Logo ROOT  
Reference Guide
rf703_effpdfprod.C
Go to the documentation of this file.
1 /// \file
2 /// \ingroup tutorial_roofit
3 /// \notebook -js
4 /// Special pdf's: using a product of an (acceptance) efficiency and a pdf as pdf
5 ///
6 /// \macro_image
7 /// \macro_output
8 /// \macro_code
9 ///
10 /// \date July 2008
11 /// \author Wouter Verkerke
12 
13 #include "RooRealVar.h"
14 #include "RooDataSet.h"
15 #include "RooGaussian.h"
16 #include "RooConstVar.h"
17 #include "RooExponential.h"
18 #include "RooEffProd.h"
19 #include "RooFormulaVar.h"
20 #include "TCanvas.h"
21 #include "TAxis.h"
22 #include "RooPlot.h"
23 using namespace RooFit;
24 
25 void rf703_effpdfprod()
26 {
27  // D e f i n e o b s e r v a b l e s a n d d e c a y p d f
28  // ---------------------------------------------------------------
29 
30  // Declare observables
31  RooRealVar t("t", "t", 0, 5);
32 
33  // Make pdf
34  RooRealVar tau("tau", "tau", -1.54, -4, -0.1);
35  RooExponential model("model", "model", t, tau);
36 
37  // D e f i n e e f f i c i e n c y f u n c t i o n
38  // ---------------------------------------------------
39 
40  // Use error function to simulate turn-on slope
41  RooFormulaVar eff("eff", "0.5*(TMath::Erf((t-1)/0.5)+1)", t);
42 
43  // D e f i n e d e c a y p d f w i t h e f f i c i e n c y
44  // ---------------------------------------------------------------
45 
46  // Multiply pdf(t) with efficiency in t
47  RooEffProd modelEff("modelEff", "model with efficiency", model, eff);
48 
49  // P l o t e f f i c i e n c y , p d f
50  // ----------------------------------------
51 
52  RooPlot *frame1 = t.frame(Title("Efficiency"));
53  eff.plotOn(frame1, LineColor(kRed));
54 
55  RooPlot *frame2 = t.frame(Title("Pdf with and without efficiency"));
56 
57  model.plotOn(frame2, LineStyle(kDashed));
58  modelEff.plotOn(frame2);
59 
60  // G e n e r a t e t o y d a t a , f i t m o d e l E f f t o d a t a
61  // ------------------------------------------------------------------------------
62 
63  // Generate events. If the input pdf has an internal generator, the internal generator
64  // is used and an accept/reject sampling on the efficiency is applied.
65  RooDataSet *data = modelEff.generate(t, 10000);
66 
67  // Fit pdf. The normalization integral is calculated numerically.
68  modelEff.fitTo(*data);
69 
70  // Plot generated data and overlay fitted pdf
71  RooPlot *frame3 = t.frame(Title("Fitted pdf with efficiency"));
72  data->plotOn(frame3);
73  modelEff.plotOn(frame3);
74 
75  TCanvas *c = new TCanvas("rf703_effpdfprod", "rf703_effpdfprod", 1200, 400);
76  c->Divide(3);
77  c->cd(1);
78  gPad->SetLeftMargin(0.15);
79  frame1->GetYaxis()->SetTitleOffset(1.4);
80  frame1->Draw();
81  c->cd(2);
82  gPad->SetLeftMargin(0.15);
83  frame2->GetYaxis()->SetTitleOffset(1.6);
84  frame2->Draw();
85  c->cd(3);
86  gPad->SetLeftMargin(0.15);
87  frame3->GetYaxis()->SetTitleOffset(1.6);
88  frame3->Draw();
89 }
RooFormulaVar.h
c
#define c(i)
Definition: RSha256.hxx:101
RooPlot::Draw
virtual void Draw(Option_t *options=0)
Draw this plot and all of the elements it contains.
Definition: RooPlot.cxx:691
rf703_effpdfprod
Definition: rf703_effpdfprod.py:1
RooGaussian.h
RooEffProd.h
TCanvas.h
RooEffProd
The class RooEffProd implements the product of a PDF with an efficiency function.
Definition: RooEffProd.h:20
RooDataSet.h
RooPlot::frame
static RooPlot * frame(const RooAbsRealLValue &var, Double_t xmin, Double_t xmax, Int_t nBins)
Create a new frame for a given variable in x.
Definition: RooPlot.cxx:249
RooFormulaVar
A RooFormulaVar is a generic implementation of a real-valued object, which takes a RooArgList of serv...
Definition: RooFormulaVar.h:30
RooFit
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
Definition: RooCFunction1Binding.h:29
RooAbsData::plotOn
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
Definition: RooAbsData.cxx:547
RooPlot.h
RooPlot::GetYaxis
TAxis * GetYaxis() const
Definition: RooPlot.cxx:1258
RooPlot
A RooPlot is a plot frame and a container for graphics objects within that frame.
Definition: RooPlot.h:44
RooRealVar.h
kRed
@ kRed
Definition: Rtypes.h:66
RooExponential.h
RooConstVar.h
RooFit::LineColor
RooCmdArg LineColor(Color_t color)
Definition: RooGlobalFunc.cxx:57
TCanvas
The Canvas class.
Definition: TCanvas.h:23
TAxis.h
kDashed
@ kDashed
Definition: TAttLine.h:48
gPad
#define gPad
Definition: TVirtualPad.h:287
RooDataSet
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
make_cnn_model.model
model
Definition: make_cnn_model.py:6
RooFit::LineStyle
RooCmdArg LineStyle(Style_t style)
Definition: RooGlobalFunc.cxx:58
TAttAxis::SetTitleOffset
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition: TAttAxis.cxx:293
RooRealVar
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:37
RooExponential
Exponential PDF.
Definition: RooExponential.h:25
RooFit::Title
RooCmdArg Title(const char *name)
Definition: RooGlobalFunc.cxx:176