Robust implementation of Concurrent KMeans to handle missing values.
This code is adapted from a version of KMeans implemented by Thinklab. Changes made to the original code include:
(1) switch from doubles to floats
(2) skipping NaNs (missing data)
(3) KMeans++ style initialization
(4) KMedians implementation
Because the original code is released under GPLv3, we are required to release this library under GPLv3 as well.
Original code (under GPLv3+) https://github.com/ariesteam/thinklab/blob/master/plugins/org.integratedmodelling.thinklab.geospace/src/org/integratedmodelling/geospace/kmeans/ConcurrentKMeans.java