use environment variables when args.gpu is not set

examples/DoReFa-Net/alexnet-dorefa.py

@@ -311,13 +311,12 @@ if __name__ == '__main__':
         sys.exit()
 
     assert args.gpu is not None, "Need to specify a list of gpu for training!"
-    NR_GPU = len(args.gpu.split(','))
-    BATCH_SIZE = TOTAL_BATCH_SIZE // NR_GPU
+    nr_tower = max(get_nr_gpu(), 1)
+    BATCH_SIZE = TOTAL_BATCH_SIZE // nr_tower
     logger.info("Batch per tower: {}".format(BATCH_SIZE))
 
     config = get_config()
     if args.load:
         config.session_init = SaverRestore(args.load)
-    if args.gpu:
-        config.nr_tower = len(args.gpu.split(','))
+    config.nr_tower = nr_tower
     SyncMultiGPUTrainer(config).train()

examples/DoReFa-Net/svhn-digit-dorefa.py

@@ -190,6 +190,5 @@ if __name__ == '__main__':
     config = get_config()
     if args.load:
         config.session_init = SaverRestore(args.load)
-    if args.gpu:
-        config.nr_tower = len(args.gpu.split(','))
+    config.nr_tower = max(get_nr_gpu(), 1)
     QueueInputTrainer(config).train()

examples/HED/hed.py

@@ -226,6 +226,5 @@ if __name__ == '__main__':
         config = get_config()
         if args.load:
             config.session_init = get_model_loader(args.load)
-        if args.gpu:
-            config.nr_tower = len(args.gpu.split(','))
+        config.nr_tower = max(get_nr_gpu(), 1)
         SyncMultiGPUTrainer(config).train()

examples/ResNet/cifar10-resnet.py

@@ -175,6 +175,5 @@ if __name__ == '__main__':
     config = get_config()
     if args.load:
         config.session_init = SaverRestore(args.load)
-    if args.gpu:
-        config.nr_tower = len(args.gpu.split(','))
+    config.nr_tower = max(get_nr_gpu(), 1)
     SyncMultiGPUTrainer(config).train()

examples/ResNet/svhn-resnet.py

@@ -93,6 +93,5 @@ if __name__ == '__main__':
     config = get_config()
     if args.load:
         config.session_init = SaverRestore(args.load)
-    if args.gpu:
-        config.nr_tower = len(args.gpu.split(','))
+    config.nr_tower = max(get_nr_gpu(), 1)
     SyncMultiGPUTrainer(config).train()

examples/Saliency/CAM-resnet.py

@@ -256,12 +256,12 @@ if __name__ == '__main__':
         viz_cam(args.load, args.data)
         sys.exit()
 
-    NR_GPU = len(args.gpu.split(','))
-    BATCH_SIZE = TOTAL_BATCH_SIZE // NR_GPU
+    nr_gpu = get_nr_gpu()
+    BATCH_SIZE = TOTAL_BATCH_SIZE // nr_gpu
 
     logger.auto_set_dir()
     config = get_config()
     if args.load:
         config.session_init = get_model_loader(args.load)
-    config.nr_tower = NR_GPU
+    config.nr_tower = nr_gpu
     SyncMultiGPUTrainer(config).train()

examples/boilerplate.py

@@ -63,14 +63,15 @@ def get_config():
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser()
-    parser.add_argument('--gpu', help='comma separated list of GPU(s) to use.', required=True)
+    parser.add_argument('--gpu', help='comma separated list of GPU(s) to use.')
     parser.add_argument('--load', help='load model')
     args = parser.parse_args()
 
-    NR_GPU = len(args.gpu.split(','))
-    with change_gpu(args.gpu):
+    if args.gpu:
+        os.environ['CUDA_VISIBLE_DEVICES'] = args.gpu
+
     config = get_config()
-        config.nr_tower = NR_GPU
+    config.nr_tower = get_nr_gpu()
 
     if args.load:
         config.session_init = SaverRestore(args.load)

examples/cifar-convnet.py

@@ -150,10 +150,8 @@ if __name__ == '__main__':
         if args.load:
             config.session_init = SaverRestore(args.load)
 
-        if args.gpu:
-            config.nr_tower = len(args.gpu.split(','))
-        nr_gpu = get_nr_gpu()
-        if nr_gpu <= 1:
+        config.nr_tower = get_nr_gpu()
+        if config.nr_tower <= 1:
             QueueInputTrainer(config).train()
         else:
             SyncMultiGPUTrainer(config).train()

tensorpack/utils/gpu.py

@@ -24,12 +24,12 @@ def change_gpu(val):
 def get_nr_gpu():
     """
     Returns:
-        int: the number of GPU from ``CUDA_VISIBLE_DEVICES``.
+        int: #available GPUs in CUDA_VISIBLE_DEVICES, or in the system.
     """
     env = os.environ.get('CUDA_VISIBLE_DEVICES', None)
     if env is not None:
         return len(env.split(','))
-    logger.info("Loading local devices by TensorFlow ...")
+    logger.info("Loading devices by TensorFlow ...")
     from tensorflow.python.client import device_lib
     device_protos = device_lib.list_local_devices()
     gpus = [x.name for x in device_protos if x.device_type == 'GPU']