MTH 655 LAB5 and LAB6: Iterative solvers and multigrid

Synopsis: this lab spans two weeks.
Please solve (1) and (2) very soon.
You will need (3) before LAB 7: we will be porting them to a parallel cluster under MPI.
Part (4) can be done later; it is in the core of this class so do not underestimate it.
Part (5) is optional but can be fascinating !

The idea is to get familiar with how the different methods work.