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MathGroup Archive 2006

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Re: NonLinearRegress Problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg68377] Re: [mg68346] NonLinearRegress Problem
  • From: Darren Glosemeyer <darreng at wolfram.com>
  • Date: Thu, 3 Aug 2006 06:06:41 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

This happens because deb gets evaluated before teta, n, and t are 
numeric.  To keep deb from evaluating before all necessary quantities are 
numeric, you can add NumericQ checks to each of the arguments as follows.

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}]

If deb has already been defined using the other definition in your session, 
you will want to

Clear[deb]

first.  Otherwise the definition without ?NumericQ checks will still be 
seen and result in the same problem as before.


Darren Glosemeyer
Wolfram Research


At 05:23 AM 8/2/2006 -0400, 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 ?


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