Hello, I have a mesh with very small cell sizes and in a Poisson equation CG solve with ML preconditioner I get the following error:
[31]PETSC ERROR: --------------------- Error Message ------------------------------------ [31]PETSC ERROR: Detected zero pivot in LU factorization see http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#ZeroPivot! [31]PETSC ERROR: Zero pivot row 537 value 9.41111e-13 tolerance 1e-12! I really would like PETSc to NOT treat matrix values lower than 1e-12 to be zero, so I'm trying to set the zero pivot to a lower value with PCFactorSetZeroPivot(), but I still get the same error message: as if the function call would have no effect. I also tried setting the zeropivot via PetscOptionsSetValue("-pc_factor_zeropivot", ...), but still no luck. Is there another way to set the zero pivot that I'm not aware of? Is there a way to query the zero pivot value? Thanks, J -- Jozsef Bakosi Computational Physics Group (CCS-2) MS T006, Los Alamos National Laboratory Los Alamos, NM 87545, USA email: jbakosi at lanl.gov work: 505-663-5607 fax : 505-663-5504
