[mpich-discuss] MPI_Dims_create() fails for nproc >1000000

[Andreas Schäfer]

Hi,

I noticed that MPICH's MPI_Dims_create() fails with a floating point
exception, if the number of processes is larger than 10^6. Apparently
the reason is that the prime factors are hard coded into the code and
are limited to 1000 (or sqrt(10^6)). Open MPI's implementation has no
such limitation.

Best
-Andreas


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Andreas Schäfer
HPC and Grid Computing
Chair of Computer Science 3
Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
+49 9131 85-27910
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