Versions tested: 2.02c, 2.02s
Optimal parameters: default
Links: ppmy_3c.rar
Authors: Eugene Shelwien
Algorithms: CM
Notable peformances: -


PPMY, ContextMixing-based data compressor: v2.02(3c) of 02/06/2001; v2.02(3c+SSE) of 26/02/2003

ppmy is a bytewise coder based on precise symbol frequencies (numbers of occurences) and linear mixing of distributions from context orders with weights determined by some adhoc function.

ppmy with SSE is [like old ppmy] plus the mixed probability of symbol previously seen in maxorder context is processed with adaptive mapping (aka Secondary Symbol Estimation) with linear interpolation. All statistics and model logic are implemented in floats, which is rather unique by itself, although slow (it wasn't at the time, in fact).

author's description, email 2009 April 5


(Have info that should be added here? E-mail.)

Disqualified (why) configurations (with qualification ratings)
Ver Rating CPR DPR S.E. R.E. Ratio C. kB/s D. kB/s
2.02c 14 13 15 10 1 3.097 84 83
2.02s 15 +7.1% + +6.7% 3.118 +0.7% 85 +1.2% 85 +2.4%

Version info

2.02c, tar: yes, mode: 32-bit, crc32: 99812e3c, decoder: 5 kB, tested: 2010 Apr 23
compression: ppmy.exe <args> <src> <cfile>
decompression: ppmy_d.exe <cfile> <src>
2.02s, tar: yes, mode: 32-bit, crc32: a479f235, decoder: 5 kB, tested: 2010 Apr 23
compression: ppmy45.exe <args> <src> <cfile>
decompression: ppmy45_d.exe <cfile> <src>