#if !defined( __CINT__) || defined(__MAKECINT__)
#include <TMath.h>
#include <TH1F.h>
#include <TF1.h>
#include <TCanvas.h>
#include <TFile.h>
#include <TROOT.h>
#endif

TF1 *y1, *y2;
double y12(double *x, double *par) {
   return y1->EvalPar(x,par)*y2->EvalPar(x,par);
}
void test() {

   TFile *f = TFile::Open("rapidity.root");
   y1 = (TF1*) f->Get("DSigmaDYMRST98L");
   y2 = (TF1*) f->Get("DSigmaDYMRST01L");

   //   TF1 *y3 = new TF1("y3","y2*y1",-8,8);
   //TF1 *y3 = new TF1("y3","2*y1",-8,8);
   TF1 *y3 = new TF1("y3",y12,-8,8,1);
   y3->SetParameter(0,y1->GetParameter(0));
   
   TCanvas *c3 = new TCanvas("c3");
   c3->Divide(1,2);
   c3->cd(1);
   y3->Draw();
   c3->cd(2);
   y1->Draw();

}