!1283 modify yolov5 train scripts to fix fps performance

Merge pull request !1283 from anzhengqi/usability-modify-yolov5

official/cv/yolov5/train.py

@@ -91,17 +91,17 @@ def run_train():
     network = nn.TrainOneStepCell(network, opt, config.loss_scale // 2)
     network.set_train()
 
-    data_loader = ds.create_dict_iterator()
+    data_loader = ds.create_tuple_iterator(do_copy=False)
     first_step = True
     t_end = time.time()
 
     for epoch_idx in range(config.max_epoch):
         for step_idx, data in enumerate(data_loader):
-            images = data["image"]
+            images = data[0]
             input_shape = images.shape[2:4]
             input_shape = ms.Tensor(tuple(input_shape[::-1]), ms.float32)
-            loss = network(images, data['bbox1'], data['bbox2'], data['bbox3'], data['gt_box1'], data['gt_box2'],
-                           data['gt_box2'], input_shape)
+            loss = network(images, data[2], data[3], data[4], data[5], data[6],
+                           data[7], input_shape)
             loss_meter.update(loss.asnumpy())
 
             # it is used for loss, performance output per config.log_interval steps.