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Topic: Incomplete diagram!
Replies: 2   Last Post: Jul 12, 2013 5:38 PM

 Messages: [ Previous | Next ]
 Sanaa Posts: 171 Registered: 3/20/12
Incomplete diagram!
Posted: Jul 12, 2013 8:32 AM

Hi,
I have a problem that I wish to plot what is called a bifurcation diagram.
The map under study is given by
x_((n+1)r)= 1 - ru *x^2_(nr),
where r is a positive constant may take 0.1,0.2,...
ru is a positive parameter, and the time t runs from nr to (n+1)r, n=0,1,2,...

I have the matlab code
%%%%%%%%%

% define the vector of values that r takes
r_vec = [0.2];
% define the vector of colors, to plot the dat aof reach value of r in
% different color
color_vec = ['b'];

for rho = 0: 0.005: 2

% do a loop of values of r
for j = 1 : size(r_vec,2)
% define delay
r = r_vec(j);
% define coefficient rho
%rho = 0.5;
% define the number of deiscrete times in interval [k*r, (k+1)*r]
n = 10;
% define the nimber of iterations k = 1,.....,Nit
Nit = 1000;
% define the initial vector which is a vector of size n
x0 = 0.3*ones(1,n);
% define vectors x_next and x_previous
x_next = zeros(1,n);
x_previous = zeros(1,n);
time = zeros(1,n);

% initialize x_previous
x_previous = x0;
x_next = x_previous;
time = linspace(0,r,n);

% set the figure details
figure(1)
xlabel('t')
ylabel('x')
%plot(time,x_next,'*')
hold on
for i = 1:Nit

x_next = 1 - rho*x_previous.^2;
x_previous = x_next;
time = linspace(i*r,(i+1)*r,n);

end
end

plot(rho,x_next(1),'.', 'Color', char(color_vec(j)),'linewidth',10)

end

hold off
% save the figure
% print -depsc map.eps
%%%%
The code works but I am wondering why I don't get a complete picture of the diagram, it seems that it is divided into 2 parts!!!!