"pietro " <firstname.lastname@example.org> wrote in message <email@example.com>... > "Sanaa" wrote in message <firstname.lastname@example.org>... > > Hello, > > I want to integrate the discrete function a*x_n*(1-x_n) from nr to t (take r=0.005) > > where a:0:0.001:4 and n=0,1,2,3,...., and t\in[nr,(n+1) r] > > Any idea please? > > Thanks a lot. > > use cumtrapz Thanks a lot for replying.
I have tried the following
%%%%%%%%%%%%%%%%%%%% % define the vector of colors, to plot the dat aof reach value of r in % different color color_vec = ['b']; r=0.05; for rho = 0: 0.001:5 r_vec=r; % 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 = 50; % define the nimber of iterations k = 1,.....,Nit Nit = 300; % 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_(n+1) x_previous = zeros(1,n); %x_n
time = zeros(1,n);
% initialize x_previous x_previous = x0; time = zeros(1,n); %x_next = x_previous; time = linspace(0,r,n);
hold on for i = 1:Nit time = linspace(i*r,(i+1)*r,Nit); y_next=rho.*x_previous.*(1-x_previous); x_next = x_previous+ cumtrapz(y_next); x_previous = x_next; end end plot(rho,x_next(1),'.', 'Color', char(color_vec(j))) end
When I execute the results, I found out that x and y go to starting from the second value for each? What's wrong in my code? Moreover, I want to integrate ''y'' from nr to time; how can I do this using cumtrapz?