This function calculates means and variances of R1 and R2 quantities using `average` method and `union` method to construct the graph.
getMV_discrete(E,vmat)An edge matrix representing a similarity graph on the distinct values with the number of edges in the similarity graph being the number of rows and 2 columns. Each row records the subject indices of the two ends of an edge in the similarity graph.
A K by 2 matrix, where K is the number of distinct values with at least one observation in either group. It specifies the counts in the K distinct values for the two samples.