David McClain writes:
 > I am about to embark on a project that seeks to reduce the computation time
 > of a large problem from 100+ hours to less than 20 minutes. This is
 > initially though to require a cluster of multiprocessors using either a
 > Beowulf architecture, or a large, shared memory, message passing,
 > architecture. I am interested in the suitability (or otherwise) of OCaml to
 > such computations and the experiences of anyone else in this group on such
 > architectures. Garbage collection across nodes in a shared memory
 > architecture seems like a particularly daunting problem.
 > 
 > Any responses would be appreciated.

Have you seen Starfish?  I haven't ever looked at it in detail but
it's at least in the same general area of ocaml + cluster MP:

http://dsl.cs.technion.ac.il/Starfish/