Shannon Entropy

[Greg_Deckler]

Given a column with a list of values, computes the Shannon Entropy for that set of values. The single measure version of this is:

ShannonEntropy = 
SUMX(
          SUMMARIZE(
                    Entities,
                    Entities[Entity],
                    "H(X)",
                    -1*COUNTROWS(Entities)/COUNTROWS(ALL(Entities))*LOG(COUNTROWS(Entities)/COUNTROWS(ALL(Entities)),2))
          ,[H(X)])

There is a single input, a column, in this case called Entities[Entity].