[petsc-users] ILU preconditioner

[Danesh Daroui]

Hi,

In this case, can I create a preconditioner in double precision format
and apply it to the system while I am using PETSc to solve a system of
complex numbers? The reason is that I am solving equations in several
iterations and I want to create an ILU-based preconditioner only on real
part of my coefficient matrix because it is unchanged and I can create
and store is once. The imaginary parts will change but they do not have
big effect.

Regards,

D.


On Tue, 2011-05-31 at 15:13 +0200, Jed Brown wrote:
> On Tue, May 31, 2011 at 08:02, Danesh Daroui <danesh.daroui at ltu.se>
> wrote:
>         I have a complex system of equations and I use PETSc to solve
>         the
>         system. I also use MKL to create the preconditioner using ILU.
>         The ILU
>         preconditioner is created only on the real part of the
>         coefficient
>         matrix and is stored in CSR format with the data type of
>         double
>         precision. I wanted to ask if it is possible to use this
>         preconditioner
>         and pass it to PETSc in CSR format? Can it be used with PETSc
>         complex
>         solver although the preconditioner is in double precision
>         format?
> 
> You can create a PCShell() that manages the factorization using MKL
> and applies the preconditioner stored in whatever format MKL likes.
> PETSc would not know that it is ILU or otherwise. It sounds like that
> would do what you want.