"""
Model definition adapted from: https://github.com/pytorch/vision/blob/master/torchvision/models/vgg.py
"""
import logging
import math
import torch.nn as nn
import torch.utils.model_zoo as model_zoo
model_urls = {
'vgg11': 'https://download.pytorch.org/models/vgg11-bbd30ac9.pth',
'vgg13': 'https://download.pytorch.org/models/vgg13-c768596a.pth',
'vgg16': 'https://download.pytorch.org/models/vgg16-397923af.pth',
'vgg19': 'https://download.pytorch.org/models/vgg19-dcbb9e9d.pth',
'vgg11_bn': 'https://download.pytorch.org/models/vgg11_bn-6002323d.pth',
'vgg13_bn': 'https://download.pytorch.org/models/vgg13_bn-abd245e5.pth',
'vgg16_bn': 'https://download.pytorch.org/models/vgg16_bn-6c64b313.pth',
'vgg19_bn': 'https://download.pytorch.org/models/vgg19_bn-c79401a0.pth',
}
[docs]class VGG(nn.Module):
def __init__(self, features, num_classes=1000, **kwargs):
super(VGG, self).__init__()
self.features = features
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),
)
self._initialize_weights()
[docs] 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):
m.weight.data.normal_(0, 0.01)
m.bias.data.zero_()
[docs]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 = {
'A': [64, 'M', 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
'B': [64, 64, 'M', 128, 128, 'M', 256, 256, 'M', 512, 512, 'M', 512, 512, 'M'],
'D': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 'M', 512, 512, 512, 'M', 512, 512, 512, 'M'],
'E': [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 256, 'M', 512, 512, 512, 512, 'M', 512, 512, 512, 512, 'M'],
}
[docs]def vgg11(pretrained=False, **kwargs):
"""VGG 11-layer model (configuration "A")
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['A']), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg11']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg11_bn(pretrained=False, **kwargs):
"""VGG 11-layer model (configuration "A") with batch normalization
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['A'], batch_norm=True), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg11_bn']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg13(pretrained=False, **kwargs):
"""VGG 13-layer model (configuration "B")
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['B']), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg13']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg13_bn(pretrained=False, **kwargs):
"""VGG 13-layer model (configuration "B") with batch normalization
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['B'], batch_norm=True), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg13_bn']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg16(pretrained=False, **kwargs):
"""VGG 16-layer model (configuration "D")
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['D']), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg16']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg16_bn(pretrained=False, **kwargs):
"""VGG 16-layer model (configuration "D") with batch normalization
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['D'], batch_norm=True), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg16_bn']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg19(pretrained=False, **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)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg19']), strict=False)
except Exception as exp:
logging.warning(exp)
return model
[docs]def vgg19_bn(pretrained=False, **kwargs):
"""VGG 19-layer model (configuration 'E') with batch normalization
Args:
pretrained (bool): If True, returns a model pre-trained on ImageNet
"""
model = VGG(make_layers(cfg['E'], batch_norm=True), **kwargs)
if pretrained:
try:
model.load_state_dict(model_zoo.load_url(model_urls['vgg19_bn']), strict=False)
except Exception as exp:
logging.warning(exp)
return model