What is MPI?

The MPI is a standard or specification, but not a specific implementation of LAMMPS. Each device manufacturer needs to provide support according to the interface specified in the specification. Therefore, a versatile MPI program should be able to run on all machines that support it. Common MPI implementations include mhich and openmpi. The standard of writing widely used information transferring programs is not only practical and transferrable, but also flexible, and it has not changed significantly over time.

MPI names have a common prefix—MPI_. There are 287 interfaces in the mpi-2 standard, but in theory, all communication functions can be realized through six basic calls. The following description of MPI is language independent and will introduce the structure of the parameters. Each call accepts parameters that are used to read quantities passed in (IN) or produce quantities to pass to the MPI (OUT).

MPI initialization

MPI_Init is the first call of...