Fill_In.m

% "Fill_In.m" computes fill-in of the input nodes in the network graph.

% SDP Solver of Optimal Power Flow: beta version
% Ramtin Madani(madani@ee.columbia.edu)
% Morteza Ashraphijuo(morteza.ashraphijuo@gmail.com)
% Javad Lavaei(lavaei@ee.columbia.edu)
% Columbia University
% Last Modified: October 07, 2014

function [ff] = Fill_In(busN,neighbour,bb)
    ff = zeros(length(bb),1);
    for ii = 1 : length(bb)
        qq = busN(bb(ii));
        dd = length(neighbour{qq});
        nn = busN(neighbour{qq});
        ll = 0;
        for jj = 1 : dd
            kk = nn(jj);
            ll = ll + length(intersect(neighbour{qq}, neighbour{kk}));
        end
        ff(ii) = (dd*(dd - 1) - ll)/2;
    end
end