A large class of scientific problems exhibit a computational load distribution which is data dependent, and possibly varying during a run.
Some problems also require algorithms that are computationally asymmetric.
Short-cutting is a speedup technique applicable in some algorithms to reduce redundant computation by allowing early termination of processes by messages from one or more processes. To implement short-cutting in a general form , it is necessary to define implicit process groups dynamically. The execution model for implicit process groups is called Pstreams. Theory is being developed to formalize Pstreams, and to define the analysis required to identify them on the program control flow graph. Experimental results are presented of the application of this library in several codes, and compared with direct MPI calls.