[petsc-users] MPI_AllReduce vs VecScatterCreateToAll

[Jed Brown]

You shouldn't see timeouts. Sounds like a misconfiguration or a bug in the
code. If you want an MPI_Allreduce, then MPI_Allreduce is the best way to
get it. VecScatter is intended for less structured operations.
On Nov 7, 2011 10:42 PM, "Robert Ellis" <Robert.Ellis at geosoft.com> wrote:

>  Hello Petsc Developers,****
>
> ** **
>
> I have a predominantly Petsc application but for simplicity it uses a very
> few MPI_AllReduce calls. I am finding that the MPI_AllReduce operations are
> sometimes causing problems (appears to be semaphore time outs) if the
> interprocess communication is slow. I never have any problem with the Petsc
> operations. Is it reasonable that Petsc would be more robust that
> MPI_AllReduce?****
>
> ** **
>
> Also, is the VecScatterCreateToAll set of operations the best way to
> replace the MPI_AllReduce?****
>
> ** **
>
> Thanks for any advice,****
>
> Rob****
>
> ** **
>
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