Re: Problem with combination NDSolve NIntegrate

• To: mathgroup at smc.vnet.net
• Subject: [mg72759] Re: Problem with combination NDSolve NIntegrate
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 18 Jan 2007 05:38:22 -0500 (EST)
• Organization: Uni Leipzig
• References: <eol09o\$44r\$1@smc.vnet.net>

```Hi,

Clear[trial]

trial[a_?NumericQ, where_] := (ti[t] /. NDSolve[{ti'[t] == ti[t], ti[0] ==
a}, ti, {t, 0, 10}][[1]]) /. t -> where

NIntegrate[trial[a, 5], {a, 0, 10}]

and
Plot[trial[a, 5], {a, 0, 10}]

Regards
Jens

Paul Schneider wrote:
> I am using version 5.2
>
>
>
> NIntegrate tries to evaluate the integrand symbolically. I try to
>
> circumvent this by using ?NumberQ but without success. Please try the
>
> following toy example:
>
>
>
> trial[a_?NumberQ] :=
>
>      NDSolve[{ti'[t] == ti[t] , ti[0] == a} , ti, {t, 0, 10}];
>
> NIntegrate[ (ti[5] /. trial[a]), {a, 0, 10}]
>
> Plot[ (ti[5] /. trial[a]), {a, 0, 10}]
>
>
>
> NIntegrate does not evaluate to a number and throws a warning, while I
>
> get a perfect plot from Plot.
>
>
>
> Does anybody know what to do?
>
>
>
> Cheers,
>
>
>
> Paul
>
>

```

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