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modeling_tf_mobilevit.py
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modeling_tf_mobilevit.py
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# coding=utf-8
# Copyright 2022 Apple Inc. and The HuggingFace Inc. team. 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.
#
# Original license: https://github.com/apple/ml-cvnets/blob/main/LICENSE
""" TensorFlow 2.0 MobileViT model."""
from __future__ import annotations
from typing import Dict, Optional, Tuple, Union
import tensorflow as tf
from ...activations_tf import get_tf_activation
from ...file_utils import (
add_code_sample_docstrings,
add_start_docstrings,
add_start_docstrings_to_model_forward,
replace_return_docstrings,
)
from ...modeling_tf_outputs import (
TFBaseModelOutput,
TFBaseModelOutputWithPooling,
TFImageClassifierOutputWithNoAttention,
TFSemanticSegmenterOutputWithNoAttention,
)
from ...modeling_tf_utils import TFPreTrainedModel, TFSequenceClassificationLoss, keras_serializable, unpack_inputs
from ...tf_utils import shape_list, stable_softmax
from ...utils import logging
from .configuration_mobilevit import MobileViTConfig
logger = logging.get_logger(__name__)
# General docstring
_CONFIG_FOR_DOC = "MobileViTConfig"
# Base docstring
_CHECKPOINT_FOR_DOC = "apple/mobilevit-small"
_EXPECTED_OUTPUT_SHAPE = [1, 640, 8, 8]
# Image classification docstring
_IMAGE_CLASS_CHECKPOINT = "apple/mobilevit-small"
_IMAGE_CLASS_EXPECTED_OUTPUT = "tabby, tabby cat"
TF_MOBILEVIT_PRETRAINED_MODEL_ARCHIVE_LIST = [
"apple/mobilevit-small",
"apple/mobilevit-x-small",
"apple/mobilevit-xx-small",
"apple/deeplabv3-mobilevit-small",
"apple/deeplabv3-mobilevit-x-small",
"apple/deeplabv3-mobilevit-xx-small",
# See all MobileViT models at https://huggingface.co/models?filter=mobilevit
]
def make_divisible(value: int, divisor: int = 8, min_value: Optional[int] = None) -> int:
"""
Ensure that all layers have a channel count that is divisible by `divisor`. This function is taken from the
original TensorFlow repo. It can be seen here:
https://github.com/tensorflow/models/blob/master/research/slim/nets/mobilenet/mobilenet.py
"""
if min_value is None:
min_value = divisor
new_value = max(min_value, int(value + divisor / 2) // divisor * divisor)
# Make sure that round down does not go down by more than 10%.
if new_value < 0.9 * value:
new_value += divisor
return int(new_value)
class TFMobileViTConvLayer(tf.keras.layers.Layer):
def __init__(
self,
config: MobileViTConfig,
in_channels: int,
out_channels: int,
kernel_size: int,
stride: int = 1,
groups: int = 1,
bias: bool = False,
dilation: int = 1,
use_normalization: bool = True,
use_activation: Union[bool, str] = True,
**kwargs,
) -> None:
super().__init__(**kwargs)
logger.warning(
f"\n{self.__class__.__name__} has backpropagation operations that are NOT supported on CPU. If you wish "
"to train/fine-tune this model, you need a GPU or a TPU"
)
padding = int((kernel_size - 1) / 2) * dilation
self.padding = tf.keras.layers.ZeroPadding2D(padding)
if out_channels % groups != 0:
raise ValueError(f"Output channels ({out_channels}) are not divisible by {groups} groups.")
self.convolution = tf.keras.layers.Conv2D(
filters=out_channels,
kernel_size=kernel_size,
strides=stride,
padding="VALID",
dilation_rate=dilation,
groups=groups,
use_bias=bias,
name="convolution",
)
if use_normalization:
self.normalization = tf.keras.layers.BatchNormalization(epsilon=1e-5, momentum=0.1, name="normalization")
else:
self.normalization = None
if use_activation:
if isinstance(use_activation, str):
self.activation = get_tf_activation(use_activation)
elif isinstance(config.hidden_act, str):
self.activation = get_tf_activation(config.hidden_act)
else:
self.activation = config.hidden_act
else:
self.activation = None
self.in_channels = in_channels
self.out_channels = out_channels
def call(self, features: tf.Tensor, training: bool = False) -> tf.Tensor:
padded_features = self.padding(features)
features = self.convolution(padded_features)
if self.normalization is not None:
features = self.normalization(features, training=training)
if self.activation is not None:
features = self.activation(features)
return features
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "convolution", None) is not None:
with tf.name_scope(self.convolution.name):
self.convolution.build([None, None, None, self.in_channels])
if getattr(self, "normalization", None) is not None:
if hasattr(self.normalization, "name"):
with tf.name_scope(self.normalization.name):
self.normalization.build([None, None, None, self.out_channels])
class TFMobileViTInvertedResidual(tf.keras.layers.Layer):
"""
Inverted residual block (MobileNetv2): https://arxiv.org/abs/1801.04381
"""
def __init__(
self, config: MobileViTConfig, in_channels: int, out_channels: int, stride: int, dilation: int = 1, **kwargs
) -> None:
super().__init__(**kwargs)
expanded_channels = make_divisible(int(round(in_channels * config.expand_ratio)), 8)
if stride not in [1, 2]:
raise ValueError(f"Invalid stride {stride}.")
self.use_residual = (stride == 1) and (in_channels == out_channels)
self.expand_1x1 = TFMobileViTConvLayer(
config, in_channels=in_channels, out_channels=expanded_channels, kernel_size=1, name="expand_1x1"
)
self.conv_3x3 = TFMobileViTConvLayer(
config,
in_channels=expanded_channels,
out_channels=expanded_channels,
kernel_size=3,
stride=stride,
groups=expanded_channels,
dilation=dilation,
name="conv_3x3",
)
self.reduce_1x1 = TFMobileViTConvLayer(
config,
in_channels=expanded_channels,
out_channels=out_channels,
kernel_size=1,
use_activation=False,
name="reduce_1x1",
)
def call(self, features: tf.Tensor, training: bool = False) -> tf.Tensor:
residual = features
features = self.expand_1x1(features, training=training)
features = self.conv_3x3(features, training=training)
features = self.reduce_1x1(features, training=training)
return residual + features if self.use_residual else features
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "expand_1x1", None) is not None:
with tf.name_scope(self.expand_1x1.name):
self.expand_1x1.build(None)
if getattr(self, "conv_3x3", None) is not None:
with tf.name_scope(self.conv_3x3.name):
self.conv_3x3.build(None)
if getattr(self, "reduce_1x1", None) is not None:
with tf.name_scope(self.reduce_1x1.name):
self.reduce_1x1.build(None)
class TFMobileViTMobileNetLayer(tf.keras.layers.Layer):
def __init__(
self,
config: MobileViTConfig,
in_channels: int,
out_channels: int,
stride: int = 1,
num_stages: int = 1,
**kwargs,
) -> None:
super().__init__(**kwargs)
self.layers = []
for i in range(num_stages):
layer = TFMobileViTInvertedResidual(
config,
in_channels=in_channels,
out_channels=out_channels,
stride=stride if i == 0 else 1,
name=f"layer.{i}",
)
self.layers.append(layer)
in_channels = out_channels
def call(self, features: tf.Tensor, training: bool = False) -> tf.Tensor:
for layer_module in self.layers:
features = layer_module(features, training=training)
return features
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "layers", None) is not None:
for layer_module in self.layers:
with tf.name_scope(layer_module.name):
layer_module.build(None)
class TFMobileViTSelfAttention(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, **kwargs) -> None:
super().__init__(**kwargs)
if hidden_size % config.num_attention_heads != 0:
raise ValueError(
f"The hidden size {hidden_size,} is not a multiple of the number of attention "
f"heads {config.num_attention_heads}."
)
self.num_attention_heads = config.num_attention_heads
self.attention_head_size = int(hidden_size / config.num_attention_heads)
self.all_head_size = self.num_attention_heads * self.attention_head_size
scale = tf.cast(self.attention_head_size, dtype=tf.float32)
self.scale = tf.math.sqrt(scale)
self.query = tf.keras.layers.Dense(self.all_head_size, use_bias=config.qkv_bias, name="query")
self.key = tf.keras.layers.Dense(self.all_head_size, use_bias=config.qkv_bias, name="key")
self.value = tf.keras.layers.Dense(self.all_head_size, use_bias=config.qkv_bias, name="value")
self.dropout = tf.keras.layers.Dropout(config.attention_probs_dropout_prob)
self.hidden_size = hidden_size
def transpose_for_scores(self, x: tf.Tensor) -> tf.Tensor:
batch_size = tf.shape(x)[0]
x = tf.reshape(x, shape=(batch_size, -1, self.num_attention_heads, self.attention_head_size))
return tf.transpose(x, perm=[0, 2, 1, 3])
def call(self, hidden_states: tf.Tensor, training: bool = False) -> tf.Tensor:
batch_size = tf.shape(hidden_states)[0]
key_layer = self.transpose_for_scores(self.key(hidden_states))
value_layer = self.transpose_for_scores(self.value(hidden_states))
query_layer = self.transpose_for_scores(self.query(hidden_states))
# Take the dot product between "query" and "key" to get the raw attention scores.
attention_scores = tf.matmul(query_layer, key_layer, transpose_b=True)
attention_scores = attention_scores / self.scale
# Normalize the attention scores to probabilities.
attention_probs = stable_softmax(attention_scores, axis=-1)
# This is actually dropping out entire tokens to attend to, which might
# seem a bit unusual, but is taken from the original Transformer paper.
attention_probs = self.dropout(attention_probs, training=training)
context_layer = tf.matmul(attention_probs, value_layer)
context_layer = tf.transpose(context_layer, perm=[0, 2, 1, 3])
context_layer = tf.reshape(context_layer, shape=(batch_size, -1, self.all_head_size))
return context_layer
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "query", None) is not None:
with tf.name_scope(self.query.name):
self.query.build([None, None, self.hidden_size])
if getattr(self, "key", None) is not None:
with tf.name_scope(self.key.name):
self.key.build([None, None, self.hidden_size])
if getattr(self, "value", None) is not None:
with tf.name_scope(self.value.name):
self.value.build([None, None, self.hidden_size])
class TFMobileViTSelfOutput(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, **kwargs) -> None:
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(hidden_size, name="dense")
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
self.hidden_size = hidden_size
def call(self, hidden_states: tf.Tensor, training: bool = False) -> tf.Tensor:
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states, training=training)
return hidden_states
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "dense", None) is not None:
with tf.name_scope(self.dense.name):
self.dense.build([None, None, self.hidden_size])
class TFMobileViTAttention(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, **kwargs) -> None:
super().__init__(**kwargs)
self.attention = TFMobileViTSelfAttention(config, hidden_size, name="attention")
self.dense_output = TFMobileViTSelfOutput(config, hidden_size, name="output")
def prune_heads(self, heads):
raise NotImplementedError
def call(self, hidden_states: tf.Tensor, training: bool = False) -> tf.Tensor:
self_outputs = self.attention(hidden_states, training=training)
attention_output = self.dense_output(self_outputs, training=training)
return attention_output
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "attention", None) is not None:
with tf.name_scope(self.attention.name):
self.attention.build(None)
if getattr(self, "dense_output", None) is not None:
with tf.name_scope(self.dense_output.name):
self.dense_output.build(None)
class TFMobileViTIntermediate(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, intermediate_size: int, **kwargs) -> None:
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(intermediate_size, name="dense")
if isinstance(config.hidden_act, str):
self.intermediate_act_fn = get_tf_activation(config.hidden_act)
else:
self.intermediate_act_fn = config.hidden_act
self.hidden_size = hidden_size
def call(self, hidden_states: tf.Tensor) -> tf.Tensor:
hidden_states = self.dense(hidden_states)
hidden_states = self.intermediate_act_fn(hidden_states)
return hidden_states
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "dense", None) is not None:
with tf.name_scope(self.dense.name):
self.dense.build([None, None, self.hidden_size])
class TFMobileViTOutput(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, intermediate_size: int, **kwargs) -> None:
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(hidden_size, name="dense")
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
self.intermediate_size = intermediate_size
def call(self, hidden_states: tf.Tensor, input_tensor: tf.Tensor, training: bool = False) -> tf.Tensor:
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states, training=training)
hidden_states = hidden_states + input_tensor
return hidden_states
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "dense", None) is not None:
with tf.name_scope(self.dense.name):
self.dense.build([None, None, self.intermediate_size])
class TFMobileViTTransformerLayer(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, intermediate_size: int, **kwargs) -> None:
super().__init__(**kwargs)
self.attention = TFMobileViTAttention(config, hidden_size, name="attention")
self.intermediate = TFMobileViTIntermediate(config, hidden_size, intermediate_size, name="intermediate")
self.mobilevit_output = TFMobileViTOutput(config, hidden_size, intermediate_size, name="output")
self.layernorm_before = tf.keras.layers.LayerNormalization(
epsilon=config.layer_norm_eps, name="layernorm_before"
)
self.layernorm_after = tf.keras.layers.LayerNormalization(
epsilon=config.layer_norm_eps, name="layernorm_after"
)
self.hidden_size = hidden_size
def call(self, hidden_states: tf.Tensor, training: bool = False) -> tf.Tensor:
attention_output = self.attention(self.layernorm_before(hidden_states), training=training)
hidden_states = attention_output + hidden_states
layer_output = self.layernorm_after(hidden_states)
layer_output = self.intermediate(layer_output)
layer_output = self.mobilevit_output(layer_output, hidden_states, training=training)
return layer_output
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "attention", None) is not None:
with tf.name_scope(self.attention.name):
self.attention.build(None)
if getattr(self, "intermediate", None) is not None:
with tf.name_scope(self.intermediate.name):
self.intermediate.build(None)
if getattr(self, "mobilevit_output", None) is not None:
with tf.name_scope(self.mobilevit_output.name):
self.mobilevit_output.build(None)
if getattr(self, "layernorm_before", None) is not None:
with tf.name_scope(self.layernorm_before.name):
self.layernorm_before.build([None, None, self.hidden_size])
if getattr(self, "layernorm_after", None) is not None:
with tf.name_scope(self.layernorm_after.name):
self.layernorm_after.build([None, None, self.hidden_size])
class TFMobileViTTransformer(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, hidden_size: int, num_stages: int, **kwargs) -> None:
super().__init__(**kwargs)
self.layers = []
for i in range(num_stages):
transformer_layer = TFMobileViTTransformerLayer(
config,
hidden_size=hidden_size,
intermediate_size=int(hidden_size * config.mlp_ratio),
name=f"layer.{i}",
)
self.layers.append(transformer_layer)
def call(self, hidden_states: tf.Tensor, training: bool = False) -> tf.Tensor:
for layer_module in self.layers:
hidden_states = layer_module(hidden_states, training=training)
return hidden_states
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "layers", None) is not None:
for layer_module in self.layers:
with tf.name_scope(layer_module.name):
layer_module.build(None)
class TFMobileViTLayer(tf.keras.layers.Layer):
"""
MobileViT block: https://arxiv.org/abs/2110.02178
"""
def __init__(
self,
config: MobileViTConfig,
in_channels: int,
out_channels: int,
stride: int,
hidden_size: int,
num_stages: int,
dilation: int = 1,
**kwargs,
) -> None:
super().__init__(**kwargs)
self.patch_width = config.patch_size
self.patch_height = config.patch_size
if stride == 2:
self.downsampling_layer = TFMobileViTInvertedResidual(
config,
in_channels=in_channels,
out_channels=out_channels,
stride=stride if dilation == 1 else 1,
dilation=dilation // 2 if dilation > 1 else 1,
name="downsampling_layer",
)
in_channels = out_channels
else:
self.downsampling_layer = None
self.conv_kxk = TFMobileViTConvLayer(
config,
in_channels=in_channels,
out_channels=in_channels,
kernel_size=config.conv_kernel_size,
name="conv_kxk",
)
self.conv_1x1 = TFMobileViTConvLayer(
config,
in_channels=in_channels,
out_channels=hidden_size,
kernel_size=1,
use_normalization=False,
use_activation=False,
name="conv_1x1",
)
self.transformer = TFMobileViTTransformer(
config, hidden_size=hidden_size, num_stages=num_stages, name="transformer"
)
self.layernorm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="layernorm")
self.conv_projection = TFMobileViTConvLayer(
config, in_channels=hidden_size, out_channels=in_channels, kernel_size=1, name="conv_projection"
)
self.fusion = TFMobileViTConvLayer(
config,
in_channels=2 * in_channels,
out_channels=in_channels,
kernel_size=config.conv_kernel_size,
name="fusion",
)
self.hidden_size = hidden_size
def unfolding(self, features: tf.Tensor) -> Tuple[tf.Tensor, Dict]:
patch_width, patch_height = self.patch_width, self.patch_height
patch_area = tf.cast(patch_width * patch_height, "int32")
batch_size = tf.shape(features)[0]
orig_height = tf.shape(features)[1]
orig_width = tf.shape(features)[2]
channels = tf.shape(features)[3]
new_height = tf.cast(tf.math.ceil(orig_height / patch_height) * patch_height, "int32")
new_width = tf.cast(tf.math.ceil(orig_width / patch_width) * patch_width, "int32")
interpolate = new_width != orig_width or new_height != orig_height
if interpolate:
# Note: Padding can be done, but then it needs to be handled in attention function.
features = tf.image.resize(features, size=(new_height, new_width), method="bilinear")
# number of patches along width and height
num_patch_width = new_width // patch_width
num_patch_height = new_height // patch_height
num_patches = num_patch_height * num_patch_width
# convert from shape (batch_size, orig_height, orig_width, channels)
# to the shape (batch_size * patch_area, num_patches, channels)
features = tf.transpose(features, [0, 3, 1, 2])
patches = tf.reshape(
features, (batch_size * channels * num_patch_height, patch_height, num_patch_width, patch_width)
)
patches = tf.transpose(patches, [0, 2, 1, 3])
patches = tf.reshape(patches, (batch_size, channels, num_patches, patch_area))
patches = tf.transpose(patches, [0, 3, 2, 1])
patches = tf.reshape(patches, (batch_size * patch_area, num_patches, channels))
info_dict = {
"orig_size": (orig_height, orig_width),
"batch_size": batch_size,
"channels": channels,
"interpolate": interpolate,
"num_patches": num_patches,
"num_patches_width": num_patch_width,
"num_patches_height": num_patch_height,
}
return patches, info_dict
def folding(self, patches: tf.Tensor, info_dict: Dict) -> tf.Tensor:
patch_width, patch_height = self.patch_width, self.patch_height
patch_area = int(patch_width * patch_height)
batch_size = info_dict["batch_size"]
channels = info_dict["channels"]
num_patches = info_dict["num_patches"]
num_patch_height = info_dict["num_patches_height"]
num_patch_width = info_dict["num_patches_width"]
# convert from shape (batch_size * patch_area, num_patches, channels)
# back to shape (batch_size, channels, orig_height, orig_width)
features = tf.reshape(patches, (batch_size, patch_area, num_patches, -1))
features = tf.transpose(features, perm=(0, 3, 2, 1))
features = tf.reshape(
features, (batch_size * channels * num_patch_height, num_patch_width, patch_height, patch_width)
)
features = tf.transpose(features, perm=(0, 2, 1, 3))
features = tf.reshape(
features, (batch_size, channels, num_patch_height * patch_height, num_patch_width * patch_width)
)
features = tf.transpose(features, perm=(0, 2, 3, 1))
if info_dict["interpolate"]:
features = tf.image.resize(features, size=info_dict["orig_size"], method="bilinear")
return features
def call(self, features: tf.Tensor, training: bool = False) -> tf.Tensor:
# reduce spatial dimensions if needed
if self.downsampling_layer:
features = self.downsampling_layer(features, training=training)
residual = features
# local representation
features = self.conv_kxk(features, training=training)
features = self.conv_1x1(features, training=training)
# convert feature map to patches
patches, info_dict = self.unfolding(features)
# learn global representations
patches = self.transformer(patches, training=training)
patches = self.layernorm(patches)
# convert patches back to feature maps
features = self.folding(patches, info_dict)
features = self.conv_projection(features, training=training)
features = self.fusion(tf.concat([residual, features], axis=-1), training=training)
return features
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "conv_kxk", None) is not None:
with tf.name_scope(self.conv_kxk.name):
self.conv_kxk.build(None)
if getattr(self, "conv_1x1", None) is not None:
with tf.name_scope(self.conv_1x1.name):
self.conv_1x1.build(None)
if getattr(self, "transformer", None) is not None:
with tf.name_scope(self.transformer.name):
self.transformer.build(None)
if getattr(self, "layernorm", None) is not None:
with tf.name_scope(self.layernorm.name):
self.layernorm.build([None, None, self.hidden_size])
if getattr(self, "conv_projection", None) is not None:
with tf.name_scope(self.conv_projection.name):
self.conv_projection.build(None)
if getattr(self, "fusion", None) is not None:
with tf.name_scope(self.fusion.name):
self.fusion.build(None)
if getattr(self, "downsampling_layer", None) is not None:
with tf.name_scope(self.downsampling_layer.name):
self.downsampling_layer.build(None)
class TFMobileViTEncoder(tf.keras.layers.Layer):
def __init__(self, config: MobileViTConfig, **kwargs) -> None:
super().__init__(**kwargs)
self.config = config
self.layers = []
# segmentation architectures like DeepLab and PSPNet modify the strides
# of the classification backbones
dilate_layer_4 = dilate_layer_5 = False
if config.output_stride == 8:
dilate_layer_4 = True
dilate_layer_5 = True
elif config.output_stride == 16:
dilate_layer_5 = True
dilation = 1
layer_1 = TFMobileViTMobileNetLayer(
config,
in_channels=config.neck_hidden_sizes[0],
out_channels=config.neck_hidden_sizes[1],
stride=1,
num_stages=1,
name="layer.0",
)
self.layers.append(layer_1)
layer_2 = TFMobileViTMobileNetLayer(
config,
in_channels=config.neck_hidden_sizes[1],
out_channels=config.neck_hidden_sizes[2],
stride=2,
num_stages=3,
name="layer.1",
)
self.layers.append(layer_2)
layer_3 = TFMobileViTLayer(
config,
in_channels=config.neck_hidden_sizes[2],
out_channels=config.neck_hidden_sizes[3],
stride=2,
hidden_size=config.hidden_sizes[0],
num_stages=2,
name="layer.2",
)
self.layers.append(layer_3)
if dilate_layer_4:
dilation *= 2
layer_4 = TFMobileViTLayer(
config,
in_channels=config.neck_hidden_sizes[3],
out_channels=config.neck_hidden_sizes[4],
stride=2,
hidden_size=config.hidden_sizes[1],
num_stages=4,
dilation=dilation,
name="layer.3",
)
self.layers.append(layer_4)
if dilate_layer_5:
dilation *= 2
layer_5 = TFMobileViTLayer(
config,
in_channels=config.neck_hidden_sizes[4],
out_channels=config.neck_hidden_sizes[5],
stride=2,
hidden_size=config.hidden_sizes[2],
num_stages=3,
dilation=dilation,
name="layer.4",
)
self.layers.append(layer_5)
def call(
self,
hidden_states: tf.Tensor,
output_hidden_states: bool = False,
return_dict: bool = True,
training: bool = False,
) -> Union[tuple, TFBaseModelOutput]:
all_hidden_states = () if output_hidden_states else None
for i, layer_module in enumerate(self.layers):
hidden_states = layer_module(hidden_states, training=training)
if output_hidden_states:
all_hidden_states = all_hidden_states + (hidden_states,)
if not return_dict:
return tuple(v for v in [hidden_states, all_hidden_states] if v is not None)
return TFBaseModelOutput(last_hidden_state=hidden_states, hidden_states=all_hidden_states)
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "layers", None) is not None:
for layer_module in self.layers:
with tf.name_scope(layer_module.name):
layer_module.build(None)
@keras_serializable
class TFMobileViTMainLayer(tf.keras.layers.Layer):
config_class = MobileViTConfig
def __init__(self, config: MobileViTConfig, expand_output: bool = True, **kwargs):
super().__init__(**kwargs)
self.config = config
self.expand_output = expand_output
self.conv_stem = TFMobileViTConvLayer(
config,
in_channels=config.num_channels,
out_channels=config.neck_hidden_sizes[0],
kernel_size=3,
stride=2,
name="conv_stem",
)
self.encoder = TFMobileViTEncoder(config, name="encoder")
if self.expand_output:
self.conv_1x1_exp = TFMobileViTConvLayer(
config,
in_channels=config.neck_hidden_sizes[5],
out_channels=config.neck_hidden_sizes[6],
kernel_size=1,
name="conv_1x1_exp",
)
self.pooler = tf.keras.layers.GlobalAveragePooling2D(data_format="channels_first", name="pooler")
def _prune_heads(self, heads_to_prune):
"""
Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer} See base
class PreTrainedModel
"""
raise NotImplementedError
@unpack_inputs
def call(
self,
pixel_values: tf.Tensor | None = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
training: bool = False,
) -> Union[Tuple[tf.Tensor], TFBaseModelOutputWithPooling]:
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
# When running on CPU, `tf.keras.layers.Conv2D` doesn't support `NCHW` format.
# So change the input format from `NCHW` to `NHWC`.
# shape = (batch_size, in_height, in_width, in_channels=num_channels)
pixel_values = tf.transpose(pixel_values, perm=(0, 2, 3, 1))
embedding_output = self.conv_stem(pixel_values, training=training)
encoder_outputs = self.encoder(
embedding_output, output_hidden_states=output_hidden_states, return_dict=return_dict, training=training
)
if self.expand_output:
last_hidden_state = self.conv_1x1_exp(encoder_outputs[0])
# Change to NCHW output format to have uniformity in the modules
last_hidden_state = tf.transpose(last_hidden_state, perm=[0, 3, 1, 2])
# global average pooling: (batch_size, channels, height, width) -> (batch_size, channels)
pooled_output = self.pooler(last_hidden_state)
else:
last_hidden_state = encoder_outputs[0]
# Change to NCHW output format to have uniformity in the modules
last_hidden_state = tf.transpose(last_hidden_state, perm=[0, 3, 1, 2])
pooled_output = None
if not return_dict:
output = (last_hidden_state, pooled_output) if pooled_output is not None else (last_hidden_state,)
# Change to NCHW output format to have uniformity in the modules
if not self.expand_output:
remaining_encoder_outputs = encoder_outputs[1:]
remaining_encoder_outputs = tuple(
[tf.transpose(h, perm=(0, 3, 1, 2)) for h in remaining_encoder_outputs[0]]
)
remaining_encoder_outputs = (remaining_encoder_outputs,)
return output + remaining_encoder_outputs
else:
return output + encoder_outputs[1:]
# Change the other hidden state outputs to NCHW as well
if output_hidden_states:
hidden_states = tuple([tf.transpose(h, perm=(0, 3, 1, 2)) for h in encoder_outputs[1]])
return TFBaseModelOutputWithPooling(
last_hidden_state=last_hidden_state,
pooler_output=pooled_output,
hidden_states=hidden_states if output_hidden_states else encoder_outputs.hidden_states,
)
def build(self, input_shape=None):
if self.built:
return
self.built = True
if getattr(self, "conv_stem", None) is not None:
with tf.name_scope(self.conv_stem.name):
self.conv_stem.build(None)
if getattr(self, "encoder", None) is not None:
with tf.name_scope(self.encoder.name):
self.encoder.build(None)
if getattr(self, "pooler", None) is not None:
with tf.name_scope(self.pooler.name):
self.pooler.build([None, None, None, None])
if getattr(self, "conv_1x1_exp", None) is not None:
with tf.name_scope(self.conv_1x1_exp.name):
self.conv_1x1_exp.build(None)
class TFMobileViTPreTrainedModel(TFPreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = MobileViTConfig
base_model_prefix = "mobilevit"
main_input_name = "pixel_values"
MOBILEVIT_START_DOCSTRING = r"""
This model inherits from [`TFPreTrainedModel`]. Check the superclass documentation for the generic methods the
library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads
etc.)
This model is also a [tf.keras.Model](https://www.tensorflow.org/api_docs/python/tf/keras/Model) subclass. Use it
as a regular TF 2.0 Keras Model and refer to the TF 2.0 documentation for all matter related to general usage and
behavior.
<Tip>
TensorFlow models and layers in `transformers` accept two formats as input:
- having all inputs as keyword arguments (like PyTorch models), or
- having all inputs as a list, tuple or dict in the first positional argument.
The reason the second format is supported is that Keras methods prefer this format when passing inputs to models
and layers. Because of this support, when using methods like `model.fit()` things should "just work" for you - just
pass your inputs and labels in any format that `model.fit()` supports! If, however, you want to use the second
format outside of Keras methods like `fit()` and `predict()`, such as when creating your own layers or models with
the Keras `Functional` API, there are three possibilities you can use to gather all the input Tensors in the first
positional argument:
- a single Tensor with `pixel_values` only and nothing else: `model(pixel_values)`
- a list of varying length with one or several input Tensors IN THE ORDER given in the docstring:
`model([pixel_values, attention_mask])` or `model([pixel_values, attention_mask, token_type_ids])`
- a dictionary with one or several input Tensors associated to the input names given in the docstring:
`model({"pixel_values": pixel_values, "token_type_ids": token_type_ids})`
Note that when creating models and layers with
[subclassing](https://keras.io/guides/making_new_layers_and_models_via_subclassing/) then you don't need to worry
about any of this, as you can just pass inputs like you would to any other Python function!
</Tip>
Parameters:
config ([`MobileViTConfig`]): Model configuration class with all the parameters of the model.
Initializing with a config file does not load the weights associated with the model, only the
configuration. Check out the [`~TFPreTrainedModel.from_pretrained`] method to load the model weights.
"""
MOBILEVIT_INPUTS_DOCSTRING = r"""
Args:
pixel_values (`np.ndarray`, `tf.Tensor`, `List[tf.Tensor]`, `Dict[str, tf.Tensor]` or `Dict[str, np.ndarray]` and each example must have the shape `(batch_size, num_channels, height, width)`):
Pixel values. Pixel values can be obtained using [`AutoImageProcessor`]. See
[`MobileViTImageProcessor.__call__`] for details.
output_hidden_states (`bool`, *optional*):
Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for
more detail. This argument can be used only in eager mode, in graph mode the value in the config will be
used instead.
return_dict (`bool`, *optional*):
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. This argument can be used in
eager mode, in graph mode the value will always be set to True.
"""
@add_start_docstrings(
"The bare MobileViT model outputting raw hidden-states without any specific head on top.",
MOBILEVIT_START_DOCSTRING,
)
class TFMobileViTModel(TFMobileViTPreTrainedModel):
def __init__(self, config: MobileViTConfig, expand_output: bool = True, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.config = config
self.expand_output = expand_output
self.mobilevit = TFMobileViTMainLayer(config, expand_output=expand_output, name="mobilevit")
@unpack_inputs
@add_start_docstrings_to_model_forward(MOBILEVIT_INPUTS_DOCSTRING)
@add_code_sample_docstrings(