dolfin team mailing list archive

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

Robert Kirby wrote:
> Hi all,
> Does DOLFIN support the notion of a "matrix action", what would be an 
> "Operator" in Trilinos or a "matrix shell" in PETSc?

Take a look at dolfin/la/uBLASKyrlovMatrix.h and 
dolfin/la/PETScKyrlovMatrix.h. The latter is a wrapper for a PETSc 
'matrix shell'. The FooKrylovMatrix classes are not derived from 
GenericMatrix and I don't think that they've been used very extensively. 
They are used by the ODE solvers.

Garth

> The basic interface would tell the dimension of the domain and range and 
> support an "apply" method.  Indexing, whether
> getting or setting values, is not allowed.  Of course, GenericMatrix 
> should implement this interface.
>
> I ask because sometimes it is advantageous to form the action of a 
> matrix without forming it explicitly, especially for high
> order methods or tensor-product domains.  I have some recent results on 
> fast matrix-free methods for the Bernstein basis,
> and would like to try them using DOLFIN meshes and solvers.
>
> Thanks,
> Rob
>
>
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