<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Jed,<div class="">I’m not sure how easy it is to put more than a few lines of code on GitLab, so I’ll just send the (tiny) source here, as a follow-up of our discussion <a href="https://gitlab.com/petsc/petsc/merge_requests/2069#note_220229648" class="">https://gitlab.com/petsc/petsc/merge_requests/2069#note_220229648</a>.</div><div class="">Please find attached a .cpp showing the brokenness of C=A*B with A of type MPIAIJ and B of type MPIDense when the LDA of B is not equal to its number of local rows.</div><div class="">It does [[1,1];[1,1]] * [[0,1,2,3];[0,1,2,3]]</div><div class="">C should be equal to 2*B, but it’s not, unless lda = m (= 1).</div><div class=""><div class="">Mat Object: 2 MPI processes</div><div class=""> type: mpidense</div><div class="">0.0000000000000000e+00 1.0000000000000000e+00 2.0000000000000000e+00 3.0000000000000000e+00</div><div class="">0.0000000000000000e+00 1.0000000000000000e+00 2.0000000000000000e+00 3.0000000000000000e+00</div></div><div class=""><br class=""></div><div class="">If you change Bm here <a href="https://www.mcs.anl.gov/petsc/petsc-dev/src/mat/impls/aij/mpi/mpimatmatmult.c.html#line549" class="">https://www.mcs.anl.gov/petsc/petsc-dev/src/mat/impls/aij/mpi/mpimatmatmult.c.html#line549</a> to the LDA of B, you’ll get the correct result.</div><div class=""><div class="">Mat Object: 2 MPI processes</div><div class=""> type: mpidense</div><div class="">0.0000000000000000e+00 2.0000000000000000e+00 4.0000000000000000e+00 6.0000000000000000e+00</div><div class="">0.0000000000000000e+00 2.0000000000000000e+00 4.0000000000000000e+00 6.0000000000000000e+00</div></div><div class=""><br class=""></div><div class="">Unfortunately, w.r.t. MR 2069, I still don’t get the same results with a plain view LDA > m (KO) and a view + duplicate LDA = m (OK).</div><div class="">So there might be something else to fix (or this might not even be a correct fix), but the only reproducer I have right now is the full solver.</div><div class=""><br class=""></div><div class="">Thanks,</div><div class="">Pierre</div><div class=""><br class=""></div><div class=""></div></body></html>