JTools/JHistogram1D.cc

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#include <string>
#include <iostream>
#include <iomanip>

#include "TROOT.h"
#include "TFile.h"
#include "TH1D.h"
#include "TMath.h"
#include "TRandom.h"

#include "JTools/JHistogram1D.hh"
#include "JTools/JCollection.hh"
#include "JTools/JGrid.hh"
#include "JTools/JSet.hh"
#include "JTools/JQuadrature.hh"
#include "JTools/JFunction1D_t.hh"
#include "JTools/JToolsToolkit.hh"

#include "Jeep/JParser.hh"
#include "Jeep/JMessage.hh"


namespace {

  /**
   * Function g1.
   *
   * \param  x       x value
   * \return         function value
   */
  inline Double_t g1(const Double_t x)
  {
    return TMath::Gaus(x, 0.0, 1.0, kTRUE);
  }
  
  
  /**
   * Integral of g1.
   *
   * \param  x       x value
   * \return         integral value
   */
  inline Double_t G1(const Double_t x)
  {
    return 0.5 * (1.0 + TMath::Erf(sqrt(0.5)*x));
  }
}


/**
 * \file
 *
 * Example program to test JTOOLS::JHistogram1D.
 * \author mdejong
 */
int main(int argc, char **argv)
{
  using namespace std;

  string  outputFile;
  int     numberOfEvents;
  int     numberOfBins;
  bool    quadrature;
  bool    subtract;
  int     debug;

  try {

    JParser<> zap("Example program to test 1D histogram.");

    zap['o'] = make_field(outputFile)     = "histogram.root";
    zap['n'] = make_field(numberOfEvents);
    zap['N'] = make_field(numberOfBins);
    zap['Q'] = make_field(quadrature);
    zap['D'] = make_field(subtract);
    zap['d'] = make_field(debug)          = 3;

    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }


  if (numberOfEvents <= 0) {
    FATAL("No events." << endl);
  }

  using namespace JPP;


  const Int_t    nx   = 1000;
  const Double_t xmin = -5.0;
  const Double_t xmax = +5.0;
  

  typedef JElement2D<double, double>    JElement_t;

  JHistogram1D<JElement_t, JCollection> histogram;


  // abscissa

  if (!quadrature)
    histogram.configure(make_grid(numberOfBins, xmin, xmax));
  else
    histogram.configure(JGaussHermite(numberOfBins));


  // fill

  for (int i = 0; i != numberOfEvents; ++i) {
    histogram.fill(gRandom->Gaus(0.0, 1.0), 1.0);
  }

  histogram.div((double) numberOfEvents);


  // interpolation

  typedef  JSplineFunction1S_t    JFunction1D_t;
  //typedef  JPolintFunction1D<3, JElement_t, JCollection, JResultHesse<double> >  JFunction1D_t;


  JFunction1D_t F1;

  integrate(histogram, F1);

  F1.compile();


  JFunction1D_t f1;

  makePDF(histogram, f1);

  f1.compile();

  f1.setExceptionHandler(new JFunction1D_t::JDefaultResult(JMATH::zero));
  F1.setExceptionHandler(new JFunction1D_t::JDefaultResult(JMATH::zero));


  TFile out(outputFile.c_str(), "recreate");

  TH1D h0("h0", NULL, nx,  xmin, xmax);
  TH1D h1("h1", NULL, nx,  xmin, xmax);
  TH1D h2("h2", NULL, nx,  xmin, xmax);

  TH1D i0("i0", NULL, nx,  xmin, xmax);
  TH1D i1("i1", NULL, nx,  xmin, xmax);

  for (int i = 1; i <= h0.GetNbinsX(); ++i) {
      
    const Double_t x = h0.GetBinCenter(i);

    h0.SetBinContent(i, g1(x));
    i0.SetBinContent(i, G1(x));
      
    try {
      h1.SetBinContent(i, get_value(F1(x).fp));
      h2.SetBinContent(i, get_value(f1(x)));
      i1.SetBinContent(i, get_value(F1(x)));
    }
    catch(const exception& error) {
      ERROR(error.what() << endl);
    }
  }

  if (subtract) {
    h1.Add(&h0, -1.0);
    h2.Add(&h0, -1.0);
    i1.Add(&i0, -1.0);
  }

  out.Write();
  out.Close();
}