[petsc-users] Is matrix analysis available in PETSc or external package?

[Danyang Su]

Hi All,

I recently have some time-dependent cases that have difficulty in 
convergence. It needs a lot of linear iterations during a specific time, 
e.g., more than 100 linear iterations for every newton iteration. In 
PETSc parallel version, this number will be doubled or even more. Our 
case usually needs less than 10 iterations for every newton iteration. 
This is NOT caused by PETSc relative routines as the original sequential 
solver (ILU) also has the same problem.

The results seems reasonable, but the large number of iterations leads 
me to suspect that something is not well implemented in a particular 
module. This module is developed a long time ago by another guy and it 
sounds impossible for me to check every line (thousands of lines) and do 
theoretical analysis.Does PETSc or external package provide matrix 
analysis to help to locate the 'suspected' entry?

Thanks and regards,

Danyang