Provided by: ppmd_10.1-4_i386 bug

NAME

       ppmd - file-to-file compressor

SYNTAX

       ppmd [e|d] [switches] filename...|wildcard...

DESCRIPTION

       It  is  written  for  embedding  in  user programs mainly and it is not
       intended for immediate use. I was interested in speed  and  performance
       improvements  of  abstract  PPM  model [1-6] only, without tuning it to
       particular data types,  therefore  compressor  works  good  enough  for
       texts, but it is not so good for nonhomogeneous files (executables) and
       for noisy analog data (sounds, pictures etc.). Program is  very  memory
       consuming,  you  can  choose balance between execution speed and memory
       economy, on one hand, and compression  performance,  on  another  hand,
       with the help of model order selection option (-o).

OPTIONS

       -d     Delete file[s] after processing, default: disabled.

       -s     Silent mode.

       -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.

       -r{0,1,2}
              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.

EXAMPLES

       To run this program the standard way type:

       ppmd e /tmp/myfile

       Alternatively you can run it as:

       ppmd -e -o 16 /tmp/myfile

AUTHORS

       PPMd  was  written  by  Dmitry  Shkarin <dmitry.shkarin@mtu-net.ru> and
       Dmitry Subbotin.

SEE ALSO

       gzip(1), bzip2(1), lzma(1).