pytorch-densenet

Simple Code Implementation of "DenseNet" architecture using PyTorch.

For simplicity, i write codes in ipynb. So, you can easliy test my code.

Last update : 2019/1/29

Contributor

• hoya012

0. Requirements

python=3.5
numpy
matplotlib
torch=1.0.0
torchvision
torchsummary

1. Usage

You only run DenseNet-BC-CIFAR10.ipynb.

Or you can use Google Colab for free!! This is colab link.

After downloading ipynb, just upload to your google drive. and run!

For training, testing, i used CIFAR-10 Dataset.

2. Paper Review & Code implementation Blog Posting (Korean Only)

“DenseNet Tutorial [1] Paper Review & Implementation details”
“DenseNet Tutorial [2] PyTorch Code Implementation”

3. DenseNet and other layers impelemtation.

In DenseNet, there are many DenseBlock. This is my simple implemenatation.

Bottleneck layer

class bottleneck_layer(nn.Sequential):
  def __init__(self, nin, growth_rate, drop_rate=0.2):    
      super(bottleneck_layer, self).__init__()
      
      self.add_module('conv_1x1', bn_relu_conv(nin=nin, nout=growth_rate*4, kernel_size=1, stride=1, padding=0, bias=False))
      self.add_module('conv_3x3', bn_relu_conv(nin=growth_rate*4, nout=growth_rate, kernel_size=3, stride=1, padding=1, bias=False))
      
      self.drop_rate = drop_rate
      
  def forward(self, x):
      bottleneck_output = super(bottleneck_layer, self).forward(x)
      if self.drop_rate > 0:
          bottleneck_output = F.dropout(bottleneck_output, p=self.drop_rate, training=self.training)
          
      bottleneck_output = torch.cat((x, bottleneck_output), 1)
      
      return bottleneck_output

Transition layer

class Transition_layer(nn.Sequential):
  def __init__(self, nin, theta=0.5):    
      super(Transition_layer, self).__init__()
      
      self.add_module('conv_1x1', bn_relu_conv(nin=nin, nout=int(nin*theta), kernel_size=1, stride=1, padding=0, bias=False))
      self.add_module('avg_pool_2x2', nn.AvgPool2d(kernel_size=2, stride=2, padding=0))

DenseBlock

class DenseBlock(nn.Sequential):
  def __init__(self, nin, num_bottleneck_layers, growth_rate, drop_rate=0.2):
      super(DenseBlock, self).__init__()
                        
      for i in range(num_bottleneck_layers):
          nin_bottleneck_layer = nin + growth_rate * i
          self.add_module('bottleneck_layer_%d' % i, bottleneck_layer(nin=nin_bottleneck_layer, growth_rate=growth_rate, drop_rate=drop_rate))

4. DenseNet architecture for CIFAR-10

The DenseNet architecture for CIFAR-10 differs from the architecture table presented in the paper. The DenseNet architecture applicable to CIFAR-10 is shown in the figure above.