On May 13, 2011, at 3:37 AM, Jed Brown wrote: > On Fri, May 13, 2011 at 06:51, Tian(ICT) <rongtian at ncic.ac.cn> wrote: > What does this output really mean? > Why does a converged Newton iteration still lead to a diverged SNES solve? > > > Newton did not converge. > > > STEP 0 (Newton iterations: 3) > > diverged reason: -6 > > You should consider using > > PetscPrintf(comm,"%s\n",SNESConvergedReasons[reason]); > > instead of printing the numeric value. Or just run with > -snes_converged_reason to have PETSc print it for you before SNESSolve > returns. The reason is SNES_DIVERGED_LINE_SEARCH
See http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#newton for hints on why SNES is not converging. Barry
