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Reference Guide
rf207_comptools.C
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1 /// \file
2 /// \ingroup tutorial_roofit
3 /// \notebook -nodraw
4 /// Addition and convolution: tools and utilities for manipulation of composite objects
5 ///
6 /// \macro_output
7 /// \macro_code
8 ///
9 /// \date July 2008
10 /// \author Wouter Verkerke
11 
12 #include "RooRealVar.h"
13 #include "RooDataSet.h"
14 #include "RooGaussian.h"
15 #include "RooChebychev.h"
16 #include "RooExponential.h"
17 #include "RooAddPdf.h"
18 #include "RooPlot.h"
19 #include "RooCustomizer.h"
20 #include "TCanvas.h"
21 #include "TAxis.h"
22 #include "TH1.h"
23 using namespace RooFit;
24 
25 void rf207_comptools()
26 {
27 
28  // S e t u p c o m p o s i t e p d f, d a t a s e t
29  // --------------------------------------------------------
30 
31  // Declare observable x
32  RooRealVar x("x", "x", 0, 10);
33 
34  // Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters
35  RooRealVar mean("mean", "mean of gaussians", 5);
36  RooRealVar sigma("sigma", "width of gaussians", 0.5);
37  RooGaussian sig("sig", "Signal component 1", x, mean, sigma);
38 
39  // Build Chebychev polynomial pdf
40  RooRealVar a0("a0", "a0", 0.5, 0., 1.);
41  RooRealVar a1("a1", "a1", 0.2, 0., 1.);
42  RooChebychev bkg1("bkg1", "Background 1", x, RooArgSet(a0, a1));
43 
44  // Build exponential pdf
45  RooRealVar alpha("alpha", "alpha", -1);
46  RooExponential bkg2("bkg2", "Background 2", x, alpha);
47 
48  // Sum the background components into a composite background pdf
49  RooRealVar bkg1frac("bkg1frac", "fraction of component 1 in background", 0.2, 0., 1.);
50  RooAddPdf bkg("bkg", "Signal", RooArgList(bkg1, bkg2), bkg1frac);
51 
52  // Sum the composite signal and background
53  RooRealVar bkgfrac("bkgfrac", "fraction of background", 0.5, 0., 1.);
54  RooAddPdf model("model", "g1+g2+a", RooArgList(bkg, sig), bkgfrac);
55 
56  // Create dummy dataset that has more observables than the above pdf
57  RooRealVar y("y", "y", -10, 10);
58  RooDataSet data("data", "data", RooArgSet(x, y));
59 
60  // ---------------------------------------------------
61  // B a s i c i n f o r m a t i o n r e q u e s t s
62  // ===================================================
63 
64  // G e t l i s t o f o b s e r v a b l e s
65  // ---------------------------------------------
66 
67  // Get list of observables of pdf in context of a dataset
68  //
69  // Observables are define each context as the variables
70  // shared between a model and a dataset. In this case
71  // that is the variable 'x'
72 
73  RooArgSet *model_obs = model.getObservables(data);
74  model_obs->Print("v");
75 
76  // G e t l i s t o f p a r a m e t e r s
77  // -------------------------------------------
78 
79  // Get list of parameters, given list of observables
80  RooArgSet *model_params = model.getParameters(x);
81  model_params->Print("v");
82 
83  // Get list of parameters, given a dataset
84  // (Gives identical results to operation above)
85  RooArgSet *model_params2 = model.getParameters(data);
86  model_params2->Print();
87 
88  // G e t l i s t o f c o m p o n e n t s
89  // -------------------------------------------
90 
91  // Get list of component objects, including top-level node
92  RooArgSet *model_comps = model.getComponents();
93  model_comps->Print("v");
94 
95  // -------------------------------------------------------------------------------
96  // M o d i f i c a t i o n s t o s t r u c t u r e o f c o m p o s i t e s
97  // ===============================================================================
98 
99  // Create a second Gaussian
100  RooRealVar sigma2("sigma2", "width of gaussians", 1);
101  RooGaussian sig2("sig2", "Signal component 1", x, mean, sigma2);
102 
103  // Create a sum of the original Gaussian plus the new second Gaussian
104  RooRealVar sig1frac("sig1frac", "fraction of component 1 in signal", 0.8, 0., 1.);
105  RooAddPdf sigsum("sigsum", "sig+sig2", RooArgList(sig, sig2), sig1frac);
106 
107  // Construct a customizer utility to customize model
108  RooCustomizer cust(model, "cust");
109 
110  // Instruct the customizer to replace node 'sig' with node 'sigsum'
111  cust.replaceArg(sig, sigsum);
112 
113  // Build a clone of the input pdf according to the above customization
114  // instructions. Each node that requires modified is clone so that the
115  // original pdf remained untouched. The name of each cloned node is that
116  // of the original node suffixed by the name of the customizer object
117  //
118  // The returned head node own all nodes that were cloned as part of
119  // the build process so when cust_clone is deleted so will all other
120  // nodes that were created in the process.
121  RooAbsPdf *cust_clone = (RooAbsPdf *)cust.build(kTRUE);
122 
123  // Print structure of clone of model with sig->sigsum replacement.
124  cust_clone->Print("t");
125 
126  delete cust_clone;
127 }
kTRUE
const Bool_t kTRUE
Definition: RtypesCore.h:91
RooChebychev.h
RooAddPdf
RooAddPdf is an efficient implementation of a sum of PDFs of the form.
Definition: RooAddPdf.h:32
RooChebychev
Chebychev polynomial p.d.f.
Definition: RooChebychev.h:25
RooCustomizer
RooCustomizer is a factory class to produce clones of a prototype composite PDF object with the same ...
Definition: RooCustomizer.h:35
RooAbsArg::Print
virtual void Print(Option_t *options=0) const
Print the object to the defaultPrintStream().
Definition: RooAbsArg.h:320
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
RooCustomizer.h
RooFit
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
Definition: RooCFunction1Binding.h:29
RooPlot.h
y
Double_t y[n]
Definition: legend1.C:17
RooRealVar.h
RooExponential.h
sigma
const Double_t sigma
Definition: h1analysisProxy.h:11
TAxis.h
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
RooAbsCollection::Print
virtual void Print(Option_t *options=0) const
This method must be overridden when a class wants to print itself.
Definition: RooAbsCollection.h:200
RooAbsPdf
Definition: RooAbsPdf.h:43
RooRealVar
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:37
RooExponential
Exponential PDF.
Definition: RooExponential.h:25
TH1.h
RooArgSet
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:29