> On Sep 16, 2015, at 8:28 AM, Alexander Lindsay <[email protected]> wrote: > > Hi all, > > I've built a MOOSE application and the problem I'm studying solves great > using serial LU. However, when I try to solve in parallel using super LU, I > encounter many DIVERGED_LINE_SEARCH errors using the default bt line search. > If I switch to line_search=none, then instead of DIVERGED_LINE_SEARCH errors > I get DIVERGED_FNORM_NAN errors. I do not have a lot of debugging experience, > but I am slowly gaining more. Is there a good way to get more information > about what's causing the NAN's? I.e. a specific residual or jacobian > statement? >
It would be useful to have full output with -snes_monitor -snes_converged_reason -snes_linesearch_monitor -ksp_monitor_true_residual -ksp_converged_reason The original DIVERGED_LINE_SEARCH is almost always an indication that the step direction is not a Newton step. This needs to be debugged see http://www.mcs.anl.gov/petsc/documentation/faq.html#newton Switching to no line search is not a useful thing to do here. Barry > This may not even be an appropriate list to post this problem in (could be > more on the MOOSE side); apologies if that's the case. > > Alex
