One matrix to rule them all

[pancetta]

We could try to speed up the setup phase(s) by allocating/creating big matrices e.g. in the Boussinesq example just once, before the levels are set up. Then, pass these matrices to the ProgramClass and just add a link here.

[danielru]

...one matrix to find them! WIll do, unless someone throws the matrix into Mt. Doom. Beware of Hobbits!