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Dynamic Markov compression
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<p>Dynamic Markov compression (DMC) is a lossless <a href="/facts/Data_compression/gMFuY4FT">data compression</a> <a href="/facts/Algorithm/fnl5NmRt">algorithm</a> developed by <a href="/facts/Gordon_Cormack/a9gDF1v5">Gordon Cormack</a> and <a href="/facts/Nigel_Horspool/uzl497aK">Nigel Horspool</a>. It uses predictive <a href="/facts/Arithmetic_coding/WU0H4oNu">arithmetic coding</a> similar to <a href="/facts/Prediction_by_partial_matching/cc621LIE">prediction by partial matching</a> (PPM), except that the input is predicted one bit at a time (rather than one byte at a time). DMC has a good compression ratio and moderate speed, similar to PPM, but requires somewhat more memory and is not widely implemented. Some recent implementations include the experimental compression programs <a href="http://cs.fit.edu/~mmahoney/compression/text.html#1781">hook</a> by Nania Francesco Antonio, <a href="https://web.archive.org/web/20091026235047/http://de.geocities.com/ocamyd/">ocamyd</a> by Frank Schwellinger, and as a submodel in <a href="/facts/PAQ/puvtoFtK">paq8l</a> by Matt Mahoney. These are based on the <a href="https://web.archive.org/web/20070630111546/http://plg.uwaterloo.ca/~ftp/dmc/dmc.c">1993 implementation</a> in C by Gordon Cormack. </p>