Fix adapter scalar handling under torch.compile (#946)

* Fix adapter scalar handling under torch.compile

* Fix instance where error could happen when merging in a lora to the base model

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Co-authored-by: Rydén Johan <johan.ryden@bostad.uppsala.se>
Co-authored-by: Jaret Burkett <jaretburkett@gmail.com>

toolkit/kohya_lora.py

@@ -63,9 +63,9 @@ class LoRAModule(torch.nn.Module):
             self.lora_up = torch.nn.Linear(self.lora_dim, out_dim, bias=False)
 
         if type(alpha) == torch.Tensor:
-            alpha = alpha.detach().float().numpy()  # without casting, bf16 causes error
+            alpha = float(alpha.detach().float().item())
         alpha = self.lora_dim if alpha is None or alpha == 0 else alpha
-        self.scale = alpha / self.lora_dim
+        self.scale = float(alpha) / self.lora_dim
         self.register_buffer("alpha", torch.tensor(alpha))  # 定数として扱える
 
         # same as microsoft's