Calculates Earth Mover's Distance (EMD) between positive vectors. Assume X is an m-by-p matrix representing m histograms with p bins each and Y is an n-by-p matrix representing another set of n histograms with p bins each. Each histogram is assumed to have the same total weight. This function compute the m-by-n distance matrix D where D(i,j) is the Earth Mover's Distance (EMD) between X(i,:) and Y(j,:). Note for 1D, with all histograms having equal weight, there is a simple closed form for the calculation of the EMD. The EMD between two histograms x and y is simply given by the sum(abs(cdf(x)-cdf(y))), where cdf is the cumulative distribution function (computed simply by cumsum). INPUTS X - m-by-p matrix of m p-bin histograms Y - n-by-p matrix of n p-bin histograms OUTPUTS D - m-by-n distance matrix EXAMPLE X=[randn(100,5)]; Y=randn(40,5)+2; D = dist_emd( [X; Y], [X; Y] ); im(D) DATESTAMP 29-Sep-2005 2:00pm See also DIST_EUCLIDEAN, DIST_CHISQUARED