[DFTB-Plus-User] Openmp vs. mpi

[Ben Hourahine]

Hello Morteza,

Could you give some more information about the system (ideally the total number of orbitals, but also if there is spin/kpoint s which the MPI code can use for improved performance with appropriate settings)? The performance improvements will saturate above a certain number of processors/cores (Amdahl's law) depending approximately on the problem size. Its possible that in both cases you may be above this limit.

Regards 

Ben


On April 11, 2018 6:46:42 PM GMT+01:00, Morteza Chehel Amirani <morteza.amirani at gmail.com> wrote:
>Dear Bálint
>
>I did a test to compare the performance of the openmp and mpi versions
>of
>dftb+18.1. I run the same input file using 32 cores (on a single node)
>for
>the openmp version and 96 cores for the mpi version. I got 58 MD steps
>from
>the openmp and 62 steps from the mpi runs. I just wanted to know if
>this is
>what you also expect from the two implementations? Thanks.
>
>Sincerely,
>Morteza

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