Help with a ode45 problem

Hi

I have the following function:

function f=matpendel(t,u,g,l,m,c)
f=[u(2)
  -g/l*sin(u(1))-c/m*u(2)];

And I'm trying to plot this:

clf;
g=9.82; l=0.1; m=0.1; c=0.2; theta(0)=[10:30:130]*pi/180;
tspan=linspace(0,1,200);
for k=1:length(theta0)
    u(0)=[theta0(k);0];
    [t,U]=ode45(@(t,u)matpendel(t,u,g,l,m,c),tspan,u(0));
    subplot(1,2,1), plot(t,U(:,1)), hold on
    subplot(1,2,2), plot(U(:,1),U(:,2)), hold on
end

But I get the error Subscript indices must either be real positive integers or logicals. Does anybody know why?

[Jan]

The term "10:30:130" does not need additional square brackets. In fact, they only waste time, because this is a vector already.

Answer 1

[Azzi Abdelmalek]

The error is in

 theta(0)=[10:30:130]*pi/180;

do you mean

 theta0=

[Esteban]

Ah yes, it is true that I meant theta0 and not theta(0), thanks!

But I still get the same error...

Edit: I changed u(0) to u0 too, now it works. Thanks!