getOdC(g)

function [OdC] = getOdC(g)
% [OdC] = getOdC(g) where g is the adjacency matrix of a graph g
% Based on the algorithm by J.C. Claussen [Physica A 375 (2007) 365373]

g = g ~= 0;             % Ensure that the adjacency matrix is binary
l = sum(g,1);           % Degree Distribution
c = zeros(max(l));      % Preallocated for speed
a = zeros(size(g,1));   % Preallocated for speed

for m = 1:max(l)
    for n = m:max(l)
        i = find(l==m);
        j = find(l==n);
        if ~isempty(i) && ~isempty(j)
            c(m,n) = sum(sum(g(i,j)));
        end
    end
end

for k = 1:length(l)
    a(k) = sum(diag(c,k-1));
end

A = sum(a);

a = a/A;

h = a.*log(a);
h(isnan(h)) = 0; % 0*ln(0) is understood to be equal to 0 and not NaN

OdC = -sum(h);