<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hello,<div class="">Am I seeing this correctly?</div><div class=""><div class="">#include <petsc.h></div><div class=""><br class=""></div><div class="">int main(int argc,char **args)</div><div class="">{</div><div class=""> Mat A;</div><div class=""> PetscBool hasMatMult;</div><div class=""> PetscErrorCode ierr;</div><div class=""><br class=""></div><div class=""> ierr = PetscInitialize(&argc,&args,NULL,NULL);if (ierr) return ierr;</div><div class=""> ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);</div><div class=""> ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);</div><div class=""> ierr = MatHasOperation(A,MATOP_MAT_MULT,&hasMatMult);CHKERRQ(ierr);</div><div class=""> printf("%s\n", PetscBools[hasMatMult]);</div><div class=""> ierr = PetscFinalize();</div><div class=""> return ierr;</div><div class="">}</div></div><div class=""><br class=""></div><div class="">=> FALSE</div><div class=""><br class=""></div><div class="">I believe this is a regression (or at least an undocumented change) introduced here: <a href="https://gitlab.com/petsc/petsc/-/merge_requests/2524/" class="">https://gitlab.com/petsc/petsc/-/merge_requests/2524/</a></div><div class="">I also believe Stefano raised a similar point there: <a href="https://gitlab.com/petsc/petsc/-/issues/608" class="">https://gitlab.com/petsc/petsc/-/issues/608</a></div><div class="">This is a performance killer in my case because I was previously using this check to know whether I could use MatMatMult or had to loop on all columns and call MatMult on all of them.</div><div class="">There is also a bunch of (previously functioning but now) broken code, e.g., <a href="https://www.mcs.anl.gov/petsc/petsc-current/src/mat/impls/transpose/transm.c.html#line105" class="">https://www.mcs.anl.gov/petsc/petsc-current/src/mat/impls/transpose/transm.c.html#line105</a> or <a href="https://www.mcs.anl.gov/petsc/petsc-current/src/mat/impls/nest/matnest.c.html#line2105" class="">https://www.mcs.anl.gov/petsc/petsc-current/src/mat/impls/nest/matnest.c.html#line2105</a></div><div class="">Is this being addressed/documented?</div><div class=""><br class=""></div><div class="">Thanks,</div><div class="">Pierre</div></body></html>