The Corosync Cluster Engine is a Group Communication System with additional features for implementing high availability within applications. The project provides four C application programming interface features. A closed process group communication model with extended virtual synchrony guarantees for creation of replicated state machines. A simple availability manager that restarts the application process when it has failed. A configuration and statistics in-memory database that provides...
Hrothgar is a parallel minimizer and Markov Chain Monte Carlo generator by Andisheh Mahdavi of San Francisco State University. It has been used to solve optimization problems in astrophysics (galaxy cluster mass profiles) as well as in experimental particle physics (hadronic tau decays). It is probably adaptable enough to be applied to your merit function if you can write it in C.
The Cell Messaging Layer is an extremely fast, MPI-like communication library for clusters of Cell Broadband Engine processors. With it, any Cell synergistic processing element (SPE) can communicate directly with any other SPE, even across a network.