ROOT   Reference Guide
graphApply.C
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1/// \file
2/// \ingroup tutorial_graphs
3/// \notebook
4/// A macro to demonstrate the functionality of TGraph::Apply() method.
5/// TGraph::Apply applies a function f to all the data TGraph points.
6/// f may be a 1-D function TF1 or 2-d function TF2.
7/// The Y values of the graph are replaced by the new values computed using
8/// the function.
9///
10/// \macro_image
11/// \macro_code
12///
13/// \author Miro Helbich
14
15void graphApply()
16{
17 const Int_t npoints=3;
18 Double_t xaxis[npoints] = {1.,2.,3.};
19 Double_t yaxis[npoints] = {10.,20.,30.};
20 Double_t errorx[npoints] = {0.5,0.5,0.5};
21 Double_t errory[npoints] = {5.,5.,5.};
22
23 Double_t exl[npoints] = {0.5,0.5,0.5};
24 Double_t exh[npoints] = {0.5,0.5,0.5};
25 Double_t eyl[npoints] = {5.,5.,5.};
26 Double_t eyh[npoints] = {5.,5.,5.};
27
28 TGraph *gr1 = new TGraph(npoints,xaxis,yaxis);
29 TGraphErrors *gr2 = new TGraphErrors(npoints,xaxis,yaxis,errorx,errory);
30 TGraphAsymmErrors *gr3 = new TGraphAsymmErrors(npoints,xaxis,yaxis,exl,exh,eyl,eyh);
31 TF2 *ff = new TF2("ff","-1./y");
32
33 TCanvas *c1 = new TCanvas("c1","c1");
34 c1->Divide(2,3);
35
36 // TGraph
37 c1->cd(1);
38 gr1->DrawClone("A*");
39 c1->cd(2);
40 gr1->Apply(ff);
41 gr1->Draw("A*");
42
43 // TGraphErrors
44 c1->cd(3);
45 gr2->DrawClone("A*");
46 c1->cd(4);
47 gr2->Apply(ff);
48 gr2->Draw("A*");
49
50 // TGraphAsymmErrors
51 c1->cd(5);
52 gr3->DrawClone("A*");
53 c1->cd(6);
54 gr3->Apply(ff);
55 gr3->Draw("A*");
56}
int Int_t
Definition: RtypesCore.h:45
double Double_t
Definition: RtypesCore.h:59
The Canvas class.
Definition: TCanvas.h:23
A 2-Dim function with parameters.
Definition: TF2.h:29
TGraph with asymmetric error bars.
virtual void Apply(TF1 *f)
Apply a function to all data points y = f(x,y)
A TGraphErrors is a TGraph with error bars.
Definition: TGraphErrors.h:26
virtual void Apply(TF1 *f)
apply function to all the data points y = f(x,y)
A TGraph is an object made of two arrays X and Y with npoints each.
Definition: TGraph.h:41
virtual void Draw(Option_t *chopt="")
Draw this graph with its current attributes.
Definition: TGraph.cxx:769
virtual void Apply(TF1 *f)
Apply function f to all the data points f may be a 1-D function TF1 or 2-d function TF2 The Y values ...
Definition: TGraph.cxx:576
virtual TObject * DrawClone(Option_t *option="") const