def __init__(self, block_fn: str, block_repeats: int, kernel_size: int,
strides: int, expand_ratio: float, in_filters: int,
out_filters: int, is_output: bool, width_scale: float,
depth_scale: float):
self.block_fn = block_fn
self.block_repeats = round_repeats(block_repeats, depth_scale)
self.kernel_size = kernel_size
self.strides = strides
self.expand_ratio = expand_ratio
self.in_filters = nn_layers.round_filters(in_filters, width_scale)
self.out_filters = nn_layers.round_filters(out_filters, width_scale)
self.is_output = is_output
def block_spec_decoder(
specs: Dict[Any, Any],
filter_size_scale: float,
# Set to 1 for mobilenetv1.
divisible_by: int = 8,
finegrain_classification_mode: bool = True):
"""Decodes specs for a block.
Args:
specs: A `dict` specification of block specs of a mobilenet version.
filter_size_scale: A `float` multiplier for the filter size for all
convolution ops. The value must be greater than zero. Typical usage will
be to set this value in (0, 1) to reduce the number of parameters or
computation cost of the model.
divisible_by: An `int` that ensures all inner dimensions are divisible by
this number.
finegrain_classification_mode: If True, the model will keep the last layer
large even for small multipliers, following
https://arxiv.org/abs/1801.04381.
Returns:
A list of `BlockSpec` that defines structure of the base network.
"""
spec_name = specs['spec_name']
block_spec_schema = specs['block_spec_schema']
block_specs = specs['block_specs']
if not block_specs:
raise ValueError(
'The block spec cannot be empty for {} !'.format(spec_name))
if len(block_specs[0]) != len(block_spec_schema):
raise ValueError('The block spec values {} do not match with '
'the schema {}'.format(block_specs[0],
block_spec_schema))
decoded_specs = []
for s in block_specs:
kw_s = dict(zip(block_spec_schema, s))
decoded_specs.append(BlockSpec(**kw_s))
# This adjustment applies to V2 and V3
if (spec_name != 'MobileNetV1' and finegrain_classification_mode
and filter_size_scale < 1.0):
decoded_specs[-1].filters /= filter_size_scale # pytype: disable=annotation-type-mismatch
for ds in decoded_specs:
if ds.filters:
ds.filters = nn_layers.round_filters(filters=ds.filters,
multiplier=filter_size_scale,
divisor=divisible_by,
min_depth=8)
return decoded_specs
def block_spec_decoder(
specs: Dict[Any, Any],
filter_size_scale: float,
divisible_by: int = 8) -> List[BlockSpec]:
"""Decodes specs for a block.
Args:
specs: A `dict` specification of block specs of a mobiledet version.
filter_size_scale: A `float` multiplier for the filter size for all
convolution ops. The value must be greater than zero. Typical usage will
be to set this value in (0, 1) to reduce the number of parameters or
computation cost of the model.
divisible_by: An `int` that ensures all inner dimensions are divisible by
this number.
Returns:
A list of `BlockSpec` that defines structure of the base network.
"""
spec_name = specs['spec_name']
block_spec_schema = specs['block_spec_schema']
block_specs = specs['block_specs']
if not block_specs:
raise ValueError(
'The block spec cannot be empty for {} !'.format(spec_name))
if len(block_specs[0]) != len(block_spec_schema):
raise ValueError('The block spec values {} do not match with '
'the schema {}'.format(block_specs[0], block_spec_schema))
decoded_specs = []
for s in block_specs:
kw_s = dict(zip(block_spec_schema, s))
decoded_specs.append(BlockSpec(**kw_s))
for ds in decoded_specs:
if ds.filters:
ds.filters = nn_layers.round_filters(filters=ds.filters,
multiplier=filter_size_scale,
divisor=divisible_by,
round_down_protect=False,
min_depth=8)
return decoded_specs
def __init__(
self,
model_id: str,
input_specs: tf.keras.layers.InputSpec = layers.InputSpec(
shape=[None, None, None, 3]),
se_ratio: float = 0.0,
stochastic_depth_drop_rate: float = 0.0,
kernel_initializer: str = 'VarianceScaling',
kernel_regularizer: tf.keras.regularizers.Regularizer = None,
bias_regularizer: tf.keras.regularizers.Regularizer = None,
activation: str = 'relu',
use_sync_bn: bool = False,
norm_momentum: float = 0.99,
norm_epsilon: float = 0.001, # pytype: disable=annotation-type-mismatch # typed-keras
**kwargs):
"""Initializes an EfficientNet model.
Args:
model_id: A `str` of model ID of EfficientNet.
input_specs: A `tf.keras.layers.InputSpec` of the input tensor.
se_ratio: A `float` of squeeze and excitation ratio for inverted
bottleneck blocks.
stochastic_depth_drop_rate: A `float` of drop rate for drop connect layer.
kernel_initializer: A `str` for kernel initializer of convolutional
layers.
kernel_regularizer: A `tf.keras.regularizers.Regularizer` object for
Conv2D. Default to None.
bias_regularizer: A `tf.keras.regularizers.Regularizer` object for Conv2D.
Default to None.
activation: A `str` of name of the activation function.
use_sync_bn: If True, use synchronized batch normalization.
norm_momentum: A `float` of normalization momentum for the moving average.
norm_epsilon: A `float` added to variance to avoid dividing by zero.
**kwargs: Additional keyword arguments to be passed.
"""
self._model_id = model_id
self._input_specs = input_specs
self._se_ratio = se_ratio
self._stochastic_depth_drop_rate = stochastic_depth_drop_rate
self._use_sync_bn = use_sync_bn
self._activation = activation
self._kernel_initializer = kernel_initializer
self._norm_momentum = norm_momentum
self._norm_epsilon = norm_epsilon
self._kernel_regularizer = kernel_regularizer
self._bias_regularizer = bias_regularizer
if use_sync_bn:
self._norm = layers.experimental.SyncBatchNormalization
else:
self._norm = layers.BatchNormalization
if tf.keras.backend.image_data_format() == 'channels_last':
bn_axis = -1
else:
bn_axis = 1
# Build EfficientNet.
inputs = tf.keras.Input(shape=input_specs.shape[1:])
width_scale = SCALING_MAP[model_id]['width_scale']
depth_scale = SCALING_MAP[model_id]['depth_scale']
# Build stem.
x = layers.Conv2D(filters=nn_layers.round_filters(32, width_scale),
kernel_size=3,
strides=2,
use_bias=False,
padding='same',
kernel_initializer=self._kernel_initializer,
kernel_regularizer=self._kernel_regularizer,
bias_regularizer=self._bias_regularizer)(inputs)
x = self._norm(axis=bn_axis,
momentum=norm_momentum,
epsilon=norm_epsilon)(x)
x = tf_utils.get_activation(activation)(x)
# Build intermediate blocks.
endpoints = {}
endpoint_level = 2
decoded_specs = block_spec_decoder(EN_B0_BLOCK_SPECS, width_scale,
depth_scale)
for i, specs in enumerate(decoded_specs):
x = self._block_group(inputs=x,
specs=specs,
name='block_group_{}'.format(i))
if specs.is_output:
endpoints[str(endpoint_level)] = x
endpoint_level += 1
# Build output specs for downstream tasks.
self._output_specs = {l: endpoints[l].get_shape() for l in endpoints}
# Build the final conv for classification.
x = layers.Conv2D(filters=nn_layers.round_filters(1280, width_scale),
kernel_size=1,
strides=1,
use_bias=False,
padding='same',
kernel_initializer=self._kernel_initializer,
kernel_regularizer=self._kernel_regularizer,
bias_regularizer=self._bias_regularizer)(x)
x = self._norm(axis=bn_axis,
momentum=norm_momentum,
epsilon=norm_epsilon)(x)
endpoints[str(endpoint_level)] = tf_utils.get_activation(activation)(x)
super(EfficientNet, self).__init__(inputs=inputs,
outputs=endpoints,
**kwargs)