[mpich-discuss] determinism in collectives

[Nichols A. Romero]

Hi,

I apologize if this has been asked a trillion times, if its documented somewhere just point it out to me online.

Are collective operations, such as sums, using MPI_Reduce deterministic? In other words, if I run MPI_Reduce N times on P tasks, will the sums always occur in the same order. Thus it would be reproducible to the expected precision.

-- 
Nichols A. Romero, Ph.D.
Argonne Leadership Computing Facility
Argonne National Laboratory
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