Re: Ode45 help

[Thomas Treichl]

Brandon Pye schrieb:
> Hey guys,
>
> I'm in a class where I need to use ode45. I keep getting an error  
> syntax when I copy the code from matlab to octave. The function that  
> contains the differential equations gets its values from a structure  
> defined in the master .m file. In matlab, when I call ode45 the code  
> looks like:
>
> [t,y] = ode45(@gene.m, [0 10], y0, [], info);
>
> Where the closed brackets are skipping the tolerance and 'info' is the  
> structure I need so that the function 'gene.m' can get the values  
> necessary for the differential equations. When I run that code in  
> octave, it can't find the values in the structure. Can anyone tell me  
> where I can put the structure in the code when I call ode45 in octave?  
> Also, I have matlab for windows. Should I just try to run it with wine?

I took a similar example than the one you sent (a modified version of the 
example that comes from "help ode45" at the Octave prompt. I don't know what the 
gene function should do but I also cannot see the problem. Can you post some 
more information from your session?

Here is my example:

  octave-3.0.3:1> fvdb = @(vt,vy) [vy(2); (1 - vy(1)^2) * vy(2) - vy(1)];
  octave-3.0.3:2> ode45 (fvdb, [0 20], [2 0], [], (struct ('a', 1, 'b', 2)))

Best regards,

  Thomas