Add hacky MPI support for grid refinement

Works but is nowhere near anything one could consider good.
Obvious issues:

* More than one cuboid per grid makes it harder to determine the next lattice cell to be coupled
	* i.e. currently lattice positions are determined ad hoc by resolving their physical position
* Coupling is not actually parallelized
	* All coupling lines are traversed by all processes, way to much communication
* Load balancing and cuboid decomposition doesn't care about refinement
	* ideally refined cuboids should be computationally near their coarse _parent_ cuboids

The first two isses should be fixable with a reasonable amount of work.
This sadly doesn't apply in any form to the last issue.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/refinement/grid2D.hh b/src/refinement/grid2D.hh
index 71b943e..65dd84d 100644
--- a/src/refinement/grid2D.hh
+++ b/src/refinement/grid2D.hh
@@ -55,7 +55,12 @@ Grid2D<T,DESCRIPTOR>::Grid2D(IndicatorF2D<T>& domainF, int resolution, T tau, in
   _cuboids(new CuboidGeometry2D<T>(
              domainF,
              _converter->getConversionFactorLength(),
-             1)),
+#ifdef PARALLEL_MODE_MPI
+             singleton::mpi().getSize()
+#else
+             1
+#endif
+             )),
   _balancer(new HeuristicLoadBalancer<T>(
               *_cuboids)),
   _geometry(new SuperGeometry2D<T>(