[petsc-users] Solving only for certain rows

[Orxan Shibliyev]

After hole cutting my unstructured mesh has some active and inactive/fringe
cells. I solve equations on active/computational/field cells only. Some of
the active cells are neighbors of inactive cells. If I prepare petsc matrix
including all cells then the solver does not converge due unchanging values
of inactive cells. How can I tell Petsc not to solve for certain rows? If I
make all cells active then the solver converge so I am sure that there is
no problem related to solver.