mindspore.communication.get_group_rank_from_world_rank

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mindspore.communication.get_group_rank_from_world_rank(world_rank_id, group)[source]

Get the rank ID in the specified user communication group corresponding to the rank ID in the world communication group.

Note

This method isn't supported in GPU and CPU versions of MindSpore. The parameter group should not be "hccl_world_group". This method should be used after init().

Parameters

  • world_rank_id (int) – A rank ID in the world communication group.

  • group (str) – The communication group to work on. The group is created by create_group.

Returns

int, the rank ID in the user communication group.

Raises

  • TypeError – If world_rank_id is not an integer or the group is not a string.

  • ValueError – If group is 'hccl_world_group' or backend is invalid.

  • RuntimeError – If HCCL is not available or MindSpore is GPU/CPU version.

Supported Platforms:

Ascend GPU CPU

Examples

Note

Before running the following examples, you need to configure the communication environment variables.

For Ascend/GPU/CPU devices, it is recommended to use the msrun startup method without any third-party or configuration file dependencies. Please see the msrun start up for more details.

>>> import mindspore as ms
>>> from mindspore import set_context
>>> from mindspore.communication import init, create_group, get_group_rank_from_world_rank, get_rank
>>> set_context(mode=ms.GRAPH_MODE)
>>> ms.set_device(device_target="Ascend")
>>> init()
>>> group = "0-4"
>>> rank_ids = [0,4]
>>> if get_rank() in rank_ids:
...     create_group(group, rank_ids)
...     group_rank_id = get_group_rank_from_world_rank(4, group)
...     print("group_rank_id is: ", group_rank_id)
group_rank_id is: 1