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1/// \file
2/// \ingroup tutorial_math
3/// \notebook
4/// Example of Chebyshev polynomials
5/// using new TFormula pre-defined definitions of chebyshev polynomials
7/// \macro_image
8/// \macro_code
10/// \author Lorenzo Moneta
12void ChebyshevPol() {
15 auto legend = new TLegend(0.88,0.4,1.,1.);
17 int colors[] = { kRed, kRed+3, kMagenta, kMagenta+3, kBlue, kBlue+3, kCyan+3, kGreen, kGreen+3, kYellow, kOrange };
19 for (int degree=0; degree <=10; ++degree) {
20 auto f1 = new TF1("f1",TString::Format("cheb%d",degree),-1,1);
21 // all parameters are zero apart from the one corresponding to the degree
22 f1->SetParameter(degree,1);
23 f1->SetLineColor( colors[degree]);
24 f1->SetMinimum(-1.2);
25 f1->SetMaximum(1.2);
26 TString opt = (degree == 0) ? "" : "same";
27 //f1->Print("V");
28 f1->SetNpx(1000);
29 f1->SetTitle("Chebyshev Polynomial");
30 f1->Draw(opt);
31 legend->AddEntry(f1,TString::Format("N=%d",degree),"L");
32 }
33 legend->Draw();
@ kRed
Definition Rtypes.h:66
@ kOrange
Definition Rtypes.h:67
@ kGreen
Definition Rtypes.h:66
@ kMagenta
Definition Rtypes.h:66
@ kCyan
Definition Rtypes.h:66
@ kBlue
Definition Rtypes.h:66
@ kYellow
Definition Rtypes.h:66
Color * colors
Definition X3DBuffer.c:21
virtual void SetLineColor(Color_t lcolor)
Set the line color.
Definition TAttLine.h:40
1-Dim function class
Definition TF1.h:213
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:3407
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:3562
virtual void SetNpx(Int_t npx=100)
Set the number of points used to draw the function.
Definition TF1.cxx:3446
virtual void SetMinimum(Double_t minimum=-1111)
Set the minimum value along Y for this function In case the function is already drawn,...
Definition TF1.cxx:3420
virtual void Draw(Option_t *option="")
Draw this function with its current attributes.
Definition TF1.cxx:1322
virtual void SetParameter(Int_t param, Double_t value)
Definition TF1.h:634
This class displays a legend box (TPaveText) containing several legend entries.
Definition TLegend.h:23
Basic string class.
Definition TString.h:136
static TString Format(const char *fmt,...)
Static method which formats a string using a printf style format descriptor and return a TString.
Definition TString.cxx:2331
TF1 * f1
Definition legend1.C:11