Re: [ROOT] TMath::BesselJ problem

From: Rene Brun (Rene.Brun@cern.ch)
Date: Wed Apr 02 2003 - 09:35:05 MEST


Hi Tom,

The TMath::BesselJ functions were introduced in version 3.05/03 only.

Rene Brun

Tom Gutierrez wrote:
> 
> Hi,
> Below is a trivial application of TMath to plot some Bessel functions.
> Uncomment your favorite one to plot.  However, while the BesselI's and
> BesselK's work fine, the BesselJ's and BesselY's
> no longer seem to be recognized by TMath -- even though the root
> TMath documentation claims otherwise.  I'm using root v.3.02/07
> (root4star) on a linux cluster (pdsf).  There must be something silly
> I'm missing here...
> 
> Thanks in advance,
> Tom
> 
> #include "TMath.h"
> 
> Double_t kp2da(Double_t* x, Double_t* par)
> {
>     double corr=TMath::BesselJ0(x[0]*par[0]);
> //    double corr=TMath::BesselY0(x[0]*par[0]);
> //    double corr=TMath::BesselJ1(x[0]*par[0]);
> //    double corr=TMath::BesselY1(x[0]*par[0]);
> 
> //    double corr=TMath::BesselI0(x[0]*par[0]);
> //    double corr=TMath::BesselK0(x[0]*par[0]);
> //    double corr=TMath::BesselI1(x[0]*par[0]);
> //    double corr=TMath::BesselK1(x[0]*par[0]);
>     return corr;
> }
> 
> void testbessel(){
> 
> TF1* fun1= new TF1("fun1",kp2da,0,3,1);
> fun1->SetParameter(0,1);
> fun1->Draw();
> 
> }



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