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Topic: ODE where y' = f(t,y0,...,yn)
Replies: 2   Last Post: Jul 23, 2007 4:13 AM

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 C�dric L Posts: 2 Registered: 4/7/05
Re: ODE where y' = f(t,y0,...,yn)
Posted: Jul 23, 2007 4:13 AM

Thanks for your answer but I've got Matlab R12.1 only and I can't find these functions on my version. Is it normal ?
What can I do ?

"Steven Lord" <slord@mathworks.com> wrote in message <f7o7lp\$8pr\$1@fred.mathworks.com>...
>
> "redcic" <cedric.louyot@gmail.com> wrote in message

> > Hi all,
> >
> > I'm currently trying to solve an ODE that looks like this :
> > y' = f(t,y0,...,yn)
> >
> > where yi is the state vector taken at step i.

>
> This is not an ODE. This is a delay-differential equation.
>

> > This requires more explanation: I want ode45 to compute the state
> > vector y at times that I choose (like I can do using tspan). However I
> > need to use the state vector y computed at all the previous time steps
> > I've choosen in order to calculate y' at the current time step.
> >
> > Is there any way I do that using ode45 ?

>
> Use the delay-differential equation solvers DDE23 or DDESD instead.
>
> http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/ref/dde23.html
> http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/ref/ddesd.html
>
> --
> Steve Lord
> slord@mathworks.com
>
>

Date Subject Author
7/19/07 redcic
7/19/07 Steven Lord
7/23/07 C�dric L