delete unnecessary code and replace

Author: cjfghk5697

labml_nn/diffusion/stable_diffusion/model/unet.py

@@ -20,7 +20,6 @@
 
 import numpy as np
 import torch
-import torch as th
 import torch.nn as nn
 import torch.nn.functional as F
 
@@ -174,7 +173,7 @@ def forward(self, x: torch.Tensor, time_steps: torch.Tensor, cond: torch.Tensor)
         x = self.middle_block(x, t_emb, cond)
         # Output half of the U-Net
         for module in self.output_blocks:
-            x = th.cat([x, x_input_block.pop()], dim=1)
+            x = torch.cat([x, x_input_block.pop()], dim=1)
             x = module(x, t_emb, cond)
 
         # Final normalization and $3 \times 3$ convolution