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Paddle/python/paddle/vision/models/mobilenetv1.py

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# Copyright (c) 2020 PaddlePaddle 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.
import paddle
import paddle.nn as nn
from paddle.utils.download import get_weights_path_from_url
__all__ = ['MobileNetV1', 'mobilenet_v1']
model_urls = {
'mobilenetv1_1.0':
('https://paddle-hapi.bj.bcebos.com/models/mobilenet_v1_x1.0.pdparams',
'42a154c2f26f86e7457d6daded114e8c')
}
class ConvBNLayer(nn.Layer):
def __init__(self,
in_channels,
out_channels,
kernel_size,
stride,
padding,
num_groups=1):
super(ConvBNLayer, self).__init__()
self._conv = nn.Conv2D(
in_channels,
out_channels,
kernel_size,
stride=stride,
padding=padding,
groups=num_groups,
bias_attr=False)
self._norm_layer = nn.BatchNorm2D(out_channels)
self._act = nn.ReLU()
def forward(self, x):
x = self._conv(x)
x = self._norm_layer(x)
x = self._act(x)
return x
class DepthwiseSeparable(nn.Layer):
def __init__(self, in_channels, out_channels1, out_channels2, num_groups,
stride, scale):
super(DepthwiseSeparable, self).__init__()
self._depthwise_conv = ConvBNLayer(
in_channels,
int(out_channels1 * scale),
kernel_size=3,
stride=stride,
padding=1,
num_groups=int(num_groups * scale))
self._pointwise_conv = ConvBNLayer(
int(out_channels1 * scale),
int(out_channels2 * scale),
kernel_size=1,
stride=1,
padding=0)
def forward(self, x):
x = self._depthwise_conv(x)
x = self._pointwise_conv(x)
return x
class MobileNetV1(nn.Layer):
"""MobileNetV1 model from
`"MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications" <https://arxiv.org/abs/1704.04861>`_.
Args:
scale (float): scale of channels in each layer. Default: 1.0.
num_classes (int): output dim of last fc layer. If num_classes <=0, last fc layer
will not be defined. Default: 1000.
with_pool (bool): use pool before the last fc layer or not. Default: True.
Examples:
.. code-block:: python
from paddle.vision.models import MobileNetV1
model = MobileNetV1()
"""
def __init__(self, scale=1.0, num_classes=1000, with_pool=True):
super(MobileNetV1, self).__init__()
self.scale = scale
self.dwsl = []
self.num_classes = num_classes
self.with_pool = with_pool
self.conv1 = ConvBNLayer(
in_channels=3,
out_channels=int(32 * scale),
kernel_size=3,
stride=2,
padding=1)
dws21 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(32 * scale),
out_channels1=32,
out_channels2=64,
num_groups=32,
stride=1,
scale=scale),
name="conv2_1")
self.dwsl.append(dws21)
dws22 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(64 * scale),
out_channels1=64,
out_channels2=128,
num_groups=64,
stride=2,
scale=scale),
name="conv2_2")
self.dwsl.append(dws22)
dws31 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(128 * scale),
out_channels1=128,
out_channels2=128,
num_groups=128,
stride=1,
scale=scale),
name="conv3_1")
self.dwsl.append(dws31)
dws32 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(128 * scale),
out_channels1=128,
out_channels2=256,
num_groups=128,
stride=2,
scale=scale),
name="conv3_2")
self.dwsl.append(dws32)
dws41 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(256 * scale),
out_channels1=256,
out_channels2=256,
num_groups=256,
stride=1,
scale=scale),
name="conv4_1")
self.dwsl.append(dws41)
dws42 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(256 * scale),
out_channels1=256,
out_channels2=512,
num_groups=256,
stride=2,
scale=scale),
name="conv4_2")
self.dwsl.append(dws42)
for i in range(5):
tmp = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(512 * scale),
out_channels1=512,
out_channels2=512,
num_groups=512,
stride=1,
scale=scale),
name="conv5_" + str(i + 1))
self.dwsl.append(tmp)
dws56 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(512 * scale),
out_channels1=512,
out_channels2=1024,
num_groups=512,
stride=2,
scale=scale),
name="conv5_6")
self.dwsl.append(dws56)
dws6 = self.add_sublayer(
sublayer=DepthwiseSeparable(
in_channels=int(1024 * scale),
out_channels1=1024,
out_channels2=1024,
num_groups=1024,
stride=1,
scale=scale),
name="conv6")
self.dwsl.append(dws6)
if with_pool:
self.pool2d_avg = nn.AdaptiveAvgPool2D(1)
if num_classes > 0:
self.fc = nn.Linear(int(1024 * scale), num_classes)
def forward(self, x):
x = self.conv1(x)
for dws in self.dwsl:
x = dws(x)
if self.with_pool:
x = self.pool2d_avg(x)
if self.num_classes > 0:
x = paddle.flatten(x, 1)
x = self.fc(x)
return x
def _mobilenet(arch, pretrained=False, **kwargs):
model = MobileNetV1(**kwargs)
if pretrained:
assert arch in model_urls, "{} model do not have a pretrained model now, you should set pretrained=False".format(
arch)
weight_path = get_weights_path_from_url(model_urls[arch][0],
model_urls[arch][1])
param = paddle.load(weight_path)
model.load_dict(param)
return model
def mobilenet_v1(pretrained=False, scale=1.0, **kwargs):
"""MobileNetV1
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet. Default: False.
scale: (float): scale of channels in each layer. Default: 1.0.
Examples:
.. code-block:: python
from paddle.vision.models import mobilenet_v1
# build model
model = mobilenet_v1()
# build model and load imagenet pretrained weight
# model = mobilenet_v1(pretrained=True)
# build mobilenet v1 with scale=0.5
model = mobilenet_v1(scale=0.5)
"""
model = _mobilenet(
'mobilenetv1_' + str(scale), pretrained, scale=scale, **kwargs)
return model