On Sep 20, 2011, at 7:52 AM, Tim Prince wrote: > Quoted comment from OP seem to show a somewhat different question: Does > OpenMPI implement any operations in a different way from MVAPICH? I would > think it probable that the answer could be affirmative for operations such as > allreduce, but this leads well outside my expertise with respect to specific > MPI implementations. It isn't out of the question to suspect that such > differences might be aggravated when using excessively aggressive ifort > options such as -fast.
This is 'zactly what I was going to say -- reductions between Open MPI and MVAPICH may well perform global arithmetic operations in different orders. -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
