dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Thu, Aug 10, 2006 at 10:08:29AM +0200, Garth N. Wells wrote:
> Anders Logg wrote:
> > Garth, what is the status of the linear algebra? If you are happy,
> > I'll take another look and then we can take care of the remaining stuff.
> 
> It's pretty much done. I still need to fix the selection of the 
> preconditioner when choosing by name,
> 
>    PETScKrylovSolver solver(PETScPreconditioner::ilu);
> 
> You'll see that there is an enum list in PETScPreconditioner and 
> uBlasPreconditioner. I'd like to change this to just one list so it 
> won't matter whether PETSc or uBlas is being used, and if the requested 
> preconditioner is not available, then a default is chosen. Should then 
> be possible to do
> 
>    KrylovSolver solver(Preconditioner::ilu);
> 
> Same story for choosing the Krylov method by name. Any suggestions?

Sounds very good. But one problem may be if we choose to make
Preconditioner a typedef as we have for the other types. Then we can't
place an enum inside the class.

On the other hand, if we keep the enums inside PETScPreconditioner and
uBlasPreconditioner respectively, then making the typedef would solve
this also so one can do

    KrylovSolver solver(Preconditioner::ilu);

Then we wouldn't need to worry about preconditioners that don't exists
since Preconditioner would be typedefed to the specific preconditioner
base class that only contains existing preconditioners. I'd suggest we
do it this way instead.

> I'm also thinking of moving the individual Krylov methods out of 
> uBlasKrylovSolver.

Yes why not. Then one would have two entries to both preconditioners
and Krylov methods (at least for uBlas): either an enum or by choosing
a specific class, like uBlasGMRES or so.

For PETSc, only enums would be available since the solvers and
preconditioners are implemented by PETSc and not by us.

> > Here's a suggested plan:
> > 
> >        1. Review/cleanup (Garth)
> >        2. Review/cleanup/class diagram (Anders)
> >        3. Fix PyDOLFIN linear algebra including typedefs (Johan J)
> >        3. Finish linear algebra section in manual (Johan H)
> >        4. Remove PETSc ifdefs from Navier-Stokes module (Johan H)
> 
> I did this yesterday. Just one PETSc ifdef left for choosing the Hypre 
> preconditioner.

ok, I just did a grep for HAVE_PETSC.

> >        4. Remove PETSc ifdefs from elasticity module (Johan J)
> 
> I removed them from elasticity (not elasticity-updates). The module 
> needs some cleaning up still.

ok, maybe Johan can look at this. If it requires too much work to sort
out now, then maybe a temporary fix could be added that generates a
run-time error with an informative message?

> >        4. Unit tests for linear algebra (Anders, Garth)
> >        4. Demos for linear algebra (Garth)
> >        4. Benchmarks for linear algebra (Garth)
> >        4. Review/cleanup of ODE solvers (Anders)
> > 
> > What more do we want to finish before the next release?
> > 
> 
> Sounds good.

ok.

/Anders


> Garth
> 
> > Hopefully we can make a concentrated effort and make the release
> > quickly so we can move on to work on the mesh.
> > 
> > /Anders
> > _______________________________________________
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> 
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