!8924 modify param

From: @wukesong
Reviewed-by: @yingjy,@oacjiewen
Signed-off-by: @yingjy

model_zoo/official/cv/alexnet/train.py

@@ -55,8 +55,12 @@ if __name__ == "__main__":
     parser.add_argument('--device_id', type=int, default=0, help='device id of GPU or Ascend. (Default: 0)')
     args = parser.parse_args()
 
+    device_num = int(os.environ.get("DEVICE_NUM", 1))
     if args.dataset_name == "cifar10":
         cfg = alexnet_cifar10_cfg
+        if device_num > 1:
+            cfg.learning_rate = cfg.learning_rate * device_num
+            cfg.epoch_size = cfg.epoch_size * 2
     elif args.dataset_name == "imagenet":
         cfg = alexnet_imagenet_cfg
     else:
@@ -65,14 +69,11 @@ if __name__ == "__main__":
     device_target = args.device_target
     context.set_context(mode=context.GRAPH_MODE, device_target=args.device_target)
     context.set_context(save_graphs=False)
-    device_num = int(os.environ.get("DEVICE_NUM", 1))
 
     if device_target == "Ascend":
         context.set_context(device_id=args.device_id)
 
         if device_num > 1:
-            cfg.learning_rate = cfg.learning_rate * device_num
-            cfg.epoch_size = cfg.epoch_size * 2
             context.reset_auto_parallel_context()
             context.set_auto_parallel_context(device_num=device_num, parallel_mode=ParallelMode.DATA_PARALLEL,
                                               gradients_mean=True)