function [adjmatrix] = LPVG(time_series,L)

[num,len,~] = size(time_series);

time_series = abs(fft(time_series))/len;

min_value=min(time_series);

if (min_value<0)

    time_series = time_series+abs(min_value);

end

adjmatrix = zeros(len,len);

xlmatrix = zeros(len,len);

for i = 1:len

    for j = i:len

        xlmatrix(i,j)=(time_series(j)-time_series(i))/abs(i-j);

    end

end

min_matrix=min(min(xlmatrix));

for k = 1:len

    Y = ones(1,L+1);

    Y = min_matrix*Y;

    for l = k+1:len

        if abs(k-l)<=L+1

            adjmatrix(k,l)=1;adjmatrix(l,k)=1;

            if Y(1,1)<xlmatrix(k,l) 

               Y(1,1)=xlmatrix(k,l);

               Y=sort(Y);

            end   

        elseif Y(1,1)<xlmatrix(k,l)

            adjmatrix(k,l)=1;adjmatrix(l,k)=1;

            Y(1,1)=xlmatrix(k,l);

            Y=sort(Y);

        else    

            adjmatrix(k,l)=0;adjmatrix(l,k)=0;

        end

    end

end