There is a Fortran code for the Horizontal Visibility Graph at
and the code below for regular visibilty graph which I have not tried but looks incomplete
function varargout=visgraph(varargin)
[k,logP]=visgraph(x)
%Generate Conway Series
N=1000;
a=ones(N,1);
out=ones(N,1);
for n=3:N
a(n)=a(a(n-1))+ a(n-a(n-1));
out(n)= a(n) - (n/2);
end
%Generate Surrogate Data
nS=5;
S=surrogate(out,nS);
subplot(3,1,1)
plot(out);title('Conway Series')
subplot(3,1,2)
plot(S(:,1),'r');title('Amplitude Adjusted Surrogate Data')
%Calculate visibility graph for all series
[k,logP]=visgraph(out);
subplot(3,1,3)
plot(k,logP);hold on;grid on
for n=1:nS
[k,logP]=visgraph(S(:,n));
subplot(3,1,3)
plot(k,logP,'r');
end
