Returning several dataset using ode45

Hi. I have a problem where I want an ode45 function to return 5 dataset using the code

clc; clear; close all;
% Defining parameters and initial conditions

    f = 0.35;
    r = [0.3:0.3:1.5];
    zeta = 0.25;
    Theta0 = [0.30, 0];
    tspan = [0 10];
    
% Solver options
    opts = odeset('RelTol',1e-6,'AbsTol',[1e-9 1e-9]);
    
% Solver
    [t,theta] = ode45(@(t,theta) odefcn(t,theta,f,r,zeta), tspan, Theta0);
    
    plot(theta(:,1),theta(:,2));
  

As you can see, r is a parameter in the function and I want to create a plot for each of the values for r. The code is running fine when using a single value for r but breaks when using a vector.

Answer 1

[VBBV]

 for i = 1:length(r)    
[t,theta] = ode45(@(t,theta) odefcn(t,theta,f,r,zeta), tspan,Theta0);
plot(theta(:,1),theta(:,2));hold on;
end

Use a for loop and try it

[Walter Roberson]

 for i = 1:length(r)    
[t,theta] = ode45(@(t,theta) odefcn(t,theta,f,r(i),zeta), tspan,Theta0);
plot(theta(:,1),theta(:,2));hold on;
end

[Frederik Bjerregaard]

No it still gives me an error. Just to be sure I have incorporated it correctly, was this what you meant?

clc; clear;close all;
% Defining parameters and initial conditions

    f = 0.35+0.1;
    r = [0.3:0.3:1.5];
    zeta = 0.25;
    Theta0 = [0.30, 0];
    tspan = [0 1000];
    
% Solver options
    opts = odeset('RelTol',1e-6,'AbsTol',[1e-9 1e-9]);
    
% Solver
    for i = 1:length(r)    
    [t,theta] = ode45(@(t,theta) odefcn(t,theta,f,r,zeta), tspan,Theta0);
    plot(theta(:,1),theta(:,2));hold on;
    end
    

I will just include the function file as well for good measure

    function dthetadt = odefcn(t,theta,f,r,zeta)
    dthetadt = zeros(2,1);
    dthetadt(1)=theta(2);
    dthetadt(2)=f.*sin(r.*t)-2.*zeta.*theta(2)-sin(theta(1));
end

[Frederik Bjerregaard]

I got it working now. Thank you!