megengine.functional.distributed.all_to_all¶
- all_to_all(inp, group=WORLD, device=None, split_axis=0, concat_axis=0)[source]¶
Each process scatter input tensor to all processes and return gathered tensor.
- Parameters
inp (
Tensor) – Input tensor.group (
Optional[Group]) – The process group to work on. The default group is WORLD which means all processes available. You can use a list of process ranks to create new group to work on it, e.g. [1, 3, 5].device (
Optional[str]) – The specific device to execute this operator. None default device means the device of inp will be used. Specify “gpu0:1” to execute this operator on diffrent cuda stream, 1 is stream id, and default stream id is 0.split_axis (
int) – The axis that collectivecomm will split data the default axis is 0
- Return type
- Returns
Result tensor.
Examples
input = Tensor([0 1]) + rank*2 # Rank 0 # input: Tensor([0 1]) # Rank 1 # input: Tensor([2 3]) output = all_to_all(input) # Rank 0 # output: Tensor([0 2]) # Rank 1 # output: Tensor([1 3]) input = Tensor([0 1]) + rank*2 group = Group([1, 0]) output = all_to_all(input, group) # Rank 0 # output: Tensor([0 3]) # Rank 1 # output: Tensor([2 1])