add mobile resnet

ppgan/models/generators/mobile_resnet.py

+#   Copyright (c) 2020 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.
+import paddle
+import paddle.nn as nn
+import functools
+from ...modules.norm import build_norm_layer
+from .builder import GENERATORS
+
+@GENERATORS.register()
+class MobileResnetGenerator(nn.Layer):
+    def __init__(self,
+                 input_channel,
+                 output_nc,
+                 ngf=64,
+                 norm_type='instance',
+                 use_dropout=False,
+                 n_blocks=9,
+                 padding_type='reflect'):
+        super(MobileResnetGenerator, self).__init__()
+
+        norm_layer = build_norm_layer(norm_type)
+        if type(norm_layer) == functools.partial:
+            use_bias = norm_layer.func == InstanceNorm
+        else:
+            use_bias = norm_layer == InstanceNorm
+
+        self.model = nn.LayerList([
+            nn.ReflectionPad2d([3, 3, 3, 3]),
+            nn.Conv2d(
+                    input_channel,
+                    int(ngf),
+                    kernel_size=7,
+                    padding=0,
+                    bias_attr=use_bias), norm_layer(ngf), nn.ReLU()
+        ])
+
+        n_downsampling = 2
+        for i in range(n_downsampling):
+            mult = 2**i
+            self.model.extend([
+                nn.Conv2d(
+                    ngf * mult,
+                    ngf * mult * 2,
+                    kernel_size=3,
+                    stride=2,
+                    padding=1,
+                    bias_attr=use_bias), norm_layer(ngf * mult * 2), nn.ReLU()
+            ])
+
+        mult = 2**n_downsampling
+
+        for i in range(n_blocks):
+            self.model.extend([
+                MobileResnetBlock(
+                    ngf * mult,
+                    ngf * mult,
+                    padding_type=padding_type,
+                    norm_layer=norm_layer,
+                    use_dropout=use_dropout,
+                    use_bias=use_bias)
+            ])
+
+
+        for i in range(n_downsampling):
+            mult = 2**(n_downsampling - i)
+            output_size = (i + 1) * 128
+            self.model.extend([
+                nn.ConvTranspose2d(
+                    ngf * mult,
+                    int(ngf * mult / 2),
+                    kernel_size=3,
+                    stride=2,
+                    padding=1,
+                    output_padding=1,
+                    bias_attr=use_bias), norm_layer(int(ngf * mult / 2)),
+                nn.ReLU()
+            ])
+
+        self.model.extend([nn.ReflectionPad2d([3, 3, 3, 3])])
+        self.model.extend([nn.Conv2d(ngf, output_nc, kernel_size=7, padding=0)])
+        self.model.extend([nn.Tanh()])
+
+    def forward(self, inputs):
+        y = inputs
+        for sublayer in self.model:
+            y = sublayer(y)
+        return y
+
+
+class MobileResnetBlock(nn.Layer):
+    def __init__(self, in_c, out_c, padding_type, norm_layer, use_dropout,
+                 use_bias):
+        super(MobileResnetBlock, self).__init__()
+        self.padding_type = padding_type
+        self.use_dropout = use_dropout
+        self.conv_block = nn.LayerList([])
+
+        p = 0
+        if self.padding_type == 'reflect':
+            self.conv_block.extend([nn.ReflectionPad2d([1, 1, 1, 1])])
+        elif self.padding_type == 'replicate':
+            self.conv_block.extend([nn.ReplicationPad2d([1, 1, 1, 1])])
+        elif self.padding_type == 'zero':
+            p = 1
+        else:
+            raise NotImplementedError('padding [%s] is not implemented' %
+                                      self.padding_type)
+
+        self.conv_block.extend([
+            SeparableConv2D(
+                num_channels=in_c,
+                num_filters=out_c,
+                filter_size=3,
+                padding=p,
+                stride=1), norm_layer(out_c), nn.ReLU()
+        ])
+
+        self.conv_block.extend([nn.Dropout(0.5)])
+
+        if self.padding_type == 'reflect':
+            self.conv_block.extend([nn.ReflectionPad2d([1, 1, 1, 1])])
+        elif self.padding_type == 'replicate':
+            self.conv_block.extend([nn.ReplicationPad2d([1, 1, 1, 1])])
+        elif self.padding_type == 'zero':
+            p = 1
+        else:
+            raise NotImplementedError('padding [%s] is not implemented' %
+                                      self.padding_type)
+
+        self.conv_block.extend([
+            SeparableConv2D(
+                num_channels=out_c,
+                num_filters=in_c,
+                filter_size=3,
+                padding=p,
+                stride=1), norm_layer(in_c)
+        ])
+
+    def forward(self, inputs):
+        y = inputs
+        for sublayer in self.conv_block:
+            y = sublayer(y)
+        out = inputs + y
+        return out
+
+class SeparableConv2D(nn.Layer):
+    def __init__(self,
+                 num_channels,
+                 num_filters,
+                 filter_size,
+                 stride=1,
+                 padding=0,
+                 norm_layer=InstanceNorm,
+                 use_bias=True,
+                 scale_factor=1,
+                 stddev=0.02):
+        super(SeparableConv2D, self).__init__()
+
+        self.conv = nn.LayerList([
+            nn.Conv2d(
+                in_channels=num_channels,
+                out_channels=num_channels * scale_factor,
+                kernel_size=filter_size,
+                stride=stride,
+                padding=padding,
+                groups=num_channels,
+                weight_attr=paddle.ParamAttr(
+                    initializer=nn.initializer.Normal(
+                        loc=0.0, scale=stddev)),
+                bias_attr=use_bias)
+        ])
+
+        self.conv.extend([norm_layer(num_channels * scale_factor)])
+
+        self.conv.extend([
+            nn.Conv2d(
+                in_channels=num_channels * scale_factor,
+                out_channels=num_filters,
+                kernel_size=1,
+                stride=1,
+                weight_attr=paddle.ParamAttr(
+                    initializer=nn.initializer.Normal(
+                        loc=0.0, scale=stddev)),
+                bias_attr=use_bias)
+        ])
+
+    def forward(self, inputs):
+        for sublayer in self.conv:
+            inputs = sublayer(inputs)
+        return inputs
+