HON95-wiki/se/frameworks/openmpi.md

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title: OpenMPI breadcrumbs:

• title: Software Engineering
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A Message Passing Interface (MPI) implementation for C, Fortran, Java, etc.

Resources

• Frequently Asked Questions (OpenMPI)

Installation

Linux

Ubuntu (APT):

1. (Prerequisite) Install buid tools: apt install build-essetial
2. Install OpenMPI binaries, docs and libs: apt install openmpi-bin openmpi-doc libopenmpi-dev

Build

• Compile and link with mpicc (C) or mpic++ (C++), which will include OpenMPI options and libs.
• (Optional) Setup IDE to include MPI libs:
  • VS Code: Set {"C_Cpp.default.includePath": ["${myDefaultIncludePath}","/usr/lib/x86_64-linux-gnu/openmpi/include/"]} in your project settings (.vscode/settings.json or ~/.config/Code/User/settings.json).

Run

• Command: mpirun [opts] <app> [app_opts]
• To run it with n processes, specify -n <n>. Specify -n $(nproc) to use all cores. If it complains about "not enough slots", specify --oversubscribe.
• If you need to run it as root (strongly discouraged), specify --allow-run-as-root.

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