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""" | |
This code is refer from: | |
https://github.com/THU-MIG/RepViT | |
""" | |
import torch.nn as nn | |
import torch | |
from torch.nn.init import constant_ | |
def _make_divisible(v, divisor, min_value=None): | |
""" | |
This function is taken from the original tf repo. | |
It ensures that all layers have a channel number that is divisible by 8 | |
It can be seen here: | |
https://github.com/tensorflow/models/blob/master/research/slim/nets/mobilenet/mobilenet.py | |
:param v: | |
:param divisor: | |
:param min_value: | |
:return: | |
""" | |
if min_value is None: | |
min_value = divisor | |
new_v = max(min_value, int(v + divisor / 2) // divisor * divisor) | |
# Make sure that round down does not go down by more than 10%. | |
if new_v < 0.9 * v: | |
new_v += divisor | |
return new_v | |
def make_divisible(v, divisor=8, min_value=None, round_limit=0.9): | |
min_value = min_value or divisor | |
new_v = max(min_value, int(v + divisor / 2) // divisor * divisor) | |
# Make sure that round down does not go down by more than 10%. | |
if new_v < round_limit * v: | |
new_v += divisor | |
return new_v | |
class SEModule(nn.Module): | |
"""SE Module as defined in original SE-Nets with a few additions | |
Additions include: | |
* divisor can be specified to keep channels % div == 0 (default: 8) | |
* reduction channels can be specified directly by arg (if rd_channels is set) | |
* reduction channels can be specified by float rd_ratio (default: 1/16) | |
* global max pooling can be added to the squeeze aggregation | |
* customizable activation, normalization, and gate layer | |
""" | |
def __init__( | |
self, | |
channels, | |
rd_ratio=1.0 / 16, | |
rd_channels=None, | |
rd_divisor=8, | |
act_layer=nn.ReLU, | |
): | |
super(SEModule, self).__init__() | |
if not rd_channels: | |
rd_channels = make_divisible(channels * rd_ratio, | |
rd_divisor, | |
round_limit=0.0) | |
self.fc1 = nn.Conv2d(channels, rd_channels, kernel_size=1, bias=True) | |
self.act = act_layer() | |
self.fc2 = nn.Conv2d(rd_channels, channels, kernel_size=1, bias=True) | |
def forward(self, x): | |
x_se = x.mean((2, 3), keepdim=True) | |
x_se = self.fc1(x_se) | |
x_se = self.act(x_se) | |
x_se = self.fc2(x_se) | |
return x * torch.sigmoid(x_se) | |
class Conv2D_BN(nn.Sequential): | |
def __init__( | |
self, | |
a, | |
b, | |
ks=1, | |
stride=1, | |
pad=0, | |
dilation=1, | |
groups=1, | |
bn_weight_init=1, | |
resolution=-10000, | |
): | |
super().__init__() | |
self.add_module( | |
'c', nn.Conv2d(a, b, ks, stride, pad, dilation, groups, | |
bias=False)) | |
self.add_module('bn', nn.BatchNorm2d(b)) | |
constant_(self.bn.weight, bn_weight_init) | |
constant_(self.bn.bias, 0) | |
def fuse(self): | |
c, bn = self._modules.values() | |
w = bn.weight / (bn.running_var + bn.eps)**0.5 | |
w = c.weight * w[:, None, None, None] | |
b = bn.bias - bn.running_mean * bn.weight / \ | |
(bn.running_var + bn.eps)**0.5 | |
m = nn.Conv2d(w.size(1) * self.c.groups, | |
w.size(0), | |
w.shape[2:], | |
stride=self.c.stride, | |
padding=self.c.padding, | |
dilation=self.c.dilation, | |
groups=self.c.groups, | |
device=c.weight.device) | |
m.weight.data.copy_(w) | |
m.bias.data.copy_(b) | |
return m | |
class Residual(torch.nn.Module): | |
def __init__(self, m, drop=0.): | |
super().__init__() | |
self.m = m | |
self.drop = drop | |
def forward(self, x): | |
if self.training and self.drop > 0: | |
return x + self.m(x) * torch.rand( | |
x.size(0), 1, 1, 1, device=x.device).ge_( | |
self.drop).div(1 - self.drop).detach() | |
else: | |
return x + self.m(x) | |
def fuse(self): | |
if isinstance(self.m, Conv2D_BN): | |
m = self.m.fuse() | |
assert (m.groups == m.in_channels) | |
identity = torch.ones(m.weight.shape[0], m.weight.shape[1], 1, 1) | |
identity = nn.functional.pad(identity, [1, 1, 1, 1]) | |
m.weight += identity.to(m.weight.device) | |
return m | |
elif isinstance(self.m, nn.Conv2d): | |
m = self.m | |
assert (m.groups != m.in_channels) | |
identity = torch.ones(m.weight.shape[0], m.weight.shape[1], 1, 1) | |
identity = nn.functional.pad(identity, [1, 1, 1, 1]) | |
m.weight += identity.to(m.weight.device) | |
return m | |
else: | |
return self | |
class RepVGGDW(nn.Module): | |
def __init__(self, ed) -> None: | |
super().__init__() | |
self.conv = Conv2D_BN(ed, ed, 3, 1, 1, groups=ed) | |
self.conv1 = nn.Conv2d(ed, ed, 1, 1, 0, groups=ed) | |
self.dim = ed | |
self.bn = nn.BatchNorm2d(ed) | |
def forward(self, x): | |
return self.bn((self.conv(x) + self.conv1(x)) + x) | |
def fuse(self): | |
conv = self.conv.fuse() | |
conv1 = self.conv1 | |
conv_w = conv.weight | |
conv_b = conv.bias | |
conv1_w = conv1.weight | |
conv1_b = conv1.bias | |
conv1_w = nn.functional.pad(conv1_w, [1, 1, 1, 1]) | |
identity = nn.functional.pad( | |
torch.ones(conv1_w.shape[0], | |
conv1_w.shape[1], | |
1, | |
1, | |
device=conv1_w.device), [1, 1, 1, 1]) | |
final_conv_w = conv_w + conv1_w + identity | |
final_conv_b = conv_b + conv1_b | |
conv.weight.data.copy_(final_conv_w) | |
conv.bias.data.copy_(final_conv_b) | |
bn = self.bn | |
w = bn.weight / (bn.running_var + bn.eps)**0.5 | |
w = conv.weight * w[:, None, None, None] | |
b = bn.bias + (conv.bias - bn.running_mean) * bn.weight / \ | |
(bn.running_var + bn.eps)**0.5 | |
conv.weight.data.copy_(w) | |
conv.bias.data.copy_(b) | |
return conv | |
class RepViTBlock(nn.Module): | |
def __init__(self, inp, hidden_dim, oup, kernel_size, stride, use_se, | |
use_hs): | |
super(RepViTBlock, self).__init__() | |
self.identity = stride == 1 and inp == oup | |
assert hidden_dim == 2 * inp | |
if stride != 1: | |
self.token_mixer = nn.Sequential( | |
Conv2D_BN(inp, | |
inp, | |
kernel_size, | |
stride, (kernel_size - 1) // 2, | |
groups=inp), | |
SEModule(inp, 0.25) if use_se else nn.Identity(), | |
Conv2D_BN(inp, oup, ks=1, stride=1, pad=0), | |
) | |
self.channel_mixer = Residual( | |
nn.Sequential( | |
# pw | |
Conv2D_BN(oup, 2 * oup, 1, 1, 0), | |
nn.GELU() if use_hs else nn.GELU(), | |
# pw-linear | |
Conv2D_BN(2 * oup, oup, 1, 1, 0, bn_weight_init=0), | |
)) | |
else: | |
assert self.identity | |
self.token_mixer = nn.Sequential( | |
RepVGGDW(inp), | |
SEModule(inp, 0.25) if use_se else nn.Identity(), | |
) | |
self.channel_mixer = Residual( | |
nn.Sequential( | |
# pw | |
Conv2D_BN(inp, hidden_dim, 1, 1, 0), | |
nn.GELU() if use_hs else nn.GELU(), | |
# pw-linear | |
Conv2D_BN(hidden_dim, oup, 1, 1, 0, bn_weight_init=0), | |
)) | |
def forward(self, x): | |
return self.channel_mixer(self.token_mixer(x)) | |
class RepViT(nn.Module): | |
def __init__(self, cfgs, in_channels=3, out_indices=None): | |
super(RepViT, self).__init__() | |
# setting of inverted residual blocks | |
self.cfgs = cfgs | |
# building first layer | |
input_channel = self.cfgs[0][2] | |
patch_embed = nn.Sequential( | |
Conv2D_BN(in_channels, input_channel // 2, 3, 2, 1), | |
nn.GELU(), | |
Conv2D_BN(input_channel // 2, input_channel, 3, 2, 1), | |
) | |
layers = [patch_embed] | |
# building inverted residual blocks | |
block = RepViTBlock | |
for k, t, c, use_se, use_hs, s in self.cfgs: | |
output_channel = _make_divisible(c, 8) | |
exp_size = _make_divisible(input_channel * t, 8) | |
layers.append( | |
block(input_channel, exp_size, output_channel, k, s, use_se, | |
use_hs)) | |
input_channel = output_channel | |
self.features = nn.ModuleList(layers) | |
self.out_indices = out_indices | |
if out_indices is not None: | |
self.out_channels = [self.cfgs[ids - 1][2] for ids in out_indices] | |
else: | |
self.out_channels = self.cfgs[-1][2] | |
def forward(self, x): | |
if self.out_indices is not None: | |
return self.forward_det(x) | |
return self.forward_rec(x) | |
def forward_det(self, x): | |
outs = [] | |
for i, f in enumerate(self.features): | |
x = f(x) | |
if i in self.out_indices: | |
outs.append(x) | |
return outs | |
def forward_rec(self, x): | |
for f in self.features: | |
x = f(x) | |
return x | |
def RepSVTREncoder(in_channels=3): | |
""" | |
Constructs a MobileNetV3-Large model | |
""" | |
# k, t, c, SE, HS, s | |
cfgs = [ | |
[3, 2, 96, 1, 0, 1], | |
[3, 2, 96, 0, 0, 1], | |
[3, 2, 96, 0, 0, 1], | |
[3, 2, 192, 0, 1, (2, 1)], | |
[3, 2, 192, 1, 1, 1], | |
[3, 2, 192, 0, 1, 1], | |
[3, 2, 192, 1, 1, 1], | |
[3, 2, 192, 0, 1, 1], | |
[3, 2, 192, 1, 1, 1], | |
[3, 2, 192, 0, 1, 1], | |
[3, 2, 384, 0, 1, (2, 1)], | |
[3, 2, 384, 1, 1, 1], | |
[3, 2, 384, 0, 1, 1], | |
] | |
return RepViT(cfgs, in_channels=in_channels) | |
def RepSVTR_det(in_channels=3, out_indices=[2, 5, 10, 13]): | |
""" | |
Constructs a MobileNetV3-Large model | |
""" | |
# k, t, c, SE, HS, s | |
cfgs = [ | |
[3, 2, 48, 1, 0, 1], | |
[3, 2, 48, 0, 0, 1], | |
[3, 2, 96, 0, 0, 2], | |
[3, 2, 96, 1, 0, 1], | |
[3, 2, 96, 0, 0, 1], | |
[3, 2, 192, 0, 1, 2], | |
[3, 2, 192, 1, 1, 1], | |
[3, 2, 192, 0, 1, 1], | |
[3, 2, 192, 1, 1, 1], | |
[3, 2, 192, 0, 1, 1], | |
[3, 2, 384, 0, 1, 2], | |
[3, 2, 384, 1, 1, 1], | |
[3, 2, 384, 0, 1, 1], | |
] | |
return RepViT(cfgs, in_channels=in_channels, out_indices=out_indices) | |