JTestKolmogorov_Slice2D.hh

Go to the documentation of this file.

#ifndef __JCOMPAREHISTOGRAMS__JTESTKOLMOGOROV_SLICE2D__
#define __JCOMPAREHISTOGRAMS__JTESTKOLMOGOROV_SLICE2D__

#include <istream>
#include <ostream>

#include "JLang/JException.hh"

#include "JCompareHistograms/JTest_t.hh"

#include "TH2.h"
#include "TMath.h"


/**
 * \author rgruiz, bjung
 */
namespace JCOMPAREHISTOGRAMS {}
namespace JPP { using namespace JCOMPAREHISTOGRAMS; }

namespace JCOMPAREHISTOGRAMS {

  /**
   * Implementation of the Kolmogorov test for 2D histograms.\n
   * This class is derived from the abstract class JTest_t(). For a general description of the implementation of this and other tests derived from JTest_t(), see its documentation.\n
   * This test compares two 2D histograms. If the parameter `slice` equals x, X y or Y, the histograms are sliced along the corresponding axis, and the Kolmogorov test is applied to each slice.\n 
   * The input parameter `threshold`, is used to evaluate whether the test is passed or failed for each slice or for the full 2D distribution.\n
   * The evaluation is done by comparing the `threshold` value with the resulting p-value.\n 
   * The parameter `threshold` should therefore be a real value between 0 and 1.
   */
  class JTestKolmogorov_Slice2D:
    public JTest_t
  { 
  public:
    
    /**
     * Default constructor.
     */    
    JTestKolmogorov_Slice2D() :
      JTest_t("KS_Slice2D", "p-Value(KS)")
    {}
    
    
    /**
     * Applies Kolmogorov test for two ROOT TH2 histograms.
     *
     * \param o1 First histogram
     * \param o2 Second histogram
     */
    void test(const TObject* o1, const TObject* o2) override
    {
      using namespace std;
      using namespace JPP;

      const TH2* h1 = dynamic_cast<const TH2*>(o1);
      const TH2* h2 = dynamic_cast<const TH2*>(o2);

      if (h1 == NULL || h2 == NULL) {
        THROW(JValueOutOfRange, "JTestKolmogorov_Slice2D::test(): Could not cast given TObjects to TH2.");
      }

      TH1* h3 = NULL;

      const char* const h3name = (h1->GetName() == h2->GetName() ?
                                  MAKE_CSTRING(h1->GetName()                            << "_" << testName << "_" << slice) :
                                  MAKE_CSTRING(h1->GetName() << "_VS_" << h2->GetName() << "_" << testName << "_" << slice));

      int  nFailures = 0;
      int  nSlices   = 0;
    
      if(slice == 'x' || slice == 'X') {
    
        const int nSlices1 = h1->GetNbinsX();
        const int nSlices2 = h2->GetNbinsX();

        if (nSlices1 != nSlices2) {
          THROW(JValueOutOfRange, "JTestKolmogorov_Slice2D::test(): Histograms with different binning. The objects: " << h1->GetName() << " and " << h2->GetName() << " can not be compared." << endl);
        }

        nSlices = nSlices1;

        h3 = h1->ProjectionX(h3name);
      
        for (int i=1 ; i<=nSlices1 ; ++i) {

          const std::string sliceName = MAKE_STRING(h3->GetName() << "_" << to_string(i));
             
          const TH1* s1 = h1->ProjectionY (sliceName.c_str(),i,i);
          const TH1* s2 = h2->ProjectionY (sliceName.c_str(),i,i);

          if (!(s1->GetSumOfWeights() > 0 && s2->GetSumOfWeights() > 0)) { continue; }    
        
          const double p = s1 -> KolmogorovTest (s2);

          if (p < threshold) nFailures++;
        
          h3->SetBinContent(i,p);
        }
            
      } else if (slice == 'y' || slice == 'Y') {
           
        const int nSlices1 = h1->GetNbinsY();
        const int nSlices2 = h2->GetNbinsY();

        if (nSlices1 != nSlices2) {
          THROW(JValueOutOfRange, "JTestKolmogorov_Slice2D::test(): Histograms with different binning. The objects: " << h1->GetName() << " and " << h2->GetName() << " can not be compared." << endl);
        }

        nSlices = nSlices1;     

        h3 = h1->ProjectionY(h3name);
        
        for (int i=1 ; i<=nSlices1 ; ++i){
             
          const std::string sliceName = MAKE_STRING(h3->GetName() << "_" << to_string(i));

          const TH1* s1 = h1->ProjectionX (sliceName.c_str(),i,i);
          const TH1* s2 = h2->ProjectionX (sliceName.c_str(),i,i);

          if (!(s1->GetSumOfWeights() > 0 && s2->GetSumOfWeights() > 0)) { continue; }

          const double p = s1 -> KolmogorovTest (s2);

          if (p < threshold) nFailures++;
        
          h3->SetBinContent(i,p);
        }
      }

      const bool passed = (nFailures/nSlices < failuresThreshold);

      const JResultTitle title(testName, resultType, passed, nFailures);

      h3->SetTitle(title.getTitle().c_str());
      h3->GetYaxis()->SetTitle(resultType.c_str());      
      
      const JTestResult r(testName,
                          JRootObjectID(MAKE_STRING(h1->GetDirectory()->GetPath() << h1->GetName())),
                          JRootObjectID(MAKE_STRING(h2->GetDirectory()->GetPath() << h1->GetName())),
                          resultType, nFailures, failuresThreshold, h3, passed);
      
      this->push_back(r);
    }

  
    /**
     * Read test parameters from input.
     *
     * \param  in            input stream
     * \return               input stream
     */
    std::istream& read(std::istream& in) override
    {
      using namespace JPP;
      
      in >> threshold >> failuresThreshold >> slice;

      if (threshold < 0.0 || threshold > 1.0) {
        THROW(JValueOutOfRange, "JTestKolmogorov_Slice2D::read(): Invalid threshold value " << threshold);
      }

      if (failuresThreshold < 0.0 || failuresThreshold > 1.0) {
        THROW(JValueOutOfRange, "JTestKolmogorov_Slice2D::read(): Invalid failuresThreshold value " << failuresThreshold);
      }
      
      if (slice != 'x' && slice != 'X' && slice != 'y' && slice != 'Y') {
        THROW(JValueOutOfRange, "JTestKolmogorov_Slice2D::read(): Invalid slice option " << slice);
      }

      return in;
    }
    
  private:
    
    double threshold;          //!< threshold p-value to decide if test is passed.
    double failuresThreshold;  //!< threshold p-value to decide if test is passed.
    char   slice;              //!< axis to slice. x or X for x-axis, y or Y for y-axis, n or N for None.
  };
}

#endif