Script error ode23

I'm trying to execute the scripts attached to this post (launch from DOF2LSim) but it gives me this error:

Error using odearguments (line 80)
The last entry in tspan must be different from the first entry.

Error in ode23 (line 114)
    odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in DOF2LSim (line 18)
[t,x] = ode23('DOF2LDE',0,tf,[0 0]',tol);

I didn't write this scripts, found it on the web. I read the help. I'm not sure the ode23 parameters are right. I think it should be something like this:

[t,x] = ode23('DOF2LDE',[0 tf]',x0);

with DOF2LDE function that evalutes differential equations tf final time of simulation 0 intial time of simulation x0 initial conditions

Another thing is that inside DOF2LDE script the function does not match the file name.

Answer 1

[Torsten]

You can't call ODE23 as

[t,x] = ode23('DOF2LDE',0,tf,[0 0]',tol);

The second argument in the call has to be a vector of length at least 2 to indicate the time for start and end of the integration (in your case [0 tf]).

Best wishes

Torsten.

[SilverSurfer]

I had just tried it but it gives me another error

f0 = feval(ode,t0,y0,args{:});   % ODE15I sets args{1} to yp0.

Error in ode23 (line 114)
    odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in DOF2LSim (line 20)
[t,x] = ode23('DOF2LDE',[0 tf],x0);

[Torsten]

[t,x]=ode23(@DOF2LDE,[0 tf],[0;0]);

still errors ?

Best wishes

Torsten.