那么令 U是ij元是<bblatex>U_ij</bblatex>， 那么following R code computes D as:
<br />
#suppose x is a vector<br />
n=length(x);<br />
U=kronecker(x,t(rep(1,n)))-kronecker(rep(1,n),t(x));<br />
U=U/sqrt(U^2);<br />
A=U^2<br />
D=sum(A)-sum(diag(A))<br />
D=D/(n-1)<br />
