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vgg_fn.py
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vgg_fn.py
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'''
VGG for CIFAR10. FC layers are removed.
'''
import torch.nn as nn
import torch.utils.model_zoo as model_zoo
import math
__all__ = [
'vgg19_bn', 'vgg19',
]
model_urls = {
'vgg19': 'https://download.pytorch.org/models/vgg19-dcbb9e9d.pth',
}
class VGG(nn.Module):
def __init__(self, features, num_classes=1000):
super(VGG, self).__init__()
self.features = features
self.classifier = nn.Linear(512, num_classes)
self._initialize_weights()
def forward(self, x):
x = self.features(x)
x = x.view(x.size(0), -1)
x = self.classifier(x)
return x
def _initialize_weights(self):
for m in self.modules():
if isinstance(m, nn.Conv2d):
n = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
m.weight.data.normal_(0, math.sqrt(2. / n))
if m.bias is not None:
m.bias.data.zero_()
elif isinstance(m, nn.BatchNorm2d):
m.weight.data.fill_(1)
m.bias.data.zero_()
elif isinstance(m, nn.Linear):
n = m.weight.size(1)
m.weight.data.normal_(0, 0.01)
m.bias.data.zero_()
def make_layers(cfg, batch_norm=False):
layers = []
in_channels = 3
for v in cfg:
if v == 'M':
layers += [nn.MaxPool2d(kernel_size=2, stride=2)]
else:
conv2d = nn.Conv2d(in_channels, v, kernel_size=3, padding=1)
if batch_norm:
layers += [conv2d, nn.BatchNorm2d(v), nn.ReLU(inplace=True)]
else:
layers += [conv2d, nn.ReLU(inplace=True)]
in_channels = v
return nn.Sequential(*layers)
cfg = {
'E': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 256, 'M', 512, 512, 512, 512, 'M', 512, 512, 512, 512, 'M'],
}
def vgg19(**kwargs):
"""VGG 19-layer model (configuration "E")
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['E']), **kwargs)
return model
def vgg19_bn(**kwargs):
"""VGG 19-layer model (configuration 'E') with batch normalization"""
model = VGG(make_layers(cfg['E'], batch_norm=True), **kwargs)
return model