%COVM Compute covariance matrix for large datasets
% 
% 	C = COVM(A)
% 
% Similar to C = COV(A) this routine computes the covariance matrix 
% for the datavectors stored in the rows of A. No large intermediate 
% matrices are created. If class(A) is 'dataset' then class(C) is 
% 'double'.