ROOT   Reference Guide
rf105_funcbinding.C
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1/// \file
2/// \ingroup tutorial_roofit
3/// \notebook -js
4///
5/// Basic functionality: binding ROOT math functions as RooFit functions and pdfs
6///
7/// \macro_image
8/// \macro_output
9/// \macro_code
10///
11/// \date 07/2008
12/// \author Wouter Verkerke
13
14#include "RooRealVar.h"
15#include "RooDataSet.h"
16#include "RooGaussian.h"
17#include "TCanvas.h"
18#include "TAxis.h"
19#include "RooPlot.h"
20#include "TMath.h"
21#include "TF1.h"
22#include "Math/DistFunc.h"
23#include "RooTFnBinding.h"
24
25using namespace RooFit;
26
27void rf105_funcbinding()
28{
29
30 // B i n d T M a t h : : E r f C f u n c t i o n
31 // ---------------------------------------------------
32
33 // Bind one-dimensional TMath::Erf function as RooAbsReal function
34 RooRealVar x("x", "x", -3, 3);
35 RooAbsReal *errorFunc = bindFunction("erf", TMath::Erf, x);
36
37 // Print erf definition
38 errorFunc->Print();
39
40 // Plot erf on frame
41 RooPlot *frame1 = x.frame(Title("TMath::Erf bound as RooFit function"));
42 errorFunc->plotOn(frame1);
43
44 // B i n d R O O T : : M a t h : : b e t a _ p d f C f u n c t i o n
45 // -----------------------------------------------------------------------
46
47 // Bind pdf ROOT::Math::Beta with three variables as RooAbsPdf function
48 RooRealVar x2("x2", "x2", 0, 0.999);
49 RooRealVar a("a", "a", 5, 0, 10);
50 RooRealVar b("b", "b", 2, 0, 10);
52
53 // Perf beta definition
54 beta->Print();
55
56 // Generate some events and fit
57 RooDataSet *data = beta->generate(x2, 10000);
58 beta->fitTo(*data);
59
60 // Plot data and pdf on frame
61 RooPlot *frame2 = x2.frame(Title("ROOT::Math::Beta bound as RooFit pdf"));
62 data->plotOn(frame2);
63 beta->plotOn(frame2);
64
65 // B i n d R O O T T F 1 a s R o o F i t f u n c t i o n
66 // ---------------------------------------------------------------
67
68 // Create a ROOT TF1 function
69 TF1 *fa1 = new TF1("fa1", "sin(x)/x", 0, 10);
70
71 // Create an observable
72 RooRealVar x3("x3", "x3", 0.01, 20);
73
74 // Create binding of TF1 object to above observable
75 RooAbsReal *rfa1 = bindFunction(fa1, x3);
76
77 // Print rfa1 definition
78 rfa1->Print();
79
80 // Make plot frame in observable, plot TF1 binding function
81 RooPlot *frame3 = x3.frame(Title("TF1 bound as RooFit function"));
82 rfa1->plotOn(frame3);
83
84 TCanvas *c = new TCanvas("rf105_funcbinding", "rf105_funcbinding", 1200, 400);
85 c->Divide(3);
86 c->cd(1);
88 frame1->GetYaxis()->SetTitleOffset(1.6);
89 frame1->Draw();
90 c->cd(2);
92 frame2->GetYaxis()->SetTitleOffset(1.6);
93 frame2->Draw();
94 c->cd(3);
96 frame3->GetYaxis()->SetTitleOffset(1.6);
97 frame3->Draw();
98}
#define b(i)
Definition: RSha256.hxx:100
#define c(i)
Definition: RSha256.hxx:101
static const double x2[5]
static const double x3[11]
virtual void Print(Option_t *options=0) const
Print the object to the defaultPrintStream().
Definition: RooAbsArg.h:302
virtual RooPlot * plotOn(RooPlot *frame, const RooCmdArg &arg1=RooCmdArg::none(), const RooCmdArg &arg2=RooCmdArg::none(), const RooCmdArg &arg3=RooCmdArg::none(), const RooCmdArg &arg4=RooCmdArg::none(), const RooCmdArg &arg5=RooCmdArg::none(), const RooCmdArg &arg6=RooCmdArg::none(), const RooCmdArg &arg7=RooCmdArg::none(), const RooCmdArg &arg8=RooCmdArg::none()) const
Calls RooPlot* plotOn(RooPlot* frame, const RooLinkedList& cmdList) const ;.
Definition: RooAbsData.cxx:546
RooAbsReal is the common abstract base class for objects that represent a real value and implements f...
Definition: RooAbsReal.h:60
virtual RooPlot * plotOn(RooPlot *frame, const RooCmdArg &arg1=RooCmdArg(), const RooCmdArg &arg2=RooCmdArg(), const RooCmdArg &arg3=RooCmdArg(), const RooCmdArg &arg4=RooCmdArg(), const RooCmdArg &arg5=RooCmdArg(), const RooCmdArg &arg6=RooCmdArg(), const RooCmdArg &arg7=RooCmdArg(), const RooCmdArg &arg8=RooCmdArg(), const RooCmdArg &arg9=RooCmdArg(), const RooCmdArg &arg10=RooCmdArg()) const
Plot (project) PDF on specified frame.
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
A RooPlot is a plot frame and a container for graphics objects within that frame.
Definition: RooPlot.h:44
TAxis * GetYaxis() const
Definition: RooPlot.cxx:1277
virtual void Draw(Option_t *options=0)
Draw this plot and all of the elements it contains.
Definition: RooPlot.cxx:712
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:35
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition: TAttAxis.cxx:294
The Canvas class.
Definition: TCanvas.h:27
1-Dim function class
Definition: TF1.h:210
double beta_pdf(double x, double a, double b)
Probability density function of the beta distribution.
double beta(double x, double y)
Calculates the beta function.
Double_t x[n]
Definition: legend1.C:17
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
RooAbsPdf * bindPdf(const char *name, CFUNCD1D func, RooAbsReal &x)
RooAbsReal * bindFunction(const char *name, CFUNCD1D func, RooAbsReal &x)
Double_t Erf(Double_t x)
Computation of the error function erf(x).
Definition: TMath.cxx:184
const char * Title
Definition: TXMLSetup.cxx:67
auto * a
Definition: textangle.C:12