[Dune] dune auf Supercomputern?

[Christian Engwer]

Dear Markus,

> Thank you very much for the quick answer.
> The altix has an intel 10.1 c++ compiler istalled and could be an option.
> http://www.lrz-muenchen.de/services/software/programmierung/intel_compilers/
> The proposed project migration would not be a mere porting but a complete
> reimplementation of the solver which is a mixture of fortran 77 and 90 with
> MPI up to now.

That should be fine.

> So there is no code that could get in the way yet, but its a lot of work to
> be done and we are anxious to get the answers to some questions before we
> start. Perhaps you can answer some of them out of hand right now.
> You mentioned some parallel grid managers. Since up to now I have written
> the code needed for discretization myself, I do not know exactly what a tool
> like a grid manager really does and, even more important, what it does not.
> So I just describe our problem and what we hope to gain using dune.
> We certainly need an inf-sup stable finite element pair( Taylor Hood for
> instance)  for a Stokes system with very strongly varying and even
> discontinuous viscosity.
> We also have to discretize a convection diffusion equation so wee need the
> ability to implement a streamline diffusion discretization, possibly with
> the same elements we used for the Stokes system.
> We want to use a parallel algebraic multigrid solver for both of the
> discretized problems (because of the discontinuities).
> We want to be able to implement adaptive mesh refinement and do not want to
> bother about load balancing issues arising from this.
> 
> So
> 1.) We would be thankful if  you could give us your opinion if you deem our
> plan possible!

I think it is feasible. The stable Dune modules currently cover the
grid interface and istl (the iterative solver template
library). dune-istl also includes an algebraic multigrid solver.

> and
> 2.) perhaps tell me what grid managers or solvers are available and how I
> can find out, what I need to know.
> (A link to a documentation of a parallel grid manager that works with dune
> perhaps)

OK. From the features page
http://www.dune-project.org/doc/devel/features.html
you find links to the documentation of the different grid
implementations. All parallel adaptive grid managers are third party
software, but accessible thorugh the dune grid interface. The grid
mangers takes care of the details of grid refinement and load
balancing. It offers you a clear interface of how to access the
entities in the grid. We two papers linked from our website, the first
one gives clear definition of what a grid is (very mathematical) and
the second one describes how this definition is transformed into a c++
interface and shows some applications.

Cheers Christian