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pytorch-image-models/models/densenet.py

211 lines
8.8 KiB

"""Pytorch Densenet implementation w/ tweaks
This file is a copy of https://github.com/pytorch/vision 'densenet.py' (BSD-3-Clause) with
fixed kwargs passthrough and addition of dynamic global avg/max pool.
"""
import torch
import torch.nn as nn
import torch.nn.functional as F
from collections import OrderedDict
from models.helpers import load_pretrained
from models.adaptive_avgmax_pool import *
from data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
import re
__all__ = ['DenseNet', 'densenet121', 'densenet169', 'densenet201', 'densenet161']
def _cfg(url=''):
return {
'url': url, 'num_classes': 1000, 'input_size': (3, 224, 244), 'pool_size': (7, 7),
'crop_pct': 0.875, 'interpolation': 'bilinear',
'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD,
'first_conv': 'features.conv0', 'classifier': 'classifier',
}
default_cfgs = {
'densenet121': _cfg(url='https://download.pytorch.org/models/densenet121-241335ed.pth'),
'densenet169': _cfg(url='https://download.pytorch.org/models/densenet169-6f0f7f60.pth'),
'densenet201': _cfg(url='https://download.pytorch.org/models/densenet201-4c113574.pth'),
'densenet161': _cfg(url='https://download.pytorch.org/models/densenet161-17b70270.pth'),
}
def _filter_pretrained(state_dict):
pattern = re.compile(
r'^(.*denselayer\d+\.(?:norm|relu|conv))\.((?:[12])\.(?:weight|bias|running_mean|running_var))$')
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]
return state_dict
def densenet121(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
r"""Densenet-121 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`
"""
default_cfg = default_cfgs['densenet121']
model = DenseNet(num_init_features=64, growth_rate=32, block_config=(6, 12, 24, 16),
num_classes=num_classes, in_chans=in_chans, **kwargs)
model.default_cfg = default_cfg
if pretrained:
load_pretrained(model, default_cfg, num_classes, in_chans, filter_fn=_filter_pretrained)
return model
def densenet169(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
r"""Densenet-169 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`
"""
default_cfg = default_cfgs['densenet169']
model = DenseNet(num_init_features=64, growth_rate=32, block_config=(6, 12, 32, 32),
num_classes=num_classes, in_chans=in_chans, **kwargs)
model.default_cfg = default_cfg
if pretrained:
load_pretrained(model, default_cfg, num_classes, in_chans, filter_fn=_filter_pretrained)
return model
def densenet201(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
r"""Densenet-201 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`
"""
default_cfg = default_cfgs['densenet201']
model = DenseNet(num_init_features=64, growth_rate=32, block_config=(6, 12, 48, 32),
num_classes=num_classes, in_chans=in_chans, **kwargs)
model.default_cfg = default_cfg
if pretrained:
load_pretrained(model, default_cfg, num_classes, in_chans, filter_fn=_filter_pretrained)
return model
def densenet161(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
r"""Densenet-201 model from
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`
"""
print(num_classes, in_chans, pretrained)
default_cfg = default_cfgs['densenet161']
model = DenseNet(num_init_features=96, growth_rate=48, block_config=(6, 12, 36, 24),
num_classes=num_classes, in_chans=in_chans, **kwargs)
model.default_cfg = default_cfg
if pretrained:
load_pretrained(model, default_cfg, num_classes, in_chans, filter_fn=_filter_pretrained)
return model
class _DenseLayer(nn.Sequential):
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):
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):
def __init__(self, num_input_features, num_output_features):
super(_Transition, self).__init__()
self.add_module('norm', nn.BatchNorm2d(num_input_features))
self.add_module('relu', nn.ReLU(inplace=True))
self.add_module('conv', nn.Conv2d(num_input_features, num_output_features,
kernel_size=1, stride=1, bias=False))
self.add_module('pool', nn.AvgPool2d(kernel_size=2, stride=2))
class DenseNet(nn.Module):
r"""Densenet-BC model class, based on
`"Densely Connected Convolutional Networks" <https://arxiv.org/pdf/1608.06993.pdf>`
Args:
growth_rate (int) - how many filters to add each layer (`k` in paper)
block_config (list of 4 ints) - how many layers in each pooling block
num_init_features (int) - the number of filters to learn in the first convolution layer
bn_size (int) - multiplicative factor for number of bottle neck layers
(i.e. bn_size * k features in the bottleneck layer)
drop_rate (float) - dropout rate after each dense layer
num_classes (int) - number of classification classes
"""
def __init__(self, growth_rate=32, block_config=(6, 12, 24, 16),
num_init_features=64, bn_size=4, drop_rate=0,
num_classes=1000, in_chans=3, global_pool='avg'):
self.global_pool = global_pool
self.num_classes = num_classes
super(DenseNet, self).__init__()
# First convolution
self.features = nn.Sequential(OrderedDict([
('conv0', nn.Conv2d(in_chans, 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(kernel_size=3, stride=2, padding=1)),
]))
# Each denseblock
num_features = num_init_features
for i, num_layers in enumerate(block_config):
block = _DenseBlock(num_layers=num_layers, num_input_features=num_features,
bn_size=bn_size, growth_rate=growth_rate, drop_rate=drop_rate)
self.features.add_module('denseblock%d' % (i + 1), block)
num_features = num_features + num_layers * growth_rate
if i != len(block_config) - 1:
trans = _Transition(
num_input_features=num_features, num_output_features=num_features // 2)
self.features.add_module('transition%d' % (i + 1), trans)
num_features = num_features // 2
# Final batch norm
self.features.add_module('norm5', nn.BatchNorm2d(num_features))
# Linear layer
self.classifier = nn.Linear(num_features, num_classes)
self.num_features = num_features
def get_classifier(self):
return self.classifier
def reset_classifier(self, num_classes, global_pool='avg'):
self.global_pool = global_pool
self.num_classes = num_classes
del self.classifier
if num_classes:
self.classifier = nn.Linear(self.num_features, num_classes)
else:
self.classifier = None
def forward_features(self, x, pool=True):
x = self.features(x)
x = F.relu(x, inplace=True)
if pool:
x = select_adaptive_pool2d(x, self.global_pool)
x = x.view(x.size(0), -1)
return x
def forward(self, x):
return self.classifier(self.forward_features(x, pool=True))