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Sanaa
Posts:
166
Registered:
3/20/12


Re: How to integrate discrete function?
Posted:
Dec 5, 2012 3:09 PM


"pietro " <bracardi82@email.it> wrote in message <k9ll5c$nfg$1@newscl01ah.mathworks.com>... > "Sanaa" wrote in message <k9lhqk$ai2$1@newscl01ah.mathworks.com>... > > Hello, > > I want to integrate the discrete function a*x_n*(1x_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.*(1x_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?
Thanks a lot in advance.



