dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

On 20/07/10 09:06, Florian Rathgeber wrote:
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> I published my branch here:
> https://code.launchpad.net/~florian-rathgeber/dolfin/gpu-wrappers

I'll take a look.

One thing from a first glance - don't put specific parameters into 
GlobalParameters.h. Set specific parameters in the relevant class.

Garth

> On 20.07.2010 09:28, Florian Rathgeber wrote:
> > Garth,
> >
> > I recently played around with and revived PETScKrylovMatrix and
> > PETSUserPreconditioner (which are not used in the current tip as far as
> > I can see). Now I'm thinking what is the best way to merge your latest
> > changes to la.
> >
> > My changes are basically:
> > - PETScKrylovMatrix can store and return PETSUserPreconditioner
> > - PETScKrylovSolver can also solve for a PETScKrylovMatrix
> > - PETScKrylovSolver respects a PETSUserPreconditioner if set (pc_dolfin)
> >
> > Your changes would provide for a cleaner interface to achieve this, but
> > there are some obstacles:
> >
> > 1) the operator is a GenericMatrix, but PETScKrylovMatrix is not
> >
> > ->  it makes no sense to derive PETScKrylovMatrix from GenericMatrix,
> > since it is only used for the spmv. I thought an option might be to
> > introduce a common base class for PETScKrylovMatrix and PETScMatrix and
> > have the operator be of that type. Might get a bit messy in setting the
> > operator then (tentative dynamic_cast to get object type?)
> >
> > 2) how to deal with user preconditioners in General?
> >
> > ->  for PETScKrylovMatrix the user needs to implement a preconditioner
> > herself if desired, PETSUserPreconditioner could be used for that (as I
> > did it), but it needs to be set by the shell matrix, since it depends on
> > its data
> > ->  for PETScMatrix, the user preconditioner could be set from outside
> > (interface for that is still there, but it's not used! might be
> > confusing anyway!)
> >
> > Curious about any thoughts and ideas.
> >
> > Florian
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