broadcast
Description
Broadcasts the data of the root rank in the communicator to other ranks.
Prototype
def broadcast(tensor, root_rank, fusion=2,fusion_id=0,group = "hccl_world_group")
Parameters
Parameter |
Input/Output |
Description |
|---|---|---|
tensor |
Input |
A list of TensorFlow tensor type. |
root_rank |
Input |
An int. Rank ID of the root rank. Must be a rank ID in the group. |
group |
Input |
A string containing a maximum of 128 bytes, including the end character. Group name, which can be a user-defined value or hccl_world_group. |
fusion |
Input |
An int. BroadCast operator fusion flag. The value can be one of the following:
|
fusion_id |
Input |
An int. Fusion ID of the BroadCast operator. If fusion is set to 2, BroadCast operators with the same fusion_id are fused during network compilation. |
Returns
The result tensor
Constraints
- The caller rank must be within the range defined by the group argument passed to this API call. Otherwise, the API call fails.
- If the input and output of two BroadCast operators depend on each other, they cannot be fused. Otherwise, a graph loop may occur.
As shown in the following figure, the input and output dependency exists between broadcast2 and broadcast1. Therefore, the broadcast1 and broadcast2 operators cannot be fused. That is, when the broadcast API is called, the fusion parameter must be set to 0.
Applicability
Example
The following is only a code snippet and cannot be executed. For details about how to call the HCCL Python APIs to perform collective communication, see Sample Code.
1 2 3 4 5 | from npu_bridge.npu_init import * tensor = tf.random_uniform((1, 3), minval=1, maxval=10, dtype=tf.float32) inputs = [tensor] root = 0 result = hccl_ops.broadcast(inputs, root) |