covariance of two variables
s=covar(x,y,fre)
real or complex vector
real or complex vector
matrix of type length(x) x length(y)
covar(x,y,fre)
computes the covariance of two variables x and y.
fre is a matrix of dimensions length(x) x length(y). In fre the element
of indices (i,j) corresponds to the value or number or frequencies of
x_i&y_j.
Wonacott, T.H. & Wonacott, R.J.; Introductory Statistics, J.Wiley & Sons, 1990.