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

[Hong]

Danyang:
>
>
> 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?
>

We need know what solvers being used. My guess is the default
gmres/bjacobi/ilu(0). Please run your code with option '-ts_view' or
'-snes_view' to find out.

Hong
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