This page contains reference data and code used in a paper by Jan Poland and myself, published back in 2005.
Variable  Meaning 

x  the matrix of the data themselves, as column vectors 
c0  a row vector of correct cluster assignments, an int for each point 
nn  a row vector of cluster sizes, an int for each cluster 
sgm  a matrix of best kernel widths (sigma) for every algorithm. Each row
contains five empirically found best values for the corresponding
algorithm. The algorithms are ordered as follows:

sgmHist  a vector of most probable sigmas according to the histogram method 
The data sets are: