MPICH is a high-performance and widely portable implementation of the
Message Passing Interface (MPI) standard (MPI-1, MPI-2 and MPI-3).
The goals of MPICH are:
(1) to provide an MPI implementation that efficiently supports different
  computation and communication platforms including commodity clusters
  (desktop systems, shared-memory systems, multicore architectures),
  high-speed networks (10 Gigabit Ethernet, InfiniBand, Myrinet,
  Quadrics) and proprietary high-end computing systems (Blue Gene,
  Cray) and
(2) to enable cutting-edge research in MPI through an easy-to-extend
  modular framework for other derived implementations.

Note: mpich conflicts with openmpi. If you install both on the same
system, unexpected results may occur.