I did some digging into the Trilinos reinit_matrix, and I've found that all of my lost time is coming from the operation
graph->FillComplete(input_col_map, input_row_map) This step is accounting for as much as 20 seconds per call for a 1x200,000 matrix on 4 processors. I also found that this bottleneck is non-existent running in serial. There is a check earlier in reinit_matrix which calls graph.reset differently for 1 processor vs. multiple processors. The comments suggest that there's an explicit reason for treating the mpi case this way, but that treatment seems to be causing the problem for my case. -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
