OPEN-MPI(7) Open MPI OPEN-MPI(7)

Open MPI - General information

# [OPEN MPI](#OPEN_MPI)

Open MPI is an open source implementation of MPI (message-passing interface), the industry-standard specification for writing message-passing programs. Message passing is a programming model that gives the programmer explicit control over interprocess communication.

The MPI specification was developed by the MPI Forum, a group of software developers, computer vendors, academics, and computer-science researchers whose goal was to develop a standard for writing message-passing programs that would be efficient, flexible, and portable.

The outcome, known as the MPI Standard, was first published in 1993; its most recent version (MPI-4.0) was published in June 2021. Open MPI includes all MPI 3.1-compliant routines.

For more information about Open MPI, see <https://www.open-mpi.org>.

The MPI standards are available at <https://www.mpi-forum.org>.

# [MAN PAGE SYNTAX](#MAN_PAGE_SYNTAX)

Man pages for Open MPI and Open MPI I/O routines are named according to C syntax, that is, they begin with the prefix **MPI\_**, all in uppercase, and the first letter following the **MPI\_** prefix is also uppercase. The rest of the letters in the routine are all lowercase, for example, MPI\_Comm\_get\_attr <#mpi-comm-get-attr>.

# [ENVIRONMENT](#ENVIRONMENT)

To fine-tune your Open MPI environment, you can either use arguments to the mpirun <#man1-mpirun> or mpiexec <#man1-mpiexec> commands, or you can use MCA parameters.

For more information on arguments, see the [mpirun(1)](/man/enterprise-packages/openmpi-cuda-13.0/mpirun.1) <#man1-mpirun> man page.

For a complete listing of MCA parameters and their descriptions, issue the command **ompi\_info --all**. See [ompi\_info(1)](/man/enterprise-packages/openmpi-cuda-13.0/ompi_info.1) <#man1-ompi-info> for more information.

# [ERRORS](#ERRORS)

See MPI Errors <#mpi-errors> for details about error values.

**See also:**

MPI\_T <#mpi-t> [mpirun(1)](/man/enterprise-packages/openmpi-cuda-13.0/mpirun.1) <#man1-mpirun> [mpiexec(1)](/man/enterprise-packages/openmpi-cuda-13.0/mpiexec.1) <#man1-mpiexec> [ompi\_info(1)](/man/enterprise-packages/openmpi-cuda-13.0/ompi_info.1) <#man1-ompi-info>

# [Copyright](#Copyright)

2003-2026, The Open MPI Community

September 23, 2026

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Document: Open-MPI(7) from openmpi-cuda-13.0 5.0.11-r0 (Chainguard OS)
Source: https://github.com/open-mpi/ompi