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visgraph

    function varargout=visgraph(varargin)

     [k,logP]=visgraph(x)

     Visibility Graph analysis of a time series as described in:

     Lacasa, Lucas, et al.
     "From time series to complex networks: The visibility graph."
      Proceedings of the National Academy of Sciences 105.13 (2008): 4972-4975.

     Required input parameter:
     x
           Nx1 matrix (doubles) of time series to be analyzed.

     Written by Ikaro Silva, 20134
     Last Modified: November 24, 2014
     Version 1.0

     Since 0.9.8

     %Example
     %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

     See also SURROGATE, DFA, MSENTROPY, CORRINT