Re: variable initial value in NDSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg99191] Re: variable initial value in NDSolve
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Wed, 29 Apr 2009 06:38:56 -0400 (EDT)
- Organization: Uni Leipzig
- References: <gt6fgd$rli$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
Hi,
and you are sure thay ou have not missed some equations ?
One initial condition for ec[t] and a differential equation for
R[t] ? And you are sure that you have not mixed up Equal[] (==)and
Set[] (=) ...
Regards
Jens
Stef wrote:
> Dear Mathematica community,
>
> I am pretty new with using Mathematica. So, maybe there is a very
> obvious solution to my problem that I missed to find out myself.
>
> I am trying to solve a problem that is setup like that:
>
> The cost function ec[t] depends on cumulative arrivals R[t]. At a
> variable starting point tstart (for which i try to find a cost-
> minimizing value in a NMinimize fct), cumulative arrivals are 0.
>
> NDSolve[{ec'[t]==0,R[tstart]=0}, R[t],t]
>
> But obviously, the derivative of R[tstart] goes to infinity, which is
> why no solution can be found.
>
>
> Thanks for helpful comments!
>