dolfin team mailing list archive

[Florian Rathgeber <florian.rathgeber@xxxxxxxxxxxxxx>]

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I published my branch here:
https://code.launchpad.net/~florian-rathgeber/dolfin/gpu-wrappers

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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