[petsc-dev] PaStiX solution

[Jed Brown]

On Wed, Dec 28, 2011 at 09:10, Alexander Grayver <agrayver at gfz-potsdam.de>wrote:

> So if I understood it right, I put diff you gave in file pastix_patch in
> petsc-dev dir and called:
>
> lib/petsc-dev> patch -Np1 < pastix_patch
>
> And built petsc again. Now
>
> lib/petsc-dev> hg diff src/mat/impls/aij/mpi/pastix/pastix.c
>

Yes, the patch applied correctly.


>
> So I guess it's patched correctly?
> Because I don't see much difference in output. Please find it attached.
> Did I make something wrong?
>

Hmm, it is hard-coded to say that the matrix is symmetric. We are setting
API_FACT_LU (you could check that it has not been changed by attaching a
debugger in MatFactorNumeric_PaStiX and printing
lu->iparm[IPARM_FACTORIZATION]). Maybe PaStiX is ignoring this and always
doing LLt instead. We probably need to set API_PARM_LDLT (and possibly
API_PARM_LU, but they claim that only does static pivoting, which might
still be a problem). You could try adding this to
src/mat/impls/aij/mpi/pastix/pastix.c or ask the PaStiX developers what
they suggest for symmetric indefinite systems.
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