Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2000
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2000

[Date Index] [Thread Index] [Author Index]

Search the Archive

NIntegrate v.s. NonlinerFit

  • To: mathgroup at smc.vnet.net
  • Subject: [mg25811] NIntegrate v.s. NonlinerFit
  • From: Carmelo La Rosa <clarosa at dipchi.unict.it>
  • Date: Sat, 28 Oct 2000 01:41:04 -0400 (EDT)
  • Organization: Dipartimento di Scienze Chimiche
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,
my problem is the following:
I have difined a function as following, in order to use in a nonlinear
bestfit containing a numerical integration (work on WinNT 4.0 and
Mathematica 3.0)

<<Statistics`NonlinearFit`
pars={a,b,c}(*parameters for the fit*)
pars0={.......}(*starting parameters of pars*)
A(X)=Exp[-a/X]
K(X)=Exp[-b/X]

f[(T_)?Number,(a_)?Number,(b_)?Number,(c_)?Number]:=
(b*K(T)/(K(T)+1)^2)*Exp[-costant*Module[{X},NIntegrate[A(X)*K(X)/(K(X)+1)),{X,Ton,T}]

the output is a error messagge:

NIntegrate::"nlim": "\!\(X$1\) = \!\(T\) is not a valid limit of
integration."
NIntegrate::"nlim": "\!\(X$1\) = \!\(T\) is not a valid limit of
integration."
NIntegrate::"nlim": "\!\(X$1\) = \!\(T\) is not a valid limit of
integration."
General::"stop":
    "Further output of \!\(NIntegrate :: \"nlim\"\) will be suppressed
during \
this calculation."

In[19]:=

fitted=NonlinearFit[data,Cp[T,pars],pars,T,MaxIterations->3000,
    Errors\[Rule]1.0,InitialGuess\[Rule]pars0,ProgressTrace\[Rule]True]

NonlinearFit::"toomany":
    "Too many variables have been provided for the size of the data;
given \!\
\(2\)-tuples for data, given \!\(4\) variables."

Any assistance will be greatly appreciated.

Carmelo la Rosa


--
____________________________________
------------------------------------
Carmelo La Rosa
Department of Chemical Science
Laboratory of Biophysical Chemistry
University of Catania
V.le A. Doria 6, 95125 Catania
ITALY
Tel1. ++39-95-7385114
Tel2. ++39-95-339572
Fax   ++39-95-580138
E-Mail clarosa at dipchi.unict.it
------------------------------------
____________________________________




  • Prev by Date: Re: Vertical Tangents
  • Next by Date: Re: LeafCount Question
  • Previous by thread: Linear system (symbolic, 10 vars): cannot handle
  • Next by thread: A stupid but practical question