[Dune] Solving Ax=b with A being a matrix of sparse matrices

[Thomas Witkowski]

Markus Blatt wrote:
> On Tue, Mar 04, 2008 at 01:43:29PM +0100, Thomas Witkowski wrote:
>   
>> Is it possible to use the dune solvers to solve a linear system of 
>> equations where A is a small (2x2 or 3x3) matrix of large sparse 
>> matrices? I've created a matrix of type Dune::Matrix<  Dune::BCRSMatrix< 
>> Dune::FieldMatrix<double, 1, 1> > >, but the program does not compile. 
>> It seems that the type Dune::Matrix<T> is never thought to be used in 
>> Dune::Preconditioner and Dune::InverseOperator. Is there another 
>> matrix-type I can use for this purpose?
>>
>>     
>
> The problem is that BCRSMatrix has no solve method. One has to set the
> blocklevel of the preconditioners to l=2 instead of 1.
>   
And how can I do this?

Thomas