!481 add resnet50

Merge pull request !481 from lvmingfu/r0.5

tutorials/tutorial_code/sample_for_cloud/resnet.py

+# Copyright 2020 Huawei Technologies Co., Ltd
+#
+# 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.
+# ============================================================================
+"""ResNet."""
+import numpy as np
+import mindspore.nn as nn
+from mindspore.ops import operations as P
+from mindspore.common.tensor import Tensor
+
+
+def _weight_variable(shape, factor=0.01):
+    init_value = np.random.randn(*shape).astype(np.float32) * factor
+    return Tensor(init_value)
+
+
+def _conv3x3(in_channel, out_channel, stride=1):
+    weight_shape = (out_channel, in_channel, 3, 3)
+    weight = _weight_variable(weight_shape)
+    return nn.Conv2d(in_channel, out_channel,
+                     kernel_size=3, stride=stride, padding=0, pad_mode='same', weight_init=weight)
+
+
+def _conv1x1(in_channel, out_channel, stride=1):
+    weight_shape = (out_channel, in_channel, 1, 1)
+    weight = _weight_variable(weight_shape)
+    return nn.Conv2d(in_channel, out_channel,
+                     kernel_size=1, stride=stride, padding=0, pad_mode='same', weight_init=weight)
+
+
+def _conv7x7(in_channel, out_channel, stride=1):
+    weight_shape = (out_channel, in_channel, 7, 7)
+    weight = _weight_variable(weight_shape)
+    return nn.Conv2d(in_channel, out_channel,
+                     kernel_size=7, stride=stride, padding=0, pad_mode='same', weight_init=weight)
+
+
+def _bn(channel):
+    return nn.BatchNorm2d(channel, eps=1e-4, momentum=0.9,
+                          gamma_init=1, beta_init=0, moving_mean_init=0, moving_var_init=1)
+
+
+def _bn_last(channel):
+    return nn.BatchNorm2d(channel, eps=1e-4, momentum=0.9,
+                          gamma_init=0, beta_init=0, moving_mean_init=0, moving_var_init=1)
+
+
+def _fc(in_channel, out_channel):
+    weight_shape = (out_channel, in_channel)
+    weight = _weight_variable(weight_shape)
+    return nn.Dense(in_channel, out_channel, has_bias=True, weight_init=weight, bias_init=0)
+
+
+class ResidualBlock(nn.Cell):
+    """
+    ResNet V1 residual block definition.
+
+    Args:
+        in_channel (int): Input channel.
+        out_channel (int): Output channel.
+        stride (int): Stride size for the first convolutional layer. Default: 1.
+
+    Returns:
+        Tensor, output tensor.
+
+    Examples:
+        >>> ResidualBlock(3, 256, stride=2)
+    """
+    expansion = 4
+
+    def __init__(self,
+                 in_channel,
+                 out_channel,
+                 stride=1):
+        super(ResidualBlock, self).__init__()
+
+        channel = out_channel // self.expansion
+        self.conv1 = _conv1x1(in_channel, channel, stride=1)
+        self.bn1 = _bn(channel)
+
+        self.conv2 = _conv3x3(channel, channel, stride=stride)
+        self.bn2 = _bn(channel)
+
+        self.conv3 = _conv1x1(channel, out_channel, stride=1)
+        self.bn3 = _bn_last(out_channel)
+
+        self.relu = nn.ReLU()
+
+        self.down_sample = False
+
+        if stride != 1 or in_channel != out_channel:
+            self.down_sample = True
+        self.down_sample_layer = None
+
+        if self.down_sample:
+            self.down_sample_layer = nn.SequentialCell([_conv1x1(in_channel, out_channel, stride),
+                                                        _bn(out_channel)])
+        self.add = P.TensorAdd()
+
+    def construct(self, x):
+        identity = x
+
+        out = self.conv1(x)
+        out = self.bn1(out)
+        out = self.relu(out)
+
+        out = self.conv2(out)
+        out = self.bn2(out)
+        out = self.relu(out)
+
+        out = self.conv3(out)
+        out = self.bn3(out)
+
+        if self.down_sample:
+            identity = self.down_sample_layer(identity)
+
+        out = self.add(out, identity)
+        out = self.relu(out)
+
+        return out
+
+
+class ResNet(nn.Cell):
+    """
+    ResNet architecture.
+
+    Args:
+        block (Cell): Block for network.
+        layer_nums (list): Numbers of block in different layers.
+        in_channels (list): Input channel in each layer.
+        out_channels (list): Output channel in each layer.
+        strides (list):  Stride size in each layer.
+        num_classes (int): The number of classes that the training images are belonging to.
+    Returns:
+        Tensor, output tensor.
+
+    Examples:
+        >>> ResNet(ResidualBlock,
+        >>>        [3, 4, 6, 3],
+        >>>        [64, 256, 512, 1024],
+        >>>        [256, 512, 1024, 2048],
+        >>>        [1, 2, 2, 2],
+        >>>        10)
+    """
+
+    def __init__(self,
+                 block,
+                 layer_nums,
+                 in_channels,
+                 out_channels,
+                 strides,
+                 num_classes):
+        super(ResNet, self).__init__()
+
+        if not len(layer_nums) == len(in_channels) == len(out_channels) == 4:
+            raise ValueError("the length of layer_num, in_channels, out_channels list must be 4!")
+
+        self.conv1 = _conv7x7(3, 64, stride=2)
+        self.bn1 = _bn(64)
+        self.relu = P.ReLU()
+        self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, pad_mode="same")
+
+        self.layer1 = self._make_layer(block,
+                                       layer_nums[0],
+                                       in_channel=in_channels[0],
+                                       out_channel=out_channels[0],
+                                       stride=strides[0])
+        self.layer2 = self._make_layer(block,
+                                       layer_nums[1],
+                                       in_channel=in_channels[1],
+                                       out_channel=out_channels[1],
+                                       stride=strides[1])
+        self.layer3 = self._make_layer(block,
+                                       layer_nums[2],
+                                       in_channel=in_channels[2],
+                                       out_channel=out_channels[2],
+                                       stride=strides[2])
+        self.layer4 = self._make_layer(block,
+                                       layer_nums[3],
+                                       in_channel=in_channels[3],
+                                       out_channel=out_channels[3],
+                                       stride=strides[3])
+
+        self.mean = P.ReduceMean(keep_dims=True)
+        self.flatten = nn.Flatten()
+        self.end_point = _fc(out_channels[3], num_classes)
+
+    def _make_layer(self, block, layer_num, in_channel, out_channel, stride):
+        """
+        Make stage network of ResNet.
+
+        Args:
+            block (Cell): Resnet block.
+            layer_num (int): Layer number.
+            in_channel (int): Input channel.
+            out_channel (int): Output channel.
+            stride (int): Stride size for the first convolutional layer.
+
+        Returns:
+            SequentialCell, the output layer.
+
+        Examples:
+            >>> _make_layer(ResidualBlock, 3, 128, 256, 2)
+        """
+        layers = []
+
+        resnet_block = block(in_channel, out_channel, stride=stride)
+        layers.append(resnet_block)
+
+        for _ in range(1, layer_num):
+            resnet_block = block(out_channel, out_channel, stride=1)
+            layers.append(resnet_block)
+
+        return nn.SequentialCell(layers)
+
+    def construct(self, x):
+        x = self.conv1(x)
+        x = self.bn1(x)
+        x = self.relu(x)
+        c1 = self.maxpool(x)
+
+        c2 = self.layer1(c1)
+        c3 = self.layer2(c2)
+        c4 = self.layer3(c3)
+        c5 = self.layer4(c4)
+
+        out = self.mean(c5, (2, 3))
+        out = self.flatten(out)
+        out = self.end_point(out)
+
+        return out
+
+
+def resnet50(class_num=10):
+    """
+    Get ResNet50 neural network.
+
+    Args:
+        class_num (int): Class number.
+
+    Returns:
+        Cell, cell instance of ResNet50 neural network.
+
+    Examples:
+        >>> net = resnet50(10)
+    """
+    return ResNet(ResidualBlock,
+                  [3, 4, 6, 3],
+                  [64, 256, 512, 1024],
+                  [256, 512, 1024, 2048],
+                  [1, 2, 2, 2],
+                  class_num)
+
+
+def resnet101(class_num=1001):
+    """
+    Get ResNet101 neural network.
+
+    Args:
+        class_num (int): Class number.
+
+    Returns:
+        Cell, cell instance of ResNet101 neural network.
+
+    Examples:
+        >>> net = resnet101(1001)
+    """
+    return ResNet(ResidualBlock,
+                  [3, 4, 23, 3],
+                  [64, 256, 512, 1024],
+                  [256, 512, 1024, 2048],
+                  [1, 2, 2, 2],
+                  class_num)

tutorials/tutorial_code/sample_for_cloud/resnet50_train.py

@@ -31,7 +31,7 @@ from mindspore.communication.management import init
 import mindspore.dataset.engine as de
 
 from dataset import create_dataset, device_id, device_num
-from mindspore.model_zoo.resnet import resnet50
+from resnet import resnet50
 
 random.seed(1)
 np.random.seed(1)