However the exterior fluid is better handled through finite volume discretization and a choice of explicit or implicit time stepping, depending on the type and goal of the simulation. This computational model is used also in shared-memory machines such as Crays and SGIs. Programs treating subproblems are mapped to available processors as per expected load balance. Each of those processors runs its program copy on the different data structures predefined by the domain decomposition. The time stepping is handled by staggered integration techniques originally developed in the 1970s by Park and Felippa on sequential machines.
Programs run with their own time steps, exchanging information at synchronization points.
Such techniques are collectivelly called subcycling methods. Information transfer between programs is of two types.