[petsc-users] ML and -pc_factor_shift_nonzero

[tribur at vision.ee.ethz.ch]

Hi,

using ML I got the error

"[0]PETSC ERROR: Detected zero pivot in LU factorization"

As recommended at  
http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html, I  
tried -pc_factor_shift_nonzero but it doesn't have the desired effect  
using ML.

How do I have to formulate the command line option? What does  
-[level]_pc_factor_shift_nonzero mean? What other parallel  
preconditioner could I try besides Hypre/Boomeramg or ML?

Thanks in advance for your precious help,

Kathrin