Method to calculate the fowlkes and mallows.
fowlkes_mallows_index_metric(true_positive, false_positive, false_negative)
true_positive
: Array with matching elements of B is in the same cluster.false_positive
: Array with non matching element of B is in the same cluster.false_negative
: Array with matching elements of B is not in the same cluster.Returns a double with the fowlkes_mallows_index calculation.