x = torch.cat([x, contracting_x], dim=1)

这行代码使用 PyTorch 的 torch.cat() 函数来将两个张量 x 和 contracting_x 沿着维度 1 进行拼接（即按列方向进行拼接）。拼接后的张量作为新的 x 张量返回。可以将这个操作理解为将两个特征图（feature map）沿着通道维度进行拼接，用于进行 U-Net 网络中的上采样（upsampling）操作。

相关问题

x = torch.cat((x_s, x_t), dim=0)

这行代码使用了 PyTorch 中的 `torch.cat()` 函数，它用于将多个张量（tensor）沿着指定的维度进行拼接（concatenate）。在这里，`x_s` 和 `x_t` 是两个张量（tensor），`dim=0` 表示沿着第0维（即行）进行拼接。因此，这行代码的作用是将 `x_s` 和 `x_t` 沿着行方向拼接成一个新的张量 `x`。

class Partial_conv3(nn.Module): def __init__(self, dim, n_div, forward): super().__init__() self.dim_conv3 = dim // n_div self.dim_untouched = dim - self.dim_conv3 self.partial_conv3 = nn.Conv2d(self.dim_conv3, self.dim_conv3, 3, 1, 1, bias=False) if forward == 'slicing': self.forward = self.forward_slicing elif forward == 'split_cat': self.forward = self.forward_split_cat else: raise NotImplementedError def forward_slicing(self, x: Tensor) -> Tensor: # only for inference x = x.clone() # !!! Keep the original input intact for the residual connection later x[:, :self.dim_conv3, :, :] = self.partial_conv3(x[:, :self.dim_conv3, :, :]) return x def forward_split_cat(self, x: Tensor) -> Tensor: x1, x2 = torch.split(x, [self.dim_conv3, self.dim_untouched], dim=1) x1 = self.partial_conv3(x1) x = torch.cat((x1, x2), 1) return x 在这段代码中插入全局平均池化做通道增强的模块

可以将全局平均池化放在每个 forward 函数的最后，对每个 channel 进行平均池化操作，然后将结果与未被改变的 channel 拼接起来，得到增强后的输出。修改后的代码如下：

class Partial_conv3(nn.Module):
    def __init__(self, dim, n_div, forward):
        super().__init__()
        self.dim_conv3 = dim // n_div
        self.dim_untouched = dim - self.dim_conv3
        self.partial_conv3 = nn.Conv2d(self.dim_conv3, self.dim_conv3, 3, 1, 1, bias=False)
        self.global_avg_pool = nn.AdaptiveAvgPool2d((1, 1))  # 添加全局平均池化层
        if forward == 'slicing':
            self.forward = self.forward_slicing
        elif forward == 'split_cat':
            self.forward = self.forward_split_cat
        else:
            raise NotImplementedError
    
    def forward_slicing(self, x: Tensor) -> Tensor:
        # only for inference
        x = x.clone()  # !!! Keep the original input intact for the residual connection later
        x[:, :self.dim_conv3, :, :] = self.partial_conv3(x[:, :self.dim_conv3, :, :])
        x[:, :self.dim_conv3, :, :] = self.global_avg_pool(x[:, :self.dim_conv3, :, :])  # 添加全局平均池化
        x = torch.cat((x, x[:, self.dim_conv3:, :, :]), 1)
        return x
    
    def forward_split_cat(self, x: Tensor) -> Tensor:
        x1, x2 = torch.split(x, [self.dim_conv3, self.dim_untouched], dim=1)
        x1 = self.partial_conv3(x1)
        x1 = self.global_avg_pool(x1)  # 添加全局平均池化
        x = torch.cat((x1, x2), 1)
        return x