JCOMPAREHISTOGRAMS::JTestKolmogorov_2D Class Reference

Implementation of the Kolmogorov test for 2D histograms. More...

#include <JTestKolmogorov_2D.hh>

Inheritance diagram for JCOMPAREHISTOGRAMS::JTestKolmogorov_2D:

Public Member Functions
	JTestKolmogorov_2D ()
	Default constructor. More...
void	test (const TObject *o1, const TObject *o2) override
	Applies Kolmogorov test for two ROOT TH2 histograms. More...
std::istream &	read (std::istream &in) override
	Read test parameters from input. More...
virtual std::ostream &	write (std::ostream &out, const char delimiter= ' ', const bool onlyFailures=false) const
	Write test result to output. More...
virtual void	save (TFile *f, const std::string &path, const bool onlyFailures=false) const
	Writes the test result to root file. More...
const std::string &	getTestName () const
	Get test name. More...
const std::string &	getResultType () const
	Get result type. More...

Protected Attributes
const std::string	testName
	test name More...
const std::string	resultType
	test result type More...

Private Attributes
double	threshold
	threshold p-value to decide if test is passed. More...

Detailed Description

Implementation of the Kolmogorov test for 2D histograms.

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.
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.
If slice equals n or N, the histograms are not sliced, and JKolmogorovTest_2D() is applied.
The input parameter threshold, is used to evaluate whether the test is passed or failed for each slice or for the full 2D distribution.
The parameter threshold should therefore be a real value between 0 and 1.

Definition at line 29 of file JTestKolmogorov_2D.hh.

Constructor & Destructor Documentation

JCOMPAREHISTOGRAMS::JTestKolmogorov_2D::JTestKolmogorov_2D ( )

inline

Default constructor.

Definition at line 37 of file JTestKolmogorov_2D.hh.

                         :
      JTest_t("KS_2D", "p-Value(KS)")
    {}

Member Function Documentation

void JCOMPAREHISTOGRAMS::JTestKolmogorov_2D::test ( const TObject *  o1, const TObject *  o2  )

inlineoverridevirtual

Applies Kolmogorov test for two ROOT TH2 histograms.

Parameters

o1	First histogram
o2	Second histogram

Implements JCOMPAREHISTOGRAMS::JTest_t.

Definition at line 48 of file JTestKolmogorov_2D.hh.

    {
      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_2D::test(): Could not cast given TObjects to TH2.");
      }
    
      const int n1x = h1->GetNbinsX();
      const int n2x = h2->GetNbinsX();
      const int n1y = h1->GetNbinsY();
      const int n2y = h2->GetNbinsY();

      if(n1x != n2x || n1y != n2y)
        THROW(JValueOutOfRange, "JTestKolmogorov_2D::test(): Histograms with different bining. The objects: " <<
              h1->GetName() << " and " << h2->GetName() << " can not be compared." << endl);
     
      if(h1->Integral() == 0 || h2->Integral() == 0) {
        THROW(JValueOutOfRange, "JTestKolmogorov_2D::test(): Empty histogram: " <<
              h1->GetName() << " and " << h2->GetName() << " can not be compared." << endl);
      }

      const double s1 = 1./h1->Integral();
      const double s2 = 1./h2->Integral();

      TH2* h3 = (TH2*) h1->Clone(h1->GetName() == h2->GetName() ?
                                 MAKE_CSTRING(h1->GetName()                            << "_" << testName) :
                                 MAKE_CSTRING(h1->GetName() << "_VS_" << h2->GetName() << "_" << testName));

      double ew1, ew2, w1 = 0, w2 = 0;

      for (int i = 1; i <= n1x; ++i) {
        for (int j = 1; j <= n1y; ++j) {
          ew1 = h1->GetBinError(i,j);
          ew2 = h2->GetBinError(i,j);
          w1 += ew1*ew1;
          w2 += ew2*ew2;
        }
      }

      bool afunc1 = false;
      bool afunc2 = false;
    
      double esum1 = 0, esum2 = 0;
      
      if (w1 > 0) {
        esum1 = 1./s1/s1/w1;
      } else {
        afunc1 = true;
      }
      
      if (w2 > 0) {
        esum2 = 1./s2/s2/w2;
      } else {
        afunc2 = true;
      }
      
      if (afunc2 && afunc1) {
        THROW(JValueOutOfRange, "JTestKolmogorov_2D::test(): Errors are zero for both histograms");
      }
      
      double c1 = 0, c2 = 0;
      
      double dmax1 = 0;
      
      for (int i=1 ; i<=n1x ; ++i){
        for (int j=1 ; j<=n1y ; ++j){
          
          c1 += s1*h1->GetBinContent(i,j);
          c2 += s2*h2->GetBinContent(i,j);
          
          double d = TMath::Abs(c1-c2)*TMath::Sqrt(esum1*esum2/(esum1+esum2));
          
          dmax1 = TMath::Max(dmax1,TMath::Abs(c1-c2));
          
          h3->Fill(i,j,d);
        }
      }

      c1 = 0, c2 = 0;
    
      double dmax2 = 0;
      
      for (int j=1 ; j<=n1y ; ++j){
        for (int i=1 ; i<=n1x ; ++i){
          
          c1 += s1*h1->GetBinContent(i,j);
          c2 += s2*h2->GetBinContent(i,j);
          
          double d = TMath::Abs(c1-c2)*TMath::Sqrt(esum1*esum2/(esum1+esum2));
          
          dmax2 = TMath::Max(dmax2,TMath::Abs(c1-c2));
          
          h3->Fill(i,j,d);
        }
      }
      
      double dmax = 0.5*(dmax1+dmax2);
      
      double z;

      if  (afunc1) {
        z = dmax*TMath::Sqrt(esum2);
      } else if (afunc2) {
        z = dmax*TMath::Sqrt(esum1);
      } else {
        z = dmax*TMath::Sqrt(esum1*esum2/(esum1+esum2));
      }
    
      const double pValue = TMath::KolmogorovProb(z);

      for (int i=1 ; i<=n1x ; ++i) {
        for (int j=1 ; j<=n1y ; ++j) {
          h3->SetBinContent(i,j,TMath::KolmogorovProb(0.5 * h3->GetBinContent(i,j)));
        }
      }

      const bool passed = (pValue > threshold);

      const JResultTitle title(testName, resultType, passed, pValue);
      
      h3->SetTitle(title.getTitle().c_str());
      h3->GetZaxis()->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, pValue, threshold, h3, passed);
      
      this->push_back(r);
    }

std::istream& JCOMPAREHISTOGRAMS::JTestKolmogorov_2D::read ( std::istream &  in )

inlineoverridevirtual

Read test parameters from input.

Parameters

in	input stream

Returns

input stream

Implements JCOMPAREHISTOGRAMS::JTest_t.

Definition at line 191 of file JTestKolmogorov_2D.hh.

    {
      using namespace JPP;
      
      in >> threshold;

      if (threshold < 0.0 || threshold > 1.0) {
        THROW(JValueOutOfRange, "JTestKolmogorov_2D::read(): Invalid threshold value " << threshold);
      }
      
      return in >> threshold;
    }

virtual std::ostream& JCOMPAREHISTOGRAMS::JTest_t::write ( std::ostream &  out, const char  delimiter = ' ', const bool  onlyFailures = false  ) const

inlinevirtualinherited

Write test result to output.

Parameters

out	output stream
delimiter	field delimiter
onlyFailures	if true, write only failures.

Returns

output stream

Definition at line 84 of file JTest_t.hh.

    {
      using namespace std;
      using namespace JPP;

      for (vector<JTestResult>::const_iterator r = this->begin() ; r != this->end() ; ++r) {

        if (onlyFailures && r->passed) { continue; }
        
        print(out, *r, delimiter, true);
      }
      
      return out;
    }

virtual void JCOMPAREHISTOGRAMS::JTest_t::save ( TFile *  f, const std::string &  path, const bool  onlyFailures = false  ) const

inlinevirtualinherited

Writes the test result to root file.

Parameters

f	A ROOT file
path	Path in root file.
onlyFailures	If true, write only failures.

Definition at line 108 of file JTest_t.hh.

    {
      using namespace std;
      using namespace JPP;

      if (f->GetDirectory(path.c_str())==0) {
        f->mkdir(path.c_str());
      }
      
      f->cd(path.c_str());

      for (vector<JTestResult>::const_iterator r = this->begin() ; r != this->end() ; ++r) {

        if (onlyFailures && r->passed) { continue; }
        
        r->obj->Write();
      }
    }

const std::string& JCOMPAREHISTOGRAMS::JTest_t::getTestName ( ) const

inlineinherited

Get test name.

Returns

test name

Definition at line 135 of file JTest_t.hh.

    {
      return testName;
    }

const std::string& JCOMPAREHISTOGRAMS::JTest_t::getResultType ( ) const

inlineinherited

Get result type.

Returns

result type

Definition at line 146 of file JTest_t.hh.

    {
      return resultType;
    }

Member Data Documentation

double JCOMPAREHISTOGRAMS::JTestKolmogorov_2D::threshold

private

threshold p-value to decide if test is passed.

Definition at line 207 of file JTestKolmogorov_2D.hh.

const std::string JCOMPAREHISTOGRAMS::JTest_t::testName

protectedinherited

test name

Definition at line 180 of file JTest_t.hh.

const std::string JCOMPAREHISTOGRAMS::JTest_t::resultType

protectedinherited

test result type

Definition at line 181 of file JTest_t.hh.

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The documentation for this class was generated from the following file:

• JTestKolmogorov_2D.hh