Update miner.py

Author: pengbo0054

minetorch/miner.py

@@ -499,12 +499,11 @@ def run_train_iteration(self, index, data, train_iters):
             total_iters=train_iters,
             iteration=self.current_train_iteration,
         )
-        if self.amp:
+        if self.amp and self.amp_scaler:
             with torch.cuda.amp.autocast():
                 _, loss = self._forward(data)
                 seperate_loss = loss / self.accumulated_iter
-            if self.amp_scaler:
-                seperate_loss = self.scaler.scale(seperate_loss)
+            seperate_loss = self.scaler.scale(seperate_loss)
         else:
             _, loss = self._forward(data)
             seperate_loss = loss / self.accumulated_iter