!1674 GPU fix resent scripts

Merge pull request !1674 from VectorSL/gpu-resnet-scripts

example/resnet50_cifar10/dataset.py

@@ -20,7 +20,7 @@ import mindspore.common.dtype as mstype
 import mindspore.dataset.engine as de
 import mindspore.dataset.transforms.vision.c_transforms as C
 import mindspore.dataset.transforms.c_transforms as C2
-from mindspore.communication.management import get_rank, get_group_size
+from mindspore.communication.management import init, get_rank, get_group_size
 from config import config
 
 

example/resnet50_imagenet2012/dataset.py

@@ -20,7 +20,7 @@ import mindspore.common.dtype as mstype
 import mindspore.dataset.engine as de
 import mindspore.dataset.transforms.vision.c_transforms as C
 import mindspore.dataset.transforms.c_transforms as C2
-from mindspore.communication.management import get_rank, get_group_size
+from mindspore.communication.management import init, get_rank, get_group_size
 
 def create_dataset(dataset_path, do_train, repeat_num=1, batch_size=32, target="Ascend"):
     """
@@ -40,6 +40,7 @@ def create_dataset(dataset_path, do_train, repeat_num=1, batch_size=32, target="
         device_num = int(os.getenv("DEVICE_NUM"))
         rank_id = int(os.getenv("RANK_ID"))
     else:
+        init("nccl")
         rank_id = get_rank()
         device_num = get_group_size()