[petsc-users] Petsc with mumps single precision

[Sylvain Mercier]

Thank you Matthew and Hong.

That's too bad...
I was wondering if it would be possible to add this alternative only in the
MUMPS interface.
Indeed, in the field of solid mechanics (where 3D, beams and shell are
often mixed thanks to Lagrange multipliers), it's very usefull to factorize
a matrix in single precision thanks to MUMPS, and use it to precondition a
sequence of systems solved in double precision. It turns to be very robust
and quite fast.

In  *src/mat/impls/aij/mpi/mumps/mumps.c,*
<http://www.mcs.anl.gov/petsc/petsc-current/src/mat/impls/aij/mpi/mumps/mumps.c.html#MATSOLVERMUMPS>
a
new type, say PetscMumpsSingleScalar, could be defined in order to pass the
required information to the single precision
MUMPS solver.

Would the Petsc team accept to integrate such a feature?

Thanks,
Sylvain


2014-08-20 17:57 GMT+02:00 Matthew Knepley <knepley at gmail.com>:

> On Wed, Aug 20, 2014 at 7:53 AM, Sylvain Mercier <
> sylvainmercier85 at gmail.com> wrote:
>
>> Hi everyone,
>>
>> I'm using PETSc to solve saddle point systems. I have found a block
>> preconditionner which requires to solve a smaller symmetric positive
>> definite system. I do it with  MUMPS which is fast an robust.
>> However, I would like to use this solver in single precision in order to
>> compare the performances.
>>
>> So is it possible to use MUMPS in single precision inside a double
>> precision solving with PETSc?
>>
>
> No, right now PETSc must have all the same precision. We have investigated
> several methods for
> using multi-precision, but none has satisfied all our needs.
>
>   Thanks,
>
>      Matt
>
>
>> Thanks,
>> Sylvain
>>
>
>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20140825/1b64f7e5/attachment-0001.html>