[petsc-users] da_overlap and zero pivot row

Barry Smith bsmith at mcs.anl.gov
Mon Jun 27 15:21:33 CDT 2016

> On Jun 27, 2016, at 3:15 PM, Xiangdong <epscodes at gmail.com> wrote:
> Hello everyone,
> I am trying different number of da_overlap to see its effects on nasm and aspin preconditioner. The codes works fine with -da_overlap 0. However, when I change the option -da_overlap 1, it crashed with the error message like "zero pivot row 12544 value 0 tolerance 2.2e-14". The option -pc_factor_nonzeros_along_diagonal does not fix this zero pivot issue.
> Do you have any quick suggestions for me to try to fix this issue?

   My guess is that it is bug in the da_overlap business or in the example; normally I would not expect this to happen. Is this a PETSc example I can run (tell me example and exact options) to reproduce the problem?



> Thank you.
> Best,
> Xiangdong

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