doc/v622/graph2derrorsfit_8C.html

#include <TMath.h>

#include <TGraph2DErrors.h>

#include <TRandom.h>

#include <TStyle.h>

#include <TCanvas.h>

#include <TF2.h>


void graph2derrorsfit()

{

   TCanvas *c1 = new TCanvas("c1");


   Double_t rnd, x, y, z, ex, ey, ez;

   Double_t e = 0.3;

   Int_t nd = 500;


   TRandom r;

   TF2  *f2 = new TF2("f2","1000*(([0]*sin(x)/x)*([1]*sin(y)/y))+200",-6,6,-6,6);

   f2->SetParameters(1,1);

   TGraph2DErrors *dte = new TGraph2DErrors(nd);


   // Fill the 2D graph

   Double_t zmax = 0;

   for (Int_t i=0; i<nd; i++) {

      f2->GetRandom2(x,y);

      rnd = r.Uniform(-e,e); // Generate a random number in [-e,e]

      z = f2->Eval(x,y)*(1+rnd);

      if (z>zmax) zmax = z;

      dte->SetPoint(i,x,y,z);

      ex = 0.05*r.Rndm();

      ey = 0.05*r.Rndm();

      ez = TMath::Abs(z*rnd);

      dte->SetPointError(i,ex,ey,ez);

   }


   f2->SetParameters(0.5,1.5);

   dte->Fit(f2);

   TF2 *fit2 = (TF2*)dte->FindObject("f2");

   fit2->SetTitle("Minuit fit result on the Graph2DErrors points");

   fit2->SetMaximum(zmax);

   gStyle->SetHistTopMargin(0);

   fit2->SetLineColor(1);

   fit2->SetLineWidth(1);

   fit2->Draw("surf1");

   dte->Draw("same p0");

}

r
ROOT::R::TRInterface & r
Definition: Object.C:4

e
#define e(i)
Definition: RSha256.hxx:103

Int_t
int Int_t
Definition: RtypesCore.h:43

Double_t
double Double_t
Definition: RtypesCore.h:57

TCanvas.h

TF2.h

TGraph2DErrors.h

TMath.h

TRandom.h

TStyle.h

gStyle
R__EXTERN TStyle * gStyle
Definition: TStyle.h:410

TAttLine::SetLineWidth
virtual void SetLineWidth(Width_t lwidth)
Set the line width.
Definition: TAttLine.h:43

TAttLine::SetLineColor
virtual void SetLineColor(Color_t lcolor)
Set the line color.
Definition: TAttLine.h:40

TCanvas
The Canvas class.
Definition: TCanvas.h:27

TF1::SetMaximum
virtual void SetMaximum(Double_t maximum=-1111)
Set the maximum value along Y for this function In case the function is already drawn,...
Definition: TF1.cxx:3396

TF1::SetTitle
virtual void SetTitle(const char *title="")
Set function title if title has the form "fffffff;xxxx;yyyy", it is assumed that the function title i...
Definition: TF1.cxx:3551

TF1::SetParameters
virtual void SetParameters(const Double_t *params)
Definition: TF1.h:638

TF1::Eval
virtual Double_t Eval(Double_t x, Double_t y=0, Double_t z=0, Double_t t=0) const
Evaluate this function.
Definition: TF1.cxx:1432

TF2
A 2-Dim function with parameters.
Definition: TF2.h:29

TF2::Draw
virtual void Draw(Option_t *option="")
Draw this function with its current attributes.
Definition: TF2.cxx:241

TF2::GetRandom2
virtual void GetRandom2(Double_t &xrandom, Double_t &yrandom)
Return 2 random numbers following this function shape.
Definition: TF2.cxx:529

TGraph2DErrors
Graph 2D class with errors.
Definition: TGraph2DErrors.h:26

TGraph2DErrors::SetPoint
virtual void SetPoint(Int_t i, Double_t x, Double_t y, Double_t z)
Set x, y and z values for point number i.
Definition: TGraph2DErrors.cxx:376

TGraph2DErrors::SetPointError
virtual void SetPointError(Int_t i, Double_t ex, Double_t ey, Double_t ez)
Set ex, ey and ez values for point number i.
Definition: TGraph2DErrors.cxx:418

TGraph2D::Fit
virtual TFitResultPtr Fit(const char *formula, Option_t *option="", Option_t *goption="")
Fits this graph with function with name fname Predefined functions such as gaus, expo and poln are au...
Definition: TGraph2D.cxx:761

TGraph2D::FindObject
virtual TObject * FindObject(const char *name) const
search object named name in the list of functions
Definition: TGraph2D.cxx:737

TGraph2D::Draw
virtual void Draw(Option_t *option="P0")
Specific drawing options can be used to paint a TGraph2D:
Definition: TGraph2D.cxx:708

TRandom
This is the base class for the ROOT Random number generators.
Definition: TRandom.h:27

TStyle::SetHistTopMargin
void SetHistTopMargin(Double_t hmax=0.05)
Definition: TStyle.h:366

c1
return c1
Definition: legend1.C:41

y
Double_t y[n]
Definition: legend1.C:17

x
Double_t x[n]
Definition: legend1.C:17

ey
Double_t ey[n]
Definition: legend1.C:17

ex
Double_t ex[n]
Definition: legend1.C:17

TMath::Abs
Short_t Abs(Short_t d)
Definition: TMathBase.h:120