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Re: NonLinearRegress and constraint parameters

• To: mathgroup at smc.vnet.net
• Subject: [mg57206] Re: [mg57148] NonLinearRegress and constraint parameters
• From: frank at kuesterei.ch (Frank Küster)
• Date: Sat, 21 May 2005 02:39:19 -0400 (EDT)
• References: <200505190708.DAA13073@smc.vnet.net> <acbec1a4050519193436b61667@mail.gmail.com>
• Sender: owner-wri-mathgroup at wolfram.com

Chris Chiasson <chris.chiasson at gmail.com> wrote:

> http://forums.wolfram.com/mathgroup/archive/2003/Sep/msg00184.html
>

Thanks for the hint - I didn't find this.  However, with Mathematica 5.1
it does not seem to work:

In[1]:=

modelgenerate[x_]:=a*x+b*x^2+c*x^3
modelanalyse[x_]:=a*x+b*x^2
dat=Range[0,10,0.1];
xydat=Map[{#,modelgenerate[#]/.{a->2,b->3,c->0.5}}&,dat];
<<Statistics`NonlinearFit`
fitresult= 
    NonlinearRegress[xydat,modelanalyse[x],{x},{a,b},
      ShowProgress->False];
fitresultconstrained1=
    NonlinearRegress[xydat,modelanalyse[x],{x},
      {{a,{-15,-14},-18,-10},{b,{5,50},0,100}},
      ShowProgress->False];
(* This gives an error message:
fitresultconstrained2=
    NonlinearRegress[xydat,modelanalyse[x],{x},
        {{a,{-18,-10},-15,-14},{b,{5,50},0,100}},
        ShowProgress->False];*)
BestFitParameters/.fitresult
BestFitParameters/.fitresultconstrained1

Out[8]=
{a->-18.1977,b->9.69956}

Out[9]=
{a->-18.1977,b->9.69956}

Regards, Frank

-- 
Frank Küster
Inst. f. Biochemie der Univ. Zürich
Debian Developer

• References:
  • NonLinearRegress and constraint parameters
    • From: frank@kuesterei.ch (Frank Küster)