N=1000;
p=15;
z=p/N;

% EL = preferential_attachment(N,3);
% adj = edgeL2adj(EL);
adj = random_graph(N,z);
E = eig(adj);
[f,x] = ksdensity(E,E,'bandwidth',0.1);
plot(x,f,'bo')

s = z*(1-z);
% s = std(E);
X = [-2*(sqrt(N*s)):0.01:2*(sqrt(N*s))];
Y = (1/(2*pi*N*s))*sqrt(4*N*s-X.*X);
hold on
plot(X,Y,'r-')