ROOT   Reference Guide
rf206_treevistools.C
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1/// \file
2/// \ingroup tutorial_roofit
3/// \notebook -nodraw
4/// Addition and convolution: tools for visualization of RooAbsArg expression trees
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"
17#include "RooExponential.h"
18#include "TCanvas.h"
19#include "TAxis.h"
20#include "RooPlot.h"
21using namespace RooFit;
22
24{
25 // S e t u p c o m p o s i t e p d f
26 // --------------------------------------
27
28 // Declare observable x
29 RooRealVar x("x", "x", 0, 10);
30
31 // Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters
32 RooRealVar mean("mean", "mean of gaussians", 5);
33 RooRealVar sigma1("sigma1", "width of gaussians", 0.5);
34 RooRealVar sigma2("sigma2", "width of gaussians", 1);
35 RooGaussian sig1("sig1", "Signal component 1", x, mean, sigma1);
36 RooGaussian sig2("sig2", "Signal component 2", x, mean, sigma2);
37
38 // Sum the signal components into a composite signal pdf
39 RooRealVar sig1frac("sig1frac", "fraction of component 1 in signal", 0.8, 0., 1.);
40 RooAddPdf sig("sig", "Signal", RooArgList(sig1, sig2), sig1frac);
41
42 // Build Chebychev polynomial pdf
43 RooRealVar a0("a0", "a0", 0.5, 0., 1.);
44 RooRealVar a1("a1", "a1", 0.2, 0., 1.);
45 RooChebychev bkg1("bkg1", "Background 1", x, RooArgSet(a0, a1));
46
47 // Build expontential pdf
48 RooRealVar alpha("alpha", "alpha", -1);
49 RooExponential bkg2("bkg2", "Background 2", x, alpha);
50
51 // Sum the background components into a composite background pdf
52 RooRealVar bkg1frac("bkg1frac", "fraction of component 1 in background", 0.2, 0., 1.);
53 RooAddPdf bkg("bkg", "Signal", RooArgList(bkg1, bkg2), bkg1frac);
54
55 // Sum the composite signal and background
56 RooRealVar bkgfrac("bkgfrac", "fraction of background", 0.5, 0., 1.);
57 RooAddPdf model("model", "g1+g2+a", RooArgList(bkg, sig), bkgfrac);
58
59 // P r i n t c o m p o s i t e t r e e i n A S C I I
60 // -----------------------------------------------------------
61
62 // Print tree to stdout
63 model.Print("t");
64
65 // Print tree to file
66 model.printCompactTree("", "rf206_asciitree.txt");
67
68 // D r a w c o m p o s i t e t r e e g r a p h i c a l l y
69 // -------------------------------------------------------------
70
71 // Print GraphViz DOT file with representation of tree
72 model.graphVizTree("rf206_model.dot");
73
74 // Make graphic output file with one of the GraphViz tools
75 // (freely available from www.graphviz.org)
76 //
77 // 'Top-to-bottom graph'
78 // unix> dot -Tgif -o rf207_model_dot.gif rf207_model.dot
79 //
80 // 'Spring-model graph'
81 // unix> fdp -Tgif -o rf207_model_fdp.gif rf207_model.dot
82}
RooAddPdf is an efficient implementation of a sum of PDFs of the form.
RooArgList is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgList.h:21
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:29
Chebychev polynomial p.d.f.
Definition: RooChebychev.h:25
Exponential PDF.
Plain Gaussian p.d.f.
Definition: RooGaussian.h:24
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:39
Double_t x[n]
Definition: legend1.C:17
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...