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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.
# ==============================================================================
"""Pooling layers."""
import tensorflow.compat.v2 as tf
import functools
from keras import backend
from keras.engine.base_layer import Layer
from keras.engine.input_spec import InputSpec
from keras.utils import conv_utils
from tensorflow.python.util.tf_export import keras_export
class Pooling1D(Layer):
"""Pooling layer for arbitrary pooling functions, for 1D inputs.
This class only exists for code reuse. It will never be an exposed API.
Args:
pool_function: The pooling function to apply, e.g. `tf.nn.max_pool2d`.
pool_size: An integer or tuple/list of a single integer,
representing the size of the pooling window.
strides: An integer or tuple/list of a single integer, specifying the
strides of the pooling operation.
padding: A string. The padding method, either 'valid' or 'same'.
Case-insensitive.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, steps, features)` while `channels_first`
corresponds to inputs with shape
`(batch, features, steps)`.
name: A string, the name of the layer.
"""
def __init__(self, pool_function, pool_size, strides,
padding='valid', data_format='channels_last',
name=None, **kwargs):
super(Pooling1D, self).__init__(name=name, **kwargs)
if data_format is None:
data_format = backend.image_data_format()
if strides is None:
strides = pool_size
self.pool_function = pool_function
self.pool_size = conv_utils.normalize_tuple(pool_size, 1, 'pool_size')
self.strides = conv_utils.normalize_tuple(
strides, 1, 'strides', allow_zero=True)
self.padding = conv_utils.normalize_padding(padding)
self.data_format = conv_utils.normalize_data_format(data_format)
self.input_spec = InputSpec(ndim=3)
def call(self, inputs):
pad_axis = 2 if self.data_format == 'channels_last' else 3
inputs = tf.expand_dims(inputs, pad_axis)
outputs = self.pool_function(
inputs,
self.pool_size + (1,),
strides=self.strides + (1,),
padding=self.padding,
data_format=self.data_format)
return tf.squeeze(outputs, pad_axis)
def compute_output_shape(self, input_shape):
input_shape = tf.TensorShape(input_shape).as_list()
if self.data_format == 'channels_first':
steps = input_shape[2]
features = input_shape[1]
else:
steps = input_shape[1]
features = input_shape[2]
length = conv_utils.conv_output_length(steps,
self.pool_size[0],
self.padding,
self.strides[0])
if self.data_format == 'channels_first':
return tf.TensorShape([input_shape[0], features, length])
else:
return tf.TensorShape([input_shape[0], length, features])
def get_config(self):
config = {
'strides': self.strides,
'pool_size': self.pool_size,
'padding': self.padding,
'data_format': self.data_format,
}
base_config = super(Pooling1D, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
@keras_export('keras.layers.MaxPool1D', 'keras.layers.MaxPooling1D')
class MaxPooling1D(Pooling1D):
"""Max pooling operation for 1D temporal data.
Downsamples the input representation by taking the maximum value over a
spatial window of size `pool_size`. The window is shifted by `strides`. The
resulting output, when using the `"valid"` padding option, has a shape of:
`output_shape = (input_shape - pool_size + 1) / strides)`
The resulting output shape when using the `"same"` padding option is:
`output_shape = input_shape / strides`
For example, for `strides=1` and `padding="valid"`:
>>> x = tf.constant([1., 2., 3., 4., 5.])
>>> x = tf.reshape(x, [1, 5, 1])
>>> max_pool_1d = tf.keras.layers.MaxPooling1D(pool_size=2,
... strides=1, padding='valid')
>>> max_pool_1d(x)
<tf.Tensor: shape=(1, 4, 1), dtype=float32, numpy=
array([[[2.],
[3.],
[4.],
[5.]]], dtype=float32)>
For example, for `strides=2` and `padding="valid"`:
>>> x = tf.constant([1., 2., 3., 4., 5.])
>>> x = tf.reshape(x, [1, 5, 1])
>>> max_pool_1d = tf.keras.layers.MaxPooling1D(pool_size=2,
... strides=2, padding='valid')
>>> max_pool_1d(x)
<tf.Tensor: shape=(1, 2, 1), dtype=float32, numpy=
array([[[2.],
[4.]]], dtype=float32)>
For example, for `strides=1` and `padding="same"`:
>>> x = tf.constant([1., 2., 3., 4., 5.])
>>> x = tf.reshape(x, [1, 5, 1])
>>> max_pool_1d = tf.keras.layers.MaxPooling1D(pool_size=2,
... strides=1, padding='same')
>>> max_pool_1d(x)
<tf.Tensor: shape=(1, 5, 1), dtype=float32, numpy=
array([[[2.],
[3.],
[4.],
[5.],
[5.]]], dtype=float32)>
Args:
pool_size: Integer, size of the max pooling window.
strides: Integer, or None. Specifies how much the pooling window moves
for each pooling step.
If None, it will default to `pool_size`.
padding: One of `"valid"` or `"same"` (case-insensitive).
`"valid"` means no padding. `"same"` results in padding evenly to
the left/right or up/down of the input such that output has the same
height/width dimension as the input.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, steps, features)` while `channels_first`
corresponds to inputs with shape
`(batch, features, steps)`.
Input shape:
- If `data_format='channels_last'`:
3D tensor with shape `(batch_size, steps, features)`.
- If `data_format='channels_first'`:
3D tensor with shape `(batch_size, features, steps)`.
Output shape:
- If `data_format='channels_last'`:
3D tensor with shape `(batch_size, downsampled_steps, features)`.
- If `data_format='channels_first'`:
3D tensor with shape `(batch_size, features, downsampled_steps)`.
"""
def __init__(self, pool_size=2, strides=None,
padding='valid', data_format='channels_last', **kwargs):
super(MaxPooling1D, self).__init__(
functools.partial(backend.pool2d, pool_mode='max'),
pool_size=pool_size,
strides=strides,
padding=padding,
data_format=data_format,
**kwargs)
@keras_export('keras.layers.AveragePooling1D', 'keras.layers.AvgPool1D')
class AveragePooling1D(Pooling1D):
"""Average pooling for temporal data.
Downsamples the input representation by taking the average value over the
window defined by `pool_size`. The window is shifted by `strides`. The
resulting output when using "valid" padding option has a shape of:
`output_shape = (input_shape - pool_size + 1) / strides)`
The resulting output shape when using the "same" padding option is:
`output_shape = input_shape / strides`
For example, for strides=1 and padding="valid":
>>> x = tf.constant([1., 2., 3., 4., 5.])
>>> x = tf.reshape(x, [1, 5, 1])
>>> x
<tf.Tensor: shape=(1, 5, 1), dtype=float32, numpy=
array([[[1.],
[2.],
[3.],
[4.],
[5.]], dtype=float32)>
>>> avg_pool_1d = tf.keras.layers.AveragePooling1D(pool_size=2,
... strides=1, padding='valid')
>>> avg_pool_1d(x)
<tf.Tensor: shape=(1, 4, 1), dtype=float32, numpy=
array([[[1.5],
[2.5],
[3.5],
[4.5]]], dtype=float32)>
For example, for strides=2 and padding="valid":
>>> x = tf.constant([1., 2., 3., 4., 5.])
>>> x = tf.reshape(x, [1, 5, 1])
>>> x
<tf.Tensor: shape=(1, 5, 1), dtype=float32, numpy=
array([[[1.],
[2.],
[3.],
[4.],
[5.]], dtype=float32)>
>>> avg_pool_1d = tf.keras.layers.AveragePooling1D(pool_size=2,
... strides=2, padding='valid')
>>> avg_pool_1d(x)
<tf.Tensor: shape=(1, 2, 1), dtype=float32, numpy=
array([[[1.5],
[3.5]]], dtype=float32)>
For example, for strides=1 and padding="same":
>>> x = tf.constant([1., 2., 3., 4., 5.])
>>> x = tf.reshape(x, [1, 5, 1])
>>> x
<tf.Tensor: shape=(1, 5, 1), dtype=float32, numpy=
array([[[1.],
[2.],
[3.],
[4.],
[5.]], dtype=float32)>
>>> avg_pool_1d = tf.keras.layers.AveragePooling1D(pool_size=2,
... strides=1, padding='same')
>>> avg_pool_1d(x)
<tf.Tensor: shape=(1, 5, 1), dtype=float32, numpy=
array([[[1.5],
[2.5],
[3.5],
[4.5],
[5.]]], dtype=float32)>
Args:
pool_size: Integer, size of the average pooling windows.
strides: Integer, or None. Factor by which to downscale.
E.g. 2 will halve the input.
If None, it will default to `pool_size`.
padding: One of `"valid"` or `"same"` (case-insensitive).
`"valid"` means no padding. `"same"` results in padding evenly to
the left/right or up/down of the input such that output has the same
height/width dimension as the input.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, steps, features)` while `channels_first`
corresponds to inputs with shape
`(batch, features, steps)`.
Input shape:
- If `data_format='channels_last'`:
3D tensor with shape `(batch_size, steps, features)`.
- If `data_format='channels_first'`:
3D tensor with shape `(batch_size, features, steps)`.
Output shape:
- If `data_format='channels_last'`:
3D tensor with shape `(batch_size, downsampled_steps, features)`.
- If `data_format='channels_first'`:
3D tensor with shape `(batch_size, features, downsampled_steps)`.
"""
def __init__(self, pool_size=2, strides=None,
padding='valid', data_format='channels_last', **kwargs):
super(AveragePooling1D, self).__init__(
functools.partial(backend.pool2d, pool_mode='avg'),
pool_size=pool_size,
strides=strides,
padding=padding,
data_format=data_format,
**kwargs)
class Pooling2D(Layer):
"""Pooling layer for arbitrary pooling functions, for 2D inputs (e.g. images).
This class only exists for code reuse. It will never be an exposed API.
Args:
pool_function: The pooling function to apply, e.g. `tf.nn.max_pool2d`.
pool_size: An integer or tuple/list of 2 integers: (pool_height, pool_width)
specifying the size of the pooling window.
Can be a single integer to specify the same value for
all spatial dimensions.
strides: An integer or tuple/list of 2 integers,
specifying the strides of the pooling operation.
Can be a single integer to specify the same value for
all spatial dimensions.
padding: A string. The padding method, either 'valid' or 'same'.
Case-insensitive.
data_format: A string, one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, height, width, channels)` while `channels_first` corresponds to
inputs with shape `(batch, channels, height, width)`.
name: A string, the name of the layer.
"""
def __init__(self, pool_function, pool_size, strides,
padding='valid', data_format=None,
name=None, **kwargs):
super(Pooling2D, self).__init__(name=name, **kwargs)
if data_format is None:
data_format = backend.image_data_format()
if strides is None:
strides = pool_size
self.pool_function = pool_function
self.pool_size = conv_utils.normalize_tuple(pool_size, 2, 'pool_size')
self.strides = conv_utils.normalize_tuple(
strides, 2, 'strides', allow_zero=True)
self.padding = conv_utils.normalize_padding(padding)
self.data_format = conv_utils.normalize_data_format(data_format)
self.input_spec = InputSpec(ndim=4)
def call(self, inputs):
if self.data_format == 'channels_last':
pool_shape = (1,) + self.pool_size + (1,)
strides = (1,) + self.strides + (1,)
else:
pool_shape = (1, 1) + self.pool_size
strides = (1, 1) + self.strides
outputs = self.pool_function(
inputs,
ksize=pool_shape,
strides=strides,
padding=self.padding.upper(),
data_format=conv_utils.convert_data_format(self.data_format, 4))
return outputs
def compute_output_shape(self, input_shape):
input_shape = tf.TensorShape(input_shape).as_list()
if self.data_format == 'channels_first':
rows = input_shape[2]
cols = input_shape[3]
else:
rows = input_shape[1]
cols = input_shape[2]
rows = conv_utils.conv_output_length(rows, self.pool_size[0], self.padding,
self.strides[0])
cols = conv_utils.conv_output_length(cols, self.pool_size[1], self.padding,
self.strides[1])
if self.data_format == 'channels_first':
return tf.TensorShape(
[input_shape[0], input_shape[1], rows, cols])
else:
return tf.TensorShape(
[input_shape[0], rows, cols, input_shape[3]])
def get_config(self):
config = {
'pool_size': self.pool_size,
'padding': self.padding,
'strides': self.strides,
'data_format': self.data_format
}
base_config = super(Pooling2D, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
@keras_export('keras.layers.MaxPool2D', 'keras.layers.MaxPooling2D')
class MaxPooling2D(Pooling2D):
"""Max pooling operation for 2D spatial data.
Downsamples the input along its spatial dimensions (height and width)
by taking the maximum value over an input window
(of size defined by `pool_size`) for each channel of the input.
The window is shifted by `strides` along each dimension.
The resulting output,
when using the `"valid"` padding option, has a spatial shape
(number of rows or columns) of:
`output_shape = math.floor((input_shape - pool_size) / strides) + 1`
(when `input_shape >= pool_size`)
The resulting output shape when using the `"same"` padding option is:
`output_shape = math.floor((input_shape - 1) / strides) + 1`
For example, for `strides=(1, 1)` and `padding="valid"`:
>>> x = tf.constant([[1., 2., 3.],
... [4., 5., 6.],
... [7., 8., 9.]])
>>> x = tf.reshape(x, [1, 3, 3, 1])
>>> max_pool_2d = tf.keras.layers.MaxPooling2D(pool_size=(2, 2),
... strides=(1, 1), padding='valid')
>>> max_pool_2d(x)
<tf.Tensor: shape=(1, 2, 2, 1), dtype=float32, numpy=
array([[[[5.],
[6.]],
[[8.],
[9.]]]], dtype=float32)>
For example, for `strides=(2, 2)` and `padding="valid"`:
>>> x = tf.constant([[1., 2., 3., 4.],
... [5., 6., 7., 8.],
... [9., 10., 11., 12.]])
>>> x = tf.reshape(x, [1, 3, 4, 1])
>>> max_pool_2d = tf.keras.layers.MaxPooling2D(pool_size=(2, 2),
... strides=(2, 2), padding='valid')
>>> max_pool_2d(x)
<tf.Tensor: shape=(1, 1, 2, 1), dtype=float32, numpy=
array([[[[6.],
[8.]]]], dtype=float32)>
Usage Example:
>>> input_image = tf.constant([[[[1.], [1.], [2.], [4.]],
... [[2.], [2.], [3.], [2.]],
... [[4.], [1.], [1.], [1.]],
... [[2.], [2.], [1.], [4.]]]])
>>> output = tf.constant([[[[1], [0]],
... [[0], [1]]]])
>>> model = tf.keras.models.Sequential()
>>> model.add(tf.keras.layers.MaxPooling2D(pool_size=(2, 2),
... input_shape=(4, 4, 1)))
>>> model.compile('adam', 'mean_squared_error')
>>> model.predict(input_image, steps=1)
array([[[[2.],
[4.]],
[[4.],
[4.]]]], dtype=float32)
For example, for stride=(1, 1) and padding="same":
>>> x = tf.constant([[1., 2., 3.],
... [4., 5., 6.],
... [7., 8., 9.]])
>>> x = tf.reshape(x, [1, 3, 3, 1])
>>> max_pool_2d = tf.keras.layers.MaxPooling2D(pool_size=(2, 2),
... strides=(1, 1), padding='same')
>>> max_pool_2d(x)
<tf.Tensor: shape=(1, 3, 3, 1), dtype=float32, numpy=
array([[[[5.],
[6.],
[6.]],
[[8.],
[9.],
[9.]],
[[8.],
[9.],
[9.]]]], dtype=float32)>
Args:
pool_size: integer or tuple of 2 integers,
window size over which to take the maximum.
`(2, 2)` will take the max value over a 2x2 pooling window.
If only one integer is specified, the same window length
will be used for both dimensions.
strides: Integer, tuple of 2 integers, or None.
Strides values. Specifies how far the pooling window moves
for each pooling step. If None, it will default to `pool_size`.
padding: One of `"valid"` or `"same"` (case-insensitive).
`"valid"` means no padding. `"same"` results in padding evenly to
the left/right or up/down of the input such that output has the same
height/width dimension as the input.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, height, width, channels)` while `channels_first`
corresponds to inputs with shape
`(batch, channels, height, width)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
Input shape:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, rows, cols, channels)`.
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, rows, cols)`.
Output shape:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, pooled_rows, pooled_cols, channels)`.
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, pooled_rows, pooled_cols)`.
Returns:
A tensor of rank 4 representing the maximum pooled values. See above for
output shape.
"""
def __init__(self,
pool_size=(2, 2),
strides=None,
padding='valid',
data_format=None,
**kwargs):
super(MaxPooling2D, self).__init__(
tf.compat.v1.nn.max_pool,
pool_size=pool_size, strides=strides,
padding=padding, data_format=data_format, **kwargs)
@keras_export('keras.layers.AveragePooling2D', 'keras.layers.AvgPool2D')
class AveragePooling2D(Pooling2D):
"""Average pooling operation for spatial data.
Downsamples the input along its spatial dimensions (height and width)
by taking the average value over an input window
(of size defined by `pool_size`) for each channel of the input.
The window is shifted by `strides` along each dimension.
The resulting output when using `"valid"` padding option has a shape
(number of rows or columns) of:
`output_shape = math.floor((input_shape - pool_size) / strides) + 1`
(when `input_shape >= pool_size`)
The resulting output shape when using the `"same"` padding option is:
`output_shape = math.floor((input_shape - 1) / strides) + 1`
For example, for `strides=(1, 1)` and `padding="valid"`:
>>> x = tf.constant([[1., 2., 3.],
... [4., 5., 6.],
... [7., 8., 9.]])
>>> x = tf.reshape(x, [1, 3, 3, 1])
>>> avg_pool_2d = tf.keras.layers.AveragePooling2D(pool_size=(2, 2),
... strides=(1, 1), padding='valid')
>>> avg_pool_2d(x)
<tf.Tensor: shape=(1, 2, 2, 1), dtype=float32, numpy=
array([[[[3.],
[4.]],
[[6.],
[7.]]]], dtype=float32)>
For example, for `stride=(2, 2)` and `padding="valid"`:
>>> x = tf.constant([[1., 2., 3., 4.],
... [5., 6., 7., 8.],
... [9., 10., 11., 12.]])
>>> x = tf.reshape(x, [1, 3, 4, 1])
>>> avg_pool_2d = tf.keras.layers.AveragePooling2D(pool_size=(2, 2),
... strides=(2, 2), padding='valid')
>>> avg_pool_2d(x)
<tf.Tensor: shape=(1, 1, 2, 1), dtype=float32, numpy=
array([[[[3.5],
[5.5]]]], dtype=float32)>
For example, for `strides=(1, 1)` and `padding="same"`:
>>> x = tf.constant([[1., 2., 3.],
... [4., 5., 6.],
... [7., 8., 9.]])
>>> x = tf.reshape(x, [1, 3, 3, 1])
>>> avg_pool_2d = tf.keras.layers.AveragePooling2D(pool_size=(2, 2),
... strides=(1, 1), padding='same')
>>> avg_pool_2d(x)
<tf.Tensor: shape=(1, 3, 3, 1), dtype=float32, numpy=
array([[[[3.],
[4.],
[4.5]],
[[6.],
[7.],
[7.5]],
[[7.5],
[8.5],
[9.]]]], dtype=float32)>
Args:
pool_size: integer or tuple of 2 integers,
factors by which to downscale (vertical, horizontal).
`(2, 2)` will halve the input in both spatial dimension.
If only one integer is specified, the same window length
will be used for both dimensions.
strides: Integer, tuple of 2 integers, or None.
Strides values.
If None, it will default to `pool_size`.
padding: One of `"valid"` or `"same"` (case-insensitive).
`"valid"` means no padding. `"same"` results in padding evenly to
the left/right or up/down of the input such that output has the same
height/width dimension as the input.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, height, width, channels)` while `channels_first`
corresponds to inputs with shape
`(batch, channels, height, width)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
Input shape:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, rows, cols, channels)`.
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, rows, cols)`.
Output shape:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, pooled_rows, pooled_cols, channels)`.
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, pooled_rows, pooled_cols)`.
"""
def __init__(self,
pool_size=(2, 2),
strides=None,
padding='valid',
data_format=None,
**kwargs):
super(AveragePooling2D, self).__init__(
tf.nn.avg_pool,
pool_size=pool_size, strides=strides,
padding=padding, data_format=data_format, **kwargs)
class Pooling3D(Layer):
"""Pooling layer for arbitrary pooling functions, for 3D inputs.
This class only exists for code reuse. It will never be an exposed API.
Args:
pool_function: The pooling function to apply, e.g. `tf.nn.max_pool2d`.
pool_size: An integer or tuple/list of 3 integers:
(pool_depth, pool_height, pool_width)
specifying the size of the pooling window.
Can be a single integer to specify the same value for
all spatial dimensions.
strides: An integer or tuple/list of 3 integers,
specifying the strides of the pooling operation.
Can be a single integer to specify the same value for
all spatial dimensions.
padding: A string. The padding method, either 'valid' or 'same'.
Case-insensitive.
data_format: A string, one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, depth, height, width, channels)`
while `channels_first` corresponds to
inputs with shape `(batch, channels, depth, height, width)`.
name: A string, the name of the layer.
"""
def __init__(self, pool_function, pool_size, strides,
padding='valid', data_format='channels_last',
name=None, **kwargs):
super(Pooling3D, self).__init__(name=name, **kwargs)
if data_format is None:
data_format = backend.image_data_format()
if strides is None:
strides = pool_size
self.pool_function = pool_function
self.pool_size = conv_utils.normalize_tuple(pool_size, 3, 'pool_size')
self.strides = conv_utils.normalize_tuple(
strides, 3, 'strides', allow_zero=True)
self.padding = conv_utils.normalize_padding(padding)
self.data_format = conv_utils.normalize_data_format(data_format)
self.input_spec = InputSpec(ndim=5)
def call(self, inputs):
pool_shape = (1,) + self.pool_size + (1,)
strides = (1,) + self.strides + (1,)
if self.data_format == 'channels_first':
# TF does not support `channels_first` with 3D pooling operations,
# so we must handle this case manually.
# TODO(fchollet): remove this when TF pooling is feature-complete.
inputs = tf.transpose(inputs, (0, 2, 3, 4, 1))
outputs = self.pool_function(
inputs,
ksize=pool_shape,
strides=strides,
padding=self.padding.upper())
if self.data_format == 'channels_first':
outputs = tf.transpose(outputs, (0, 4, 1, 2, 3))
return outputs
def compute_output_shape(self, input_shape):
input_shape = tf.TensorShape(input_shape).as_list()
if self.data_format == 'channels_first':
len_dim1 = input_shape[2]
len_dim2 = input_shape[3]
len_dim3 = input_shape[4]
else:
len_dim1 = input_shape[1]
len_dim2 = input_shape[2]
len_dim3 = input_shape[3]
len_dim1 = conv_utils.conv_output_length(len_dim1, self.pool_size[0],
self.padding, self.strides[0])
len_dim2 = conv_utils.conv_output_length(len_dim2, self.pool_size[1],
self.padding, self.strides[1])
len_dim3 = conv_utils.conv_output_length(len_dim3, self.pool_size[2],
self.padding, self.strides[2])
if self.data_format == 'channels_first':
return tf.TensorShape(
[input_shape[0], input_shape[1], len_dim1, len_dim2, len_dim3])
else:
return tf.TensorShape(
[input_shape[0], len_dim1, len_dim2, len_dim3, input_shape[4]])
def get_config(self):
config = {
'pool_size': self.pool_size,
'padding': self.padding,
'strides': self.strides,
'data_format': self.data_format
}
base_config = super(Pooling3D, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
@keras_export('keras.layers.MaxPool3D', 'keras.layers.MaxPooling3D')
class MaxPooling3D(Pooling3D):
"""Max pooling operation for 3D data (spatial or spatio-temporal).
Downsamples the input along its spatial dimensions (depth, height, and width)
by taking the maximum value over an input window
(of size defined by `pool_size`) for each channel of the input.
The window is shifted by `strides` along each dimension.
Args:
pool_size: Tuple of 3 integers,
factors by which to downscale (dim1, dim2, dim3).
`(2, 2, 2)` will halve the size of the 3D input in each dimension.
strides: tuple of 3 integers, or None. Strides values.
padding: One of `"valid"` or `"same"` (case-insensitive).
`"valid"` means no padding. `"same"` results in padding evenly to
the left/right or up/down of the input such that output has the same
height/width dimension as the input.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
while `channels_first` corresponds to inputs with shape
`(batch, channels, spatial_dim1, spatial_dim2, spatial_dim3)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
Input shape:
- If `data_format='channels_last'`:
5D tensor with shape:
`(batch_size, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
- If `data_format='channels_first'`:
5D tensor with shape:
`(batch_size, channels, spatial_dim1, spatial_dim2, spatial_dim3)`
Output shape:
- If `data_format='channels_last'`:
5D tensor with shape:
`(batch_size, pooled_dim1, pooled_dim2, pooled_dim3, channels)`
- If `data_format='channels_first'`:
5D tensor with shape:
`(batch_size, channels, pooled_dim1, pooled_dim2, pooled_dim3)`
Example:
```python
depth = 30
height = 30
width = 30
input_channels = 3
inputs = tf.keras.Input(shape=(depth, height, width, input_channels))
layer = tf.keras.layers.MaxPooling3D(pool_size=3)
outputs = layer(inputs) # Shape: (batch_size, 10, 10, 10, 3)
```
"""
def __init__(self,
pool_size=(2, 2, 2),
strides=None,
padding='valid',
data_format=None,
**kwargs):
super(MaxPooling3D, self).__init__(
tf.nn.max_pool3d,
pool_size=pool_size, strides=strides,
padding=padding, data_format=data_format, **kwargs)
@keras_export('keras.layers.AveragePooling3D', 'keras.layers.AvgPool3D')
class AveragePooling3D(Pooling3D):
"""Average pooling operation for 3D data (spatial or spatio-temporal).
Downsamples the input along its spatial dimensions (depth, height, and width)
by taking the average value over an input window
(of size defined by `pool_size`) for each channel of the input.
The window is shifted by `strides` along each dimension.
Args:
pool_size: tuple of 3 integers,
factors by which to downscale (dim1, dim2, dim3).
`(2, 2, 2)` will halve the size of the 3D input in each dimension.
strides: tuple of 3 integers, or None. Strides values.
padding: One of `"valid"` or `"same"` (case-insensitive).
`"valid"` means no padding. `"same"` results in padding evenly to
the left/right or up/down of the input such that output has the same
height/width dimension as the input.
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
while `channels_first` corresponds to inputs with shape
`(batch, channels, spatial_dim1, spatial_dim2, spatial_dim3)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
Input shape:
- If `data_format='channels_last'`:
5D tensor with shape:
`(batch_size, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
- If `data_format='channels_first'`:
5D tensor with shape:
`(batch_size, channels, spatial_dim1, spatial_dim2, spatial_dim3)`
Output shape:
- If `data_format='channels_last'`:
5D tensor with shape:
`(batch_size, pooled_dim1, pooled_dim2, pooled_dim3, channels)`
- If `data_format='channels_first'`:
5D tensor with shape:
`(batch_size, channels, pooled_dim1, pooled_dim2, pooled_dim3)`
Example:
```python
depth = 30
height = 30
width = 30
input_channels = 3
inputs = tf.keras.Input(shape=(depth, height, width, input_channels))
layer = tf.keras.layers.AveragePooling3D(pool_size=3)
outputs = layer(inputs) # Shape: (batch_size, 10, 10, 10, 3)
```
"""
def __init__(self,
pool_size=(2, 2, 2),
strides=None,
padding='valid',
data_format=None,
**kwargs):
super(AveragePooling3D, self).__init__(
tf.nn.avg_pool3d,
pool_size=pool_size, strides=strides,
padding=padding, data_format=data_format, **kwargs)
class GlobalPooling1D(Layer):
"""Abstract class for different global pooling 1D layers."""
def __init__(self, data_format='channels_last', keepdims=False, **kwargs):
super(GlobalPooling1D, self).__init__(**kwargs)
self.input_spec = InputSpec(ndim=3)
self.data_format = conv_utils.normalize_data_format(data_format)
self.keepdims = keepdims
def compute_output_shape(self, input_shape):
input_shape = tf.TensorShape(input_shape).as_list()
if self.data_format == 'channels_first':
if self.keepdims:
return tf.TensorShape([input_shape[0], input_shape[1], 1])
else:
return tf.TensorShape([input_shape[0], input_shape[1]])
else:
if self.keepdims:
return tf.TensorShape([input_shape[0], 1, input_shape[2]])
else:
return tf.TensorShape([input_shape[0], input_shape[2]])
def call(self, inputs):
raise NotImplementedError
def get_config(self):
config = {'data_format': self.data_format, 'keepdims': self.keepdims}
base_config = super(GlobalPooling1D, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
@keras_export('keras.layers.GlobalAveragePooling1D',
'keras.layers.GlobalAvgPool1D')
class GlobalAveragePooling1D(GlobalPooling1D):
"""Global average pooling operation for temporal data.
Examples:
>>> input_shape = (2, 3, 4)
>>> x = tf.random.normal(input_shape)
>>> y = tf.keras.layers.GlobalAveragePooling1D()(x)
>>> print(y.shape)
(2, 4)
Args:
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, steps, features)` while `channels_first`
corresponds to inputs with shape
`(batch, features, steps)`.
keepdims: A boolean, whether to keep the temporal dimension or not.
If `keepdims` is `False` (default), the rank of the tensor is reduced
for spatial dimensions.
If `keepdims` is `True`, the temporal dimension are retained with
length 1.
The behavior is the same as for `tf.reduce_mean` or `np.mean`.
Call arguments:
inputs: A 3D tensor.
mask: Binary tensor of shape `(batch_size, steps)` indicating whether
a given step should be masked (excluded from the average).
Input shape:
- If `data_format='channels_last'`:
3D tensor with shape:
`(batch_size, steps, features)`
- If `data_format='channels_first'`:
3D tensor with shape:
`(batch_size, features, steps)`
Output shape:
- If `keepdims`=False:
2D tensor with shape `(batch_size, features)`.
- If `keepdims`=True:
- If `data_format='channels_last'`:
3D tensor with shape `(batch_size, 1, features)`
- If `data_format='channels_first'`:
3D tensor with shape `(batch_size, features, 1)`
"""
def __init__(self, data_format='channels_last', **kwargs):
super(GlobalAveragePooling1D, self).__init__(data_format=data_format,
**kwargs)
self.supports_masking = True
def call(self, inputs, mask=None):
steps_axis = 1 if self.data_format == 'channels_last' else 2
if mask is not None:
mask = tf.cast(mask, inputs[0].dtype)
mask = tf.expand_dims(
mask, 2 if self.data_format == 'channels_last' else 1)
inputs *= mask
return backend.sum(
inputs, axis=steps_axis,
keepdims=self.keepdims) / tf.reduce_sum(
mask, axis=steps_axis, keepdims=self.keepdims)
else:
return backend.mean(inputs, axis=steps_axis, keepdims=self.keepdims)
def compute_mask(self, inputs, mask=None):
return None
@keras_export('keras.layers.GlobalMaxPool1D', 'keras.layers.GlobalMaxPooling1D')
class GlobalMaxPooling1D(GlobalPooling1D):
"""Global max pooling operation for 1D temporal data.
Downsamples the input representation by taking the maximum value over
the time dimension.
For example:
>>> x = tf.constant([[1., 2., 3.], [4., 5., 6.], [7., 8., 9.]])
>>> x = tf.reshape(x, [3, 3, 1])
>>> x
<tf.Tensor: shape=(3, 3, 1), dtype=float32, numpy=
array([[[1.], [2.], [3.]],
[[4.], [5.], [6.]],
[[7.], [8.], [9.]]], dtype=float32)>
>>> max_pool_1d = tf.keras.layers.GlobalMaxPooling1D()
>>> max_pool_1d(x)
<tf.Tensor: shape=(3, 1), dtype=float32, numpy=
array([[3.],
[6.],
[9.], dtype=float32)>
Args:
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, steps, features)` while `channels_first`
corresponds to inputs with shape
`(batch, features, steps)`.
keepdims: A boolean, whether to keep the temporal dimension or not.
If `keepdims` is `False` (default), the rank of the tensor is reduced
for spatial dimensions.
If `keepdims` is `True`, the temporal dimension are retained with
length 1.
The behavior is the same as for `tf.reduce_max` or `np.max`.
Input shape:
- If `data_format='channels_last'`:
3D tensor with shape:
`(batch_size, steps, features)`
- If `data_format='channels_first'`:
3D tensor with shape:
`(batch_size, features, steps)`
Output shape:
- If `keepdims`=False:
2D tensor with shape `(batch_size, features)`.
- If `keepdims`=True:
- If `data_format='channels_last'`:
3D tensor with shape `(batch_size, 1, features)`
- If `data_format='channels_first'`:
3D tensor with shape `(batch_size, features, 1)`
"""
def call(self, inputs):
steps_axis = 1 if self.data_format == 'channels_last' else 2
return backend.max(inputs, axis=steps_axis, keepdims=self.keepdims)
class GlobalPooling2D(Layer):
"""Abstract class for different global pooling 2D layers.
"""
def __init__(self, data_format=None, keepdims=False, **kwargs):
super(GlobalPooling2D, self).__init__(**kwargs)
self.data_format = conv_utils.normalize_data_format(data_format)
self.input_spec = InputSpec(ndim=4)
self.keepdims = keepdims
def compute_output_shape(self, input_shape):
input_shape = tf.TensorShape(input_shape).as_list()
if self.data_format == 'channels_last':
if self.keepdims:
return tf.TensorShape([input_shape[0], 1, 1, input_shape[3]])
else:
return tf.TensorShape([input_shape[0], input_shape[3]])
else:
if self.keepdims:
return tf.TensorShape([input_shape[0], input_shape[1], 1, 1])
else:
return tf.TensorShape([input_shape[0], input_shape[1]])
def call(self, inputs):
raise NotImplementedError
def get_config(self):
config = {'data_format': self.data_format, 'keepdims': self.keepdims}
base_config = super(GlobalPooling2D, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
@keras_export('keras.layers.GlobalAveragePooling2D',
'keras.layers.GlobalAvgPool2D')
class GlobalAveragePooling2D(GlobalPooling2D):
"""Global average pooling operation for spatial data.
Examples:
>>> input_shape = (2, 4, 5, 3)
>>> x = tf.random.normal(input_shape)
>>> y = tf.keras.layers.GlobalAveragePooling2D()(x)
>>> print(y.shape)
(2, 3)
Args:
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, height, width, channels)` while `channels_first`
corresponds to inputs with shape
`(batch, channels, height, width)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
keepdims: A boolean, whether to keep the spatial dimensions or not.
If `keepdims` is `False` (default), the rank of the tensor is reduced
for spatial dimensions.
If `keepdims` is `True`, the spatial dimensions are retained with
length 1.
The behavior is the same as for `tf.reduce_mean` or `np.mean`.
Input shape:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, rows, cols, channels)`.
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, rows, cols)`.
Output shape:
- If `keepdims`=False:
2D tensor with shape `(batch_size, channels)`.
- If `keepdims`=True:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, 1, 1, channels)`
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, 1, 1)`
"""
def call(self, inputs):
if self.data_format == 'channels_last':
return backend.mean(inputs, axis=[1, 2], keepdims=self.keepdims)
else:
return backend.mean(inputs, axis=[2, 3], keepdims=self.keepdims)
@keras_export('keras.layers.GlobalMaxPool2D', 'keras.layers.GlobalMaxPooling2D')
class GlobalMaxPooling2D(GlobalPooling2D):
"""Global max pooling operation for spatial data.
Examples:
>>> input_shape = (2, 4, 5, 3)
>>> x = tf.random.normal(input_shape)
>>> y = tf.keras.layers.GlobalMaxPool2D()(x)
>>> print(y.shape)
(2, 3)
Args:
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, height, width, channels)` while `channels_first`
corresponds to inputs with shape
`(batch, channels, height, width)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
keepdims: A boolean, whether to keep the spatial dimensions or not.
If `keepdims` is `False` (default), the rank of the tensor is reduced
for spatial dimensions.
If `keepdims` is `True`, the spatial dimensions are retained with
length 1.
The behavior is the same as for `tf.reduce_max` or `np.max`.
Input shape:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, rows, cols, channels)`.
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, rows, cols)`.
Output shape:
- If `keepdims`=False:
2D tensor with shape `(batch_size, channels)`.
- If `keepdims`=True:
- If `data_format='channels_last'`:
4D tensor with shape `(batch_size, 1, 1, channels)`
- If `data_format='channels_first'`:
4D tensor with shape `(batch_size, channels, 1, 1)`
"""
def call(self, inputs):
if self.data_format == 'channels_last':
return backend.max(inputs, axis=[1, 2], keepdims=self.keepdims)
else:
return backend.max(inputs, axis=[2, 3], keepdims=self.keepdims)
class GlobalPooling3D(Layer):
"""Abstract class for different global pooling 3D layers."""
def __init__(self, data_format=None, keepdims=False, **kwargs):
super(GlobalPooling3D, self).__init__(**kwargs)
self.data_format = conv_utils.normalize_data_format(data_format)
self.input_spec = InputSpec(ndim=5)
self.keepdims = keepdims
def compute_output_shape(self, input_shape):
input_shape = tf.TensorShape(input_shape).as_list()
if self.data_format == 'channels_last':
if self.keepdims:
return tf.TensorShape(
[input_shape[0], 1, 1, 1, input_shape[4]])
else:
return tf.TensorShape([input_shape[0], input_shape[4]])
else:
if self.keepdims:
return tf.TensorShape(
[input_shape[0], input_shape[1], 1, 1, 1])
else:
return tf.TensorShape([input_shape[0], input_shape[1]])
def call(self, inputs):
raise NotImplementedError
def get_config(self):
config = {'data_format': self.data_format, 'keepdims': self.keepdims}
base_config = super(GlobalPooling3D, self).get_config()
return dict(list(base_config.items()) + list(config.items()))
@keras_export('keras.layers.GlobalAveragePooling3D',
'keras.layers.GlobalAvgPool3D')
class GlobalAveragePooling3D(GlobalPooling3D):
"""Global Average pooling operation for 3D data.
Args:
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
while `channels_first` corresponds to inputs with shape
`(batch, channels, spatial_dim1, spatial_dim2, spatial_dim3)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
keepdims: A boolean, whether to keep the spatial dimensions or not.
If `keepdims` is `False` (default), the rank of the tensor is reduced
for spatial dimensions.
If `keepdims` is `True`, the spatial dimensions are retained with
length 1.
The behavior is the same as for `tf.reduce_mean` or `np.mean`.
Input shape:
- If `data_format='channels_last'`:
5D tensor with shape:
`(batch_size, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
- If `data_format='channels_first'`:
5D tensor with shape:
`(batch_size, channels, spatial_dim1, spatial_dim2, spatial_dim3)`
Output shape:
- If `keepdims`=False:
2D tensor with shape `(batch_size, channels)`.
- If `keepdims`=True:
- If `data_format='channels_last'`:
5D tensor with shape `(batch_size, 1, 1, 1, channels)`
- If `data_format='channels_first'`:
5D tensor with shape `(batch_size, channels, 1, 1, 1)`
"""
def call(self, inputs):
if self.data_format == 'channels_last':
return backend.mean(inputs, axis=[1, 2, 3], keepdims=self.keepdims)
else:
return backend.mean(inputs, axis=[2, 3, 4], keepdims=self.keepdims)
@keras_export('keras.layers.GlobalMaxPool3D', 'keras.layers.GlobalMaxPooling3D')
class GlobalMaxPooling3D(GlobalPooling3D):
"""Global Max pooling operation for 3D data.
Args:
data_format: A string,
one of `channels_last` (default) or `channels_first`.
The ordering of the dimensions in the inputs.
`channels_last` corresponds to inputs with shape
`(batch, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
while `channels_first` corresponds to inputs with shape
`(batch, channels, spatial_dim1, spatial_dim2, spatial_dim3)`.
It defaults to the `image_data_format` value found in your
Keras config file at `~/.keras/keras.json`.
If you never set it, then it will be "channels_last".
keepdims: A boolean, whether to keep the spatial dimensions or not.
If `keepdims` is `False` (default), the rank of the tensor is reduced
for spatial dimensions.
If `keepdims` is `True`, the spatial dimensions are retained with
length 1.
The behavior is the same as for `tf.reduce_max` or `np.max`.
Input shape:
- If `data_format='channels_last'`:
5D tensor with shape:
`(batch_size, spatial_dim1, spatial_dim2, spatial_dim3, channels)`
- If `data_format='channels_first'`:
5D tensor with shape:
`(batch_size, channels, spatial_dim1, spatial_dim2, spatial_dim3)`
Output shape:
- If `keepdims`=False:
2D tensor with shape `(batch_size, channels)`.
- If `keepdims`=True:
- If `data_format='channels_last'`:
5D tensor with shape `(batch_size, 1, 1, 1, channels)`
- If `data_format='channels_first'`:
5D tensor with shape `(batch_size, channels, 1, 1, 1)`
"""
def call(self, inputs):
if self.data_format == 'channels_last':
return backend.max(inputs, axis=[1, 2, 3], keepdims=self.keepdims)
else:
return backend.max(inputs, axis=[2, 3, 4], keepdims=self.keepdims)
# Aliases
AvgPool1D = AveragePooling1D
MaxPool1D = MaxPooling1D
AvgPool2D = AveragePooling2D
MaxPool2D = MaxPooling2D
AvgPool3D = AveragePooling3D
MaxPool3D = MaxPooling3D
GlobalMaxPool1D = GlobalMaxPooling1D
GlobalMaxPool2D = GlobalMaxPooling2D
GlobalMaxPool3D = GlobalMaxPooling3D
GlobalAvgPool1D = GlobalAveragePooling1D
GlobalAvgPool2D = GlobalAveragePooling2D
GlobalAvgPool3D = GlobalAveragePooling3D