ROOT   Reference Guide
Legendre.C File Reference

## Detailed Description

Example of first few Legendre Polynomials

Draws a graph.

#include "TMath.h"
#include "TF1.h"
#include "TCanvas.h"
#include <Riostream.h>
#include "TLegend.h"
#include "TLegendEntry.h"
#include "Math/IFunction.h"
#include <cmath>
#include "TSystem.h"
void Legendre()
{
R__LOAD_LIBRARY(libMathMore);
TCanvas *Canvas = new TCanvas("DistCanvas", "Legendre polynomials example", 10, 10, 750, 600);
Canvas->SetGrid();
TLegend *leg = new TLegend(0.5, 0.7, 0.4, 0.89);
//drawing the set of Legendre functions
TF1* L[5];
for(int nu = 0; nu <= 4; nu++)
{
L[nu]= new TF1("L_0", "ROOT::Math::legendre([0],x)", -1, 1);
L[nu]->SetParameters(nu, 0.0);
L[nu]->SetLineStyle(1);
L[nu]->SetLineWidth(2);
L[nu]->SetLineColor(nu+1);
}
L[0]->SetMaximum(1);
L[0]->SetMinimum(-1);
L[0]->SetTitle("Legendre polynomials");
leg->AddEntry(L[0]->DrawCopy(), " L_{0}(x)", "l");
leg->AddEntry(L[1]->DrawCopy("same"), " L_{1}(x)", "l");
leg->AddEntry(L[2]->DrawCopy("same"), " L_{2}(x)", "l");
leg->AddEntry(L[3]->DrawCopy("same"), " L_{3}(x)", "l");
leg->AddEntry(L[4]->DrawCopy("same"), " L_{4}(x)", "l");
leg->Draw();
Canvas->cd();
}
#define R__LOAD_LIBRARY(LIBRARY)
Definition: Rtypes.h:489
The Canvas class.
Definition: TCanvas.h:23
TVirtualPad * cd(Int_t subpadnumber=0) override
Set current canvas & pad.
Definition: TCanvas.cxx:711
1-Dim function class
Definition: TF1.h:213
This class displays a legend box (TPaveText) containing several legend entries.
Definition: TLegend.h:23
void SetGrid(Int_t valuex=1, Int_t valuey=1) override
Definition: TPad.h:330
leg
Definition: legend1.C:34
static constexpr double L

Definition in file Legendre.C.