How to pass a function handle as an argument in ode45?

Consider the following code:

  R = 0.5;
  l = 1;
  g = 9.81;
  omega = 0.25;
 F = @(t,y) [y(2), (R*omega^2/l)*cos(y(1) - omega*t) - (g/l)*sin(y(1))];
 t0 = 0;
 T = 10;
 y0 = [pi/4,pi/4];
 h = 0.05;
 [ts,yt] = VectorRK4(F,t0,T,y0,h);
 [T,Y] = ode45(F,[0 10],[pi/4 pi/4]);
 figure;
 plot(T,Y(:,1),'-',T,Y(:,2),'-.');

I am trying to simulate my own RK4 algorithm. The error arises in using the ode45 command I am obtaining the following line of error:

Error using odearguments

@(T,Y)[Y(2),(R*OMEGA^2/L)*COS(Y(1)-OMEGA*T)-(G/L)*SIN(Y(1))] must return a column vector.

How can this be fixed?

Answer 1

[Davide Masiello]

Just use a semicolon, ode45 requires the output to be a column array.

R = 0.5;
 l = 1;
 g = 9.81;
 omega = 0.25;
 F = @(t,y) [y(2); (R*omega^2/l)*cos(y(1) - omega*t) - (g/l)*sin(y(1))];
 t0 = 0;
 T = 10;
 y0 = [pi/4,pi/4];
 h = 0.05;
%  [ts,yt] = VectorRK4(F,t0,T,y0,h);
 [T,Y] = ode45(F,[0 10],[pi/4 pi/4]);
 figure;
 plot(T,Y(:,1),'-',T,Y(:,2),'-.')

[Tarek Hajj Shehadi]

Semi-colons.... are the mother and father of all evil.