[petsc-users] How to use command line option for separate matrix

[Matthew Knepley]

On Tue, Mar 18, 2014 at 2:28 AM, TAY wee-beng <zonexo at gmail.com> wrote:

>  On 18/3/2014 3:07 PM, Matthew Knepley wrote:
>
>  On Tue, Mar 18, 2014 at 1:58 AM, TAY wee-beng <zonexo at gmail.com> wrote:
>
>>  Hi Barry,
>>
>> My command line is :
>>
>> mpiexec -np 46 ./a.out -options_left -poisson_ksp_view -poisson_ksp_type
>> gmres -poisson_pc_type hypre -poisson_pc_type_hypre boomeramg > log
>>
>
>
>
>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>    It should be  -pisson_pc_hypre_type boomeramg, but BoomerAMG is the
> default.
>
> So in other words, -poisson_pc_type hypre is sufficient, is that so?
>
> Also if only my RHS of the Poisson eqn's changes at every timestep, do I
> set the ksp and pc only once at the start? E.g. :
>

Yes, only at the start.

  Matt


> call KSPSetType(ksp,ksptype,ierr)
>
> ksptype=KSPGMRES
>
> call PCSetType(pc,'hypre',ierr)
>
> call PCHYPREGetType(pc,'boomeramg',ierr)
>
> or do I have to do it at every time step?
>
>
>      Matt
>
>   My result is :
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>> *KSP Object:(poisson_) 46 MPI processes   type: gmres     GMRES:
>> restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization
>> with no iterative refinement     GMRES: happy breakdown tolerance 1e-30
>> maximum iterations=10000, initial guess is zero   tolerances:
>> relative=1e-05, absolute=1e-50, divergence=10000   left preconditioning
>> using PRECONDITIONED norm type for convergence test PC Object:(poisson_) 46
>> MPI processes   type: hypre     HYPRE BoomerAMG preconditioning     HYPRE
>> BoomerAMG: Cycle type V     HYPRE BoomerAMG: Maximum number of levels 25
>>     HYPRE BoomerAMG: Maximum number of iterations PER hypre call 1
>> HYPRE BoomerAMG: Convergence tolerance PER hypre call 0     HYPRE
>> BoomerAMG: Threshold for strong coupling 0.25     HYPRE BoomerAMG:
>> Interpolation truncation factor 0     HYPRE BoomerAMG: Interpolation: max
>> elements per row 0     HYPRE BoomerAMG: Number of levels of aggressive
>> coarsening 0     HYPRE BoomerAMG: Number of paths for aggressive coarsening
>> 1     HYPRE BoomerAMG: Maximum row sums 0.9     HYPRE BoomerAMG: Sweeps
>> down         1     HYPRE BoomerAMG: Sweeps up           1     HYPRE
>> BoomerAMG: Sweeps on coarse    1     HYPRE BoomerAMG: Relax down
>> symmetric-SOR/Jacobi     HYPRE BoomerAMG: Relax up
>> symmetric-SOR/Jacobi     HYPRE BoomerAMG: Relax on coarse
>> Gaussian-elimination     HYPRE BoomerAMG: Relax weight  (all)      1
>> HYPRE BoomerAMG: Outer relax weight (all) 1     HYPRE BoomerAMG: Using
>> CF-relaxation     HYPRE BoomerAMG: Measure type        local     HYPRE
>> BoomerAMG: Coarsen type        Falgout     HYPRE BoomerAMG: Interpolation
>> type  classical   linear system matrix = precond matrix:   Matrix Object:
>> 46 MPI processes .... ... *
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>> *#PETSc Option Table entries: -options_left -poisson_ksp_type gmres
>> -poisson_pc_type hypre -poisson_pc_type_hypre boomeramg #End of PETSc
>> Option Table entries There is one unused database option. It is: Option
>> left: name:-poisson_pc_type_hypre value: boomeramg*
>>
>> It seems that it is using boomeramg but why does it say "one unused
>> database option"?
>>
>> Did I do something wrong?
>>
>> Also if only my RHS of the Poisson eqn's changes, do I set the ksp and pc
>> once at the start? E.g. :
>>
>> call KSPSetType(ksp,ksptype,ierr)
>>
>> ksptype=KSPGMRES
>>
>> call PCSetType(pc,'hypre',ierr)
>>
>> call PCHYPREGetType(pc,'boomeramg',ierr)
>>
>> or do I have to do it at each time step?
>>
>> Thank you
>>
>> Yours sincerely,
>>
>> TAY wee-beng
>>
>> On 18/3/2014 2:23 AM, Barry Smith wrote:
>>
>>  Yes. You can run with -poisson_ksp_view and -options_left to make sure the options you provide are actually used.
>>
>>    Barry
>>
>> On Mar 17, 2014, at 9:39 AM, TAY wee-beng <zonexo at gmail.com> <zonexo at gmail.com> wrote:
>>
>>
>>  Hi,
>>
>> I use
>>
>> call KSPSetOptionsPrefix(ksp_semi_xyz,"momentum_",ierr)
>>
>> and
>>
>> call KSPSetOptionsPrefix(ksp,"poisson_",ierr)
>>
>> so that I can choose separate ksp/pc options for my momentum and poisson equations through command line e.g.
>>
>> -poisson_ksp_type gmres -poisson_pc_type hypre -poisson_pc_type_hypre boomeramg
>>
>> In general, I need to use boomeramg as the preconditioner and gmres as the solver for my poisson eqn, separate from my momentum eqn, which has its own default pc and ksp. Is the above the correct way?
>>
>> Thanks!
>>
>> --
>> Yours sincerely,
>>
>> TAY wee-beng
>>
>>
>>
>>
>
>
>  --
> 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
>
>
>


-- 
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
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