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rf501_simultaneouspdf.C
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1 /// \file
2 /// \ingroup tutorial_roofit
3 /// \notebook -js
4 /// Organisation and simultaneous fits: using simultaneous pdfs to describe simultaneous
5 /// fits to multiple datasets
6 ///
7 /// \macro_image
8 /// \macro_output
9 /// \macro_code
10 ///
11 /// \date July 2008
12 /// \author Wouter Verkerke
13 
14 #include "RooRealVar.h"
15 #include "RooDataSet.h"
16 #include "RooGaussian.h"
17 #include "RooConstVar.h"
18 #include "RooChebychev.h"
19 #include "RooAddPdf.h"
20 #include "RooSimultaneous.h"
21 #include "RooCategory.h"
22 #include "TCanvas.h"
23 #include "TAxis.h"
24 #include "RooPlot.h"
25 using namespace RooFit;
26 
28 {
29  // C r e a t e m o d e l f o r p h y s i c s s a m p l e
30  // -------------------------------------------------------------
31 
32  // Create observables
33  RooRealVar x("x", "x", -8, 8);
34 
35  // Construct signal pdf
36  RooRealVar mean("mean", "mean", 0, -8, 8);
37  RooRealVar sigma("sigma", "sigma", 0.3, 0.1, 10);
38  RooGaussian gx("gx", "gx", x, mean, sigma);
39 
40  // Construct background pdf
41  RooRealVar a0("a0", "a0", -0.1, -1, 1);
42  RooRealVar a1("a1", "a1", 0.004, -1, 1);
43  RooChebychev px("px", "px", x, RooArgSet(a0, a1));
44 
45  // Construct composite pdf
46  RooRealVar f("f", "f", 0.2, 0., 1.);
47  RooAddPdf model("model", "model", RooArgList(gx, px), f);
48 
49  // C r e a t e m o d e l f o r c o n t r o l s a m p l e
50  // --------------------------------------------------------------
51 
52  // Construct signal pdf.
53  // NOTE that sigma is shared with the signal sample model
54  RooRealVar mean_ctl("mean_ctl", "mean_ctl", -3, -8, 8);
55  RooGaussian gx_ctl("gx_ctl", "gx_ctl", x, mean_ctl, sigma);
56 
57  // Construct the background pdf
58  RooRealVar a0_ctl("a0_ctl", "a0_ctl", -0.1, -1, 1);
59  RooRealVar a1_ctl("a1_ctl", "a1_ctl", 0.5, -0.1, 1);
60  RooChebychev px_ctl("px_ctl", "px_ctl", x, RooArgSet(a0_ctl, a1_ctl));
61 
62  // Construct the composite model
63  RooRealVar f_ctl("f_ctl", "f_ctl", 0.5, 0., 1.);
64  RooAddPdf model_ctl("model_ctl", "model_ctl", RooArgList(gx_ctl, px_ctl), f_ctl);
65 
66  // G e n e r a t e e v e n t s f o r b o t h s a m p l e s
67  // ---------------------------------------------------------------
68 
69  // Generate 1000 events in x and y from model
70  RooDataSet *data = model.generate(RooArgSet(x), 100);
71  RooDataSet *data_ctl = model_ctl.generate(RooArgSet(x), 2000);
72 
73  // C r e a t e i n d e x c a t e g o r y a n d j o i n s a m p l e s
74  // ---------------------------------------------------------------------------
75 
76  // Define category to distinguish physics and control samples events
77  RooCategory sample("sample", "sample");
78  sample.defineType("physics");
79  sample.defineType("control");
80 
81  // Construct combined dataset in (x,sample)
82  RooDataSet combData("combData", "combined data", x, Index(sample), Import("physics", *data),
83  Import("control", *data_ctl));
84 
85  // C o n s t r u c t a s i m u l t a n e o u s p d f i n ( x , s a m p l e )
86  // -----------------------------------------------------------------------------------
87 
88  // Construct a simultaneous pdf using category sample as index
89  RooSimultaneous simPdf("simPdf", "simultaneous pdf", sample);
90 
91  // Associate model with the physics state and model_ctl with the control state
92  simPdf.addPdf(model, "physics");
93  simPdf.addPdf(model_ctl, "control");
94 
95  // P e r f o r m a s i m u l t a n e o u s f i t
96  // ---------------------------------------------------
97 
98  // Perform simultaneous fit of model to data and model_ctl to data_ctl
99  simPdf.fitTo(combData);
100 
101  // P l o t m o d e l s l i c e s o n d a t a s l i c e s
102  // ----------------------------------------------------------------
103 
104  // Make a frame for the physics sample
105  RooPlot *frame1 = x.frame(Bins(30), Title("Physics sample"));
106 
107  // Plot all data tagged as physics sample
108  combData.plotOn(frame1, Cut("sample==sample::physics"));
109 
110  // Plot "physics" slice of simultaneous pdf.
111  // NBL You _must_ project the sample index category with data using ProjWData
112  // as a RooSimultaneous makes no prediction on the shape in the index category
113  // and can thus not be integrated.
114  // In other words: Since the PDF doesn't know the number of events in the different
115  // category states, it doesn't know how much of each component it has to project out.
116  // This information is read from the data.
117  simPdf.plotOn(frame1, Slice(sample, "physics"), ProjWData(sample, combData));
118  simPdf.plotOn(frame1, Slice(sample, "physics"), Components("px"), ProjWData(sample, combData), LineStyle(kDashed));
119 
120  // The same plot for the control sample slice
121  RooPlot *frame2 = x.frame(Bins(30), Title("Control sample"));
122  combData.plotOn(frame2, Cut("sample==sample::control"));
123  simPdf.plotOn(frame2, Slice(sample, "control"), ProjWData(sample, combData));
124  simPdf.plotOn(frame2, Slice(sample, "control"), Components("px_ctl"), ProjWData(sample, combData),
125  LineStyle(kDashed));
126 
127  TCanvas *c = new TCanvas("rf501_simultaneouspdf", "rf403_simultaneouspdf", 800, 400);
128  c->Divide(2);
129  c->cd(1);
130  gPad->SetLeftMargin(0.15);
131  frame1->GetYaxis()->SetTitleOffset(1.4);
132  frame1->Draw();
133  c->cd(2);
134  gPad->SetLeftMargin(0.15);
135  frame2->GetYaxis()->SetTitleOffset(1.4);
136  frame2->Draw();
137 }
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
RooFit::ProjWData
RooCmdArg ProjWData(const RooAbsData &projData, Bool_t binData=kFALSE)
Definition: RooGlobalFunc.cxx:47
RooChebychev.h
RooAddPdf
RooAddPdf is an efficient implementation of a sum of PDFs of the form.
Definition: RooAddPdf.h:32
f
#define f(i)
Definition: RSha256.hxx:104
RooFit::Bins
RooCmdArg Bins(Int_t nbin)
Definition: RooGlobalFunc.cxx:177
RooSimultaneous.h
rf501_simultaneouspdf
Definition: rf501_simultaneouspdf.py:1
RooChebychev
Chebychev polynomial p.d.f.
Definition: RooChebychev.h:25
RooArgList
RooArgList is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgList.h:21
RooGaussian.h
x
Double_t x[n]
Definition: legend1.C:17
RooGaussian
Plain Gaussian p.d.f.
Definition: RooGaussian.h:24
RooAddPdf.h
TCanvas.h
RooDataSet.h
RooFit::Slice
RooCmdArg Slice(const RooArgSet &sliceSet)
Definition: RooGlobalFunc.cxx:40
RooFit::Cut
RooCmdArg Cut(const char *cutSpec)
Definition: RooGlobalFunc.cxx:81
RooFit
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
Definition: RooCFunction1Binding.h:29
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
RooCategory.h
RooRealVar.h
RooConstVar.h
sigma
const Double_t sigma
Definition: h1analysisProxy.h:11
TCanvas
The Canvas class.
Definition: TCanvas.h:23
RooCategory
RooCategory is an object to represent discrete states.
Definition: RooCategory.h:27
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
RooFit::Index
RooCmdArg Index(RooCategory &icat)
Definition: RooGlobalFunc.cxx:98
RooSimultaneous
RooSimultaneous facilitates simultaneous fitting of multiple PDFs to subsets of a given dataset.
Definition: RooSimultaneous.h:37
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
RooFit::Components
RooCmdArg Components(const RooArgSet &compSet)
Definition: RooGlobalFunc.cxx:75
RooFit::Title
RooCmdArg Title(const char *name)
Definition: RooGlobalFunc.cxx:176
RooArgSet
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:29
RooFit::Import
RooCmdArg Import(const char *state, TH1 &histo)
Definition: RooGlobalFunc.cxx:99