Jemma and I are working some more on this REXI+averaging approach. Basically the way it works is you solve a lot of independent (but with different coefficients) elliptic problems with the same RHS, and then compute a weighted sum of the solutions (with different weights for each elliptic problem) which you then use to progress the solution. Eventually we want to make a proper parallel implementation of this, but right now we just need to see what works, and are just running over the loop in serial and getting hammered either by memory to store all of the solvers, or by time if we rebuild the solver for each elliptic problem. Is there a quick-and-dirty way to implement this parallelism so that we can make progress? Our starting point is that we don't have a clue about MPI programming!

all the best

--cjc