CompareFunction

absDiff: absolute difference c(x,y) = |x-y|

gaussSim: gaussian similarity c(x,y) = exp(-ln(2)zz/(s*s)) where z=x-y, and s is the value of attribute similarityScale (required in this case) in the ClusteringField

delta: c(x,y) = 0 if x=y, 1 else

equal: c(x,y) = 1 if x=y, 0 else

table: c(x,y) = lookup in similarity matrix