_prob(
sess_run_fn=sess.run,
dist=dist,
num_samples=int(1e5),
radius=2.,
center=0.,
rtol=0.02)
if __name__ == "__main__":
test.main()
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