[Bug Fixed] use torch.cuda.is_available() (#2661)

Co-authored-by: Olatunji Ruwase <[email protected]>

deepspeed/runtime/fp16/fused_optimizer.py

@@ -41,7 +41,7 @@ def __init__(self,
         self.deepspeed = deepspeed
         self.has_moe_layers = has_moe_layers
         self.using_pipeline = self.deepspeed.pipeline_parallelism
-        if not torch.cuda.is_available:
+        if not torch.cuda.is_available():
             raise SystemError("Cannot use fp16 without CUDA.")
         self.optimizer = init_optimizer
 

deepspeed/runtime/fp16/unfused_optimizer.py

@@ -40,7 +40,7 @@ def __init__(self,
         if dist.get_rank() == 0:
             logger.info(f'Fused Lamb Legacy : {self.fused_lamb_legacy} ')
 
-        if not torch.cuda.is_available:
+        if not torch.cuda.is_available():
             raise SystemError("Cannot use fp16 without CUDA.")
         self.optimizer = init_optimizer
 

deepspeed/runtime/zero/stage3.py

@@ -122,7 +122,7 @@ def __init__(self,
         # - assume all params requires grad
         # - flat by groups, not keeping state. TODO: remove state explicitly?
         # - master grad and unflat master weight never exist. TODO: a way to save out unflat master?
-        if not torch.cuda.is_available:
+        if not torch.cuda.is_available():
             raise SystemError("Cannot use fp16 without CUDA.")
 
         self.optimizer = init_optimizer

deepspeed/runtime/zero/stage_1_and_2.py

@@ -154,7 +154,7 @@ def __init__(self,
         # - assume all params requires grad
         # - flat by groups, not keeping state. TODO: remove state explicitly?
         # - master grad and unflat master weight never exist. TODO: a way to save out unflat master?
-        if not torch.cuda.is_available:
+        if not torch.cuda.is_available():
             raise SystemError("Cannot use fp16 without CUDA.")
         self.optimizer = init_optimizer