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Re: FindFit & NIntegrate

  • To: mathgroup at smc.vnet.net
  • Subject: [mg96265] Re: FindFit & NIntegrate
  • From: alrobnett <alrobnett at alumni.princeton.edu>
  • Date: Tue, 10 Feb 2009 05:54:04 -0500 (EST)
  • References: <gmecbc$acc$1@smc.vnet.net> <gmguqa$2u0$1@smc.vnet.net>

On Feb 9, 4:34 am, Jens-Peer Kuska <ku... at informatik.uni-leipzig.de>
wrote:
> Hi,
>
> no, but the news group has ruleshttp://smc.vnet.net/mathgroup.html
> and one of these rules is:
>
> "PLEASE SEARCH THE ARCHIVES BEFORE YOU ASK WHAT MIGHT BE A COMMON QUESTION"
>
> and I think a poster in the group should
> try to follow the group rules.
>
> Regards
>    Jens
>
> ADL wrote:
> > Dear Jens-Peer,
> > if a questions appears over and over ("10^6 times before") it should
> > mean something to thinking people!
>
> > Latins used to say, "Errare humanum est, perseverare diabolicum". Does
> > this mean anything to Mathematica developers? Do you mean that it is
> > impossible to find a sensible way to do something that 10^6 people
> > would do differently?
>
> > ADL
>
> > On 6 Feb, 10:10, Jens-Peer Kuska <ku... at informatik.uni-leipzig.de>
> > wrote:
> >> Hi,
>
> >> and
>
> >> model[x_?NumericQ,a_?NumericQ,b_?NumericQ,c_?NumericQ]:=
> >>    NIntegrate[function[x_,t_,a_,b_,c_],{t,0,inf}];
>
> >> will work. We had this 10^6 times before.
>
> >> Regards
> >>    Jens
>
> >> hmalissa wrote:
> >>> I want to use the FindFit function (or similar) to fit some
> >>> experimental data:
> >>> fit=FindFit[data,expr,pars,vars]
> >>> Usually this works very well, but in this particular case the model
> >>> expr consists of a NIntegrate over another function, like:
> >>> model[x_,a_,b_,c_]:=NIntegrate[function[x_,t_,a_,b_,c_],{t,0,inf}];
> >>> fit=FindFit[data,model[x,a,b,c],{a,b,c},x]
> >>> FindFit now complains about non-numerical values; of course that makes
> >>> sense.
> >>> How can I force FindFit to do the fitting anyway?

My opinion counts for nothing, but I found the topic very useful.
Perhaps posters who ask questions that have already been treated
should have to provide a supply of extra electrons to replace for
those that were wasted.


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