Re: NDSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg8582] Re: [mg8536] NDSolve
- From: seanross at worldnet.att.net
- Date: Sun, 7 Sep 1997 22:13:03 -0400
- Sender: owner-wri-mathgroup at wolfram.com
N. Kinoshita wrote:
>
> I wonder why the following did not work.
>
> NDSolve[{q'[k]==If[k==kss,qprimess,kdotfun/qdotfun],q[kss]=qss},...
> ***************
> The trouble is here.
>
> kdotfun and qdotfun are both defined previously as functions of [k].
> The error message was like
>
> ...does not evaluate at 34.5444 <-this is the value for kss ...
>
> When I just typed in the same function instead of using 'kdotfun/qdotfun',
> it worked. But I would rather not like to do it because the expression for
> it is sometimes quite complicated.
>
have you tried including the argument? ie. kdotfun[k]/qdotfun[k] ?
If you want to mark a point with a special mark, try using a graphics
primitive like Text, Circle, etc.