[dune-pdelab] Matrix setup costs with StationaryLinearProblemSolver

[Bath Uni]

Dear dune-pdelab list,

In my code I have so far always used the StationaryLinearProblemSolver like this, for example:

[…]
typedef Dune::PDELab::ISTLBackend_CG_AMG_SSOR<GO> LS;
    LS ls(gfs, maxiter, verbose);
Dune::PDELab::StationaryLinearProblemSolver<GO,LS,U>
      slp(go,u,ls, model_parameters.solver.resreduction);
slp.apply();
[…]

This reports matrix setup, matrix assembly and residual assembly times, which to me appear to be quite high (actually they are the dominant costs in my calculation).
I am only using a 7 point stencil finite volume discretisation and the problem I am solving is always linear, so I'm wondering whether StationaryLinearProblemSolver produces a huge overhead in this case.

Are there any cheaper methods for setting up the matrix, in this case?

Thank you very much,

Eike