TGraphErrors

class TGraphErrors : public TGraph

    protected:

      virtual Double_t** Allocate(Int_t size)
            virtual void CopyAndRelease(Double_t** newarrays, Int_t ibegin, Int_t iend, Int_t obegin)
          virtual Bool_t CopyPoints(Double_t** arrays, Int_t ibegin, Int_t iend, Int_t obegin)
                  Bool_t CtorAllocate()
            virtual void FillZero(Int_t begin, Int_t end, Bool_t from_ctor = kTRUE)
            virtual void SwapPoints(Int_t pos1, Int_t pos2)

    public:

                        TGraphErrors()
                        TGraphErrors(Int_t n)
                        TGraphErrors(Int_t n, const Float_t* x, const Float_t* y, const Float_t* ex = 0, const Float_t* ey = 0)
                        TGraphErrors(Int_t n, const Double_t* x, const Double_t* y, const Double_t* ex = 0, const Double_t* ey = 0)
                        TGraphErrors(const TVector& vx, const TVector& vy, const TVector& vex, const TVector& vey)
                        TGraphErrors(const TVectorD& vx, const TVectorD& vy, const TVectorD& vex, const TVectorD& vey)
                        TGraphErrors(const TGraphErrors& gr)
                        TGraphErrors(const TH1* h)
                        TGraphErrors(const char* filename, const char* format = "%lg %lg %lg %lg", Option_t* option = "")
                virtual ~TGraphErrors()
           virtual void Apply(TF1* f)
           static Int_t CalculateScanfFields(const char* fmt)
         static TClass* Class()
           virtual void ComputeRange(Double_t& xmin, Double_t& ymin, Double_t& xmax, Double_t& ymax) const
       virtual Double_t GetErrorX(Int_t bin) const
       virtual Double_t GetErrorXhigh(Int_t bin) const
       virtual Double_t GetErrorXlow(Int_t bin) const
       virtual Double_t GetErrorY(Int_t bin) const
       virtual Double_t GetErrorYhigh(Int_t bin) const
       virtual Double_t GetErrorYlow(Int_t bin) const
      virtual Double_t* GetEX() const
      virtual Double_t* GetEY() const
        virtual TClass* IsA() const
          TGraphErrors& operator=(const TGraphErrors&)
           virtual void Paint(Option_t* chopt = "")
           virtual void Print(Option_t* chopt = "") const
           virtual void SavePrimitive(ofstream& out, Option_t* option)
           virtual void SetPointError(Double_t ex, Double_t ey)
           virtual void SetPointError(Int_t i, Double_t ex, Double_t ey)
           virtual void ShowMembers(TMemberInspector& insp, char* parent)
           virtual void Streamer(TBuffer& b)
                   void StreamerNVirtual(TBuffer& b)

Data Members

    protected:

      Double_t* fEX  [fNpoints] array of X errors
      Double_t* fEY  [fNpoints] array of Y errors

Class Description

   A TGraphErrors is a TGraph with error bars.
   The various format options to draw a TGraphErrors are explained in
     TGraphErrors::Paint.

  The picture below has been generated by the following macro:
------------------------------------------------------------------------
{
   gROOT->Reset();
   c1 = new TCanvas("c1","A Simple Graph with error bars",200,10,700,500);

   c1->SetFillColor(42);
   c1->SetGrid();
   c1->GetFrame()->SetFillColor(21);
   c1->GetFrame()->SetBorderSize(12);

   Int_t n = 10;
   Double_t x[n]  = {-0.22, 0.05, 0.25, 0.35, 0.5, 0.61,0.7,0.85,0.89,0.95};
   Double_t y[n]  = {1,2.9,5.6,7.4,9,9.6,8.7,6.3,4.5,1};
   Double_t ex[n] = {.05,.1,.07,.07,.04,.05,.06,.07,.08,.05};
   Double_t ey[n] = {.8,.7,.6,.5,.4,.4,.5,.6,.7,.8};
   gr = new TGraphErrors(n,x,y,ex,ey);
   gr->SetTitle("TGraphErrors Example");
   gr->SetMarkerColor(4);
   gr->SetMarkerStyle(21);
   gr->Draw("ALP");

   c1->Update();
}

 TGraphErrors default constructor.

 TGraphErrors normal constructor.

  the arrays are preset to zero

 TGraphErrors normal constructor.

  if ex or ey are null, the corresponding arrays are preset to zero

 TGraphErrors normal constructor.

  if ex or ey are null, the corresponding arrays are preset to zero

 constructor with four vectors of floats in input
 A grapherrors is built with the X coordinates taken from vx and Y coord from vy
 and the errors from vectors vex and vey.
 The number of points in the graph is the minimum of number of points
 in vx and vy.

 constructor with four vectors of doubles in input
 A grapherrors is built with the X coordinates taken from vx and Y coord from vy
 and the errors from vectors vex and vey.
 The number of points in the graph is the minimum of number of points
 in vx and vy.

 TGraphErrors copy constructor

 TGraphErrors constructor importing its parameters from the TH1 object passed as argument

 GraphErrors constructor reading input from filename
 filename is assumed to contain at least 3 columns of numbers
 convention for format (default="%lg %lg %lg %lg)
  format = "%lg %lg"         read only 2 first columns into X,Y
  format = "%lg %lg %lg"     read only 3 first columns into X,Y and EY
  format = "%lg %lg %lg %lg" read only 4 first columns into X,Y,EX,EY

 TGraphErrors default destructor.

 apply function to all the data points
 y = f(x,y)

 The error is calculated as ey=(f(x,y+ey)-f(x,y-ey))/2
 This is the same as error(fy) = df/dy * ey for small errors

 For generic functions the symmetric errors might become non-symmetric
 and are averaged here. Use TGraphAsymmErrors if desired.

 error on x doesn't change
 function suggested/implemented by Miroslav Helbich <helbich@mail.desy.de>

 Calculate scan fields.

 Compute range.

 Copy and release.

 Copy errors from fEX and fEY to arrays[0] and arrays[1]
 or to fX and fY. Copy points.

 Constructor allocate.

 Set zero values for point arrays in the range [begin, end]

 This function is called by GraphFitChisquare.
 It returns the error along X at point i.

 This function is called by GraphFitChisquare.
 It returns the error along Y at point i.

 This function is called by GraphFitChisquare.
 It returns the error along X at point i.

 This function is called by GraphFitChisquare.
 It returns the error along X at point i.

 This function is called by GraphFitChisquare.
 It returns the error along X at point i.

 This function is called by GraphFitChisquare.
 It returns the error along X at point i.

 Paint this TGraphErrors with its current attributes

 by default horizonthal and vertical small lines are drawn at
 the end of the error bars. if option "z" or "Z" is specified,
 these lines are not drawn.

 if option contains ">" an arrow is drawn at the end of the error bars
 if option contains "|>" a full arrow is drawn at the end of the error bars
 the size of the arrow is set to 2/3 of the marker size.

 By default, error bars are drawn. If option "X" is specified,
 the errors are not drawn (TGraph::Paint equivalent).

 if option "[]" is specified only the end vertical/horizonthal lines
 of the error bars are drawn. This option is interesting to superimpose
 systematic errors on top of a graph with statistical errors.

 if option "2" is specified error rectangles are drawn.

 if option "3" is specified a filled area is drawn through the end points of
 the vertical error bars.

 if option "4" is specified a smoothed filled area is drawn through the end
 points of the vertical error bars.

 Use gStyle->SetErrorX(dx) to control the size of the error along x.
 set dx = 0 to suppress the error along x.

 Use gStyle->SetEndErrorSize(np) to control the size of the lines
 at the end of the error bars (when option 1 is used).
 By default np=1. (np represents the number of pixels).

 Print graph and errors values.

 Save primitive as a C++ statement(s) on output stream out

 Set ex and ey values for point pointed by the mouse.

 Set ex and ey values for point number i.

 Stream an object of class TGraphErrors.

 Swap points

Inline Functions

           Double_t** Allocate(Int_t size)
            Double_t* GetEX() const
            Double_t* GetEY() const
              TClass* Class()
              TClass* IsA() const
                 void ShowMembers(TMemberInspector& insp, char* parent)
                 void StreamerNVirtual(TBuffer& b)
        TGraphErrors& operator=(const TGraphErrors&)