Versions tested: 9.1
Optimal parameters: -
Authors: Charles Bloom
Algorithms: PPM
Notable peformances: -


PPMZ is a file to file (like gzip) compressor based on the PPM method. PPM stands for Prediction by Partial Match. What this means is: PPM learns the statistics of the file - i.e. it learns how to look at the data and predict what will happen next. When PPM is predicting successfully, it can use arithmetic coding to transmit the data in a much more compact way (i.e. you only need 1 bit to write a correct-guess flag, instead of 1 byte for the character; with arithmetic coding this kind of tradeoff can be adaptively adjusted to the estimated likely-hood of the guess being right.
the program readme.txt


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9.1 (NT) version crashes while compressing Qualification1.

Disqualified (why) configurations (with qualification ratings)
Ver Rating CPR DPR S.E. R.E. Ratio C. kB/s D. kB/s
9.1 crash while compressing (q1)

Version info

9.1, tar: yes, mode: n/a, crc32: n/a, decoder: n/a, tested: 2010 Mar 19
compression: ppmz.exe <args> <src> <cfile>
decompression: ppmz.exe <cfile> <src>