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# Copyright (c) Xuanyi Dong [GitHub D-X-Y], 2019.01 #
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import torch.nn as nn
import torch.nn.functional as F
from ..initialization import initialize_resnet
class ConvBNReLU(nn.Module):
def __init__(self, nIn, nOut, kernel, stride, padding, bias, has_avg, has_bn, has_relu):
super(ConvBNReLU, self).__init__()
if has_avg : self.avg = nn.AvgPool2d(kernel_size=2, stride=2, padding=0)
else : self.avg = None
self.conv = nn.Conv2d(nIn, nOut, kernel_size=kernel, stride=stride, padding=padding, dilation=1, groups=1, bias=bias)
if has_bn : self.bn = nn.BatchNorm2d(nOut)
else : self.bn = None
if has_relu: self.relu = nn.ReLU(inplace=True)
else : self.relu = None
def forward(self, inputs):
if self.avg : out = self.avg( inputs )
else : out = inputs
conv = self.conv( out )
if self.bn : out = self.bn( conv )
else : out = conv
if self.relu: out = self.relu( out )
else : out = out
return out
class ResNetBasicblock(nn.Module):
num_conv = 2
expansion = 1
def __init__(self, iCs, stride):
super(ResNetBasicblock, self).__init__()
assert stride == 1 or stride == 2, 'invalid stride {:}'.format(stride)
assert isinstance(iCs, tuple) or isinstance(iCs, list), 'invalid type of iCs : {:}'.format( iCs )
assert len(iCs) == 3,'invalid lengths of iCs : {:}'.format(iCs)
self.conv_a = ConvBNReLU(iCs[0], iCs[1], 3, stride, 1, False, has_avg=False, has_bn=True, has_relu=True)
self.conv_b = ConvBNReLU(iCs[1], iCs[2], 3, 1, 1, False, has_avg=False, has_bn=True, has_relu=False)
residual_in = iCs[0]
if stride == 2:
self.downsample = ConvBNReLU(iCs[0], iCs[2], 1, 1, 0, False, has_avg=True, has_bn=False, has_relu=False)
residual_in = iCs[2]
elif iCs[0] != iCs[2]:
self.downsample = ConvBNReLU(iCs[0], iCs[2], 1, 1, 0, False, has_avg=False,has_bn=True , has_relu=False)
else:
self.downsample = None
#self.out_dim = max(residual_in, iCs[2])
self.out_dim = iCs[2]
def forward(self, inputs):
basicblock = self.conv_a(inputs)
basicblock = self.conv_b(basicblock)
if self.downsample is not None:
residual = self.downsample(inputs)
else:
residual = inputs
out = residual + basicblock
return F.relu(out, inplace=True)
class ResNetBottleneck(nn.Module):
expansion = 4
num_conv = 3
def __init__(self, iCs, stride):
super(ResNetBottleneck, self).__init__()
assert stride == 1 or stride == 2, 'invalid stride {:}'.format(stride)
assert isinstance(iCs, tuple) or isinstance(iCs, list), 'invalid type of iCs : {:}'.format( iCs )
assert len(iCs) == 4,'invalid lengths of iCs : {:}'.format(iCs)
self.conv_1x1 = ConvBNReLU(iCs[0], iCs[1], 1, 1, 0, False, has_avg=False, has_bn=True, has_relu=True)
self.conv_3x3 = ConvBNReLU(iCs[1], iCs[2], 3, stride, 1, False, has_avg=False, has_bn=True, has_relu=True)
self.conv_1x4 = ConvBNReLU(iCs[2], iCs[3], 1, 1, 0, False, has_avg=False, has_bn=True, has_relu=False)
residual_in = iCs[0]
if stride == 2:
self.downsample = ConvBNReLU(iCs[0], iCs[3], 1, 1, 0, False, has_avg=True , has_bn=False, has_relu=False)
residual_in = iCs[3]
elif iCs[0] != iCs[3]:
self.downsample = ConvBNReLU(iCs[0], iCs[3], 1, 1, 0, False, has_avg=False, has_bn=False, has_relu=False)
residual_in = iCs[3]
else:
self.downsample = None
#self.out_dim = max(residual_in, iCs[3])
self.out_dim = iCs[3]
def forward(self, inputs):
bottleneck = self.conv_1x1(inputs)
bottleneck = self.conv_3x3(bottleneck)
bottleneck = self.conv_1x4(bottleneck)
if self.downsample is not None:
residual = self.downsample(inputs)
else:
residual = inputs
out = residual + bottleneck
return F.relu(out, inplace=True)
class InferWidthCifarResNet(nn.Module):
def __init__(self, block_name, depth, xchannels, num_classes, zero_init_residual):
super(InferWidthCifarResNet, self).__init__()
#Model type specifies number of layers for CIFAR-10 and CIFAR-100 model
if block_name == 'ResNetBasicblock':
block = ResNetBasicblock
assert (depth - 2) % 6 == 0, 'depth should be one of 20, 32, 44, 56, 110'
layer_blocks = (depth - 2) // 6
elif block_name == 'ResNetBottleneck':
block = ResNetBottleneck
assert (depth - 2) % 9 == 0, 'depth should be one of 164'
layer_blocks = (depth - 2) // 9
else:
raise ValueError('invalid block : {:}'.format(block_name))
self.message = 'InferWidthCifarResNet : Depth : {:} , Layers for each block : {:}'.format(depth, layer_blocks)
self.num_classes = num_classes
self.xchannels = xchannels
self.layers = nn.ModuleList( [ ConvBNReLU(xchannels[0], xchannels[1], 3, 1, 1, False, has_avg=False, has_bn=True, has_relu=True) ] )
last_channel_idx = 1
for stage in range(3):
for iL in range(layer_blocks):
num_conv = block.num_conv
iCs = self.xchannels[last_channel_idx:last_channel_idx+num_conv+1]
stride = 2 if stage > 0 and iL == 0 else 1
module = block(iCs, stride)
last_channel_idx += num_conv
self.xchannels[last_channel_idx] = module.out_dim
self.layers.append ( module )
self.message += "\nstage={:}, ilayer={:02d}/{:02d}, block={:03d}, iCs={:}, oC={:3d}, stride={:}".format(stage, iL, layer_blocks, len(self.layers)-1, iCs, module.out_dim, stride)
self.avgpool = nn.AvgPool2d(8)
self.classifier = nn.Linear(self.xchannels[-1], num_classes)
self.apply(initialize_resnet)
if zero_init_residual:
for m in self.modules():
if isinstance(m, ResNetBasicblock):
nn.init.constant_(m.conv_b.bn.weight, 0)
elif isinstance(m, ResNetBottleneck):
nn.init.constant_(m.conv_1x4.bn.weight, 0)
def get_message(self):
return self.message
def forward(self, inputs):
x = inputs
for i, layer in enumerate(self.layers):
x = layer( x )
features = self.avgpool(x)
features = features.view(features.size(0), -1)
logits = self.classifier(features)
return features, logits