You can use MPI_Op_create to create the appropriate operation (see here: http://www.mcs.anl.gov/research/projects/mpi/www/www3/MPI_Op_create.html ) then use it in MPI_Reduce (instead of MPI_MIN).

Matthieu Dorier
PhD student at ENS Rennes
http://people.irisa.fr/Matthieu.Dorier

De: "Wesley B. Bland" <wbland@anl.gov>
À: discuss@mpich.org
Envoyé: Dimanche 16 Février 2014 06:43:25
Objet: Re: [mpich-discuss] Can i use MPI_REDUCE(with MPI_MIN) to get a "min array"?

It depends on how you define min array. Do you want to get the minimum value at each index? The full array with the minimum sum? Something else?

On Feb 15, 2014, at 6:22 AM, 维洛逐风 <wu_0317@qq.com> wrote:

HI.

Say,I have 10 process，each one has a array called gbest, I want to get the min array(with a compare operation I want to define).

Is there a way to use MPI_REDUCE to do this?As I know, MPI_MIN specifies datatypes(without arrays).

------------------

Jie-Jun Wu
Department of Computer Science,
Sun Yat-sen University,
Guangzhou,
P.R. China

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