Hi all, These days I am dealing with a very bad conditioned problem. ksp solver can not convergence. Although direct linear solver such as mumps works, memory is a limitation to me. So I am still seeking a method to make iterative method work.
I know the bad condition number comes from a lumped boundary. For this boundary, the sum of flux comes from all the boundary elements shoule equals to a fixed given flux. If I set the value of each boundary elements equals to a const value (first type boundary condition) the condition number of final matrix is in moderate range. I image if I can do Gaussian elimination first to the boundary elements, (create schur complement), is it possible to reduce condition number of origin matrix? Then I can solve the problem by ksp method.
