// -*- mode: c++ -*- 
//
// $Id: BrStatistics.h,v 1.7 2002/04/24 18:15:14 cholm Exp $
// 
#ifndef ROOT_BrStatistics
#define ROOT_BrStatistics
#ifndef ROOT_TObject
#include "TObject.h"
#endif 
#ifndef ROOT_TArrayD
#include "TArrayD.h"
#endif
#ifndef ROOT_TH1
#include "TH1.h"
#endif 
class TBrowser;


class BrStatistics : public TObject 
{
private:
  Int_t     fN;              // Dimension of sample 
  Int_t     fM;              // Size of sample
  TArrayD   fAverage;        // Average of the sample variables 
  TArrayD   fMax;            // Max of the sample variables 
  TArrayD   fMin;            // Min of the sample variables
  TArrayD   fCovariance;     // Covariance matrix
  
  
  Bool_t    fDataStored;     // Store data tuples? 
  Int_t     fMmem;           // Allocated memory 
  TArrayD   fData;           // The sample  
public:
  BrStatistics();
  BrStatistics(Int_t dimension, Bool_t storeData=kFALSE, Int_t size = 100);
  virtual ~BrStatistics();

  static  void           CombineSamples(UInt_t n1, Double_t m1, Double_t s1, 
					UInt_t n2, Double_t m2, Double_t s2,
					Double_t& m, Double_t& s);
  static  void           AddPoint(Double_t data, UInt_t n, 
				  Double_t& average, Double_t& sqvar); 
  virtual void           AddRow(Double_t* row);
  virtual void           Browse(TBrowser* b) { Draw("c color"); }
  virtual Int_t          GetSampleSize() { return fM; }
  virtual Double_t       GetMax(Int_t i) const;
  virtual const TArrayD& GetMaxArray() const { return fMax; }
  virtual Double_t       GetCovariance(Int_t i, Int_t j) const;
  virtual const TArrayD& GetCovarianceArray() const { return fCovariance; }
  virtual Double_t       GetAverage(Int_t i) const;
  virtual const TArrayD& GetAverageArray() const { return fAverage; }
  virtual Double_t       GetMin(Int_t i) const;
  virtual const TArrayD& GetMinArray() const { return fMin; }
  virtual Double_t       GetVariance(Int_t i) const;  
  virtual Double_t       GetFluctuation(Int_t i, Int_t j) const;
  virtual Double_t       GetCorrelation(Int_t i, Int_t j) const;
  virtual Bool_t         IsDataStored() const { return fDataStored; }

  virtual void           Print(Option_t* option="balus") const; //*MENU*
  virtual void           Draw(Option_t* option="");      //*MENU*
  virtual Double_t*      GetRow(Int_t i) const;
  virtual TH1*           Project(Int_t i);
  virtual TH1*           Project(Int_t i, Int_t j);
  virtual TH1*           Project(Int_t i, Int_t j, Int_t k);
  virtual void           Set(Int_t n, Bool_t store=kFALSE, Int_t m=100);
  
  ClassDef(BrStatistics,2) // Class for low-level statistics 
}
;

//____________________________________________________________________
inline Double_t BrStatistics::GetCovariance(Int_t i, Int_t j) const 
{ 
  // return the i,j element of the covariance matrix
  // return fCovariance[i * fN +  j]; //  * fM / (fM - 1); 
  return fCovariance.At(i * fN +  j); //  * fM / (fM - 1); 
}

//____________________________________________________________________
inline Double_t BrStatistics::GetCorrelation(Int_t i, Int_t j) const 
{ 
  // return the i,j element of the correlation matrix
  return (i == j ? 1 : GetCovariance(i, j) /
   	  TMath::Sqrt(GetCovariance(i, i) * GetCovariance(j, j))); 
}

//____________________________________________________________________
inline Double_t BrStatistics::GetFluctuation(Int_t i, Int_t j) const 
{ 
  // return the i,j element of the fluctuation matrix
  return (i == j ? GetCovariance(i, i) / GetAverage(i) :
	  GetCovariance(i, j) / TMath::Sqrt(GetAverage(i) *
					    GetAverage(j))); 
}

//____________________________________________________________________
inline Double_t BrStatistics::GetMax(Int_t i) const 
{ 
  // return the maximum element of variable i 
  // return fMax[i]; 
  return fMax.At(i); 
}

//____________________________________________________________________
inline Double_t BrStatistics::GetMin(Int_t i) const 
{ 
  // return the minimum element of variable i 
  // return fMin[i]; 
  return fMin.At(i);  
}

//____________________________________________________________________
inline Double_t BrStatistics::GetAverage(Int_t i) const 
{ 
  // return the average element of variable i 
  // return fAverage[i]; 
  return fAverage.At(i);
}

//____________________________________________________________________
inline Double_t BrStatistics::GetVariance(Int_t i) const 
{ 
  // return the Variance element of variable i 
  // return fCovariance[i * fN + i]; 
  return fCovariance.At(i * fN + 1);
}


#endif 
// 
// EOF
//