at 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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I have been comparing sequential SuperLU on one of my linear solves versus
PETSc LU. I am finding SuperLU to be a little over 2x slower than PETSc LU.
I was wondering if this is due to SuperLU not being tuned to my problem or if
the PETSc LU algorithm performance is expected to be superior to that
Hi Mark,
I would like to try GAMG on some of my linear solves. Could you suggest how
to get started? Is it more complicated than something like:
-ksp_type cg -pc_type gamg
I'm guessing I should first try it on one of my easier linear solves. I have
5 of them that would have a block size of 1.
ulations.
>
> Thanks,
>
> Dave
>
--
Stefano
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? what is the principal symbol (if its a
> PDE)? The pattern
> > >>> is not enough to recommend a PC.
> > >>>
> > >>> Matt
> > >>>
> > >>> I'm wondering if there are suggestions of other preconditioners in
> petsc that
> > >>> I should try. The only third party package that I have tried is the
> > >>> txpetscgpu package. I have not tried hypre or any of the multigrid
> > >>> preconditioners yet. I'm not sure how difficult it is to try those
> > >>> packages. Anyway, so far I have not found a preconditioner
> available in
> > >>> petsc that provides a robust solution to this problem and would be
> interested
> > >>> in any suggestions that anyone might have of things to try.
> > >>>
> > >>> I'd be happy to provide additional info and am planning on
> packaging up a
> > >>> couple of examples of the matrix and rhs for people I am
> interacting with at
> > >>> Tech-X and EMPhotonics. So I'd be happy to provide the matrix
> examples for
> > >>> this forum as well if anyone wants a copy.
> > >>>
> > >>> Thanks,
> > >>>
> > >>> Dave
> > >>>
> > >>> --
> > >>> Dave Nystrom
> > >>>
> > >>> phone: 505-661-9943 (home office)
> > >>> 505-662-6893 (home)
> > >>> skype: dave.nystrom76
> > >>> email: dnystrom1 at comcast.net
> > >>> smail: 219 Loma del Escolar
> > >>> Los Alamos, NM 87544
> > >>>
> > >>>
> > >>>
> > >>> --
> > >>> 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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Dave :
I've observed same performance. PETSc LU uses simple algorithm and
implementation,
and our recent releases pay particular attention to efficient data
accessing in solve phase,
thus it outperforms other packages sometime.
SuperLU has built-in schemes, such at row/col permutation, equil etc,
Right now, I'm
> just
> doing serial, single node calculations.
>
> Thanks,
>
> Dave
>
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.
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On Dec 20, 2011, at 10:33 AM, Dave Nystrom wrote:
> Hi Mark,
>
> I would like to try GAMG on some of my linear solves. Could you suggest how
> to get started? Is it more complicated than something like:
>
> -ksp_type cg -pc_type gamg
This is a good start. for scalar SPD problems '-pc_gamg_t
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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The use of PetscBT always makes the algorithm unscalable. It works fine even
for large max index because it only uses on bit per max index but eventually
even that is not scalable so for moderate sizes likely using PetscBT is good,
but super large sizes needs to be avoided.
Barry
On Dec
Matt, what was your intent here? How should we fix this?
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ially thought of this as a sibling of IS, so I put it in src/vec, but
perhaps it should be moved to src/sys because it's really generic.
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