function N = mk_matching_matrix_N(lab1,lab2)
% MK_MATCHING_MATRIX_N - Returns the matching matrix corresponding to two partitions 
% 
% Written by:
% -- 
% John L. Weatherwax                2009-03-17
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

% Get some of the preliminary information.
ulab1 = unique(lab1); ulab2 = unique(lab2);
n1 = length(ulab1); n2 = length(ulab2);
n = length(lab1);
% Now find the matching matrix N
N = zeros(n1,n2);
I = 0; 
for i = ulab1(:)'
    I = I + 1;
    J = 0;
    for j = ulab2(:)'
        J = J + 1;
        indI = find(lab1 == i);
        indJ = find(lab2 == j);
        N(I,J) = length(intersect(indI,indJ));
    end
end