[petsc-users] da_overlap and zero pivot row

[Barry Smith]

> 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?

   Thanks

   Barry

> 
> Thank you.
> 
> Best,
> Xiangdong