JPlex

jPlex is a homology software developed at CompTop, Stanford University.

Initially, PLEX was developed as a set of routines written for MATLAB, developed by Vin de Silva at Stanford University with the help of Gunnar Carlson. Plex computes the Betti numbers of simplicial complexes as well as the Betti numbers of maps. One may only enter data as a list of vertices. After defining an epsilon value (similar to the alpha-value in persistent homology), PLEX calculates the appropriate edges for the vertex set.

jPlex is a new version of PLEX written in Java. Persistent homology is computed for point clouds or filtrations of simplicial complexes.

A recent project provided code for computing persistent relative homology of datasets: The topology of data. The main issues encountered were:

• JPlex only allows analysis up to dimension 7, which is a major obstacle for serious data analysis.
• JPlex has memory issues with even relatively small data sets when analyzing higher dimensions (four and up).
• Overall quite slow.

The lack of multi-parameter persistence is also a problem for data analysis.

In light of these drawbacks, Ayasdi, which is something like the commercial branch of ComTop, may be making a better product based on the same methods.

See also JPlex examples and other homology software.