covariance of 3 D matrix

How do we find out covariance of a 3 D matrix? knowing the fact that covariance is always measured between two dimensions

[Andrew Newell]

What do the elements of the 3D matrix represent? For example, if the matrix is M, are the elements in M(i,j,:) estimates of variable (i,j)?

Answer 1

[Andrew Newell]

Probably what you need is in this discussion of covariance.