File size: 3,620 Bytes
98068b3 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 |
"""Split-Attention"""
import torch
from torch import nn
import torch.nn.functional as F
from torch.nn import Conv2d, Module, Linear, BatchNorm2d, ReLU
from torch.nn.modules.utils import _pair
__all__ = ['SplAtConv2d']
class SplAtConv2d(Module):
"""Split-Attention Conv2d
"""
def __init__(self, in_channels, channels, kernel_size, stride=(1, 1), padding=(0, 0),
dilation=(1, 1), groups=1, bias=True,
radix=2, reduction_factor=4,
rectify=False, rectify_avg=False, norm_layer=None,
dropblock_prob=0.0, **kwargs):
super(SplAtConv2d, self).__init__()
padding = _pair(padding)
self.rectify = rectify and (padding[0] > 0 or padding[1] > 0)
self.rectify_avg = rectify_avg
inter_channels = max(in_channels*radix//reduction_factor, 32)
self.radix = radix
self.cardinality = groups
self.channels = channels
self.dropblock_prob = dropblock_prob
if self.rectify:
from rfconv import RFConv2d
self.conv = RFConv2d(in_channels, channels*radix, kernel_size, stride, padding, dilation,
groups=groups*radix, bias=bias, average_mode=rectify_avg, **kwargs)
else:
self.conv = Conv2d(in_channels, channels*radix, kernel_size, stride, padding, dilation,
groups=groups*radix, bias=bias, **kwargs)
self.use_bn = norm_layer is not None
if self.use_bn:
self.bn0 = norm_layer(channels*radix)
self.relu = ReLU(inplace=True)
self.fc1 = Conv2d(channels, inter_channels, 1, groups=self.cardinality)
if self.use_bn:
self.bn1 = norm_layer(inter_channels)
self.fc2 = Conv2d(inter_channels, channels*radix, 1, groups=self.cardinality)
if dropblock_prob > 0.0:
self.dropblock = DropBlock2D(dropblock_prob, 3)
self.rsoftmax = rSoftMax(radix, groups)
def forward(self, x):
x = self.conv(x)
if self.use_bn:
x = self.bn0(x)
if self.dropblock_prob > 0.0:
x = self.dropblock(x)
x = self.relu(x)
batch, rchannel = x.shape[:2]
if self.radix > 1:
if torch.__version__ < '1.5':
splited = torch.split(x, int(rchannel//self.radix), dim=1)
else:
splited = torch.split(x, rchannel//self.radix, dim=1)
gap = sum(splited)
else:
gap = x
gap = F.adaptive_avg_pool2d(gap, 1)
gap = self.fc1(gap)
if self.use_bn:
gap = self.bn1(gap)
gap = self.relu(gap)
atten = self.fc2(gap)
atten = self.rsoftmax(atten).view(batch, -1, 1, 1)
if self.radix > 1:
if torch.__version__ < '1.5':
attens = torch.split(atten, int(rchannel//self.radix), dim=1)
else:
attens = torch.split(atten, rchannel//self.radix, dim=1)
out = sum([att*split for (att, split) in zip(attens, splited)])
else:
out = atten * x
return out.contiguous()
class rSoftMax(nn.Module):
def __init__(self, radix, cardinality):
super().__init__()
self.radix = radix
self.cardinality = cardinality
def forward(self, x):
batch = x.size(0)
if self.radix > 1:
x = x.view(batch, self.cardinality, self.radix, -1).transpose(1, 2)
x = F.softmax(x, dim=1)
x = x.reshape(batch, -1)
else:
x = torch.sigmoid(x)
return x
|