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2025-10-18 23:01:31 +08:00

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Python

import torch
import itertools
from timm.models.vision_transformer import trunc_normal_
from timm.layers import SqueezeExcite
from timm.models import register_model
from .ska import SKA
from timm.models import build_model_with_cfg
from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
class Conv2d_BN(torch.nn.Sequential):
def __init__(self, a, b, ks=1, stride=1, pad=0, dilation=1,
groups=1, bn_weight_init=1):
super().__init__()
self.add_module('c', torch.nn.Conv2d(
a, b, ks, stride, pad, dilation, groups, bias=False))
self.add_module('bn', torch.nn.BatchNorm2d(b))
torch.nn.init.constant_(self.bn.weight, bn_weight_init)
torch.nn.init.constant_(self.bn.bias, 0)
@torch.no_grad()
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 = torch.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 BN_Linear(torch.nn.Sequential):
def __init__(self, a, b, bias=True, std=0.02):
super().__init__()
self.add_module('bn', torch.nn.BatchNorm1d(a))
self.add_module('l', torch.nn.Linear(a, b, bias=bias))
trunc_normal_(self.l.weight, std=std)
if bias:
torch.nn.init.constant_(self.l.bias, 0)
@torch.no_grad()
def fuse(self):
bn, l = self._modules.values()
w = bn.weight / (bn.running_var + bn.eps)**0.5
b = bn.bias - self.bn.running_mean * \
self.bn.weight / (bn.running_var + bn.eps)**0.5
w = l.weight * w[None, :]
if l.bias is None:
b = b @ self.l.weight.T
else:
b = (l.weight @ b[:, None]).view(-1) + self.l.bias
m = torch.nn.Linear(w.size(1), w.size(0), device=l.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)
class FFN(torch.nn.Module):
def __init__(self, ed, h):
super().__init__()
self.pw1 = Conv2d_BN(ed, h)
self.act = torch.nn.ReLU()
self.pw2 = Conv2d_BN(h, ed, bn_weight_init=0)
def forward(self, x):
x = self.pw2(self.act(self.pw1(x)))
return x
class Attention(torch.nn.Module):
def __init__(self, dim, key_dim, num_heads=8,
attn_ratio=4,
resolution=14):
super().__init__()
self.num_heads = num_heads
self.scale = key_dim ** -0.5
self.key_dim = key_dim
self.nh_kd = nh_kd = key_dim * num_heads
self.d = int(attn_ratio * key_dim)
self.dh = int(attn_ratio * key_dim) * num_heads
self.attn_ratio = attn_ratio
h = self.dh + nh_kd * 2
self.qkv = Conv2d_BN(dim, h, ks=1)
self.proj = torch.nn.Sequential(torch.nn.ReLU(), Conv2d_BN(
self.dh, dim, bn_weight_init=0))
self.dw = Conv2d_BN(nh_kd, nh_kd, 3, 1, 1, groups=nh_kd)
points = list(itertools.product(range(resolution), range(resolution)))
N = len(points)
attention_offsets = {}
idxs = []
for p1 in points:
for p2 in points:
offset = (abs(p1[0] - p2[0]), abs(p1[1] - p2[1]))
if offset not in attention_offsets:
attention_offsets[offset] = len(attention_offsets)
idxs.append(attention_offsets[offset])
self.attention_biases = torch.nn.Parameter(
torch.zeros(num_heads, len(attention_offsets)))
self.register_buffer('attention_bias_idxs',
torch.LongTensor(idxs).view(N, N))
@torch.no_grad()
def train(self, mode=True):
super().train(mode)
if mode and hasattr(self, 'ab'):
del self.ab
else:
self.ab = self.attention_biases[:, self.attention_bias_idxs]
def forward(self, x):
B, _, H, W = x.shape
N = H * W
qkv = self.qkv(x)
q, k, v = qkv.view(B, -1, H, W).split([self.nh_kd, self.nh_kd, self.dh], dim=1)
q = self.dw(q)
q, k, v = q.view(B, self.num_heads, -1, N), k.view(B, self.num_heads, -1, N), v.view(B, self.num_heads, -1, N)
attn = (
(q.transpose(-2, -1) @ k) * self.scale
+
(self.attention_biases[:, self.attention_bias_idxs]
if self.training else self.ab)
)
attn = attn.softmax(dim=-1)
x = (v @ attn.transpose(-2, -1)).reshape(B, -1, H, W)
x = self.proj(x)
return x
class RepVGGDW(torch.nn.Module):
def __init__(self, ed) -> None:
super().__init__()
self.conv = Conv2d_BN(ed, ed, 3, 1, 1, groups=ed)
self.conv1 = Conv2d_BN(ed, ed, 1, 1, 0, groups=ed)
self.dim = ed
def forward(self, x):
return self.conv(x) + self.conv1(x) + x
@torch.no_grad()
def fuse(self):
conv = self.conv.fuse()
conv1 = self.conv1.fuse()
conv_w = conv.weight
conv_b = conv.bias
conv1_w = conv1.weight
conv1_b = conv1.bias
conv1_w = torch.nn.functional.pad(conv1_w, [1,1,1,1])
identity = torch.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)
return conv
import torch.nn as nn
class LKP(nn.Module):
def __init__(self, dim, lks, sks, groups):
super().__init__()
self.cv1 = Conv2d_BN(dim, dim // 2)
self.act = nn.ReLU()
self.cv2 = Conv2d_BN(dim // 2, dim // 2, ks=lks, pad=(lks - 1) // 2, groups=dim // 2)
self.cv3 = Conv2d_BN(dim // 2, dim // 2)
self.cv4 = nn.Conv2d(dim // 2, sks ** 2 * dim // groups, kernel_size=1)
self.norm = nn.GroupNorm(num_groups=dim // groups, num_channels=sks ** 2 * dim // groups)
self.sks = sks
self.groups = groups
self.dim = dim
def forward(self, x):
x = self.act(self.cv3(self.cv2(self.act(self.cv1(x)))))
w = self.norm(self.cv4(x))
b, _, h, width = w.size()
w = w.view(b, self.dim // self.groups, self.sks ** 2, h, width)
return w
class LSConv(nn.Module):
def __init__(self, dim):
super(LSConv, self).__init__()
self.lkp = LKP(dim, lks=7, sks=3, groups=8)
self.ska = SKA()
self.bn = nn.BatchNorm2d(dim)
def forward(self, x):
return self.bn(self.ska(x, self.lkp(x))) + x
class Block(torch.nn.Module):
def __init__(self,
ed, kd, nh=8,
ar=4,
resolution=14,
stage=-1, depth=-1):
super().__init__()
if depth % 2 == 0:
self.mixer = RepVGGDW(ed)
self.se = SqueezeExcite(ed, 0.25)
else:
self.se = torch.nn.Identity()
if stage == 3:
self.mixer = Residual(Attention(ed, kd, nh, ar, resolution=resolution))
else:
self.mixer = LSConv(ed)
self.ffn = Residual(FFN(ed, int(ed * 2)))
def forward(self, x):
return self.ffn(self.se(self.mixer(x)))
class LSNet(torch.nn.Module):
def __init__(self, img_size=224,
patch_size=16,
in_chans=3,
num_classes=1000,
embed_dim=[64, 128, 192, 256],
key_dim=[16, 16, 16, 16],
depth=[1, 2, 3, 4],
num_heads=[4, 4, 4, 4],
distillation=False,
**kwargs):
super().__init__()
default_cfg = kwargs.pop('default_cfg', None)
pretrained_cfg = kwargs.pop('pretrained_cfg', None)
pretrained_cfg_overlay = kwargs.pop('pretrained_cfg_overlay', None)
if default_cfg is not None:
self.default_cfg = default_cfg
if pretrained_cfg is not None:
self.pretrained_cfg = pretrained_cfg
if pretrained_cfg_overlay is not None:
self.pretrained_cfg_overlay = pretrained_cfg_overlay
if kwargs:
self.extra_init_kwargs = kwargs
resolution = img_size
self.patch_embed = torch.nn.Sequential(Conv2d_BN(in_chans, embed_dim[0] // 4, 3, 2, 1), torch.nn.ReLU(),
Conv2d_BN(embed_dim[0] // 4, embed_dim[0] // 2, 3, 2, 1), torch.nn.ReLU(),
Conv2d_BN(embed_dim[0] // 2, embed_dim[0], 3, 2, 1)
)
resolution = img_size // patch_size
attn_ratio = [embed_dim[i] / (key_dim[i] * num_heads[i]) for i in range(len(embed_dim))]
self.blocks1 = nn.Sequential()
self.blocks2 = nn.Sequential()
self.blocks3 = nn.Sequential()
self.blocks4 = nn.Sequential()
blocks = [self.blocks1, self.blocks2, self.blocks3, self.blocks4]
for i, (ed, kd, dpth, nh, ar) in enumerate(
zip(embed_dim, key_dim, depth, num_heads, attn_ratio)):
for d in range(dpth):
blocks[i].append(Block(ed, kd, nh, ar, resolution, stage=i, depth=d))
if i != len(depth) - 1:
blk = blocks[i+1]
resolution_ = (resolution - 1) // 2 + 1
blk.append(Conv2d_BN(embed_dim[i], embed_dim[i], ks=3, stride=2, pad=1, groups=embed_dim[i]))
blk.append(Conv2d_BN(embed_dim[i], embed_dim[i+1], ks=1, stride=1, pad=0))
resolution = resolution_
self.head = BN_Linear(embed_dim[-1], num_classes) if num_classes > 0 else torch.nn.Identity()
self.distillation = distillation
if distillation:
self.head_dist = BN_Linear(embed_dim[-1], num_classes) if num_classes > 0 else torch.nn.Identity()
self.num_classes = num_classes
self.num_features = embed_dim[-1]
@torch.jit.ignore # type: ignore
def no_weight_decay(self):
return {x for x in self.state_dict().keys() if 'attention_biases' in x}
def forward(self, x):
x = self.patch_embed(x)
x = self.blocks1(x)
x = self.blocks2(x)
x = self.blocks3(x)
x = self.blocks4(x)
x = torch.nn.functional.adaptive_avg_pool2d(x, 1).flatten(1)
if self.distillation:
x = self.head(x), self.head_dist(x)
if not self.training:
x = (x[0] + x[1]) / 2
else:
x = self.head(x)
return x
def _cfg(url='', **kwargs):
return {
'url': url,
'num_classes': 1000, 'input_size': (3, 224, 224), 'pool_size': (4, 4),
'crop_pct': .9, 'interpolation': 'bicubic',
'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD,
'first_conv': 'patch_embed.0.c', 'classifier': ('head.linear', 'head_dist.linear'),
**kwargs
}
def _with_hf_hub(kwargs):
"""兼容不同 timm 版本的 hf hub 配置字段"""
if 'hf_hub' in kwargs and 'hf_hub_id' not in kwargs:
kwargs['hf_hub_id'] = kwargs.pop('hf_hub')
return kwargs
default_cfgs = dict(
lsnet_t=_cfg(**_with_hf_hub({'hf_hub': 'jameslahm/lsnet_t'})),
lsnet_t_distill=_cfg(**_with_hf_hub({'hf_hub': 'jameslahm/lsnet_t_distill'})),
lsnet_s=_cfg(**_with_hf_hub({'hf_hub': 'jameslahm/lsnet_s'})),
lsnet_s_distill=_cfg(**_with_hf_hub({'hf_hub': 'jameslahm/lsnet_s_distill'})),
lsnet_b=_cfg(**_with_hf_hub({'hf_hub': 'jameslahm/lsnet_b'})),
lsnet_b_distill=_cfg(**_with_hf_hub({'hf_hub': 'jameslahm/lsnet_b_distill'})),
)
def _create_lsnet(variant, pretrained=False, **kwargs):
cfg = default_cfgs.get(variant, None)
if cfg is not None:
kwargs.setdefault('default_cfg', cfg)
kwargs.setdefault('pretrained_cfg', cfg)
model = build_model_with_cfg(
LSNet,
variant,
pretrained,
**kwargs,
)
return model
@register_model
def lsnet_t(num_classes=1000, distillation=False, pretrained=False, **kwargs):
model = _create_lsnet("lsnet_t" + ("_distill" if distillation else ""),
pretrained=pretrained,
num_classes=num_classes,
distillation=distillation,
img_size=224,
patch_size=8,
embed_dim=[64, 128, 256, 384],
depth=[0, 2, 8, 10],
num_heads=[3, 3, 3, 4],
)
return model
@register_model
def lsnet_s(num_classes=1000, distillation=False, pretrained=False, **kwargs):
model = _create_lsnet("lsnet_s" + ("_distill" if distillation else ""),
pretrained=pretrained,
num_classes=num_classes,
distillation=distillation,
img_size=224,
patch_size=8,
embed_dim=[96, 192, 320, 448],
depth=[1, 2, 8, 10],
num_heads=[3, 3, 3, 4],
)
return model
@register_model
def lsnet_b(num_classes=1000, distillation=False, pretrained=False, **kwargs):
model = _create_lsnet("lsnet_b" + ("_distill" if distillation else ""),
pretrained=pretrained,
num_classes=num_classes,
distillation=distillation,
img_size=224,
patch_size=8,
embed_dim=[128, 256, 384, 512],
depth=[4, 6, 8, 10],
num_heads=[3, 3, 3, 4],
)
return model
@register_model
def lsnet_t_distill(**kwargs):
kwargs["distillation"] = True
return lsnet_t(**kwargs)
@register_model
def lsnet_s_distill(**kwargs):
kwargs["distillation"] = True
return lsnet_s(**kwargs)
@register_model
def lsnet_b_distill(**kwargs):
kwargs["distillation"] = True
return lsnet_b(**kwargs)