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.
Example of SPMD Flow in oneDAL

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.
- sendrecv_replaceSends and receives data using a single buffer.
Backend-specific restrictions
- 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.