Single Program Multiple Data¶
This section includes concepts and descriptions of objects that support distributed computations using SPMD model.
Distributed computation using SPMD model¶
In a typical usage scenario, a user provides a communicator object as a first parameter of a free function to indicate that the algorithm can process data simultaneously. All internal inter-process communications at sync points are hidden from the user.
General expectation is that input dataset is distributed among processes. Results are distributed in accordance with the input.
Supported Collective Operations¶
The following collective operations are supported:
bcastBroadcasts data from specified process.
allreduceReduces data among all processes.
allgathervGathers data from all processes and shares the result among all processes.
oneCCL: Allgetherv does not support arbitrary displacements. The result is expected to be closely packed without gaps.
oneMPI: Collective operations in oneMPI do not support asynchronous executions. They block the process till completion.