I looked at the code and it is handled in the PETSc way. The user should not expect KSP to error just because it was unable to solve a linear system; they should be calling KSPGetConvergedReason() after KSPSolve() to check that the solution was computed successfully.
Barry > On Oct 10, 2018, at 2:12 PM, Zhang, Junchao <[email protected]> wrote: > > I met a case where MUMPS numeric factorization returned an error code -9 in > mumps->id.INFOG(1) but A->erroriffailure was false in the following code in > mumps.c > 1199: PetscErrorCode MatFactorNumeric_MUMPS(Mat F,Mat A,const MatFactorInfo > *info) > 1200: > { > ... > > 1227: PetscMUMPS_c(mumps); > 1228: if > (mumps->id.INFOG(1) < 0) { > > 1229: if > (A->erroriffailure) { > > 1230: SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error reported by MUMPS > in numerical factorization phase: INFOG(1)=%d, INFO(2)=%d\n" > ,mumps->id.INFOG(1),mumps->id.INFO(2)); > > 1231: } else > { > > 1232: if (mumps->id.INFOG(1) == -10) { /* numerically singular matrix */ > 1233: PetscInfo2(F,"matrix is numerically singular, INFOG(1)=%d, > INFO(2)=%d\n" > ,mumps->id.INFOG(1),mumps->id.INFO(2)); > > 1234: > F->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT; > > > The code continued to KSPSolve and finished successfully (with wrong answer). > The user did not call KSPGetConvergedReason() after KSPSolve. I found I had > to either add -ksp_error_if_not_converged or call > KSPSetErrorIfNotConverged(ksp,PETSC_TRUE) to make the code fail. > Is it expected? In my view, it is dangerous. If MUMPS fails in one stage, > PETSc should not proceed to the next stage because it may hang there.
