JRebin1D.cc

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#include <string>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <cmath>

#include "TROOT.h"
#include "TFile.h"
#include "TObject.h"
#include "TKey.h"
#include "TH1D.h"
#include "TString.h"
#include "TRegexp.h"

#include "JGizmo/JRootObjectID.hh"
#include "JGizmo/JGizmoToolkit.hh"

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

  
/**
 * \file
 *
 * Auxiliary program to rebin ROOT histograms.
 * The option <tt>-f</tt> corresponds to <tt><file name>:<object name></tt>.
 * 
 * \author mdejong
 */
int main(int argc, char **argv)
{
  using namespace std;
  using namespace JPP;

  vector<JRootObjectID>   inputFile;
  string                  outputFile;
  vector<Double_t>        X;
  int                     debug;
 
  try {

    JParser<> zap("Auxiliary program to rebin ROOT histograms.");
    
    zap['f'] = make_field(inputFile,  "<input file>:<object name>");
    zap['o'] = make_field(outputFile, "ROOT file with histogram(s)") = "rebin.root";
    zap['x'] = make_field(X,          "abscissa values");
    zap['d'] = make_field(debug)      = 0;
     
    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }


  if (X.empty()) {
    FATAL("No abscissa values." << endl);
  }  

  TFile out(outputFile.c_str(), "recreate");
  
  for (vector<JRootObjectID>::const_iterator input = inputFile.begin(); input != inputFile.end(); ++input) {

    DEBUG("Input: " << *input << endl);

    TDirectory* dir = getDirectory(*input);

    if (dir == NULL) {
      ERROR("File: " << input->getFullFilename() << " not opened." << endl);
      continue;
    }

    const TRegexp regexp(input->getObjectName());

    TIter iter(dir->GetListOfKeys());

    for (TKey* key; (key = (TKey*) iter.Next()) != NULL; ) {

      const TString tag(key->GetName());

      DEBUG("Key: " << tag << " match = " << tag.Contains(regexp) << endl);
        
      // option match

      if (tag.Contains(regexp)) {

        TObject* object = key->ReadObj();

        try {

          TH1D& h0 = dynamic_cast<TH1D&>(*object);

          TH1D  h1(h0.GetName(), NULL, X.size() - 1, X.data()); 

          for (int ix = 1; ix <= h1.GetXaxis()->GetNbins(); ++ix) {

            const Double_t xmin = h0.GetXaxis()->FindBin(h1.GetXaxis()->GetBinLowEdge(ix));
            const Double_t xmax = h0.GetXaxis()->FindBin(h1.GetXaxis()->GetBinUpEdge (ix));

            const Int_t imin = xmin;
            const Int_t imax = xmax;
            
            if (imax != imin) {

              Double_t Y = 0.0;
              Double_t Z = 0.0;
              Double_t W = 0.0;

              for (Int_t i = imin; i != imax; ++i) {

                const Double_t y = h0.GetBinContent(i);
                const Double_t z = h0.GetBinWidth  (i);
                const Double_t w = h0.GetBinError  (i);

                Y += y*z;
                Z += z;
                W += w*z * w*z;
              }

              Y = Y       / Z;
              W = sqrt(W) / Z;

              h1.SetBinContent(ix, Y);
              h1.SetBinError  (ix, W);

            } else {

              ERROR("Invalid bin " << ix << " [" << FIXED(9,3) << xmin << "," << FIXED(9,3) << xmax << "]" << " -> " << imin << ' ' << imax << endl);
            }
          }

          out.WriteTObject(&h1);
        }
        catch(exception&) {}
      }
    }
  }

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