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/Go4FitExample/Example3.cxx

Go to the documentation of this file.

//---------------------------------------------------------------
//        Go4 Release Package v2.10-5 (build 21005) 
//                      03-Nov-2005
//---------------------------------------------------------------
//       The GSI Online Offline Object Oriented (Go4) Project
//       Experiment Data Processing at DVEE department, GSI
//---------------------------------------------------------------
//
//Copyright (C) 2000- Gesellschaft f. Schwerionenforschung, GSI
//                    Planckstr. 1, 64291 Darmstadt, Germany
//Contact:            http://go4.gsi.de
//----------------------------------------------------------------
//This software can be used under the license agreements as stated
//in Go4License.txt file which is part of the distribution.
//----------------------------------------------------------------
// Go4Fit Examples N3

#ifndef __CINT__

#include <iostream.h>

#include "TH1.h"
#include "TFile.h"
#include "TApplication.h"

#include "../Go4Fit/TGo4Fitter.h"
#include "../Go4Fit/TGo4FitModelFunction.h"

void Example3();

int main(int argc, char **argv)
{
   TApplication theApp("Application", 0, 0);

   Example3();

   theApp.Run();

   return 0;
}

extern "C" Double_t gaussian_(Double_t *axis, Double_t *pars);

// routine to read histogram from examples file
TH1D* GetHistogram(const char* HistogramName) {
   TFile f1("histograms.root");
   TH1D* histo = (TH1D*) f1.Get(HistogramName);
   histo->SetDirectory(0);
   return histo;
}

void Example3() {
// create fitter, select fit function and add standard actions list
   TGo4Fitter fitter("Fitter", TGo4Fitter::ff_ML_Poisson, kTRUE);

// add histogram to fitter, which should be fitted
   fitter.AddH1("data1", GetHistogram("hDeg120_P_c"), kTRUE, 2200., 2900.);

// create polynom of first order
   fitter.AddPolynomX( "data1", "Pol", 1);

// create model, which uses user function to calculate gaussian shape
   fitter.AddModel( "data1", new TGo4FitModelFunction("Gauss1",&gaussian_,2,kTRUE) );
   fitter.AddModel( "data1", new TGo4FitModelFunction("Gauss2",&gaussian_,2,kTRUE) );

// set initial values of user model parameters
   fitter.SetParValue("Gauss1.Par0",2553.);
   fitter.SetParValue("Gauss1.Par1",15.);
   fitter.SetParValue("Gauss2.Par0",2672.);
   fitter.SetParValue("Gauss2.Par1",15.);

// add output actions
   fitter.AddOutputAction("Draw","#data1,Gauss1,Gauss2");
   fitter.AddOutputAction("Print","Pars");

// perform all actions
   fitter.DoActions();
}

#else

void Example3() {
   cout << "This example uses linked FORTRAN libraray," << endl;
   cout << "therefore it can not be run in CINT" << endl;
}

#endif


//----------------------------END OF GO4 SOURCE FILE ---------------------

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