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.