The PETSc Krylov methods are not coded to take directly both a left and
right preconditioner. Therefor the way to use both left and right
preconditioning together is to "fake" it by using a Mat that actually applies
right preconditioner followed by the operator followed by the left
preconditioner.
Take a look at src/ksp/pc/impls/eisen/eisen.c and mimic that code.
(basically copy all the subroutines and in that file and modify each one to
your specific needs.)
Barry
On May 23, 2010, at 1:01 PM, hxie at umn.edu wrote:
> Hi,
>
> I want to use both left and right preconditioners for a linear system. Both
> the preconditioners are based on part of the matrix. How can I implement it?
> I can construct the preconditioner matrices. Thanks.
>
> Bests,
> Hui
