Release 6.0

• Renamed the functions in the interface to avoid collisions with S3 functions within the R environment. We know that this is another renaming of the POPSOM interface and we apologize for any inconvenience. We expect that the interface is now stable for the foreseeable future.
• New features:
  • The map.minimal object. This is an object that only contains the trained neurons and nothing else. This is an appropriate model when POPSOM is used as a preprocessing step and no other model information is needed. Note that map.minimal objects cannot be processed by any of the other functions in the POPSOM interface.
  • The map.convergence function provides details about the underlying convergence characteristics.
• Bugfixes
  • Most importantly the artificial limit of a minimum of 50 instances in the training data has been removed.

Release 5.2

Reworked the description of the package in order to reflect the capabilities of the package better.

Release 5.1

• Something got rattled with the S3 interface in 4.x. It no longer works the way it did in release 3.x. I took the S3 interface out because I want the package to work with both 3.x and 4.x installations.
  
• Implemented a ‘summary’ function for map objects.

Release 5.0

• completely rearchitected package
• new, streamlined S3 based API
• popsom now supports two models:
  1. a self-organizing map model,
  2. a centroid based clustering model
• quality measures available for both models
• cleaned up map visualization
• extremely fast training algorithm based on ideas from tensor algebra