add densenet

Author: xiaohu2015

CNNs/densenet.py

@@ -0,0 +1,228 @@
+"""
+DenseNet, original: https://github.com/pytorch/vision/blob/master/torchvision/models/densenet.py
+"""
+import re
+from collections import OrderedDict
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+import torch.utils.model_zoo as model_zoo
+import torchvision.transforms as transforms
+
+from PIL import Image
+import numpy as np
+
+model_urls = {
+    'densenet121': 'https://download.pytorch.org/models/densenet121-a639ec97.pth',
+    'densenet169': 'https://download.pytorch.org/models/densenet169-b2777c0a.pth',
+    'densenet201': 'https://download.pytorch.org/models/densenet201-c1103571.pth',
+    'densenet161': 'https://download.pytorch.org/models/densenet161-8d451a50.pth',
+}
+
+
+class _DenseLayer(nn.Sequential):
+    """Basic unit of DenseBlock (using bottleneck layer) """
+    def __init__(self, num_input_features, growth_rate, bn_size, drop_rate):
+        super(_DenseLayer, self).__init__()
+        self.add_module("norm1", nn.BatchNorm2d(num_input_features))
+        self.add_module("relu1", nn.ReLU(inplace=True))
+        self.add_module("conv1", nn.Conv2d(num_input_features, bn_size*growth_rate,
+                                           kernel_size=1, stride=1, bias=False))
+        self.add_module("norm2", nn.BatchNorm2d(bn_size*growth_rate))
+        self.add_module("relu2", nn.ReLU(inplace=True))
+        self.add_module("conv2", nn.Conv2d(bn_size*growth_rate, growth_rate,
+                                           kernel_size=3, stride=1, padding=1, bias=False))
+        self.drop_rate = drop_rate
+
+    def forward(self, x):
+        new_features = super(_DenseLayer, self).forward(x)
+        if self.drop_rate > 0:
+            new_features = F.dropout(new_features, p=self.drop_rate, training=self.training)
+        return torch.cat([x, new_features], 1)
+
+class _DenseBlock(nn.Sequential):
+    """DenseBlock"""
+    def __init__(self, num_layers, num_input_features, bn_size, growth_rate, drop_rate):
+        super(_DenseBlock, self).__init__()
+        for i in range(num_layers):
+            layer = _DenseLayer(num_input_features+i*growth_rate, growth_rate, bn_size,
+                                drop_rate)
+            self.add_module("denselayer%d" % (i+1,), layer)
+
+
+class _Transition(nn.Sequential):
+    """Transition layer between two adjacent DenseBlock"""
+    def __init__(self, num_input_feature, num_output_features):
+        super(_Transition, self).__init__()
+        self.add_module("norm", nn.BatchNorm2d(num_input_feature))
+        self.add_module("relu", nn.ReLU(inplace=True))
+        self.add_module("conv", nn.Conv2d(num_input_feature, num_output_features,
+                                          kernel_size=1, stride=1, bias=False))
+        self.add_module("pool", nn.AvgPool2d(2, stride=2))
+
+
+class DenseNet(nn.Module):
+    "DenseNet-BC model"
+    def __init__(self, growth_rate=32, block_config=(6, 12, 24, 16), num_init_features=64,
+                 bn_size=4, compression_rate=0.5, drop_rate=0, num_classes=1000):
+        """
+        :param growth_rate: (int) number of filters used in DenseLayer, `k` in the paper
+        :param block_config: (list of 4 ints) number of layers in each DenseBlock
+        :param num_init_features: (int) number of filters in the first Conv2d
+        :param bn_size: (int) the factor using in the bottleneck layer
+        :param compression_rate: (float) the compression rate used in Transition Layer
+        :param drop_rate: (float) the drop rate after each DenseLayer
+        :param num_classes: (int) number of classes for classification
+        """
+        super(DenseNet, self).__init__()
+        # first Conv2d
+        self.features = nn.Sequential(OrderedDict([
+            ("conv0", nn.Conv2d(3, num_init_features, kernel_size=7, stride=2, padding=3, bias=False)),
+            ("norm0", nn.BatchNorm2d(num_init_features)),
+            ("relu0", nn.ReLU(inplace=True)),
+            ("pool0", nn.MaxPool2d(3, stride=2, padding=1))
+        ]))
+
+        # DenseBlock
+        num_features = num_init_features
+        for i, num_layers in enumerate(block_config):
+            block = _DenseBlock(num_layers, num_features, bn_size, growth_rate, drop_rate)
+            self.features.add_module("denseblock%d" % (i + 1), block)
+            num_features += num_layers*growth_rate
+            if i != len(block_config) - 1:
+                transition = _Transition(num_features, int(num_features*compression_rate))
+                self.features.add_module("transition%d" % (i + 1), transition)
+                num_features = int(num_features * compression_rate)
+
+        # final bn+ReLU
+        self.features.add_module("norm5", nn.BatchNorm2d(num_features))
+        self.features.add_module("relu5", nn.ReLU(inplace=True))
+
+        # classification layer
+        self.classifier = nn.Linear(num_features, num_classes)
+
+        # params initialization
+        for m in self.modules():
+            if isinstance(m, nn.Conv2d):
+                nn.init.kaiming_normal_(m.weight)
+            elif isinstance(m, nn.BatchNorm2d):
+                nn.init.constant_(m.bias, 0)
+                nn.init.constant_(m.weight, 1)
+            elif isinstance(m, nn.Linear):
+                nn.init.constant_(m.bias, 0)
+
+    def forward(self, x):
+        features = self.features(x)
+        out = F.avg_pool2d(features, 7, stride=1).view(features.size(0), -1)
+        out = self.classifier(out)
+        return out
+
+class DenseNet_MNIST(nn.Module):
+    """DenseNet for MNIST dataset"""
+    def __init__(self, growth_rate=12, block_config=(6, 6, 6), num_init_features=16,
+                 bn_size=4, compression_rate=0.5, drop_rate=0, num_classes=10):
+        """
+        :param growth_rate: (int) number of filters used in DenseLayer, `k` in the paper
+        :param block_config: (list of 2 ints) number of layers in each DenseBlock
+        :param num_init_features: (int) number of filters in the first Conv2d
+        :param bn_size: (int) the factor using in the bottleneck layer
+        :param compression_rate: (float) the compression rate used in Transition Layer
+        :param drop_rate: (float) the drop rate after each DenseLayer
+        :param num_classes: (int) number of classes for classification
+        """
+        super(DenseNet_MNIST, self).__init__()
+        # first Conv2d
+        self.features = nn.Sequential(OrderedDict([
+            ("conv0", nn.Conv2d(1, num_init_features, kernel_size=3, stride=1, padding=1, bias=False)),
+            ("norm0", nn.BatchNorm2d(num_init_features)),
+            ("relu0", nn.ReLU(inplace=True)),
+        ]))
+
+        # DenseBlock
+        num_features = num_init_features
+        for i, num_layers in enumerate(block_config):
+            block = _DenseBlock(num_layers, num_features, bn_size, growth_rate, drop_rate)
+            self.features.add_module("denseblock%d" % (i + 1), block)
+            num_features += num_layers * growth_rate
+            if i != len(block_config) - 1:
+                transition = _Transition(num_features, int(num_features * compression_rate))
+                self.features.add_module("transition%d" % (i + 1), transition)
+                num_features = int(num_features * compression_rate)
+
+        # final bn+ReLU
+        self.features.add_module("norm5", nn.BatchNorm2d(num_features))
+        self.features.add_module("relu5", nn.ReLU(inplace=True))
+
+        # classification layer
+        self.classifier = nn.Linear(num_features, num_classes)
+
+        # params initialization
+        for m in self.modules():
+            if isinstance(m, nn.Conv2d):
+                nn.init.kaiming_normal_(m.weight)
+            elif isinstance(m, nn.BatchNorm2d):
+                nn.init.constant_(m.bias, 0)
+                nn.init.constant_(m.weight, 1)
+            elif isinstance(m, nn.Linear):
+                nn.init.constant_(m.bias, 0)
+
+    def forward(self, x):
+        features = self.features(x)
+        out = F.avg_pool2d(features, 7, stride=1).view(features.size(0), -1)
+        out = self.classifier(out)
+        return out
+
+
+def densenet121(pretrained=False, **kwargs):
+    """DenseNet121"""
+    model = DenseNet(num_init_features=64, growth_rate=32, block_config=(6, 12, 24, 16),
+                     **kwargs)
+
+    if pretrained:
+        # '.'s are no longer allowed in module names, but pervious _DenseLayer
+        # has keys 'norm.1', 'relu.1', 'conv.1', 'norm.2', 'relu.2', 'conv.2'.
+        # They are also in the checkpoints in model_urls. This pattern is used
+        # to find such keys.
+        pattern = re.compile(
+            r'^(.*denselayer\d+\.(?:norm|relu|conv))\.((?:[12])\.(?:weight|bias|running_mean|running_var))$')
+        state_dict = model_zoo.load_url(model_urls['densenet121'])
+        for key in list(state_dict.keys()):
+            res = pattern.match(key)
+            if res:
+                new_key = res.group(1) + res.group(2)
+                state_dict[new_key] = state_dict[key]
+                del state_dict[key]
+        model.load_state_dict(state_dict)
+    return model
+
+if __name__ == "__main__":
+    densenet = densenet121(pretrained=True)
+    densenet.eval()
+
+    img = Image.open("./images/cat.jpg")
+
+    trans_ops = transforms.Compose([
+        transforms.Resize(256),
+        transforms.CenterCrop(224),
+        transforms.ToTensor(),
+        transforms.Normalize(mean=[0.485, 0.456, 0.406],
+                             std=[0.229, 0.224, 0.225])
+    ])
+
+    images = trans_ops(img).view(-1, 3, 224, 224)
+    print(images)
+    outputs = densenet(images)
+
+    _, predictions = outputs.topk(5, dim=1)
+
+    labels = list(map(lambda s: s.strip(), open("./data/imagenet/synset_words.txt").readlines()))
+    for idx in predictions.numpy()[0]:
+        print("Predicted labels:", labels[idx])
+
+
+
+
+
+
+