I released an update to my 40H collection of PGN utilities.
The only major change is the addition of a new utility called "cluster".
A cluster is self-contained subset of a ".pgn" file. The players in a cluster only played games against each other. Most of the ".pgn" files I have come across only have 1 cluster, namely, the whole ".pgn" file. However there are ".pgn" files with multiple clusters. This program will detect that and list the players in each cluster.
I got the idea for "cluster" from the program "Elostat 1.3" by Dr. Frank Schubert. That program finds the clusters as a side issue while computing Elo values. However "Elostat" will only work with 1500 players or less. My program "cluster" has a much higher player maximum.
All my code is original.
The link for the entire 40H collection is located on my download page:
http://hoflink.com/~npollock/chess.html
If you just want to download "cluster", use this link:
http://www.orbitfiles.com/download/id2462625369.html
-Norm