Software for Low Density Parity Check Codes

Radford M. Neal, Dept. of Statistics and Dept. of Computer Science, University of Toronto

Version of 2000-03-19.

NOTE: There is now a newer version of this software, available here.

This collection of programs and modules, written in C, is intended to support research and education concerning Low Density Parity Check (LDPC) codes. These codes were invented by Robert Gallager in the early 1960's, and re-invented and shown to have very good performance by David MacKay and myself in the mid-1990's. The decoding algorithm for LDPC codes is related to that used for Turbo codes, and to probabilistic inference methods used in other fields. Variations on LDPC and Turbo codes are currently the best practical codes known, in terms of their ability to transmit data at rates approaching channel capacity with very low error probability.

Index to Documentation

Installation instructions. How to get and compile the programs and modules.
Program documentation. Programs for creating and using LDPC and other linear codes, which can be used in their present form, or modified to try out new ideas.
Examples of program usage. Some simple examples involving Hamming codes, and some more interesting examples of LDPC codes.
Module documentation. Modules used by the programs for modulo-2 matrix operations and random number generation.
References. Classic and more recent papers on LDPC codes and related topics.

Copyright and Lack of Warranty

Permission is granted for anyone to copy, use, or modify these programs and documents for purposes of research or education, provided this copyright notice is retained, and note is made of any changes that have been made.

These programs and documents are distributed without any warranty, express or implied. As the programs were written for research purposes only, they have not been tested to the degree that would be advisable in any important application. All use of these programs is entirely at the user's own risk.