mindspore.communication

Collective communication interface.

• class mindspore.communication.GlobalComm[source]
• Global communication info.

• mindspore.communication.init(backend_name='hccl')[source]
• Init distributed backend, e.g., hccl/nccl, it is required before communication service can be used.

Note

The full name of hccl is Huawei Collective Communication Library.The full name of nccl is NVIDIA Collective Communication Library.

• Parameters

• backend_name (str) – Backend.

• Raises

• • TypeError – If backend name is not a string.

  • RuntimeError – If backend is invalid or distributed init fails.

• mindspore.communication.release()[source]

• Release distributed resource. e.g., hccl/nccl.

  • Raises
  • RuntimeError – If distributed resource release fails.

• mindspore.communication.getrank(_group='hccl_world_group')[source]

• Gets rank ID for current device in specified collective communication group.

  • Parameters

  • group (str) – ProcessGroup, the process group to work on. Default: WORLD_COMM_GROUP.

  • Returns

  • int, the rank ID of the calling process within the group.

  • Raises

  • • TypeError – If group is not a string.

    • ValueError – If backend is invalid.

    • RuntimeError – If hccl/nccl is not available or nccl not supports.

• mindspore.communication.getgroup_size(_group='hccl_world_group')[source]

• Gets rank size of the specified collective communication group.

  • Parameters

  • group (str) – ProcessGroup, the process group to work on.

  • Returns

  • int, the rank size of the group.

  • Raises

  • • TypeError – If group is not a string.

    • ValueError – If backend is invalid.

    • RuntimeError – If hccl/nccl is not available or nccl not supports.

• mindspore.communication.getworld_rank_from_group_rank(_group, group_rank_id)[source]
• Gets the rank ID in world communication group corresponding to the rank ID in specified user communication group.

Note

Nccl is not supported.The parameter group should not be “hccl_world_group”.

• Parameters

• • group (str) – The user communication group.

  • group_rank_id (int) – A rank ID in user communication group.

• Returns

• int, the rank ID in world communication group.

• Raises

• • TypeError – If group_rank_id is not a int or group is not a string.

  • ValueError – If group is ‘hccl_world_group’ or backend is invalid.

  • RuntimeError – If hccl/nccl is not available or nccl not supports.

• mindspore.communication.getgroup_rank_from_world_rank(_world_rank_id, group)[source]
• Gets the rank ID in specified user communication group corresponding to the rank ID in world communication group.

Note

Nccl is not supported.The parameter group should not be “hccl_world_group”.

• Parameters

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

  • group (str) – The user communication group.

• Returns

• int, the rank ID in user communication group.

• Raises

• • TypeError – If world_rank_id is not a int or group is not a string.

  • ValueError – If group is ‘hccl_world_group’ or backend is invalid.

  • RuntimeError – If hccl/nccl is not available or nccl not supports.

• mindspore.communication.creategroup(_group, rank_ids)[source]
• Creates user collective communication group.

Note

Nccl is not supported.The size of rank_ids should be larger than 1.Rank_ids should not have duplicate data.

• Parameters

• • group (str) – ProcessGroup, the process group to create.

  • rank_ids (list) – List of device ID.

• Raises

• • TypeError – If group is not a string or rank_ids is not a list.

  • ValueError – If rank_ids size is not larger than 1 or rank_ids has duplicate data or backend is invalid.

  • RuntimeError – If hccl/nccl is not available or nccl not supports.

Examples

Copy>>> group = "0-1"
>>> rank_ids = [0,1]
>>> create_group(group, rank_ids)

• mindspore.communication.getgroup(_group)[source]
• Get the global world group if the group is default world comm group.

• mindspore.communication.getlocal_rank(_group='hccl_world_group')[source]
• Gets local rank ID for current device in specified collective communication group.

Note

Nccl is not supported.

• Parameters

• group (str) – ProcessGroup, the process group to work on. Default: WORLD_COMM_GROUP.

• Returns

• int, the local rank ID of the calling process within the group.

• Raises

• • TypeError – If group is not a string.

  • ValueError – If backend is invalid.

  • RuntimeError – If hccl/nccl is not available or nccl not supports.

• mindspore.communication.getlocal_rank_size(_group='hccl_world_group')[source]
• Gets local rank size of the specified collective communication group.

Note

Nccl is not supported.

• Parameters

• group (str) – ProcessGroup, the process group to work on.

• Returns

• int, the local rank size where the calling process is being within the group.

• Raises

• • TypeError – If group is not a string.

  • ValueError – If backend is invalid.

  • RuntimeError – If hccl/nccl is not available or nccl not supports.

• mindspore.communication.destroygroup(_group)[source]
• Destroys user collective communication group.

Note

Nccl is not supported.The parameter group should not be “hccl_world_group”.

• Parameters

• group (str) – ProcessGroup, the process group to destroy.

• Raises

• • TypeError – If group is not a string.

  • ValueError – If group is “hccl_world_group” or backend is invalid.

  • RuntimeError – If hccl/nccl is not available or nccl not supports.