code: def test_hsdp_init_with_device_mesh(self):
      mesh_2d = init_device_mesh(
          self.device_type, (2, self.world_size // 2)
      )
      model, optim = self._create_model(mesh_2d)
  
      FSDP.set_state_dict_type(
          model,
          StateDictType.SHARDED_STATE_DICT,
      )
      state_dict = model.state_dict()
      optim_state_dict = FSDP.optim_state_dict(model, optim)
  
      for v in state_dict.values():
          self.assertEqual(type(v), DTensor)
          self.assertEqual(len(v.placements), 2)
          self.assertEqual(v.placements, (Replicate(), Shard(0)))
          self.assertEqual(v.device_mesh, mesh_2d)
  
      for state in optim_state_dict["state"].values():
          for k, v in state.items():
              if k != "step":
                  self.assertEqual(type(v), DTensor)
                  self.assertEqual(len(v.placements), 2)
                  self.assertEqual(
                      v.placements, (Replicate(), Shard(0))
                  )
                  self.assertEqual(v.device_mesh, mesh_2d)
  
      state_dict_type = model.get_state_dict_type(model)
      # If device_mesh is used when initializing FSDP, the field _use_dtensor will
      # automatically be set to True.
      self.assertEqual(
          state_dict_type.state_dict_config._use_dtensor, True
      )
      self.assertEqual(
          state_dict_type.optim_state_dict_config._use_dtensor, True
      )
  
imports: import io
  from copy import deepcopy
  import torch
  import torch.distributed
  import torch.nn
  from torch.distributed._shard.sharded_tensor import ShardedTensor
  from torch.distributed._tensor import DTensor, Replicate, Shard
  from torch.distributed.device_mesh import _mesh_resources, init_device_mesh
  from torch.distributed.fsdp import FullyShardedDataParallel
  from torch.distributed.fsdp.api import ShardedOptimStateDictConfig, ShardedStateDictConfig, ShardingStrategy, StateDictType
  from torch.testing._internal.common_utils import instantiate_parametrized_tests, parametrize, run_tests
  from torch.testing._internal.distributed._tensor.common_dtensor import DTensorTestBase, skip_if_lt_x_gpu, with_comms
label_desc: Use image node_id 3 for calling the TestHSDPWithDeviceMeshAndDTensor obj's underlying member method code with example usage: obj.test_hsdp_init_with_device_mesh() without return types