Zero Pivot Row in LU Factorization

[Tim Stitt]

I should also add that the code executes without this error when using 1 
processor...but then displays the error when running in parallel with 
more than one process.

Tim Stitt wrote:
> Hi all,
>
> Can anyone suggest ways of overcoming the following pivot error I keep 
> receiving in my PETSc code during a KSPSolve().
>
> [1]PETSC ERROR: Detected zero pivot in LU factorization
> see 
> http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#ZeroPivot! 
>
> [1]PETSC ERROR: Zero pivot row 1801 value 0.00102826 tolerance 
> 0.00165189 * rowsum 1.65189e+09!
>
> From checking the documentation....the error is in row 1801, which 
> means it is most likely not a matrix assembly issue?
>
> I tried the following prior to the solve with no luck either.....
>
> call KSPGetPC(ksp,pc,error)
> call PCFactorSetShiftNonzero(pc,PETSC_DECIDE,error)
>
> Is there anything else I can try?
>
> Thanks,
>
> Tim.
>


-- 
Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
HPC Application Consultant - ICHEC (www.ichec.ie)

Dublin Institute for Advanced Studies
5 Merrion Square - Dublin 2 - Ireland

+353-1-6621333 (tel) / +353-1-6621477 (fax)