Introduction to MPI

This tutorial is intended to be used as a basic introduction to parallel programming on the NERSC parallel machines. It introduces a number of concepts and the MPI message passing library.

This tutorial assumes that you are familiar with FORTRAN or C, basic UNIX commands, and a UNIX text editor.

Access to the examples can be gained with the following commands on the SP:

% module load training
% cd $EXAMPLES/mpi/intro

Basic Concepts

Introduces basic concepts of using MPI and passing simple messages.

Initialization

Initializing the library.

Data Types

Mapping MPI datatypes to machine data types.

Basic Send

Moving data to another task.

Basic Receive

Moving data from another task.

Broadcast

Sending data from one processor to all others.

Reduction

How to get data from all other processors.

Example

A small example using broadcast and reduction routines.

Related information

• MPI Resources
• LLNL MPI Tutorial