On 18/3/2014 3:07 PM, Matthew Knepley wrote:
On Tue, Mar 18, 2014 at 1:58 AM, TAY wee-beng <[email protected]
<mailto:[email protected]>> 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. :
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 :
/*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
....
...
*//*#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<[email protected]>
<mailto:[email protected]> 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
