[petsc-users] Sparse Approximate Inverse (SPAI) preconditioner

[Danesh Daroui]

Hi,

I am using PETSc to solve a linear system of complex double precision
data type. I intend to use SPAI preconditioner to solve the equation and
I know that SPAI is not supported with complex systems. Since I have
imaginary values only on diagonal, so according to my tests, approximate
inverse of only real part of the coefficient matrix is a good
preconditioner for my need. Therefore, I would like to install SPAI with
PETSc and use it just to calculate approximate inverse of the real part
of the matrix which should be possible. The problem is that PETSc can be
configured to install SPAI when complex solver is being installed or I
don't know how! The other questions that, is there any way to store the
complex matrix in PETSc (like I do) and pass only real part of it to the
routine which calculates approximate inverse? Otherwise I need to store
both complex and real values which will eat up the memory.

Regards,

Danesh