-d <delete file[s] after processing, default: disabled>
-fName <set output file name to Name>
-mN <use N MB memory - [1,256], default: 10> The PPMII algorithm
|might need a lot of memory, especially when used on large files and/or used with large model order. If ppmd needs more memory than you give it, the compression will be worse. The exact effect is dependent on the -r option.|
|-oN <set model order to N - [2,16], default: 4> Bigger model|
|orders almost surely results in better compression and surely more memory and CPU usage.|
Methods of restoration of model correctness at memory insufficiency:
-r0 - restart model from scratch. This method is not optimal for any type of data sources, but it works fast and efficient in average, so it is the recommended method (default).
-r1 - cut off model. This method is optimal for quasistationary sources when the period of stationarity is much larger than period between cutoffs. As a rule, it gives better results, but it is slower than other methods and it is unstable against fragmentation of memory heap at high model orders and low memory.
-r2 - freeze model. This method is optimal for stationary sources (show me such source when You will find it ;-)). It is fast and efficient for such sources.
To run this program the standard way type:
ppmd e /tmp/myfile
Alternatively you can run it as:
ppmd -e -o 16 /tmp/myfile
PPMd was written by Dmitry Shkarin <firstname.lastname@example.org> and Dmitry Subbotin.