Re: TF1 with CINT preloaded function

From: Rene Brun (Rene.Brun@cern.ch)
Date: Mon Feb 28 2000 - 15:49:47 MET


Hi Anton,
Look at the small example stress1 in $ROOTSYS/test/stress.cxx

Rene Brun

Anton Fokin wrote:
> 
> Hi Rene,
> 
> One of TF1 constructors is to create TF1 from a user defined function
> 
> TF1 TF1(const char* name, void* fcn, Float_t xmin, Float_t xmax, Int_t npar)
> 
> It works fine in case of CINT
> 
> Double_t myfunction(Double_t *x, Double_t *par)
> {
>    Float_t xx =x[0];
>    Double_t f = TMath::Abs(par[0]*sin(par[1]*xx)/xx);
>    return f;
> }
> void myfunc()
> {
>    TF1 *f1 = new TF1("myfunc",myfunction,0,10,2);
>    f1->SetParameters(2,1);
>    f1->SetParNames("constant","coefficient");
>    f1->Draw();
> }
> 
> Now if I want to create TF1 in my compiled code with myfunction defined in a
> macro loaded via gROOT->LoadMacro() ... where can I get a pointer (void*
> fcn) to myfunction for TF1 constructor?
> 
> Best regards,
> Anton



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