Merge pull request #15 from open-mmlab/cnn

Add cnn module

mmcv/cnn/__init__.py

+from .alexnet import AlexNet
+from .vgg import VGG, make_vgg_layer
+from .resnet import ResNet, make_res_layer
+from .weight_init import (constant_init, xavier_init, normal_init,
+                          uniform_init, kaiming_init)
+
+__all__ = [
+    'AlexNet', 'VGG', 'make_vgg_layer', 'ResNet', 'make_res_layer',
+    'constant_init', 'xavier_init', 'normal_init', 'uniform_init',
+    'kaiming_init'
+]

mmcv/cnn/alexnet.py

+import logging
+
+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),
+                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/resnet.py

+import logging
+
+import torch.nn as nn
+import torch.utils.checkpoint as cp
+
+from .weight_init import constant_init, kaiming_init
+from ..runner import load_checkpoint
+
+
+def conv3x3(in_planes, out_planes, stride=1, dilation=1):
+    "3x3 convolution with padding"
+    return nn.Conv2d(
+        in_planes,
+        out_planes,
+        kernel_size=3,
+        stride=stride,
+        padding=dilation,
+        dilation=dilation,
+        bias=False)
+
+
+class BasicBlock(nn.Module):
+    expansion = 1
+
+    def __init__(self,
+                 inplanes,
+                 planes,
+                 stride=1,
+                 dilation=1,
+                 downsample=None,
+                 style='pytorch',
+                 with_cp=False):
+        super(BasicBlock, self).__init__()
+        self.conv1 = conv3x3(inplanes, planes, stride, dilation)
+        self.bn1 = nn.BatchNorm2d(planes)
+        self.relu = nn.ReLU(inplace=True)
+        self.conv2 = conv3x3(planes, planes)
+        self.bn2 = nn.BatchNorm2d(planes)
+        self.downsample = downsample
+        self.stride = stride
+        self.dilation = dilation
+        assert not with_cp
+
+    def forward(self, x):
+        residual = x
+
+        out = self.conv1(x)
+        out = self.bn1(out)
+        out = self.relu(out)
+
+        out = self.conv2(out)
+        out = self.bn2(out)
+
+        if self.downsample is not None:
+            residual = self.downsample(x)
+
+        out += residual
+        out = self.relu(out)
+
+        return out
+
+
+class Bottleneck(nn.Module):
+    expansion = 4
+
+    def __init__(self,
+                 inplanes,
+                 planes,
+                 stride=1,
+                 dilation=1,
+                 downsample=None,
+                 style='pytorch',
+                 with_cp=False):
+        """Bottleneck block.
+
+        If style is "pytorch", the stride-two layer is the 3x3 conv layer,
+        if it is "caffe", the stride-two layer is the first 1x1 conv layer.
+        """
+        super(Bottleneck, self).__init__()
+        assert style in ['pytorch', 'caffe']
+        if style == 'pytorch':
+            conv1_stride = 1
+            conv2_stride = stride
+        else:
+            conv1_stride = stride
+            conv2_stride = 1
+        self.conv1 = nn.Conv2d(
+            inplanes, planes, kernel_size=1, stride=conv1_stride, bias=False)
+        self.conv2 = nn.Conv2d(
+            planes,
+            planes,
+            kernel_size=3,
+            stride=conv2_stride,
+            padding=dilation,
+            dilation=dilation,
+            bias=False)
+
+        self.bn1 = nn.BatchNorm2d(planes)
+        self.bn2 = nn.BatchNorm2d(planes)
+        self.conv3 = nn.Conv2d(
+            planes, planes * self.expansion, kernel_size=1, bias=False)
+        self.bn3 = nn.BatchNorm2d(planes * self.expansion)
+        self.relu = nn.ReLU(inplace=True)
+        self.downsample = downsample
+        self.stride = stride
+        self.dilation = dilation
+        self.with_cp = with_cp
+
+    def forward(self, x):
+
+        def _inner_forward(x):
+            residual = 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.downsample is not None:
+                residual = self.downsample(x)
+
+            out += residual
+
+            return out
+
+        if self.with_cp and x.requires_grad:
+            out = cp.checkpoint(_inner_forward, x)
+        else:
+            out = _inner_forward(x)
+
+        out = self.relu(out)
+
+        return out
+
+
+def make_res_layer(block,
+                   inplanes,
+                   planes,
+                   blocks,
+                   stride=1,
+                   dilation=1,
+                   style='pytorch',
+                   with_cp=False):
+    downsample = None
+    if stride != 1 or inplanes != planes * block.expansion:
+        downsample = nn.Sequential(
+            nn.Conv2d(
+                inplanes,
+                planes * block.expansion,
+                kernel_size=1,
+                stride=stride,
+                bias=False),
+            nn.BatchNorm2d(planes * block.expansion),
+        )
+
+    layers = []
+    layers.append(
+        block(
+            inplanes,
+            planes,
+            stride,
+            dilation,
+            downsample,
+            style=style,
+            with_cp=with_cp))
+    inplanes = planes * block.expansion
+    for i in range(1, blocks):
+        layers.append(
+            block(inplanes, planes, 1, dilation, style=style, with_cp=with_cp))
+
+    return nn.Sequential(*layers)
+
+
+class ResNet(nn.Module):
+    """ResNet backbone.
+
+    Args:
+        depth (int): Depth of resnet, from {18, 34, 50, 101, 152}.
+        num_stages (int): Resnet stages, normally 4.
+        strides (Sequence[int]): Strides of the first block of each stage.
+        dilations (Sequence[int]): Dilation of each stage.
+        out_indices (Sequence[int]): Output from which stages.
+        style (str): `pytorch` or `caffe`. If set to "pytorch", the stride-two
+            layer is the 3x3 conv layer, otherwise the stride-two layer is
+            the first 1x1 conv layer.
+        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.
+        with_cp (bool): Use checkpoint or not. Using checkpoint will save some
+            memory while slowing down the training speed.
+    """
+
+    arch_settings = {
+        18: (BasicBlock, (2, 2, 2, 2)),
+        34: (BasicBlock, (3, 4, 6, 3)),
+        50: (Bottleneck, (3, 4, 6, 3)),
+        101: (Bottleneck, (3, 4, 23, 3)),
+        152: (Bottleneck, (3, 8, 36, 3))
+    }
+
+    def __init__(self,
+                 depth,
+                 num_stages=4,
+                 strides=(1, 2, 2, 2),
+                 dilations=(1, 1, 1, 1),
+                 out_indices=(0, 1, 2, 3),
+                 style='pytorch',
+                 frozen_stages=-1,
+                 bn_eval=True,
+                 bn_frozen=False,
+                 with_cp=False):
+        super(ResNet, self).__init__()
+        if depth not in self.arch_settings:
+            raise KeyError('invalid depth {} for resnet'.format(depth))
+        assert num_stages >= 1 and num_stages <= 4
+        block, stage_blocks = self.arch_settings[depth]
+        stage_blocks = stage_blocks[:num_stages]
+        assert len(strides) == len(dilations) == num_stages
+        assert max(out_indices) < num_stages
+
+        self.out_indices = out_indices
+        self.style = style
+        self.frozen_stages = frozen_stages
+        self.bn_eval = bn_eval
+        self.bn_frozen = bn_frozen
+        self.with_cp = with_cp
+
+        self.inplanes = 64
+        self.conv1 = nn.Conv2d(
+            3, 64, kernel_size=7, stride=2, padding=3, bias=False)
+        self.bn1 = nn.BatchNorm2d(64)
+        self.relu = nn.ReLU(inplace=True)
+        self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1)
+
+        self.res_layers = []
+        for i, num_blocks in enumerate(stage_blocks):
+            stride = strides[i]
+            dilation = dilations[i]
+            planes = 64 * 2**i
+            res_layer = make_res_layer(
+                block,
+                self.inplanes,
+                planes,
+                num_blocks,
+                stride=stride,
+                dilation=dilation,
+                style=self.style,
+                with_cp=with_cp)
+            self.inplanes = planes * block.expansion
+            layer_name = 'layer{}'.format(i + 1)
+            self.add_module(layer_name, res_layer)
+            self.res_layers.append(layer_name)
+
+        self.feat_dim = block.expansion * 64 * 2**(len(stage_blocks) - 1)
+
+    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):
+                    kaiming_init(m)
+                elif isinstance(m, nn.BatchNorm2d):
+                    constant_init(m, 1)
+        else:
+            raise TypeError('pretrained must be a str or None')
+
+    def forward(self, x):
+        x = self.conv1(x)
+        x = self.bn1(x)
+        x = self.relu(x)
+        x = self.maxpool(x)
+        outs = []
+        for i, layer_name in enumerate(self.res_layers):
+            res_layer = getattr(self, layer_name)
+            x = res_layer(x)
+            if i in self.out_indices:
+                outs.append(x)
+        if len(outs) == 1:
+            return outs[0]
+        else:
+            return tuple(outs)
+
+    def train(self, mode=True):
+        super(ResNet, 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 param in self.conv1.parameters():
+                param.requires_grad = False
+            for param in self.bn1.parameters():
+                param.requires_grad = False
+            self.bn1.eval()
+            self.bn1.weight.requires_grad = False
+            self.bn1.bias.requires_grad = False
+            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

mmcv/cnn/vgg.py

+import logging
+
+import torch.nn as nn
+
+from .weight_init import constant_init, normal_init, kaiming_init
+from ..runner import load_checkpoint
+
+
+def conv3x3(in_planes, out_planes, dilation=1):
+    "3x3 convolution with padding"
+    return nn.Conv2d(
+        in_planes,
+        out_planes,
+        kernel_size=3,
+        padding=dilation,
+        dilation=dilation)
+
+
+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))
+        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 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]
+        self.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
+        start_idx = 0
+        vgg_layers = []
+        self.range_sub_modules = []
+        for i, num_blocks in enumerate(self.stage_blocks):
+            num_modules = num_blocks * (2 + with_bn) + 1
+            end_idx = start_idx + num_modules
+            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)
+            vgg_layers.extend(vgg_layer)
+            self.inplanes = planes
+            self.range_sub_modules.append([start_idx, end_idx])
+            start_idx = end_idx
+        self.module_name = 'features'
+        self.add_module(self.module_name, nn.Sequential(*vgg_layers))
+
+        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):
+                    kaiming_init(m)
+                elif isinstance(m, nn.BatchNorm2d):
+                    constant_init(m, 1)
+                elif isinstance(m, nn.Linear):
+                    normal_init(m, std=0.01)
+        else:
+            raise TypeError('pretrained must be a str or None')
+
+    def forward(self, x):
+        outs = []
+        vgg_layers = getattr(self, self.module_name)
+        for i, num_blocks in enumerate(self.stage_blocks):
+            for j in range(*self.range_sub_modules[i]):
+                vgg_layer = vgg_layers[j]
+                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
+        vgg_layers = getattr(self, self.module_name)
+        if mode and self.frozen_stages >= 0:
+            for i in range(self.frozen_stages):
+                for j in range(*self.range_sub_modules[i]):
+                    mod = vgg_layers[j]
+                    mod.eval()
+                    for param in mod.parameters():
+                        param.requires_grad = False

mmcv/cnn/weight_init.py

+import torch.nn as nn
+
+
+def constant_init(module, val, bias=0):
+    nn.init.constant_(module.weight, val)
+    if hasattr(module, 'bias'):
+        nn.init.constant_(module.bias, bias)
+
+
+def xavier_init(module, gain=1, bias=0, distribution='normal'):
+    assert distribution in ['uniform', 'normal']
+    if distribution == 'uniform':
+        nn.init.xavier_uniform_(module.weight, gain=gain)
+    else:
+        nn.init.xavier_normal_(module.weight, gain=gain)
+    if hasattr(module, 'bias'):
+        nn.init.constant_(module.bias, bias)
+
+
+def normal_init(module, mean=0, std=1, bias=0):
+    nn.init.normal_(module.weight, mean, std)
+    if hasattr(module, 'bias'):
+        nn.init.constant_(module.bias, bias)
+
+
+def uniform_init(module, a=0, b=1, bias=0):
+    nn.init.uniform_(module.weight, a, b)
+    if hasattr(module, 'bias'):
+        nn.init.constant_(module.bias, bias)
+
+
+def kaiming_init(module,
+                 mode='fan_out',
+                 nonlinearity='relu',
+                 bias=0,
+                 distribution='normal'):
+    assert distribution in ['uniform', 'normal']
+    if distribution == 'uniform':
+        nn.init.kaiming_uniform_(
+            module.weight, mode=mode, nonlinearity=nonlinearity)
+    else:
+        nn.init.kaiming_normal_(
+            module.weight, mode=mode, nonlinearity=nonlinearity)
+    if hasattr(module, 'bias'):
+        nn.init.constant_(module.bias, bias)