modelzoo_unet fix training continue problem.

model_zoo/official/cv/unet/README.md

@@ -19,7 +19,6 @@
     - [How to use](#how-to-use)
         - [Inference](#inference) 
         - [Continue Training on the Pretrained Model](#continue-training-on-the-pretrained-model)
-       - [Transfer Learning](#transfer-learning)
 - [Description of Random Situation](#description-of-random-situation)
 - [ModelZoo Homepage](#modelzoo-homepage)
 
@@ -130,6 +129,8 @@ Parameters for both training and evaluation can be set in config.py
   'weight_decay': 0.0005,             # weight decay value
   'loss_scale': 1024.0,               # loss scale
   'FixedLossScaleManager': 1024.0,    # fix loss scale
+  'resume': False,                    # whether training with pretrain model
+  'resume_ckpt': './',                # pretrain model path
   ```
 
 
@@ -260,8 +261,42 @@ If you need to use the trained model to perform inference on multiple hardware p
   print("============== Cross valid dice coeff is:", dice_score) 
   ```
 
-### Transfer Learning
-To be added.
+### Continue Training on the Pretrained Model 
+
+- running on Ascend
+
+  ```
+  # Define model
+  net = UNet(n_channels=cfg['num_channels'], n_classes=cfg['num_classes'])
+  # Continue training if set 'resume' to be True
+  if cfg['resume']:
+      param_dict = load_checkpoint(cfg['resume_ckpt'])
+      load_param_into_net(net, param_dict)
+
+  # Load dataset
+  train_dataset, _ = create_dataset(data_dir, epochs, batch_size, True, cross_valid_ind, run_distribute)
+  train_data_size = train_dataset.get_dataset_size()
+  
+  optimizer = nn.Adam(params=net.trainable_params(), learning_rate=lr, weight_decay=cfg['weight_decay'],
+                        loss_scale=cfg['loss_scale'])
+  criterion = CrossEntropyWithLogits()
+  loss_scale_manager = mindspore.train.loss_scale_manager.FixedLossScaleManager(cfg['FixedLossScaleManager'], False)
+  
+  model = Model(net, loss_fn=criterion, loss_scale_manager=loss_scale_manager, optimizer=optimizer, amp_level="O3")
+
+  
+  # Set callbacks 
+  ckpt_config = CheckpointConfig(save_checkpoint_steps=train_data_size,
+                                 keep_checkpoint_max=cfg['keep_checkpoint_max'])
+  ckpoint_cb = ModelCheckpoint(prefix='ckpt_unet_medical_adam',
+                               directory='./ckpt_{}/'.format(device_id),
+                               config=ckpt_config)
+  
+  print("============== Starting Training ==============")
+  model.train(1, train_dataset, callbacks=[StepLossTimeMonitor(batch_size=batch_size), ckpoint_cb],
+              dataset_sink_mode=False)
+  print("============== End Training ==============")
+  ```
 
 
 # [Description of Random Situation](#contents)

model_zoo/official/cv/unet/src/config.py

@@ -27,4 +27,7 @@ cfg_unet = {
     'weight_decay': 0.0005,
     'loss_scale': 1024.0,
     'FixedLossScaleManager': 1024.0,
+
+    'resume': False,
+    'resume_ckpt': './',
 }

model_zoo/official/cv/unet/train.py

@@ -24,6 +24,7 @@ from mindspore import Model, context
 from mindspore.communication.management import init, get_group_size
 from mindspore.train.callback import CheckpointConfig, ModelCheckpoint
 from mindspore.context import ParallelMode
+from mindspore.train.serialization import load_checkpoint, load_param_into_net
 
 from src.unet import UNet
 from src.data_loader import create_dataset
@@ -54,6 +55,10 @@ def train_net(data_dir,
                                           gradients_mean=False)
     net = UNet(n_channels=cfg['num_channels'], n_classes=cfg['num_classes'])
 
+    if cfg['resume']:
+        param_dict = load_checkpoint(cfg['resume_ckpt'])
+        load_param_into_net(net, param_dict)
+
     criterion = CrossEntropyWithLogits()
     train_dataset, _ = create_dataset(data_dir, epochs, batch_size, True, cross_valid_ind, run_distribute)
     train_data_size = train_dataset.get_dataset_size()