Re: Multiple variables in ode45

[Paul Probert]

Ron Crummett wrote:
> Hi all -
>
> I am trying to solve a differential equation with ode45 that has two 
> input variables and one output, but one of the input variables is 
> dependent on the other.  When I try searching for anything like this it 
> is to no avail (maybe I don't know what to search for).
>
> Anyway, the equation is
>
> u_dot = 0.5*e_dot+1.64*(e-1.14*Vf_dot)
>
> where e = Vf-Vl, Vl is my input, and Vf is my output.  The value of u is 
> then fed into another system (which I do have the diff. eq. for) to get 
> Vf, if that helps.
>
> Could someone give me some pointers on how to do this?  Thanks.
>
> -Ron
You might want to take a look at daspk, for solving problems
like 0=f(x,xdot,t) where you supply the f. Just lump all your variables
into one big system and let 'er rip. Works great for me!

hth,
Paul Probert
University of Wisconsin



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