Mark McClure <m...@resfrac.com> writes: > Thank you, I will try BCGSL. > > And good to know that this is worth pursuing, and that it is possible. Step > 1, I guess I should upgrade to the latest release on Petsc. > > How can I make sure that I am "using an MPI that follows the suggestion for > implementers about determinism"? I am using MPICH version 3.3a2. > > I am pretty sure that I'm assembling the same matrix every time, but I'm > not sure how it would depend on 'how you do the communication'. Each > process is doing a series of MatSetValues with INSERT_VALUES, > assembling the matrix by rows. My understanding of this process is that > it'd be deterministic.
In the typical FD implementation, you only set local rows, but with FE and sometimes FV, you also create values that need to be communicated and summed on other processors.
