TGraph

class TGraph : public TNamed, public TAttLine, public TAttFill, public TAttMarker

    public:

               TGraph TGraph()
               TGraph TGraph(Int_t n, Float_t* x = 0, Float_t* y = 0)
               TGraph TGraph(TGraph&)
         virtual void ~TGraph()
              TClass* Class()
                 void ComputeLogs(Int_t npoints, Int_t opt)
         virtual void ComputeRange(Float_t& xmin, Float_t& ymin, Float_t& xmax, Float_t& ymax)
        virtual Int_t DistancetoPrimitive(Int_t px, Int_t py)
         virtual void Draw(Option_t* chopt)
         virtual void DrawGraph(Int_t n, Float_t* x, Float_t* y, Option_t* option)
         virtual void DrawPanel()
         virtual void ExecuteEvent(Int_t event, Int_t px, Int_t py)
         virtual void Fit(Text_t* formula, Option_t* option, Option_t* goption)
         virtual void FitPanel()
      virtual Float_t GetErrorX(Int_t bin)
      virtual Float_t GetErrorY(Int_t bin)
                TH1F* GetHistogram()
               TList* GetListOfFunctions()
                Int_t GetN()
         virtual void GetPoint(Int_t i, Float_t& x, Float_t& y)
             Float_t* GetX()
               TAxis* GetXaxis()
             Float_t* GetY()
               TAxis* GetYaxis()
         virtual void InitExpo()
         virtual void InitGaus()
         virtual void InitPolynom()
      virtual TClass* IsA()
         virtual void LeastSquareFit(Int_t n, Int_t m, Double_t* a)
         virtual void LeastSquareLinearFit(Int_t ndata, Double_t& a0, Double_t& a1, Int_t& ifail)
         virtual void Paint(Option_t* chopt)
         virtual void PaintGraph(Int_t npoints, Float_t* x, Float_t* y, Option_t* option)
         virtual void PaintGrapHist(Int_t npoints, Float_t* x, Float_t* y, Option_t* option)
         virtual void Print(Option_t* chopt)
         virtual void SavePrimitive(ofstream& out, Option_t* option)
         virtual void SetMaximum(Float_t maximum = -1111)
         virtual void SetMinimum(Float_t minimum = -1111)
         virtual void SetPoint(Int_t i, Float_t x, Float_t y)
         virtual void ShowMembers(TMemberInspector& insp, char* parent)
                 void Smooth(Int_t npoints, Float_t* x, Float_t* y, Int_t drawtype)
         virtual void Streamer(TBuffer& b)
                 void Zero(Int_t& k, Float_t AZ, Float_t BZ, Float_t E2, Float_t& X, Float_t& Y, Int_t maxiterations)

  Data Members

    protected:

          Int_t fNpoints    Number of points
       Float_t* fX          array of X points
       Float_t* fY          array of Y points
      Option_t* fOption     Axis options
         TList* fFunctions  Pointer to list of functions (fits and user)
          TH1F* fHistogram  Pointer to histogram used for drawing axis
        Float_t fMaximum    Maximum value for plotting along y
        Float_t fMinimum    Minimum value for plotting along y

See also

TCutG, TGraphAsymmErrors, TGraphErrors

Class Description

   A Graph is a graphics object made of two arrays X and Y
   with npoints each.
   This class supports essentially two graph categories:
     - General case with non equidistant points
     - Special case with equidistant points
   The various format options to draw a Graph are explained in
     TGraph::PaintGraph  and TGraph::PaintGrapHist
   These two functions are derived from the HIGZ routines IGRAPH and IGHIST
   and many modifications.

  The picture below has been generated by the following macro:
------------------------------------------------------------------
{
   TCanvas *c1 = new TCanvas("c1","A Simple Graph Example",200,10,700,500);
   Float_t x[100], y[100];
   Int_t n = 20;
   for (Int_t i=0;i<n;i++) {
     x[i] = i*0.1;
     y[i] = 10*sin(x[i]+0.2);
   }
   gr = new TGraph(n,x,y);
   gr->Draw("AC*");
}

/*

*/

*-*-*-*-*-*-*-*-*-*-*Graph default constructor-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*-*                  =========================

*-*-*-*-*-*-*-*-*-*-*Graph normal constructor-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*-*                  ========================

*-*-*-*-*-*-*-*-*-*-*Graph default destructor-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
*-*                  =======================

 this function is dummy in TGraph, but redefined by TGraphErrors

*-*-*-*-*-*-*-*-*-*-*Draw this graph with its current attributes*-*-*-*-*-*-*
*-*                  ==========================================

   Options to draw a graph are described in TGraph::PaintGraph

*-*-*-*-*-*-*-*-*-*-*Compute distance from point px,py to a graph*-*-*-*-*-*
*-*                  ===========================================
  Compute the closest distance of approach from point px,py to this line.
  The distance is computed in pixels units.

*-*-*-*-*-*-*-*-*-*-*Draw this graph with new attributes*-*-*-*-*-*-*-*-*-*
*-*                  ===================================

*-*-*-*-*-*-*Display a panel with all graph drawing options*-*-*-*-*-*
*-*          ==============================================

*-*-*-*-*-*-*-*-*-*-*Execute action corresponding to one event*-*-*-*
*-*                  =========================================
  This member function is called when a graph is clicked with the locator

  If Left button clicked on one of the line end points, this point
     follows the cursor until button is released.

  if Middle button clicked, the line is moved parallel to itself
     until the button is released.

*-*-*-*-*-*-*-*-*-*-*Fit this graph with function fname*-*-*-*-*-*-*-*-*-*
*-*                  ==================================

   fname is the name of an already predefined function created by TF1
   Predefined functions such as Gaus, Expo and Poln are automatically
   created by ROOT.

   The list of fit options is given in parameter option.
      option = "W"  Set all errors to 1
             = "Q" Quiet mode (minimum printing)
             = "V" Verbose mode (default is between Q and V)
             = "R" Use the Range specified in the function range
             = "N" Do not store the graphics function, do not draw
             = "0" Do not plot the result of the fit. By default the fitted function
                   is drawn unless the option"N" above is specified.
             = "+" Add this new fitted function to the list of fitted functions
                   (by default, any previous function is deleted)

   When the fit is drawn (by default), the parameter goption may be used
   to specify a list of graphics options. See TGraph::Paint for a complete
   list of these options.

   In order to use the Range option, one must first create a function
   with the expression to be fitted. For example, if your graph
   has a defined range between -4 and 4 and you want to fit a gaussian
   only in the interval 1 to 3, you can do:
        TF1 *f1 = new TF1("f1","gaus",1,3);
        graph->Fit("f1","R");

   You can specify boundary limits for some or all parameters via
        f1->SetParLimits(p_number, parmin, parmax);
   if parmin>=parmax, the parameter is fixed
   Note that you are not forced to fix the limits for all parameters.
   For example, if you fit a function with 6 parameters, you can do:
     func->SetParameters(0,3.1,1.e-6,0.1,-8,100);
     func->SetParLimits(4,-10,-4);
     func->SetParLimits(5, 1,1);
   With this setup, parameters 0->3 can vary freely
   Parameter 4 has boundaries [-10,-4] with initial value -8
   Parameter 5 is fixed to 100.

*-*-*-*-*-*-*Display a panel with all graph fit options*-*-*-*-*-*
*-*          ==========================================

   See class TFitPanel for example

    This function is called by GraphFitChisquare.
    It always returns a negative value. Real implementation in TGraphErrors

    This function is called by GraphFitChisquare.
    It always returns a negative value. Real implementation in TGraphErrors

    Returns a pointer to the histogram used to draw the axis
    Takes into account the two following cases.
       1- option 'A' was specified in TGraph::Draw. Return fHistogram
       2- user had called TPad::DrawFrame. return pointer to hframe histogram

*-*-*-*-*-*-*-*-*-*-*Get x and y values for point number i*-*-*-*-*-*-*-*-*
*-*                  =====================================

 Get x axis of the graph.

 Get y axis of the graph.

*-*-*-*-*-*Compute Initial values of parameters for a gaussian*-*-*-*-*-*-*
*-*        ===================================================

*-*-*-*-*-*Compute Initial values of parameters for an exponential*-*-*-*-*
*-*        =======================================================

*-*-*-*-*-*Compute Initial values of parameters for a polynom*-*-*-*-*-*-*
*-*        ===================================================

*-*-*-*-*-*-*-*Least squares lpolynomial fitting without weights*-*-*-*-*-*-*
*-*            =================================================

  n   number of points to fit
  m   number of parameters
  a   array of parameters

   based on CERNLIB routine LSQ: Translated to C++ by Rene Brun
   (E.Keil.  revised by B.Schorr, 23.10.1981.)

*-*-*-*-*-*-*-*-*-*Least square linear fit without weights*-*-*-*-*-*-*-*-*
*-*                =======================================

   extracted from CERNLIB LLSQ: Translated to C++ by Rene Brun
   (added to LSQ by B. Schorr, 15.02.1982.)

*-*-*-*-*-*-*-*-*-*-*Draw this graph with its current attributes*-*-*-*-*-*-*
*-*                  ===========================================

*-*-*-*-*-*-*-*-*-*-*-*Control function to draw a graph*-*-*-*-*-*-*-*-*-*-*
*-*                    ================================


   Draws one dimensional graphs. The aspect of the graph is done
 according to the value of the chopt.

 _Input parameters:

  npoints : Number of points in X or in Y.
  X(N) or X(2) : X coordinates or (XMIN,XMAX) (WC space).
  Y(N) or Y(2) : Y coordinates or (YMIN,YMAX) (WC space).
  chopt : Option.

  chopt='L' :  A simple polyline beetwen every points is drawn

  chopt='F' :  A fill area is drawn ('CF' draw a smooth fill area)

  chopt='A' :  Axis are drawn around the graph

  chopt='C' :  A smooth Curve is drawn

  chopt='*' :  A Star is plotted at each point

  chopt='P' :  Idem with the current marker

  chopt='B' :  A Bar chart is drawn at each point

  chopt='1' :  ylow=rwymin

*-*-*-*-*-*-*-*-*Control function to draw a graphistogram*-*-*-*-*-*-*-*-*-*
*-*              ========================================


   Draws one dimensional graphs. The aspect of the graph is done
 according to the value of the chopt.

 _Input parameters:

  npoints : Number of points in X or in Y.
  X(N) or x[1] : X coordinates or (XMIN,XMAX) (WC space).
  Y(N) or y[1] : Y coordinates or (YMIN,YMAX) (WC space).
  chopt : Option.

  chopt='R' :  Graph is drawn horizontaly, parallel to X axis.
               (default is vertically, parallel to Y axis)
               If option R is selected the user must give:
                 2 values for Y (y[0]=YMIN and y[1]=YMAX)
                 N values for X, one for each channel.
               Otherwise the user must give:
                 N values for Y, one for each channel.
                 2 values for X (x[0]=XMIN and x[1]=XMAX)

  chopt='L' :  A simple polyline beetwen every points is drawn

  chopt='H' :  An Histogram with equidistant bins is drawn
               as a polyline.

  chopt='F' :  An histogram with equidistant bins is drawn
               as a fill area. Contour is not drawn unless
               chopt='H' is also selected..

  chopt='N' :  Non equidistant bins (default is equidistant)
               If N is the number of channels array X and Y
               must be dimensionned as follow:
               If option R is not selected (default) then
               the user must give:
                 (N+1) values for X (limits of channels).
                  N values for Y, one for each channel.
               Otherwise the user must give:
                 (N+1) values for Y (limits of channels).
                  N values for X, one for each channel.

  chopt='F1':  Idem as 'F' except that fill area is no more
               reparted arround axis X=0 or Y=0 .

  chopt='C' :  A smooth Curve is drawn.

  chopt='*' :  A Star is plotted at the center of each bin.

  chopt='P' :  Idem with the current marker

  chopt='B' :  A Bar chart with equidistant bins is drawn as fill
               areas (Contours are drawn).

*-*-*-*-*-*-*-*-*-*-*-*Convert WC from Log scales*-*-*-*-*-*-*-*-*-*-*-*
*-*                    ==========================

   Take the LOG10 of xwork and ywork according to the value of Options
   and put it in xworkl and yworkl.

  npoints : Number of points in xwork and in ywork.

*-*-*-*-*-*-*-*-*-*-*Print graph values*-*-*-*-*-*-*-*-*-*-*-*
*-*                  ==================

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

*-*-*-*-*-*-*-*-*-*-*Set x and y values for point number i*-*-*-*-*-*-*-*-*
*-*                  =====================================

*-*-*-*-*-*-*-*-*-*-*-*Smooth a curve given by N points*-*-*-*-*-*-*-*-*-*
*-*                    ================================

   Underlaying routine for Draw based on the CERN GD3 routine TVIPTE

     Author - Marlow etc.   Modified by - P. Ward     Date -  3.10.1973

   This routine draws a smooth tangentially continuous curve through
 the sequence of data points P(I) I=1,N where P(I)=(X(I),Y(I))
 the curve is approximated by a polygonal arc of short vectors .
 the data points can represent open curves, P(1) != P(N) or closed
 curves P(2) == P(N) . If a tangential discontinuity at P(I) is
 required , then set P(I)=P(I+1) . loops are also allowed .

 Reference Marlow and Powell,Harwell report No.R.7092.1972
 MCCONALOGUE,Computer Journal VOL.13,NO4,NOV1970PP392 6

 _Input parameters:

  npoints   : Number of data points.
  x         : Abscissa
  y         : Ordinate


 delta is the accuracy required in constructing the curve.
 if it is zero then the routine calculates a value other-
 wise it uses this value. (default is 0.0)

 Stream an object of class TGraph.

*-*-*-*-*-*-*-*-*-*-*-*Find zero of a continuous function*-*-*-*-*-*-*-*-*-*
*-*                    ==================================

  Underlaying routine for PaintGraph
 This function finds a real zero of the continuous real
 function Y(X) in a given interval (A,B). See accompanying
 notes for details of the argument list and calling sequence

Inline Functions

             TList* GetListOfFunctions()
              Int_t GetN()
           Float_t* GetX()
           Float_t* GetY()
            TClass* Class()
            TClass* IsA()
               void ShowMembers(TMemberInspector& insp, char* parent)
             TGraph TGraph(TGraph&)