MPICH2
From HP-SEE Wiki
MPICH2 is a high-performance portable implementation of the MPI Standard, which aims to implement all of MPI-1 and MPI-2, including the more advanced features of MPI-2 like dynamic process management, one-sided operations, parallel I/O, and other extensions.
Previous versions of MPICH2 used the mpd deamons for launching parallel processes. Current version of MPICH2 does not use this daemon, using mpiexec command with a hostfile instead. When using the torque batch system, it is preferable the compile a version of mpiexec based on http://www.osc.edu/~djohnson/mpiexec/index.php which supports the special tm interface of torque. In this way the parallel job is subjected to stricter control of the batch system.