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import torch
import torch.nn as nn
import torch.nn.functional as F
from torchvision import ops
class DMlp(nn.Module):
def __init__(self, dim, growth_rate=2.0):
super().__init__()
hidden_dim = int(dim * growth_rate)
self.conv_0 = nn.Sequential(
nn.Conv2d(dim,hidden_dim,3,1,1,groups=dim),
nn.Conv2d(hidden_dim,hidden_dim,1,1,0)
)
self.act =nn.GELU()
self.conv_1 = nn.Conv2d(hidden_dim, dim, 1, 1, 0)
def forward(self, x):
x = self.conv_0(x)
x = self.act(x)
x = self.conv_1(x)
return x
class PCFN(nn.Module):
def __init__(self, dim, growth_rate=2.0, p_rate=0.25):
super().__init__()
hidden_dim = int(dim * growth_rate)
p_dim = int(hidden_dim * p_rate)
self.conv_0 = nn.Conv2d(dim,hidden_dim,1,1,0)
self.conv_1 = nn.Conv2d(p_dim, p_dim ,3,1,1)
self.act =nn.GELU()
self.conv_2 = nn.Conv2d(hidden_dim, dim, 1, 1, 0)
self.p_dim = p_dim
self.hidden_dim = hidden_dim
def forward(self, x):
if self.training:
x = self.act(self.conv_0(x))
x1, x2 = torch.split(x,[self.p_dim,self.hidden_dim-self.p_dim],dim=1)
x1 = self.act(self.conv_1(x1))
x = self.conv_2(torch.cat([x1,x2], dim=1))
else:
x = self.act(self.conv_0(x))
x[:,:self.p_dim,:,:] = self.act(self.conv_1(x[:,:self.p_dim,:,:]))
x = self.conv_2(x)
return x
class SMFA(nn.Module):
def __init__(self, dim=36):
super(SMFA, self).__init__()
self.linear_0 = nn.Conv2d(dim,dim*2,1,1,0)
self.linear_1 = nn.Conv2d(dim,dim,1,1,0)
self.linear_2 = nn.Conv2d(dim,dim,1,1,0)
self.lde = DMlp(dim,2)
self.dw_conv = nn.Conv2d(dim,dim,3,1,1,groups=dim)
self.gelu = nn.GELU()
self.down_scale = 8
self.alpha = nn.Parameter(torch.ones((1,dim,1,1)))
self.belt = nn.Parameter(torch.zeros((1,dim,1,1)))
def forward(self, f):
_,_,h,w = f.shape
y, x = self.linear_0(f).chunk(2, dim=1)
x_s = self.dw_conv(F.adaptive_max_pool2d(x, (h // self.down_scale, w // self.down_scale)))
x_v = torch.var(x, dim=(-2,-1), keepdim=True)
x_l = x * F.interpolate(self.gelu(self.linear_1(x_s * self.alpha + x_v * self.belt)), size=(h,w), mode='nearest')
y_d = self.lde(y)
return self.linear_2(x_l + y_d)
class FMB(nn.Module):
def __init__(self, dim, ffn_scale=2.0):
super().__init__()
self.smfa = SMFA(dim)
self.pcfn = PCFN(dim, ffn_scale)
def forward(self, x):
x = self.smfa(F.normalize(x)) + x
x = self.pcfn(F.normalize(x)) + x
return x
class SMFANet(nn.Module):
def __init__(self, dim=36, n_blocks=8, ffn_scale=2, upscaling_factor=4):
super().__init__()
self.scale = upscaling_factor
self.to_feat = nn.Conv2d(3, dim, 3, 1, 1)
self.feats = nn.Sequential(*[FMB(dim, ffn_scale) for _ in range(n_blocks)])
self.to_img = nn.Sequential(
nn.Conv2d(dim, 3 * upscaling_factor**2, 3, 1, 1),
nn.PixelShuffle(upscaling_factor)
)
def forward(self, x):
x = self.to_feat(x)
x = self.feats(x) + x
x = self.to_img(x)
return x |