laywerrobot/lib/python3.6/site-packages/tensorflow/python/layers/normalization.py
2020-08-27 21:55:39 +02:00

319 lines
15 KiB
Python

# 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.
# =============================================================================
# pylint: disable=unused-import,g-bad-import-order
"""Contains the normalization layer classes and their functional aliases.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import six
from six.moves import xrange # pylint: disable=redefined-builtin
import numpy as np
from tensorflow.python.keras import layers as keras_layers
from tensorflow.python.layers import base
from tensorflow.python.ops import init_ops
from tensorflow.python.util.tf_export import tf_export
@tf_export('layers.BatchNormalization')
class BatchNormalization(keras_layers.BatchNormalization, base.Layer):
"""Batch Normalization layer from http://arxiv.org/abs/1502.03167.
"Batch Normalization: Accelerating Deep Network Training by Reducing
Internal Covariate Shift"
Sergey Ioffe, Christian Szegedy
Arguments:
axis: An `int` or list of `int`, the axis or axes that should be
normalized, typically the features axis/axes. For instance, after a
`Conv2D` layer with `data_format="channels_first"`, set `axis=1`. If a
list of axes is provided, each axis in `axis` will be normalized
simultaneously. Default is `-1` which uses the last axis. Note: when
using multi-axis batch norm, the `beta`, `gamma`, `moving_mean`, and
`moving_variance` variables are the same rank as the input Tensor, with
dimension size 1 in all reduced (non-axis) dimensions).
momentum: Momentum for the moving average.
epsilon: Small float added to variance to avoid dividing by zero.
center: If True, add offset of `beta` to normalized tensor. If False, `beta`
is ignored.
scale: If True, multiply by `gamma`. If False, `gamma` is
not used. When the next layer is linear (also e.g. `nn.relu`), this can be
disabled since the scaling can be done by the next layer.
beta_initializer: Initializer for the beta weight.
gamma_initializer: Initializer for the gamma weight.
moving_mean_initializer: Initializer for the moving mean.
moving_variance_initializer: Initializer for the moving variance.
beta_regularizer: Optional regularizer for the beta weight.
gamma_regularizer: Optional regularizer for the gamma weight.
beta_constraint: An optional projection function to be applied to the `beta`
weight after being updated by an `Optimizer` (e.g. used to implement
norm constraints or value constraints for layer weights). The function
must take as input the unprojected variable and must return the
projected variable (which must have the same shape). Constraints are
not safe to use when doing asynchronous distributed training.
gamma_constraint: An optional projection function to be applied to the
`gamma` weight after being updated by an `Optimizer`.
renorm: Whether to use Batch Renormalization
(https://arxiv.org/abs/1702.03275). This adds extra variables during
training. The inference is the same for either value of this parameter.
renorm_clipping: A dictionary that may map keys 'rmax', 'rmin', 'dmax' to
scalar `Tensors` used to clip the renorm correction. The correction
`(r, d)` is used as `corrected_value = normalized_value * r + d`, with
`r` clipped to [rmin, rmax], and `d` to [-dmax, dmax]. Missing rmax, rmin,
dmax are set to inf, 0, inf, respectively.
renorm_momentum: Momentum used to update the moving means and standard
deviations with renorm. Unlike `momentum`, this affects training
and should be neither too small (which would add noise) nor too large
(which would give stale estimates). Note that `momentum` is still applied
to get the means and variances for inference.
fused: if `None` or `True`, use a faster, fused implementation if possible.
If `False`, use the system recommended implementation.
trainable: Boolean, if `True` also add variables to the graph collection
`GraphKeys.TRAINABLE_VARIABLES` (see tf.Variable).
virtual_batch_size: An `int`. By default, `virtual_batch_size` is `None`,
which means batch normalization is performed across the whole batch. When
`virtual_batch_size` is not `None`, instead perform "Ghost Batch
Normalization", which creates virtual sub-batches which are each
normalized separately (with shared gamma, beta, and moving statistics).
Must divide the actual batch size during execution.
adjustment: A function taking the `Tensor` containing the (dynamic) shape of
the input tensor and returning a pair (scale, bias) to apply to the
normalized values (before gamma and beta), only during training. For
example, if axis==-1,
`adjustment = lambda shape: (
tf.random_uniform(shape[-1:], 0.93, 1.07),
tf.random_uniform(shape[-1:], -0.1, 0.1))`
will scale the normalized value by up to 7% up or down, then shift the
result by up to 0.1 (with independent scaling and bias for each feature
but shared across all examples), and finally apply gamma and/or beta. If
`None`, no adjustment is applied. Cannot be specified if
virtual_batch_size is specified.
name: A string, the name of the layer.
"""
def __init__(self,
axis=-1,
momentum=0.99,
epsilon=1e-3,
center=True,
scale=True,
beta_initializer=init_ops.zeros_initializer(),
gamma_initializer=init_ops.ones_initializer(),
moving_mean_initializer=init_ops.zeros_initializer(),
moving_variance_initializer=init_ops.ones_initializer(),
beta_regularizer=None,
gamma_regularizer=None,
beta_constraint=None,
gamma_constraint=None,
renorm=False,
renorm_clipping=None,
renorm_momentum=0.99,
fused=None,
trainable=True,
virtual_batch_size=None,
adjustment=None,
name=None,
**kwargs):
super(BatchNormalization, self).__init__(
axis=axis,
momentum=momentum,
epsilon=epsilon,
center=center,
scale=scale,
beta_initializer=beta_initializer,
gamma_initializer=gamma_initializer,
moving_mean_initializer=moving_mean_initializer,
moving_variance_initializer=moving_variance_initializer,
beta_regularizer=beta_regularizer,
gamma_regularizer=gamma_regularizer,
beta_constraint=beta_constraint,
gamma_constraint=gamma_constraint,
renorm=renorm,
renorm_clipping=renorm_clipping,
renorm_momentum=renorm_momentum,
fused=fused,
trainable=trainable,
virtual_batch_size=virtual_batch_size,
adjustment=adjustment,
name=name,
**kwargs)
def call(self, inputs, training=False):
return super(BatchNormalization, self).call(inputs, training=training)
@tf_export('layers.batch_normalization')
def batch_normalization(inputs,
axis=-1,
momentum=0.99,
epsilon=1e-3,
center=True,
scale=True,
beta_initializer=init_ops.zeros_initializer(),
gamma_initializer=init_ops.ones_initializer(),
moving_mean_initializer=init_ops.zeros_initializer(),
moving_variance_initializer=init_ops.ones_initializer(),
beta_regularizer=None,
gamma_regularizer=None,
beta_constraint=None,
gamma_constraint=None,
training=False,
trainable=True,
name=None,
reuse=None,
renorm=False,
renorm_clipping=None,
renorm_momentum=0.99,
fused=None,
virtual_batch_size=None,
adjustment=None):
"""Functional interface for the batch normalization layer.
Reference: http://arxiv.org/abs/1502.03167
"Batch Normalization: Accelerating Deep Network Training by Reducing
Internal Covariate Shift"
Sergey Ioffe, Christian Szegedy
Note: when training, the moving_mean and moving_variance need to be updated.
By default the update ops are placed in `tf.GraphKeys.UPDATE_OPS`, so they
need to be added as a dependency to the `train_op`. Also, be sure to add
any batch_normalization ops before getting the update_ops collection.
Otherwise, update_ops will be empty, and training/inference will not work
properly. For example:
```python
x_norm = tf.layers.batch_normalization(x, training=training)
# ...
update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS)
with tf.control_dependencies(update_ops):
train_op = optimizer.minimize(loss)
```
Arguments:
inputs: Tensor input.
axis: An `int`, the axis that should be normalized (typically the features
axis). For instance, after a `Convolution2D` layer with
`data_format="channels_first"`, set `axis=1` in `BatchNormalization`.
momentum: Momentum for the moving average.
epsilon: Small float added to variance to avoid dividing by zero.
center: If True, add offset of `beta` to normalized tensor. If False, `beta`
is ignored.
scale: If True, multiply by `gamma`. If False, `gamma` is
not used. When the next layer is linear (also e.g. `nn.relu`), this can be
disabled since the scaling can be done by the next layer.
beta_initializer: Initializer for the beta weight.
gamma_initializer: Initializer for the gamma weight.
moving_mean_initializer: Initializer for the moving mean.
moving_variance_initializer: Initializer for the moving variance.
beta_regularizer: Optional regularizer for the beta weight.
gamma_regularizer: Optional regularizer for the gamma weight.
beta_constraint: An optional projection function to be applied to the `beta`
weight after being updated by an `Optimizer` (e.g. used to implement
norm constraints or value constraints for layer weights). The function
must take as input the unprojected variable and must return the
projected variable (which must have the same shape). Constraints are
not safe to use when doing asynchronous distributed training.
gamma_constraint: An optional projection function to be applied to the
`gamma` weight after being updated by an `Optimizer`.
training: Either a Python boolean, or a TensorFlow boolean scalar tensor
(e.g. a placeholder). Whether to return the output in training mode
(normalized with statistics of the current batch) or in inference mode
(normalized with moving statistics). **NOTE**: make sure to set this
parameter correctly, or else your training/inference will not work
properly.
trainable: Boolean, if `True` also add variables to the graph collection
`GraphKeys.TRAINABLE_VARIABLES` (see tf.Variable).
name: String, the name of the layer.
reuse: Boolean, whether to reuse the weights of a previous layer
by the same name.
renorm: Whether to use Batch Renormalization
(https://arxiv.org/abs/1702.03275). This adds extra variables during
training. The inference is the same for either value of this parameter.
renorm_clipping: A dictionary that may map keys 'rmax', 'rmin', 'dmax' to
scalar `Tensors` used to clip the renorm correction. The correction
`(r, d)` is used as `corrected_value = normalized_value * r + d`, with
`r` clipped to [rmin, rmax], and `d` to [-dmax, dmax]. Missing rmax, rmin,
dmax are set to inf, 0, inf, respectively.
renorm_momentum: Momentum used to update the moving means and standard
deviations with renorm. Unlike `momentum`, this affects training
and should be neither too small (which would add noise) nor too large
(which would give stale estimates). Note that `momentum` is still applied
to get the means and variances for inference.
fused: if `None` or `True`, use a faster, fused implementation if possible.
If `False`, use the system recommended implementation.
virtual_batch_size: An `int`. By default, `virtual_batch_size` is `None`,
which means batch normalization is performed across the whole batch. When
`virtual_batch_size` is not `None`, instead perform "Ghost Batch
Normalization", which creates virtual sub-batches which are each
normalized separately (with shared gamma, beta, and moving statistics).
Must divide the actual batch size during execution.
adjustment: A function taking the `Tensor` containing the (dynamic) shape of
the input tensor and returning a pair (scale, bias) to apply to the
normalized values (before gamma and beta), only during training. For
example, if axis==-1,
`adjustment = lambda shape: (
tf.random_uniform(shape[-1:], 0.93, 1.07),
tf.random_uniform(shape[-1:], -0.1, 0.1))`
will scale the normalized value by up to 7% up or down, then shift the
result by up to 0.1 (with independent scaling and bias for each feature
but shared across all examples), and finally apply gamma and/or beta. If
`None`, no adjustment is applied. Cannot be specified if
virtual_batch_size is specified.
Returns:
Output tensor.
Raises:
ValueError: if eager execution is enabled.
"""
layer = BatchNormalization(
axis=axis,
momentum=momentum,
epsilon=epsilon,
center=center,
scale=scale,
beta_initializer=beta_initializer,
gamma_initializer=gamma_initializer,
moving_mean_initializer=moving_mean_initializer,
moving_variance_initializer=moving_variance_initializer,
beta_regularizer=beta_regularizer,
gamma_regularizer=gamma_regularizer,
beta_constraint=beta_constraint,
gamma_constraint=gamma_constraint,
renorm=renorm,
renorm_clipping=renorm_clipping,
renorm_momentum=renorm_momentum,
fused=fused,
trainable=trainable,
virtual_batch_size=virtual_batch_size,
adjustment=adjustment,
name=name,
_reuse=reuse,
_scope=name)
return layer.apply(inputs, training=training)
# Aliases
BatchNorm = BatchNormalization
batch_norm = batch_normalization