MPI - Message Passing Interface

MPI is a message passing library interface specification. The goal of the MPI is to establish a portable, efficient, and flexible standard for message passing. The MPI is the first library that has become the standard for writing message passing programs on HPC platforms. Thus, there is no need to modify the source code when it is ported to a different platform that supports the MPI standard.

The MPI is used on distributed and shared memory systems (SMP/NUMA), and on Hybrid architectures SMP clusters, PC clusters, or on heterogeneous networks. The programmer is responsible for correctly identifying parallelism and implementing parallel algorithms.

An introduction to MPI(pdf)