[petsc-users] MPI_AllReduce vs VecScatterCreateToAll

[Robert Ellis]

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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