#!/usr/bin/env python
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"""
Layers blocks definitions.
"""
from functools import partial
from keras.layers import (BatchNormalization, ReLU, Conv2D, DepthwiseConv2D, SeparableConv2D, Dense,
MaxPool2D, GlobalAvgPool2D, LayerNormalization, Dropout, Add,
Conv2DTranspose, Reshape, Conv3D)
from keras.activations import swish
from keras.initializers import TruncatedNormal
from tensorflow_addons.layers import GELU, GroupNormalization
from quantizeml.layers import (Attention, LayerMadNormalization, DepthwiseConv2DTranspose,
ExtractToken)
from .utils import get_params_by_version
def _add_pooling_layer(x, pooling_type, pool_size, padding, layer_base_name):
"""Add a pooling layer in the graph.
From an input tensor 'x', the function returns the output tensor after
a pooling layer defined by 'pooling_type'.
Args:
x (tf.Tensor): the input tensor
pooling_type (str): type of pooling among the following: 'max' or 'global_avg'.
pool_size (int 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.
padding (str): one of "valid" or "same" (case-insensitive).
layer_base_name (str): base name for the pooling layer.
Returns:
tf.Tensor: an output tensor after pooling
"""
if pooling_type == 'max':
return MaxPool2D(pool_size=pool_size,
padding=padding,
name=layer_base_name + '/maxpool')(x)
if pooling_type == 'global_avg':
return GlobalAvgPool2D(name=layer_base_name + '/global_avg')(x)
raise ValueError("'pooling_type' argument must be 'max' or 'global_avg'.")
[docs]def conv_block(inputs,
filters,
kernel_size,
pooling=None,
post_relu_gap=False,
pool_size=(2, 2),
add_batchnorm=False,
relu_activation='ReLU3.75',
**kwargs):
"""Adds a convolutional layer with optional layers in the following order:
max pooling, batch normalization, activation.
Args:
inputs (tf.Tensor): input tensor of shape `(rows, cols, channels)`
filters (int): the dimensionality of the output space
(i.e. the number of output filters in the convolution).
kernel_size (int or tuple of 2 integers): specifying the
height and width of the 2D convolution kernel.
Can be a single integer to specify the same value for
all spatial dimensions.
pooling (str, optional): add a pooling layer of type 'pooling' among the values 'max' or
'global_avg', with pooling size set to pool_size. If 'None', no pooling will be added.
post_relu_gap (bool, optional): when pooling is 'global_avg', indicates if the pooling comes
before or after ReLU activation. Defaults to False.
pool_size (int or tuple of 2 integers, optional): 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.
add_batchnorm (bool, optional): add a BatchNormalization layer
relu_activation (str, optional): the ReLU activation to add to the layer in the form 'ReLUx'
where 'x' is the max_value to use. Set to False to disable activation. Defaults to
'ReLU3.75'.
**kwargs: arguments passed to the keras.Conv2D layer, such as
strides, padding, use_bias, weight_regularizer, etc.
Returns:
tf.Tensor: output tensor of conv2D block.
"""
if 'activation' in kwargs and kwargs['activation']:
raise ValueError("Keyword argument 'activation' in conv_block must be None.")
if 'dilation_rate' in kwargs and kwargs['dilation_rate'] not in [1, [1, 1], (1, 1)]:
raise ValueError("Keyword argument 'dilation_rate' is not supported in conv_block.")
conv_layer = Conv2D(filters, kernel_size, **kwargs)
x = conv_layer(inputs)
if pooling == 'max' or (pooling == 'global_avg' and not post_relu_gap):
x = _add_pooling_layer(x, pooling, pool_size, conv_layer.padding, conv_layer.name)
if add_batchnorm:
x = BatchNormalization(name=conv_layer.name + '/BN')(x)
if relu_activation:
x = act_to_layer(relu_activation, name=conv_layer.name + '/relu')(x)
if post_relu_gap and pooling == 'global_avg':
x = _add_pooling_layer(x, pooling, pool_size, conv_layer.padding, conv_layer.name)
return x
[docs]def separable_conv_block(inputs,
filters,
kernel_size,
strides=1,
padding="same",
use_bias=True,
pooling=None,
post_relu_gap=False,
pool_size=(2, 2),
add_batchnorm=False,
relu_activation='ReLU3.75',
fused=True,
name=None,
kernel_initializer='glorot_uniform',
pointwise_regularizer=None):
"""Adds a separable convolutional layer with optional layers in the
following order: global average pooling, max pooling, batch normalization,
activation.
Args:
inputs (tf.Tensor): input tensor of shape `(height, width, channels)`
filters (int): the dimensionality of the output space
(i.e. the number of output filters in the pointwise convolution).
kernel_size (int or tuple of 2 integers): specifying the
height and width of the 2D convolution window. Can be a single
integer to specify the same value for all spatial dimensions.
strides (int or tuple of 2 integers, optional): strides of the depthwise convolution.
Defaults to 1.
padding (str, optional): padding mode for the depthwise convolution. Defaults to 'same'.
use_bias (bool, optional): whether the layer uses a bias vector. Defaults to True.
pooling (str, optional): add a pooling layer of type 'pooling' among the values 'max', or
'global_avg', with pooling size set to pool_size. If 'None', no pooling will be added.
post_relu_gap (bool, optional): when pooling is 'global_avg', indicates if the pooling comes
before or after ReLU activation. Defaults to False.
pool_size (int or tuple of 2 integers, optional): 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.
add_batchnorm (bool, optional): add a BatchNormalization layer
relu_activation (str, optional): the ReLU activation to add to the layer in the form 'ReLUx'
where 'x' is the max_value to use. Set to False to disable activation. Defaults to
'ReLU3.75'.
fused (bool, optional): If True use a SeparableConv2D layer otherwise use a
DepthwiseConv2D + Conv2D layers. Defaults to True.
name (str, optional): name of the layer. Defaults to None.
kernel_initializer (keras.initializer, optional): initializer for both kernels. Defaults to
'glorot_uniform'.
pointwise_regularizer (keras.regularizers, optional): regularizer function applied to the
pointwise kernel matrix. Defaults to None.
Returns:
tf.Tensor: output tensor of separable conv block.
"""
if name:
dw_name = "dw_" + name
pw_name = "pw_" + name
else:
dw_name = pw_name = None
# if fused set a SeparableConv2D layer
if fused:
sep_conv_layer = SeparableConv2D(filters, kernel_size, strides=strides, padding=padding,
use_bias=use_bias,
depthwise_initializer=kernel_initializer,
pointwise_initializer=kernel_initializer,
pointwise_regularizer=pointwise_regularizer,
name=name)
x = sep_conv_layer(inputs)
main_layer_name = sep_conv_layer.name
# if not fused set a DepthwiseConv2D + Conv2D layer (the Conv2D applies a Pointwise convolution)
else:
depth_conv_layer = DepthwiseConv2D(kernel_size, strides=strides, padding=padding,
use_bias=False,
depthwise_initializer=kernel_initializer,
name=dw_name)
point_conv_layer = Conv2D(filters, (1, 1), use_bias=use_bias, padding='same',
kernel_initializer=kernel_initializer,
kernel_regularizer=pointwise_regularizer,
name=pw_name)
x = depth_conv_layer(inputs)
x = point_conv_layer(x)
main_layer_name = point_conv_layer.name
if pooling == 'max' or (pooling == 'global_avg' and not post_relu_gap):
x = _add_pooling_layer(x, pooling, pool_size, padding, main_layer_name)
if add_batchnorm:
x = BatchNormalization(name=main_layer_name + '/BN')(x)
if relu_activation:
x = act_to_layer(relu_activation, name=main_layer_name + '/relu')(x)
if post_relu_gap and pooling == 'global_avg':
x = _add_pooling_layer(x, pooling, pool_size, padding, main_layer_name)
return x
[docs]def dense_block(inputs,
units,
add_batchnorm=False,
relu_activation='ReLU3.75',
**kwargs):
"""Adds a dense layer with optional layers in the following order:
batch normalization, activation.
Args:
inputs (tf.Tensor): Input tensor of shape `(rows, cols, channels)`
units (int): dimensionality of the output space
add_batchnorm (bool, optional): add a BatchNormalization layer
relu_activation (str, optional): the ReLU activation to add to the layer in the form 'ReLUx'
where 'x' is the max_value to use. Set to False to disable activation. Defaults to
'ReLU3.75'.
**kwargs: arguments passed to the Dense layer, such as
use_bias, kernel_initializer, weight_regularizer, etc.
Returns:
tf.Tensor: output tensor of the dense block.
"""
if 'activation' in kwargs and kwargs['activation']:
raise ValueError("Keyword argument 'activation' in dense_block must be None.")
dense_layer = Dense(units, **kwargs)
x = dense_layer(inputs)
if add_batchnorm:
x = BatchNormalization(name=dense_layer.name + '/BN')(x)
if relu_activation:
x = act_to_layer(relu_activation, name=dense_layer.name + '/relu')(x)
return x
def act_to_layer(act, **kwargs):
""" Get activation layer from string.
This is needed because one cannot serialize a class in layer.get_config, the string is thus
serialized instead.
Args:
act (str): string that values in ['GeLU', 'ReLUx', 'swish'] and that allows to choose from
GeLU, ReLUx or swish activation inside MLP.
Returns:
keras.layers: the activation layer class
"""
if act == 'GeLU':
act_funct = GELU(**kwargs)
elif 'ReLU' in act:
if act == 'ReLU':
max_value = None
else:
try:
max_value = float(act[4:])
except ValueError:
raise ValueError("ReLU must be in the form 'ReLUx', where x is the max-value")
act_funct = ReLU(max_value=max_value, **kwargs)
elif act == 'swish':
act_funct = swish
else:
raise NotImplementedError(
f"act should be in ['GeLU', 'ReLUx', 'swish'] but received {act}.")
return act_funct
def norm_to_layer(norm):
""" Get normalization layer from string.
This is needed because one cannot serialize a class in layer.get_config, the string is thus
serialized instead.
Args:
norm (str): string that values in ['LN', 'GN1', 'BN', 'LMN'] and that allows to choose from
LayerNormalization, GroupNormalization(groups=1, ...), BatchNormalization or
LayerMadNormalization layers respectively in the model.
Returns:
keras.layers: the normalization layer class
"""
if norm == 'LN':
norm_funct = LayerNormalization
elif norm == 'GN1':
norm_funct = partial(GroupNormalization, groups=1)
elif norm == 'BN':
norm_funct = BatchNormalization
elif norm == 'LMN':
norm_funct = LayerMadNormalization
else:
raise NotImplementedError("norm should be in ['LN', 'GN1', 'BN', 'LMN']"
f" but received {norm}.")
return norm_funct
[docs]def mlp_block(inputs, mlp_dim, dropout, name, mlp_act="GeLU"):
""" MLP block definition.
Args:
inputs (tf.Tensor): inputs
mlp_dim (int): number of units in the first dense layer
dropout (float): dropout rate
name (str): used as a base name for the layers in the block
mlp_act (str, optional): string that values in ['GeLU', 'ReLUx', 'swish'] and that allows to
choose from GeLU, ReLUx or swish activation. Defaults to "GeLU".
Returns:
tf.Tensor: MLP block outputs
"""
initializer = {
"kernel_initializer": TruncatedNormal(stddev=0.02),
"bias_initializer": "zeros",
}
x = Dense(
mlp_dim,
name=f"{name}/Dense_0",
**initializer,
)(inputs)
x = act_to_layer(mlp_act, name=f"{name}/activation")(x)
x = Dropout(dropout)(x)
x = Dense(
inputs.shape[-1],
name=f"{name}/Dense_1",
**initializer,
)(x)
outputs = Dropout(dropout)(x)
return outputs
[docs]def multi_head_attention(x, num_heads, hidden_size, name, softmax="softmax"):
"""Multi-head attention block definition.
Args:
x (tf.Tensor): inputs
num_heads (int): the number of attention heads
hidden_size (int): query, key and value dense layers representation size (units)
name (str): used as a base name for the layers in the block
softmax (str, optional): string with values in ['softmax', 'softmax2'] that allows to choose
between softmax and softmax2 activation. Defaults to 'softmax'.
Raises:
ValueError: if hidden_size is not a multiple of num_heads
Returns:
(tf.Tensor, tf.Tensor): block outputs and attention softmaxed scores
"""
if hidden_size % num_heads != 0:
raise ValueError(
f"Embedding dimension = {hidden_size} should be divisible "
f"by number of heads = {num_heads}"
)
initializer = {
"kernel_initializer": TruncatedNormal(stddev=0.02),
"bias_initializer": "zeros",
}
query = Dense(hidden_size, name=f"{name}/query", **initializer)(x)
key = Dense(hidden_size, name=f"{name}/key", **initializer)(x)
value = Dense(hidden_size, name=f"{name}/value", **initializer)(x)
attention, weights = Attention(num_heads=num_heads, softmax=softmax,
name=f"{name}/attention")([query, key, value])
output = Dense(hidden_size, name=f"{name}/out", **initializer)(attention)
return output, weights
[docs]def conv_transpose_block(inputs,
filters,
kernel_size,
add_batchnorm=False,
relu_activation='ReLU8',
**kwargs):
"""Adds a transposed convolutional layer with optional layers in the following order:
batch normalization, activation.
Args:
inputs (tf.Tensor): input tensor of shape `(rows, cols, channels)`
filters (int): the dimensionality of the output space (i.e. the number of output filters in
the convolution).
kernel_size (int or tuple of 2 integers): specifying the height and width of the 2D
convolution kernel. Can be a single integer to specify the same value for all spatial
dimensions.
add_batchnorm (bool, optional): add a BatchNormalization layer. Defaults to False.
relu_activation (str, optional): the ReLU activation to add to the layer in the form 'ReLUx'
where 'x' is the max_value to use. Set to False to disable activation. Defaults to
'ReLU3.75'.
**kwargs: arguments passed to the keras.Conv2DTranspose layer, such as strides, padding,
use_bias, weight_regularizer, etc.
Returns:
tf.Tensor: output tensor of transposed convolution block.
"""
if 'activation' in kwargs and kwargs['activation']:
raise ValueError("Keyword argument 'activation' in conv_transpose_block must be None.")
if 'dilation_rate' in kwargs and kwargs['dilation_rate'] not in [1, [1, 1], (1, 1)]:
raise ValueError("Keyword argument 'dilation_rate' is not supported in "
"conv_transpose_block.")
conv_trans_layer = Conv2DTranspose(filters, kernel_size, **kwargs)
x = conv_trans_layer(inputs)
if add_batchnorm:
x = BatchNormalization(name=conv_trans_layer.name + '/BN')(x)
if relu_activation:
x = act_to_layer(relu_activation, name=conv_trans_layer.name + '/relu')(x)
return x
[docs]def sepconv_transpose_block(inputs,
filters,
kernel_size,
strides=2,
padding='same',
use_bias=True,
add_batchnorm=False,
relu_activation='ReLU3.75',
name=None,
kernel_initializer='glorot_uniform',
pointwise_regularizer=None):
"""Adds a transposed separable convolutional layer with optional layers in the following order:
batch normalization, activation.
The separable operation is made of a DepthwiseConv2DTranspose followed by a pointwise Conv2D.
Args:
inputs (tf.Tensor): input tensor of shape `(rows, cols, channels)`
filters (int): the dimensionality of the output space (i.e. the number of output filters in
the pointwise convolution).
kernel_size (int or tuple of 2 integers): specifying the height and width of the depthwise
transpose kernel. Can be a single integer to specify the same value for all spatial
dimensions.
strides (int or tuple of 2 integers, optional): strides of the transposed depthwise.
Defaults to 2.
padding (str, optional): padding mode for the transposed depthwise. Defaults to 'same'.
use_bias (bool, optional): whether the layer uses a bias vectors. Defaults to True.
add_batchnorm (bool, optional): add a BatchNormalization layer. Defaults to False.
relu_activation (str, optional): the ReLU activation to add to the layer in the form 'ReLUx'
where 'x' is the max_value to use. Set to False to disable activation. Defaults to
'ReLU3.75'.
name (str, optional): name of the layer. Defaults to None.
kernel_initializer (keras.initializer, optional): initializer for both kernels. Defaults to
'glorot_uniform'.
pointwise_regularizer (keras.regularizers, optional): regularizer function applied to the
pointwise kernel matrix. Defaults to None.
Returns:
tf.Tensor: output tensor of transposed separable convolution block.
"""
if name:
dw_name = "dw_" + name
pw_name = "pw_" + name
else:
dw_name, pw_name = None, None
dw_trans_layer = DepthwiseConv2DTranspose(kernel_size,
strides=strides,
padding=padding,
use_bias=use_bias,
depthwise_initializer=kernel_initializer,
name=dw_name)
pw_layer = Conv2D(filters,
kernel_size=1,
padding='valid',
use_bias=use_bias,
kernel_regularizer=pointwise_regularizer,
kernel_initializer=kernel_initializer,
name=pw_name)
x = dw_trans_layer(inputs)
x = pw_layer(x)
if add_batchnorm:
x = BatchNormalization(name=pw_layer.name + '/BN')(x)
if relu_activation:
x = act_to_layer(relu_activation, name=pw_layer.name + '/relu')(x)
return x
[docs]def yolo_head_block(x, num_boxes, classes, filters=1024):
"""Adds the `YOLOv2 detection head <https://arxiv.org/pdf/1612.08242.pdf>`_, at the output
of a model.
Args:
x (:obj:`tf.Tensor`): input tensor of shape `(rows, cols, channels)`.
num_boxes (int): number of boxes.
classes (int): number of classes.
filters (int, optional): number of filters in hidden layers. Defaults to 1024.
Returns:
:obj:`tf.Tensor`: output tensor of yolo detection head block.
Notes:
This block replaces conv layers by separable_conv, to decrease the amount of parameters.
"""
# Model version management
fused, _, relu_activation = get_params_by_version(relu_v2='ReLU7.5')
x = separable_conv_block(x, filters=filters, name='1conv',
kernel_size=(3, 3), padding='same', use_bias=False,
relu_activation=relu_activation, add_batchnorm=True, fused=fused)
x = separable_conv_block(x, filters=filters, name='2conv',
kernel_size=(3, 3), padding='same', use_bias=False,
relu_activation=relu_activation, add_batchnorm=True, fused=fused)
x = separable_conv_block(x, filters=filters, name='3conv',
kernel_size=(3, 3), padding='same', use_bias=False,
relu_activation=relu_activation, add_batchnorm=True, fused=fused)
x = separable_conv_block(x, filters=(num_boxes * (4 + 1 + classes)), name='detection_layer',
kernel_size=(3, 3), padding='same', use_bias=True,
relu_activation=False, add_batchnorm=False, fused=fused)
return x
def vit_extract_feature_map(y, feat_shape, num_non_patch=1):
"""Add a ExtractToken + Reshape layers to convert the plain ViT output into a feature map.
All tokens will be extracted except those considered as class tokens (``num_non_patch``)
Args:
y (:obj:`tf.Tensor`): output of ViT classifier model.
feat_shape (tuple of int): height/width desired output size
num_non_patch (int, optional): number of non-patch tokens to exclude on the final output.
Defaults to 1.
Returns:
:obj:`keras.Model`: ViT with new layers
"""
y = ExtractToken(name="extract_features", token=list(range(num_non_patch, y.shape[1])))(y)
y = Reshape(target_shape=(*feat_shape, y.shape[-1]), name="features")(y)
return y
def conv3d_block(inputs,
filters,
kernel_size,
add_batchnorm=False,
relu_activation='ReLU3.75',
**kwargs):
"""Adds a Conv3D layer with optional layers: batch normalization and activation.
Args:
inputs (tf.Tensor): input tensor
filters (int): the dimensionality of the output space
kernel_size (int or tuple): dimensions of the convolution kernel.
add_batchnorm (bool, optional): add a BatchNormalization layer. Defaults to False.
relu_activation (str, optional): the ReLU activation to add to the layer in the form 'ReLUx'
where 'x' is the max_value to use. Set to False to disable activation. Defaults to
'ReLU3.75'.
**kwargs: arguments passed to the keras.Conv3D layer, such as strides, use_bias, etc.
Returns:
tf.Tensor: output tensor of conv2D block.
"""
if 'activation' in kwargs and kwargs['activation']:
raise ValueError("Keyword argument 'activation' in conv3d_block must be None.")
conv_layer = Conv3D(filters, kernel_size, **kwargs)
x = conv_layer(inputs)
if add_batchnorm:
x = BatchNormalization(name=conv_layer.name + '/BN')(x)
if relu_activation:
x = act_to_layer(relu_activation, name=conv_layer.name + '/relu')(x)
return x
def spatiotemporal_block(inputs, in_channels, med_channels, out_channels, t_kernel_size, t_stride,
t_depthwise, s_depthwise, index):
""" Add a spatiotemporal block to the inputs.
The spatio-temporal block consists of a temporal convolution (potentially separable) followed by
a spatial convolution (potentially separable).
Note that the depthwise layers are implemented as Conv3D with groups=filters because TensorFlow
does not have a DepthwiseConv3D layer.
Args:
inputs (tf.Tensor): input tensor
in_channels (int): input channels
med_channels (int): middle channels (channels after the temporal conv layer)
out_channels (int): output channels (channels after the spatial conv layer)
t_kernel_size (int): the temporal kernel size
t_stride (int): the temporal kernel stride
t_depthwise (bool): whether the temporal layer is dw_separable
s_depthwise (bool): whether the spatial layer is dw_separable
index (int): index of the block
Returns:
tf.Tensor: output tensor of the spatiotemporal block.
"""
if not t_depthwise:
x = conv3d_block(inputs,
med_channels,
(t_kernel_size, 1, 1),
add_batchnorm=True,
relu_activation='ReLU',
strides=(t_stride, 1, 1),
name=f'convt_full_{index}')
else:
# This is a DepthwiseConv3D (groups=filters)
x = conv3d_block(inputs,
in_channels,
(t_kernel_size, 1, 1),
add_batchnorm=True,
relu_activation='ReLU',
strides=(t_stride, 1, 1),
groups=in_channels,
use_bias=False,
name=f'convt_dw_{index}')
x = conv3d_block(x,
med_channels,
(1, 1, 1),
add_batchnorm=True,
relu_activation='ReLU',
name=f'convt_pw_{index}')
if not s_depthwise:
x = conv3d_block(x,
out_channels,
(1, 3, 3),
add_batchnorm=True,
relu_activation='ReLU',
strides=(1, 2, 2),
padding='same',
name=f'convs_full_{index}')
else:
# This is a DepthwiseConv3D (groups=filters)
x = conv3d_block(x,
med_channels,
(1, 3, 3),
add_batchnorm=True,
relu_activation='ReLU',
strides=(1, 2, 2),
padding='same',
groups=med_channels,
use_bias=False,
name=f'convs_dw_{index}')
x = conv3d_block(x,
out_channels,
(1, 1, 1),
add_batchnorm=True,
relu_activation='ReLU',
name=f'convs_pw_{index}')
return x