I'm trying to use MATMPIDENSE matrices to solve a system of type Ax=b, but I have some problems. The KSP documentation says that KSPSolve for dense matrices requires to set a 'gmres' solver and a 'lu' preconditioner, the problem is that a 'lu' preconditioner doesn't work in parallel and the corresponding 'asm' doesn't work with dense matrices. How can I solve this "loop" ?
Also, I need to do some operations with these dense matrices, like call a MatMatMult that seems to not work with MATMPIDENSE. Is it the case ? What can I do ?
I have even tried to compute a gather of my matrices, to allow these operations, but I have an error message if run with more than 1 processor on the calls SetMatType(A,MATSEQDENSE) and MatGetRow(A,...).
Thank you in advance, Elisa