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
