Merge branch 'torch_dist_env_init' into 'main'

changed torch distributed init method from tcp to env

See merge request ADLR/megatron-lm!297

megatron/initialize.py

@@ -176,14 +176,10 @@ def _initialize_distributed():
                 args.local_rank = device
             torch.cuda.set_device(device)
         # Call the init process
-        init_method = 'tcp://'
-        master_ip = os.getenv('MASTER_ADDR', 'localhost')
-        master_port = os.getenv('MASTER_PORT', '6000')
-        init_method += master_ip + ':' + master_port
         torch.distributed.init_process_group(
             backend=args.distributed_backend,
-            world_size=args.world_size, rank=args.rank,
-            init_method=init_method)
+            world_size=args.world_size, rank=args.rank)
+
 
     # Set the tensor model-parallel, pipeline model-parallel, and
     # data-parallel communicators.