Re: NonLinearRegress Problem

• To: mathgroup at smc.vnet.net
• Subject: [mg68370] Re: NonLinearRegress Problem
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Thu, 3 Aug 2006 06:06:27 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <eapr5l\$s0h\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```jour wrote:
> I have the following problem with NonLinearRegress
>
> I have defined the following function
>
> deb[teta_,n_,t]:= 9 n (t/teta)^3 Nintegrate[(x^4
> Exp[x])/(1+Exp[x])^2,{x,0,t/teta}]
>
> I can Table this function without problem
>
> Table[{t, deb2[100, 3, t]}, {t, 1, 200, 5}]
>
> but when I try to use this function in NonlinearRegress
>
> fut = NonlinearRegress[dat,
> deb2[teta, n, t],
> {t}, {{teta, {10., 50.}, 0., 1000.}, {n, {1, 3}, 1, 70}}]
>
> I get an error message
>
> NIntegrate::"nlim"  t/teta is not a valid limit of integration
>
> any suggestions ?
>

deb[(teta_)?NumericQ, (n_)?NumericQ, (t_)?NumericQ] :=
9*n*(t/teta)^3*NIntegrate[(x^4*Exp[x])/(1 + Exp[x])^2, {x, 0, t/teta}]

will prevent NIntegrate to be called with symbolic arguments.

HTH,
Jean-Marc

```

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