New approach for external direct solvers in PETSc

[Barry Smith]

On Jul 25, 2008, at 5:47 PM, Lisandro Dalcin wrote:
>
> BTW, Have you ever considered the posibility of not using the 'Mat'
> class for factored matrices?? I believe that normal matrices and
> factored matrices share very few in common as to being instances of
> the same class. Looking at the source code in src/mat, there are many
> checks like 'if (mat-->factor)' or  'if (!mat->factor)' that seems to
> support my concern. What do you think?
>
    After a (tiny) bit more thought I think we really should make this  
change:

pros
1) it will simplify the code a good amount hence less bugs
2) conceptually it makes sense
cons
1) requires a large reorganization of the Mat code (will introduce bugs)
2) requires the user to deal with one more PETSc object (MatFactor)
      But since most users deal with SNES/KSP/PC most users will
      never see this new object.

   The question is when/how to make this massive change. It is as big
or bigger than the change I already made with MatGetFactor().

    Barry



>
>
> On Fri, Jul 25, 2008 at 7:02 PM, Barry Smith <bsmith at mcs.anl.gov>  
> wrote:
>>
>>  petsc-dev users,
>>
>>    I have finally completed my changes to PETSc for a new approach to
>> accessing external direct solvers
>> in PETSc like Spooles, MUMPS etc. I will be pushing it to petsc-dev  
>> sometime
>> the middle of next week.
>> If you are using the direct solvers you might consider cloning from
>>
>> http://petsc.cs.iit.edu/hg/petsc/petsc-dev-new-solvers  or
>>
>> ssh://petsc@petsc.cs.iit.edu//hg/petsc/petsc-dev-new-solvers
>>
>> and trying it out before then. Please report problem to
>> petsc-maint at mcs.anl.gov as you hit them.
>>
>>
>>  Barry
>>
>> From the changes file
>>
>> The "parallel direct solver" matrix types like
>> MATAIJSPOOLES are ALL gone. Now you use -pc_factor_mat_solver_package
>> spooles etc or PCFactorSetMatSolverPackage() or if working directly  
>> with
>> matrices, MatGetFactor(A,MATSPOOLES,...)
>>
>>
>
>
>
> -- 
> Lisandro Dalcín
> ---------------
> Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
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> Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
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>