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Subject: [OMPI users] MPI_Allgather(): Which algorithm is used?
From: Dr. Hans Ekkehard Plesser (hans.ekkehard.plesser_at_[hidden])
Date: 2009-08-22 12:05:00


Hi!

OpenMPI 1.3.3 comes with a range of algorithms for MPI_Allgather(), but I have not been able to
find out how to check which algorithms is actually used.

>From the following message on the list I got an idea about how to select the algoritm by hand

        http://www.open-mpi.org/community/lists/users/2008/10/6847.php,

but I should like to be able to find out at runtime which algorithm Open MPI has chosen.

BTW, is one algorithm chosen the first time MPI_Allgather() is called, or is a new algorithm
chosen for every call based on message properties?

Best regards,
Hans

-- 
Dr. Hans Ekkehard Plesser
Associate Professor
Dept. of Mathematical Sciences and Technology
Norwegian University of Life Sciences
Phone +47 6496 5467
Fax   +47 6496 5401
Email hans.ekkehard.plesser_at_[hidden]
Home  http://arken.umb.no/~plesser