add alexnet & vgg

mmcv/cnn/__init__.py

+from .alexnet import AlexNet
+from .vgg import VGG, make_vgg_layer
 from .resnet import ResNet, make_res_layer
 
-__all__ = ['ResNet', 'make_res_layer']
+__all__ = ['AlexNet',
+           'VGG', 'make_vgg_layer',
+           'ResNet', 'make_res_layer']

mmcv/cnn/alexnet.py

+import logging
+import math
+
+import torch.nn as nn
+
+from ..runner import load_checkpoint
+
+
+class AlexNet(nn.Module):
+    """AlexNet backbone.
+
+    Args:
+        num_classes (int): number of classes for classification.
+    """
+
+
+    def __init__(self,
+                 num_classes=-1):
+        super(AlexNet, self).__init__()
+        self.num_classes = num_classes
+        self.features = nn.Sequential(
+            nn.Conv2d(3, 64, kernel_size=11, stride=4, padding=2),
+            nn.ReLU(inplace=True),
+            nn.MaxPool2d(kernel_size=3, stride=2),
+            nn.Conv2d(64, 192, kernel_size=5, padding=2),
+            nn.ReLU(inplace=True),
+            nn.MaxPool2d(kernel_size=3, stride=2),
+            nn.Conv2d(192, 384, kernel_size=3, padding=1),
+            nn.ReLU(inplace=True),
+            nn.Conv2d(384, 256, kernel_size=3, padding=1),
+            nn.ReLU(inplace=True),
+            nn.Conv2d(256, 256, kernel_size=3, padding=1),
+            nn.ReLU(inplace=True),
+            nn.MaxPool2d(kernel_size=3, stride=2),
+        )
+        if self.num_classes > 0:
+            self.classifier = nn.Sequential(
+                nn.Dropout(),
+                nn.Linear(256 * 6 * 6, 4096),
+                nn.ReLU(inplace=True),
+                nn.Dropout(),
+                nn.Linear(4096, 4096),
+                nn.ReLU(inplace=True), # caffe has dropout
+                nn.Linear(4096, num_classes),
+            )
+
+    def init_weights(self, pretrained=None):
+        if isinstance(pretrained, str):
+            logger = logging.getLogger()
+            load_checkpoint(self, pretrained, strict=False, logger=logger)
+        elif pretrained is None:
+            # use default initializer
+            pass
+        else:
+            raise TypeError('pretrained must be a str or None')
+
+    def forward(self, x):
+
+        x = self.features(x)
+        if self.num_classes > 0:
+            x = x.view(x.size(0), 256 * 6 * 6)
+            x = self.classifier(x)
+
+        return x

mmcv/cnn/vgg.py

+import logging
+import math
+
+import torch.nn as nn
+
+from ..runner import load_checkpoint
+
+
+def conv3x3(in_planes, out_planes, dilation=1, bias=False):
+    "3x3 convolution with padding"
+    return nn.Conv2d(
+        in_planes,
+        out_planes,
+        kernel_size=3,
+        padding=dilation,
+        dilation=dilation,
+        bias=bias)
+
+
+def make_vgg_layer(inplanes,
+                   planes,
+                   num_blocks,
+                   dilation=1,
+                   with_bn=False):
+    layers = []
+    for _ in range(num_blocks):
+        layers.append(
+            conv3x3(inplanes, planes, dilation, not with_bn))
+        if with_bn:
+            layers.append(nn.BatchNorm2d(planes))
+        layers.append(nn.ReLU(inplace=True))
+        inplanes = planes
+    layers.append(nn.MaxPool2d(kernel_size=2, stride=2))
+
+    return nn.Sequential(*layers)
+
+
+class VGG(nn.Module):
+    """VGG backbone.
+
+    Args:
+        depth (int): Depth of vgg, from {11, 13, 16, 19}.
+        with_bn (bool): Use BatchNorm or not.
+        num_classes (int): number of classes for classification.
+        num_stages (int): VGG stages, normally 5.
+        dilations (Sequence[int]): Dilation of each stage.
+        out_indices (Sequence[int]): Output from which stages.
+        frozen_stages (int): Stages to be frozen (all param fixed). -1 means
+            not freezing any parameters.
+        bn_eval (bool): Whether to set BN layers as eval mode, namely, freeze
+            running stats (mean and var).
+        bn_frozen (bool): Whether to freeze weight and bias of BN layers.
+    """
+
+    arch_settings = {
+        11: (1, 1, 2, 2, 2),
+        13: (2, 2, 2, 2, 2),
+        16: (2, 2, 3, 3, 3),
+        19: (2, 2, 4, 4, 4)
+    }
+
+    def __init__(self,
+                 depth,
+                 with_bn=False,
+                 num_classes=-1,
+                 num_stages=5,
+                 dilations=(1, 1, 1, 1, 1),
+                 out_indices=(0, 1, 2, 3, 4),
+                 frozen_stages=-1,
+                 bn_eval=True,
+                 bn_frozen=False):
+        super(VGG, self).__init__()
+        if depth not in self.arch_settings:
+            raise KeyError('invalid depth {} for vgg'.format(depth))
+        assert num_stages >= 1 and num_stages <= 5
+        stage_blocks = self.arch_settings[depth]
+        stage_blocks = stage_blocks[:num_stages]
+        assert len(dilations) == num_stages
+        assert max(out_indices) < num_stages
+
+        self.num_classes = num_classes
+        self.out_indices = out_indices
+        self.frozen_stages = frozen_stages
+        self.bn_eval = bn_eval
+        self.bn_frozen = bn_frozen
+
+        self.inplanes = 3
+        self.vgg_layers = []
+        for i, num_blocks in enumerate(stage_blocks):
+            dilation = dilations[i]
+            planes = 64 * 2**i if i < 4 else 512
+            vgg_layer = make_vgg_layer(
+                    self.inplanes,
+                    planes,
+                    num_blocks,
+                    dilation=dilation,
+                    with_bn=with_bn)
+            self.inplanes = planes
+            layer_name = 'layer{}'.format(i + 1)
+            self.add_module(layer_name, vgg_layer)
+            self.vgg_layers.append(layer_name)
+
+        if self.num_classes > 0:
+            self.classifier = nn.Sequential(
+                nn.Linear(512 * 7 * 7, 4096),
+                nn.ReLU(True),
+                nn.Dropout(),
+                nn.Linear(4096, 4096),
+                nn.ReLU(True),
+                nn.Dropout(),
+                nn.Linear(4096, num_classes),
+            )
+
+    def init_weights(self, pretrained=None):
+        if isinstance(pretrained, str):
+            logger = logging.getLogger()
+            load_checkpoint(self, pretrained, strict=False, logger=logger)
+        elif pretrained is None:
+            for m in self.modules():
+                if isinstance(m, nn.Conv2d):
+                    nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
+                    if m.bias is not None:
+                        nn.init.constant_(m.bias, 0)
+                elif isinstance(m, nn.BatchNorm2d):
+                    nn.init.constant_(m.weight, 1)
+                    nn.init.constant_(m.bias, 0)
+                elif isinstance(m, nn.Linear):
+                    nn.init.normal_(m.weight, 0, 0.01)
+                    nn.init.constant_(m.bias, 0)
+        else:
+            raise TypeError('pretrained must be a str or None')
+
+    def forward(self, x):
+        for i, layer_name in enumerate(self.vgg_layers):
+            vgg_layer = getattr(self, layer_name)
+            x = vgg_layer(x)
+            if i in self.out_indices:
+                outs.append(x)
+        if self.num_classes > 0:
+            x = x.view(x.size(0), -1)
+            x = self.classifier(x)
+            outs.append(x)
+        if len(outs) == 1:
+            return outs[0]
+        else:
+            return tuple(outs)
+
+    def train(self, mode=True):
+        super(VGG, self).train(mode)
+        if self.bn_eval:
+            for m in self.modules():
+                if isinstance(m, nn.BatchNorm2d):
+                    m.eval()
+                    if self.bn_frozen:
+                        for params in m.parameters():
+                            params.requires_grad = False
+        if mode and self.frozen_stages >= 0:
+            for i in range(1, self.frozen_stages + 1):
+                mod = getattr(self, 'layer{}'.format(i))
+                mod.eval()
+                for param in mod.parameters():
+                    param.requires_grad = False