public class ArrayOfDoublesSketchToEstimates
extends org.apache.pig.EvalFunc<org.apache.pig.data.Tuple>
This UDF converts an ArrayOfDoubles sketch to estimates.
The result will be a tuple with N + 1 double values, where
N is the number of double values kept in the sketch per key.
The first estimate is the estimate of the number of unique
keys in the original population.
Next there are N estimates of the sums of the parameters
in the original population (sums of the values in the sketch
scaled to the original population).