TProfile2D


class description - source file - inheritance tree

class TProfile2D : public TH2D

    private:
Double_t* GetB() Double_t* GetW() Double_t* GetW2() public:
TProfile2D TProfile2D() TProfile2D TProfile2D(const char* name, const char* title, Int_t nbinsx, Axis_t xlow, Axis_t xup, Int_t nbinsy, Axis_t ylow, Axis_t yup, Option_t* option) TProfile2D TProfile2D(const char* name, const char* title, Int_t nbinsx, Axis_t xlow, Axis_t xup, Int_t nbinsy, Axis_t ylow, Axis_t yup, Axis_t zlow, Axis_t zup, Option_t* option) TProfile2D TProfile2D(const TProfile2D& profile) virtual void ~TProfile2D() virtual void Add(TF1* h1, Double_t c1 = 1) virtual void Add(TH1* h1, Double_t c1 = 1) virtual void Add(TH1* h1, TH1* h2, Double_t c1 = 1, Double_t c2 = 1) void BuildOptions(Double_t zmin, Double_t zmax, Option_t* option) static TClass* Class() virtual void Copy(TObject& hnew) virtual void Divide(TF1* h1, Double_t c1 = 1) virtual void Divide(TH1* h1) virtual void Divide(TH1* h1, TH1* h2, Double_t c1 = 1, Double_t c2 = 1, Option_t* option) virtual TH1* DrawCopy(Option_t* option) virtual Int_t Fill(Axis_t) virtual Int_t Fill(Axis_t, Stat_t) virtual Int_t Fill(Axis_t x, Axis_t y, Stat_t z) virtual Int_t Fill(Axis_t x, Axis_t y, Axis_t z, Stat_t w) virtual Stat_t GetBinContent(Int_t bin) const virtual Stat_t GetBinContent(Int_t binx, Int_t biny) const virtual Stat_t GetBinContent(Int_t binx, Int_t biny, Int_t) const virtual Stat_t GetBinEntries(Int_t bin) const virtual Stat_t GetBinError(Int_t bin) const virtual Stat_t GetBinError(Int_t binx, Int_t biny) const virtual Stat_t GetBinError(Int_t binx, Int_t biny, Int_t) const Option_t* GetErrorOption() const virtual void GetStats(Stat_t* stats) const virtual Double_t GetZmax() const virtual Double_t GetZmin() const virtual TClass* IsA() const virtual void Multiply(TF1* h1, Double_t c1 = 1) virtual void Multiply(TH1* h1) virtual void Multiply(TH1* h1, TH1* h2, Double_t c1 = 1, Double_t c2 = 1, Option_t* option) TH2D* ProjectionXY(const char* name = _pxy, Option_t* option = e) virtual void Reset(Option_t* option) virtual void Scale(Double_t c1 = 1) virtual void SetBinEntries(Int_t bin, Stat_t w) virtual void SetBins(Int_t, Double_t, Double_t) virtual void SetBins(Int_t nbinsx, Double_t xmin, Double_t xmax, Int_t nbinsy, Double_t ymin, Double_t ymax) virtual void SetBins(Int_t, Double_t, Double_t, Int_t, Double_t, Double_t, Int_t, Double_t, Double_t) virtual void SetErrorOption(Option_t* option) virtual void ShowMembers(TMemberInspector& insp, char* parent) virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b)

Data Members

    private:
protected:
TArrayD fBinEntries number of entries per bin EErrorType fErrorMode Option to compute errors Double_t fZmin Lower limit in Z (if set) Double_t fZmax Upper limit in Z (if set) public:

Class Description

  Profile2D histograms are used to display the mean
  value of Z and its RMS for each cell in X,Y.
  Profile2D histograms are in many cases an
  elegant replacement of three-dimensional histograms : the inter-relation of three
  measured quantities X, Y and Z can always be visualized by a three-dimensional
  histogram or scatter-plot; its representation on the line-printer is not particularly
  satisfactory, except for sparse data. If Z is an unknown (but single-valued)
  approximate function of X,Y this function is displayed by a profile2D histogram with
  much better precision than by a scatter-plot.

  The following formulae show the cumulated contents (capital letters) and the values
  displayed by the printing or plotting routines (small letters) of the elements for cell I, J.

                                                        2
      H(I,J)  =  sum Z                  E(I,J)  =  sum Z
      l(I,J)  =  sum l                  L(I,J)  =  sum l
      h(I,J)  =  H(I,J)/L(I,J)          s(I,J)  =  sqrt(E(I,J)/L(I,J)- h(I,J)**2)
      e(I,J)  =  s(I,J)/sqrt(L(I,J))

  In the special case where s(I,J) is zero (eg, case of 1 entry only in one cell)
  e(I,J) is computed from the average of the s(I,J) for all cells.
  This simple/crude approximation was suggested in order to keep the cell
  during a fit operation.

           Example of a profile2D histogram
{
  TCanvas *c1 = new TCanvas("c1","Profile histogram example",200,10,700,500);
  hprof2d  = new TProfile2D("hprof2d","Profile of pz versus px and py",40,-4,4,40,-4,4,0,20);
  Float_t px, py, pz;
  for ( Int_t i=0; i<25000; i++) {
     gRandom->Rannor(px,py);
     pz = px*px + py*py;
     hprof2d->Fill(px,py,pz,1);
  }
  hprof2d->Draw();
}


TProfile2D() : TH2D()
*-*-*-*-*-*Default constructor for Profile2D histograms*-*-*-*-*-*-*-*-*
*-*        ============================================

~TProfile2D()
*-*-*-*-*-*Default destructor for Profile2D histograms*-*-*-*-*-*-*-*-*
*-*        ===========================================

TProfile2D(const char *name,const char *title,Int_t nx,Axis_t xlow,Axis_t xup,Int_t ny,Axis_t ylow,Axis_t yup,Option_t *option) : TH2D(name,title,nx,xlow,xup,ny,ylow,yup)
*-*-*-*-*-*Normal Constructor for Profile histograms*-*-*-*-*-*-*-*-*-*
*-*        ==========================================

  The first eight parameters are similar to TH2D::TH2D.
  All values of z are accepted at filling time.
  To fill a profile2D histogram, one must use TProfile2D::Fill function.

  Note that when filling the profile histogram the function Fill
  checks if the variable z is betyween fZmin and fZmax.
  If a minimum or maximum value is set for the Z scale before filling,
  then all values below zmin or above zmax will be discarded.
  Setting the minimum or maximum value for the Z scale before filling
  has the same effect as calling the special TProfile2D constructor below
  where zmin and zmax are specified.

  H(I,J) is printed as the cell contents. The errors computed are s(I,J) if CHOPT='S'
  (spread option), or e(I,J) if CHOPT=' ' (error on mean).

        See TProfile2D::BuildOptions for explanation of parameters


TProfile2D(const char *name,const char *title,Int_t nx,Axis_t xlow,Axis_t xup,Int_t ny, Axis_t ylow,Axis_t yup,Axis_t zlow,Axis_t zup,Option_t *option) : TH2D(name,title,nx,xlow,xup,ny,ylow,yup)
*-*-*-*-*-*Constructor for Profile2D histograms with range in z*-*-*-*-*-*
*-*        ====================================================
  The first eight parameters are similar to TH2D::TH2D.
  Only the values of Z between ZMIN and ZMAX will be considered at filling time.
  zmin and zmax will also be the maximum and minimum values
  on the z scale when drawing the profile2D.

        See TProfile2D::BuildOptions for more explanations on errors


void BuildOptions(Double_t zmin, Double_t zmax, Option_t *option)
*-*-*-*-*-*-*Set Profile2D histogram structure and options*-*-*-*-*-*-*-*-*
*-*          =============================================

    If a cell has N data points all with the same value Z (especially
    possible when dealing with integers), the spread in Z for that cell
    is zero, and the uncertainty assigned is also zero, and the cell is
    ignored in making subsequent fits. If SQRT(Z) was the correct error
    in the case above, then SQRT(Z)/SQRT(N) would be the correct error here.
    In fact, any cell with non-zero number of entries N but with zero spread
    should have an uncertainty SQRT(Z)/SQRT(N).

    Now, is SQRT(Z)/SQRT(N) really the correct uncertainty?
    that it is only in the case where the Z variable is some sort
    of counting statistics, following a Poisson distribution. This should
    probably be set as the default case. However, Z can be any variable
    from an original NTUPLE, not necessarily distributed "Poissonly".
    The computation of errors is based on the parameter option:
    option:
     ' '  (Default) Errors are Spread/SQRT(N) for Spread.ne.0. ,
                      "     "  SQRT(Z)/SQRT(N) for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0
     's'            Errors are Spread  for Spread.ne.0. ,
                      "     "  SQRT(Z)  for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0
     'i'            Errors are Spread/SQRT(N) for Spread.ne.0. ,
                      "     "  1./SQRT(12.*N) for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0

    The third case above corresponds to Integer Z values for which the
    uncertainty is +-0.5, with the assumption that the probability that Z
    takes any value between Z-0.5 and Z+0.5 is uniform (the same argument
    goes for Z uniformly distributed between Z and Z+1); this would be
    useful if Z is an ADC measurement, for example. Other, fancier options
    would be possible, at the cost of adding one more parameter to the PROFILE2D
    For example, if all Z variables are distributed according to some
    known Gaussian of standard deviation Sigma, then:
     'G'            Errors are Spread/SQRT(N) for Spread.ne.0. ,
                      "     "  Sigma/SQRT(N) for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0
    For example, this would be useful when all Z's are experimental quantities
    measured with the same instrument with precision Sigma.



TProfile2D(const TProfile2D &profile)

void Add(TF1 *, Double_t )
 Performs the operation: this = this + c1*f1

void Add(TH1 *h1, Double_t c1)
 Performs the operation: this = this + c1*h1

void Add(TH1 *h1, TH1 *h2, Double_t c1, Double_t c2)
*-*-*-*-*Replace contents of this profile2D by the addition of h1 and h2*-*-*
*-*      ===============================================================

   this = c1*h1 + c2*h2


void Copy(TObject &obj)
*-*-*-*-*-*-*-*Copy a Profile2D histogram to a new profile2D histogram*-*-*-*
*-*            =======================================================

void Divide(TF1 *, Double_t )
 Performs the operation: this = this/(c1*f1)

void Divide(TH1 *h1)
*-*-*-*-*-*-*-*-*-*-*Divide this profile2D by h1*-*-*-*-*-*-*-*-*-*-*-*-*
*-*                  ===========================

   this = this/h1


void Divide(TH1 *h1, TH1 *h2, Double_t c1, Double_t c2, Option_t *option)
*-*-*-*-*Replace contents of this profile2D by the division of h1 by h2*-*-*
*-*      ==============================================================

   this = c1*h1/(c2*h2)


TH1* DrawCopy(Option_t *option)
*-*-*-*-*-*-*-*Draw a copy of this profile2D histogram*-*-*-*-*-*-*-*-*-*-*
*-*            =======================================

Int_t Fill(Axis_t x, Axis_t y, Axis_t z)
*-*-*-*-*-*-*-*-*-*-*Fill a Profile2D histogram (no weights)*-*-*-*-*-*-*-*
*-*                  =======================================

Int_t Fill(Axis_t x, Axis_t y, Axis_t z, Stat_t w)
*-*-*-*-*-*-*-*-*-*-*Fill a Profile2D histogram with weights*-*-*-*-*-*-*-*
*-*                  =======================================

Stat_t GetBinContent(Int_t bin) const
*-*-*-*-*-*-*Return bin content of a Profile2D histogram*-*-*-*-*-*-*-*-*
*-*          ===========================================

Stat_t GetBinEntries(Int_t bin) const
*-*-*-*-*-*-*Return bin entries of a Profile2D histogram*-*-*-*-*-*-*-*-*
*-*          ===========================================

Stat_t GetBinError(Int_t bin) const
*-*-*-*-*-*-*Return bin error of a Profile2D histogram*-*-*-*-*-*-*-*-*
*-*          =========================================

Option_t* GetErrorOption() const
*-*-*-*-*-*-*-*-*-*Return option to compute profile2D errors*-*-*-*-*-*-*-*
*-*                =========================================

void GetStats(Stat_t *stats) const
 fill the array stats from the contents of this profile
 The array stats must be correctly dimensionned in the calling program.
 stats[0] = sumw
 stats[1] = sumw2
 stats[2] = sumwx
 stats[3] = sumwx2
 stats[4] = sumwy
 stats[5] = sumwy2
 stats[6] = sumwxy
 stats[7] = sumwz
 stats[8] = sumwz2

 The function recomputes the statistics quantities
 from the bin contents in the current axis range.

void Multiply(TF1 *, Double_t )
 Performs the operation: this = this*c1*f1

void Multiply(TH1 *)
*-*-*-*-*-*-*-*-*-*-*Multiply this profile2D by h1*-*-*-*-*-*-*-*-*-*-*-*
*-*                  =============================

   this = this*h1


void Multiply(TH1 *, TH1 *, Double_t, Double_t, Option_t *)
*-*-*-*-*Replace contents of this profile2D by multiplication of h1 by h2*-*
*-*      ================================================================

   this = (c1*h1)*(c2*h2)


TH2D* ProjectionXY(const char *name, Option_t *option)
*-*-*-*-*Project this profile2D into a 2-D histogram along X,Y*-*-*-*-*-*-*
*-*      =====================================================

   The projection is always of the type TH2D.

   if option "E" is specified, the errors are computed. (default)



void Reset(Option_t *option)
*-*-*-*-*-*-*-*-*-*Reset contents of a Profile2D histogram*-*-*-*-*-*-*-*
*-*                =======================================

void Scale(Double_t c1)
*-*-*-*-*Multiply this profile2D by a constant c1*-*-*-*-*-*-*-*-*
*-*      ========================================

   this = c1*this

 This function uses the services of TProfile2D::Add


void SetBinEntries(Int_t bin, Stat_t w)
*-*-*-*-*-*-*-*-*Set the number of entries in bin*-*-*-*-*-*-*-*-*-*-*-*
*-*              ================================

void SetBins(Int_t nx, Double_t xmin, Double_t xmax, Int_t ny, Double_t ymin, Double_t ymax)
*-*-*-*-*-*-*-*-*Redefine  x axis parameters*-*-*-*-*-*-*-*-*-*-*-*
*-*              ===========================

void SetErrorOption(Option_t *option)
*-*-*-*-*-*-*-*-*-*Set option to compute profile2D errors*-*-*-*-*-*-*-*
*-*                =======================================

    The computation of errors is based on the parameter option:
    option:
     ' '  (Default) Errors are Spread/SQRT(N) for Spread.ne.0. ,
                      "     "  SQRT(Z)/SQRT(N) for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0
     's'            Errors are Spread  for Spread.ne.0. ,
                      "     "  SQRT(Z)  for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0
     'i'            Errors are Spread/SQRT(N) for Spread.ne.0. ,
                      "     "  1./SQRT(12.*N) for Spread.eq.0,N.gt.0 ,
                      "     "  0.  for N.eq.0
   See TProfile2D::BuildOptions for explanation of all options

void Streamer(TBuffer &R__b)
 Stream an object of class TProfile2D.



Inline Functions


          Double_t* GetB()
          Double_t* GetW()
          Double_t* GetW2()
              Int_t Fill(Axis_t x, Axis_t y, Stat_t z)
              Int_t Fill(Axis_t x, Axis_t y, Axis_t z, Stat_t w)
             Stat_t GetBinContent(Int_t binx, Int_t biny) const
             Stat_t GetBinContent(Int_t binx, Int_t biny, Int_t) const
             Stat_t GetBinError(Int_t binx, Int_t biny) const
             Stat_t GetBinError(Int_t binx, Int_t biny, Int_t) const
           Double_t GetZmin() const
           Double_t GetZmax() const
               void SetBins(Int_t nbinsx, Double_t xmin, Double_t xmax, Int_t nbinsy, Double_t ymin, Double_t ymax)
               void SetBins(Int_t, Double_t, Double_t, Int_t, Double_t, Double_t, Int_t, Double_t, Double_t)
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void StreamerNVirtual(TBuffer& b)


Author: Rene Brun 16/04/2000
Last update: root/hist:$Name: $:$Id: TProfile2D.cxx,v 1.6 2001/02/21 14:57:37 brun Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *


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