Version History for plantri
---------------------------

The original edition of plantri, which performed only a few of the
functions of the current edition, was released in June 1996.  Here
we will list the changes made in the functionality of recent editions
only.  Internal changes are listed in plantri.c.

Version 3.0:
  Released on April 25, 2000.

Version 3.1:
  Released on July 3, 2000.

  It was discovered by Thom Sulanke that the code for simple
  triangulations stopped working correctly at 26 or more vertices.
  The bug does not affect any of the calculation sizes listed in
  Appendix D of the plantri manual, and it does not affect operation
  at all with the -m4, -c4 or -b switches.  

  We believe that the only plausible way of encountering the bug
  with the distributed software was to use the maxdeg or allowed_deg
  plugins for 26 or more vertices.  The min5 plugin was not affected.

  Version 3.1 corrects the bug without otherwise changing program
  behaviour.  Many thanks to Thom for his assistance.

Minor update on December 15, 2000:

  allowed_deg.c (source for plantri_ad) updated to permit larger
  graphs to be generated.  plantri-guide.txt updated to contain
  more graph counts.

Version 4.0:
  Released on April 20, 2001.

  Added -q for 3-connected quadrangulations.
  Added -pc1 and -pc2 for general planar graphs.
  Added -m5 and variants.  The plug-in min5.c is no longer required.
  sparse6 output now represents loops only once.

Version 4.1:
  Released on November 30, 2001.

  Added -qc2, -qc4, -qm2c2 for types of quadrangulation.