[ET Trac] [Einstein Toolkit] #1090: use efficient RK4 in multirate RK4 RK2 scheme

#1090: use efficient RK4 in multirate RK4 RK2 scheme -------------------------+-------------------------------------------------- Reporter: rhaas | Owner: Type: enhancement | Status: new Priority: minor | Milestone: Component: Cactus | Version: Keywords: MoL | -------------------------+-------------------------------------------------- This patch cleans up the code, improves performance of the MoL loops since it combines several loops into one, and reduces the required scratch space.

Code originally by Erik, the imported into Zelmani by Christian Reisswig.