So you have a 2D Poisson solver and it is working on large problems but the linear solver is diverging on small problems.
I would verify the the solution is good on the large problem. You might have a problem with boundary conditions. What BCs do you think you are using? On Fri, Apr 5, 2019 at 4:33 PM Maahi Talukder via petsc-users < petsc-users@mcs.anl.gov> wrote: > Dear All, > > I am solving a linear system arising from 9-point discretization of > Poisson equation to generate grid. KSP solvers are giving nice converged > result when I am dealing with a large matrix. But when I am trying to > implement KSP solvers when the matrix is smaller and the values are smaller > too, the solution is diverging. > Any suggestions how to get around this problem? > > > Regards, > Maahi Talukder > > > > >
