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paddlepaddle--paddle/python/paddle/vision/models/densenet.py
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# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
#
# 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.
from __future__ import annotations
import math
from typing import TYPE_CHECKING
from typing_extensions import Unpack
import paddle
from paddle import nn
from paddle.base.param_attr import ParamAttr
from paddle.nn import (
AdaptiveAvgPool2D,
AvgPool2D,
BatchNorm,
Conv2D,
Dropout,
Linear,
MaxPool2D,
)
from paddle.nn.initializer import Uniform
from paddle.utils.download import get_weights_path_from_url
if TYPE_CHECKING:
from typing import Literal, TypedDict
from typing_extensions import NotRequired
from paddle import Tensor
from paddle._typing import Size2
_DenseNetArch = Literal[
"densenet121",
"densenet161",
"densenet169",
"densenet201",
"densenet264",
]
class _DenseNetOptions(TypedDict):
bn_size: NotRequired[int]
dropout: NotRequired[float]
num_classes: NotRequired[int]
with_pool: NotRequired[bool]
__all__ = []
model_urls: dict[str, tuple[str, str]] = {
'densenet121': (
'https://paddle-imagenet-models-name.bj.bcebos.com/dygraph/DenseNet121_pretrained.pdparams',
'db1b239ed80a905290fd8b01d3af08e4',
),
'densenet161': (
'https://paddle-imagenet-models-name.bj.bcebos.com/dygraph/DenseNet161_pretrained.pdparams',
'62158869cb315098bd25ddbfd308a853',
),
'densenet169': (
'https://paddle-imagenet-models-name.bj.bcebos.com/dygraph/DenseNet169_pretrained.pdparams',
'82cc7c635c3f19098c748850efb2d796',
),
'densenet201': (
'https://paddle-imagenet-models-name.bj.bcebos.com/dygraph/DenseNet201_pretrained.pdparams',
'16ca29565a7712329cf9e36e02caaf58',
),
'densenet264': (
'https://paddle-imagenet-models-name.bj.bcebos.com/dygraph/DenseNet264_pretrained.pdparams',
'3270ce516b85370bba88cfdd9f60bff4',
),
}
class BNACConvLayer(nn.Layer):
def __init__(
self,
num_channels: int,
num_filters: int,
filter_size: Size2,
stride: Size2 = 1,
pad: Size2 = 0,
groups: int = 1,
act: str = "relu",
) -> None:
super().__init__()
self._batch_norm = BatchNorm(num_channels, act=act)
self._conv = Conv2D(
in_channels=num_channels,
out_channels=num_filters,
kernel_size=filter_size,
stride=stride,
padding=pad,
groups=groups,
weight_attr=ParamAttr(),
bias_attr=False,
)
def forward(self, input: Tensor) -> Tensor:
y = self._batch_norm(input)
y = self._conv(y)
return y
class DenseLayer(nn.Layer):
dropout: float
def __init__(
self, num_channels: int, growth_rate: int, bn_size: int, dropout: float
) -> None:
super().__init__()
self.dropout = dropout
self.bn_ac_func1 = BNACConvLayer(
num_channels=num_channels,
num_filters=bn_size * growth_rate,
filter_size=1,
pad=0,
stride=1,
)
self.bn_ac_func2 = BNACConvLayer(
num_channels=bn_size * growth_rate,
num_filters=growth_rate,
filter_size=3,
pad=1,
stride=1,
)
if dropout:
self.dropout_func = Dropout(p=dropout, mode="downscale_in_infer")
def forward(self, input: Tensor) -> Tensor:
conv = self.bn_ac_func1(input)
conv = self.bn_ac_func2(conv)
if self.dropout:
conv = self.dropout_func(conv)
conv = paddle.concat([input, conv], axis=1)
return conv
class DenseBlock(nn.Layer):
dropout: float
def __init__(
self,
num_channels: int,
num_layers: int,
bn_size: int,
growth_rate: int,
dropout: float,
name: str | None = None,
) -> None:
super().__init__()
self.dropout = dropout
self.dense_layer_func = []
pre_channel = num_channels
for layer in range(num_layers):
self.dense_layer_func.append(
self.add_sublayer(
f"{name}_{layer + 1}",
DenseLayer(
num_channels=pre_channel,
growth_rate=growth_rate,
bn_size=bn_size,
dropout=dropout,
),
)
)
pre_channel = pre_channel + growth_rate
def forward(self, input: Tensor) -> Tensor:
conv = input
for func in self.dense_layer_func:
conv = func(conv)
return conv
class TransitionLayer(nn.Layer):
def __init__(self, num_channels: int, num_output_features: int) -> None:
super().__init__()
self.conv_ac_func = BNACConvLayer(
num_channels=num_channels,
num_filters=num_output_features,
filter_size=1,
pad=0,
stride=1,
)
self.pool2d_avg = AvgPool2D(kernel_size=2, stride=2, padding=0)
def forward(self, input: Tensor) -> Tensor:
y = self.conv_ac_func(input)
y = self.pool2d_avg(y)
return y
class ConvBNLayer(nn.Layer):
def __init__(
self,
num_channels: int,
num_filters: int,
filter_size: Size2,
stride: Size2 = 1,
pad: Size2 = 0,
groups: int = 1,
act: str = "relu",
) -> None:
super().__init__()
self._conv = Conv2D(
in_channels=num_channels,
out_channels=num_filters,
kernel_size=filter_size,
stride=stride,
padding=pad,
groups=groups,
weight_attr=ParamAttr(),
bias_attr=False,
)
self._batch_norm = BatchNorm(num_filters, act=act)
def forward(self, input: Tensor) -> Tensor:
y = self._conv(input)
y = self._batch_norm(y)
return y
class DenseNet(nn.Layer):
"""DenseNet model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_.
Args:
layers (int, optional): Layers of DenseNet. Default: 121.
bn_size (int, optional): Expansion of growth rate in the middle layer. Default: 4.
dropout (float, optional): Dropout rate. Default: :math:`0.0`.
num_classes (int, optional): Output dim of last fc layer. If num_classes <= 0, last fc layer
will not be defined. Default: 1000.
with_pool (bool, optional): Use pool before the last fc layer or not. Default: True.
Returns:
:ref:`api_paddle_nn_Layer`. An instance of DenseNet model.
Examples:
.. code-block:: pycon
>>> import paddle
>>> from paddle.vision.models import DenseNet
>>> # Build model
>>> densenet = DenseNet()
>>> x = paddle.rand([1, 3, 224, 224])
>>> out = densenet(x)
>>> print(out.shape)
paddle.Size([1, 1000])
"""
num_classes: int
with_pool: bool
def __init__(
self,
layers: int = 121,
bn_size: int = 4,
dropout: float = 0.0,
num_classes: int = 1000,
with_pool: bool = True,
) -> None:
super().__init__()
self.num_classes = num_classes
self.with_pool = with_pool
supported_layers = [121, 161, 169, 201, 264]
assert layers in supported_layers, (
f"supported layers are {supported_layers} but input layer is {layers}"
)
densenet_spec = {
121: (64, 32, [6, 12, 24, 16]),
161: (96, 48, [6, 12, 36, 24]),
169: (64, 32, [6, 12, 32, 32]),
201: (64, 32, [6, 12, 48, 32]),
264: (64, 32, [6, 12, 64, 48]),
}
num_init_features, growth_rate, block_config = densenet_spec[layers]
self.conv1_func = ConvBNLayer(
num_channels=3,
num_filters=num_init_features,
filter_size=7,
stride=2,
pad=3,
act='relu',
)
self.pool2d_max = MaxPool2D(kernel_size=3, stride=2, padding=1)
self.block_config = block_config
self.dense_block_func_list = []
self.transition_func_list = []
pre_num_channels = num_init_features
num_features = num_init_features
for i, num_layers in enumerate(block_config):
self.dense_block_func_list.append(
self.add_sublayer(
f"db_conv_{i + 2}",
DenseBlock(
num_channels=pre_num_channels,
num_layers=num_layers,
bn_size=bn_size,
growth_rate=growth_rate,
dropout=dropout,
name='conv' + str(i + 2),
),
)
)
num_features = num_features + num_layers * growth_rate
pre_num_channels = num_features
if i != len(block_config) - 1:
self.transition_func_list.append(
self.add_sublayer(
f"tr_conv{i + 2}_blk",
TransitionLayer(
num_channels=pre_num_channels,
num_output_features=num_features // 2,
),
)
)
pre_num_channels = num_features // 2
num_features = num_features // 2
self.batch_norm = BatchNorm(num_features, act="relu")
if self.with_pool:
self.pool2d_avg = AdaptiveAvgPool2D(1)
if self.num_classes > 0:
stdv = 1.0 / math.sqrt(num_features * 1.0)
self.out = Linear(
num_features,
num_classes,
weight_attr=ParamAttr(initializer=Uniform(-stdv, stdv)),
bias_attr=ParamAttr(),
)
def forward(self, input: Tensor) -> Tensor:
conv = self.conv1_func(input)
conv = self.pool2d_max(conv)
for i, num_layers in enumerate(self.block_config):
conv = self.dense_block_func_list[i](conv)
if i != len(self.block_config) - 1:
conv = self.transition_func_list[i](conv)
conv = self.batch_norm(conv)
if self.with_pool:
y = self.pool2d_avg(conv)
if self.num_classes > 0:
y = paddle.flatten(y, start_axis=1, stop_axis=-1)
y = self.out(y)
return y
def _densenet(
arch: _DenseNetArch,
layers: int,
pretrained: bool,
**kwargs: Unpack[_DenseNetOptions],
) -> DenseNet:
model = DenseNet(layers=layers, **kwargs)
if pretrained:
assert arch in model_urls, (
f"{arch} model do not have a pretrained model now, you should set pretrained=False"
)
weight_path = get_weights_path_from_url(
model_urls[arch][0], model_urls[arch][1]
)
param = paddle.load(weight_path)
model.set_dict(param)
return model
def densenet121(
pretrained: bool = False, **kwargs: Unpack[_DenseNetOptions]
) -> DenseNet:
"""DenseNet 121-layer model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_.
Args:
pretrained (bool, optional): Whether to load pre-trained weights. If True, returns a model pre-trained
on ImageNet. Default: False.
**kwargs (optional): Additional keyword arguments. For details, please refer to :ref:`DenseNet <api_paddle_vision_models_DenseNet>`.
Returns:
:ref:`api_paddle_nn_Layer`. An instance of DenseNet 121-layer model.
Examples:
.. code-block:: pycon
>>> import paddle
>>> from paddle.vision.models import densenet121
>>> # Build model
>>> model = densenet121()
>>> # Build model and load imagenet pretrained weight
>>> # model = densenet121(pretrained=True)
>>> x = paddle.rand([1, 3, 224, 224])
>>> out = model(x)
>>> print(out.shape)
paddle.Size([1, 1000])
"""
return _densenet('densenet121', 121, pretrained, **kwargs)
def densenet161(
pretrained: bool = False, **kwargs: Unpack[_DenseNetOptions]
) -> DenseNet:
"""DenseNet 161-layer model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_.
Args:
pretrained (bool, optional): Whether to load pre-trained weights. If True, returns a model pre-trained
on ImageNet. Default: False.
**kwargs (optional): Additional keyword arguments. For details, please refer to :ref:`DenseNet <api_paddle_vision_models_DenseNet>`.
Returns:
:ref:`api_paddle_nn_Layer`. An instance of DenseNet 161-layer model.
Examples:
.. code-block:: pycon
>>> import paddle
>>> from paddle.vision.models import densenet161
>>> # Build model
>>> model = densenet161()
>>> # Build model and load imagenet pretrained weight
>>> # model = densenet161(pretrained=True)
>>> x = paddle.rand([1, 3, 224, 224])
>>> out = model(x)
>>> print(out.shape)
paddle.Size([1, 1000])
"""
return _densenet('densenet161', 161, pretrained, **kwargs)
def densenet169(
pretrained: bool = False, **kwargs: Unpack[_DenseNetOptions]
) -> DenseNet:
"""DenseNet 169-layer model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_.
Args:
pretrained (bool, optional): Whether to load pre-trained weights. If True, returns a model pre-trained
on ImageNet. Default: False.
**kwargs (optional): Additional keyword arguments. For details, please refer to :ref:`DenseNet <api_paddle_vision_models_DenseNet>`.
Returns:
:ref:`api_paddle_nn_Layer`. An instance of DenseNet 169-layer model.
Examples:
.. code-block:: pycon
>>> import paddle
>>> from paddle.vision.models import densenet169
>>> # Build model
>>> model = densenet169()
>>> # Build model and load imagenet pretrained weight
>>> # model = densenet169(pretrained=True)
>>> x = paddle.rand([1, 3, 224, 224])
>>> out = model(x)
>>> print(out.shape)
paddle.Size([1, 1000])
"""
return _densenet('densenet169', 169, pretrained, **kwargs)
def densenet201(
pretrained: bool = False, **kwargs: Unpack[_DenseNetOptions]
) -> DenseNet:
"""DenseNet 201-layer model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_.
Args:
pretrained (bool, optional): Whether to load pre-trained weights. If True, returns a model pre-trained
on ImageNet. Default: False.
**kwargs (optional): Additional keyword arguments. For details, please refer to :ref:`DenseNet <api_paddle_vision_models_DenseNet>`.
Returns:
:ref:`api_paddle_nn_Layer`. An instance of DenseNet 201-layer model.
Examples:
.. code-block:: pycon
>>> import paddle
>>> from paddle.vision.models import densenet201
>>> # Build model
>>> model = densenet201()
>>> # Build model and load imagenet pretrained weight
>>> # model = densenet201(pretrained=True)
>>> x = paddle.rand([1, 3, 224, 224])
>>> out = model(x)
>>> print(out.shape)
paddle.Size([1, 1000])
"""
return _densenet('densenet201', 201, pretrained, **kwargs)
def densenet264(
pretrained: bool = False, **kwargs: Unpack[_DenseNetOptions]
) -> DenseNet:
"""DenseNet 264-layer model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`_.
Args:
pretrained (bool, optional): Whether to load pre-trained weights. If True, returns a model pre-trained
on ImageNet. Default: False.
**kwargs (optional): Additional keyword arguments. For details, please refer to :ref:`DenseNet <api_paddle_vision_models_DenseNet>`.
Returns:
:ref:`api_paddle_nn_Layer`. An instance of DenseNet 264-layer model.
Examples:
.. code-block:: pycon
>>> import paddle
>>> from paddle.vision.models import densenet264
>>> # Build model
>>> model = densenet264()
>>> # Build model and load imagenet pretrained weight
>>> # model = densenet264(pretrained=True)
>>> x = paddle.rand([1, 3, 224, 224])
>>> out = model(x)
>>> print(out.shape)
paddle.Size([1, 1000])
"""
return _densenet('densenet264', 264, pretrained, **kwargs)