move model to device in DistTrainer

fastNLP/core/dist_trainer.py

@@ -165,11 +165,11 @@ class DistTrainer:
         self.grad_scaler = grad_scaler
 
         self.set_grad_to_none = kwargs.get('set_grad_to_none', False)
-
         # init DataParallel
         if isinstance(model, DDP):
             self.ddp_model = model
         else:
+            model.to(self.device)
             if parse_version(torch.__version__)>=parse_version('1.1'):
                 self.ddp_model = DDP(model, device_ids=[self.local_rank],
                                      output_device=self.local_rank,
@@ -182,7 +182,6 @@ class DistTrainer:
         self._forward_func = self.model.forward
         self.model.to(self.device)
 
-
         optimizer = self._get_optimizer(optimizer)
         self.optimizer = optimizer
         if isinstance(self.train_data, DataSet):