[petsc-users] Using factored complex matrices from MUMPS as a preconditioner in PETSC

[Hong]

Evan,
ICNTL(35) and CNTL(7) are added to petsc-mumps interface in branch
hzhang/update-mumps-5.1.1-cntl

You may give it a try. Once it passes our regression tests, I'll merge it
to petsc master branch.

Hong

On Sun, Sep 24, 2017 at 8:08 PM, Hong <hzhang at mcs.anl.gov> wrote:

> I'll check it.
> Hong
>
> On Sun, Sep 24, 2017 at 3:42 PM, Evan Um <evanum at gmail.com> wrote:
>
>> Hi Barry,
>>
>> Thanks for your comments. To activate block low rank (BLR) approximation
>> in MUMPS version 5.1.1, a user needs to turn on the functionality (i.e.
>> ICNTL(35)=1) and specify the tolerance value (e.g. CNTL(7)=1e-4). In PETSC,
>> I think that we can set up ICNTL and CNTL parameters for MUMPS. I was
>> wondering if we can still use BLR approximation for a preconditioner for
>> Krylov solvers.
>>
>> Best,
>> Evan
>>
>>
>> On Sat, Sep 23, 2017 at 6:45 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>
>>>
>>> > On Sep 23, 2017, at 8:38 PM, Evan Um <evanum at gmail.com> wrote:
>>> >
>>> > Dear PETSC Users,
>>> >
>>> > My system matrix comes from finite element modeling and is complex and
>>> unstructured. Its typical size is a few millions-by a few millions. I
>>> wondering if I can use MUMPS parallel direct solver as a preconditioner in
>>> PETSC. For example, I want to pass factored matrices to Krylov iterative
>>> solvers such as QMR. Is there any PETSC+MUMPS example code for the purpose?
>>>
>>>   You don't pass factored matrices you just pass the original matrix and
>>> use -pc_type lu -pc_factor_mat_solver_package mumps
>>>
>>> > Can PETSC call the latest MUMPS that supports block low rank
>>> approximation?
>>>
>>>   No, send us info on it and we'll see if we can add an interface
>>>
>>>
>>> >
>>> > In advance, thank you very much for your comments.
>>> >
>>> > Best,
>>> > Evan
>>> >
>>> >
>>> >
>>> >
>>> >
>>>
>>>
>>
>
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