Complex matrices with UMFPACK

[Hong Zhang]

Christophe,

Thanks for contributing the interface.
I'll test it, then include it as the new petsc-umfpack interface.
We'll acknowledge your contribution in the source code.

I'll let you know after it is included in petsc-dev.

Best,

Hong

On Wed, 6 Jun 2007, Christophe Geuzaine wrote:

>
> Barry,
>
> Attached is a new version of the "umfpack.c" interface, which brings
> support for complex arithmetic and 64 bit addressing to the UMFPACK LU
> solvers:
>
> - complex arithmetic support is achieved by using a new UMFPACK feature
> introduced in UMFACK 4.4, which allows to pass complex matrices directly
> in packed format, with real and imaginary parts interleaved. This allows
> to use complex matrices in UMFPACK without copying data around (this was
> impossible with UMPACK <= 4.3, as these versions required passing real
> and imaginary parts separately);
>
> - 64 bit addressing is achieved by switching to the "long" version of
> the UMFPACK API, where all integers are replaced by "UF_long"s. This
> does not change anything on 32 bit architectures, but allows to
> manipulate >2Gb matrices on 64 bit machines.
>
> Notes:
>
> 1) This new version has only been tested with the latest version of
> UMFPACK (version 5.1). Everything should work with UMFPACK >= 4.4, but
> complex matrices will *not* work with UMFPACK <= 4.3.
>
> 2) To enable complex UMFPACK matrices one needs to remove the
> "#requiresscalar real" directive in
> "src/mat/impls/aij/seq/umfpack/makefile" and add "self.complex = 1" in
> the "Configure" class in "python/PETSc/packages/UMFPACK.py".
>
> 3) If you integrate these changes in the official PETSc tree, you should
> probably also upgrade "python/PETSc/packages/UMFPACK.py" to download
> UMFPACK 5.1 instead of UMFPACK 4.3 (and fix any related configuration
> magic...).
>
>
> Cheers,
>
> Christophe
>
>
> Barry Smith wrote:
> >
> >
> >    Christophe,
> >
> >     We didn't plan to do it, but if UMFPACK supports complex
> > numbers by compiling in C++ it should be trivial to add.
> > Just edit src/mat/impls/aij/seq/makefile remove the
> > rule at the top that requires real and see what happens
> > when you compile in that directory. You may have to make some
> > minor changes to the file to get it working. Properly completely
> > the job also requires some changes to python/Petsc/packages/umfpack.py
> >
> >    Good luck,
> >
> >   If UMFPACK supports complex by some non-standard extension
> > of C for the complex data type (like gnu gcc provides) it will
> > not be so simple because we don't currently PETSc working this way.
> > Actually a user was going to add this support but we haven't
> > heard back. It may have been too difficult.
> >
> >    Barry
> >
> >
> > On Sun, 25 Jun 2006, Christophe Geuzaine wrote:
> >
> >>
> >> Just a quick question: are there any plans to support complex matrices
> >> with UMFPACK in the (relatively near) future? If not, how hard do you
> >> think it would be to extend the current integration of UMFPACK to deal
> >> with complex numbers?
> >>
> >> Many thanks for all your work on PETSc: it's proven a very useful and
> >> reliable tool over the years!
> >>
> >> Best,
> >>
> >> Christophe
> >>
> >>
> >
>
>
> --
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science
> http://www.montefiore.ulg.ac.be/~geuzaine
>
>