function s = init_crossums(gam)
global Aing
m = size(gam,1);

rind=0;
Aing = zeros(0,m^2);

mm = repmat([m],[1 m]);
minds = list_all_ind(mm);
for jind = 1:size(minds,1)
  rind = rind+1;
  iseq = minds(jind,:);
  rho = ~all(iseq==iseq(1));
  for j=1:m
    i = iseq(j);
    cind = coord2ind([i j],[m m]);
    Aing(rind,cind) = 1;
  end
end

s = max(abs(Aing*gam(:)));

return