 ROOT   Reference Guide rf304_uncorrprod.C
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1 /// \file
2 /// \ingroup tutorial_roofit
3 /// \notebook -js
4 /// Multidimensional models: simple uncorrelated multi-dimensional pdfs
5 ///
6 /// pdf = gauss(x,mx,sx) * gauss(y,my,sy)
7 ///
8 /// \macro_image
9 /// \macro_output
10 /// \macro_code
11 ///
12 /// \date July 2008
13 /// \author Wouter Verkerke
14
15 #include "RooRealVar.h"
16 #include "RooDataSet.h"
17 #include "RooGaussian.h"
18 #include "RooProdPdf.h"
19 #include "TCanvas.h"
20 #include "TAxis.h"
21 #include "RooPlot.h"
22 using namespace RooFit;
23
24 void rf304_uncorrprod()
25 {
26
27  // C r e a t e c o m p o n e n t p d f s i n x a n d y
28  // ----------------------------------------------------------------
29
30  // Create two pdfs gaussx(x,meanx,sigmax) gaussy(y,meany,sigmay) and its variables
31  RooRealVar x("x", "x", -5, 5);
32  RooRealVar y("y", "y", -5, 5);
33
34  RooRealVar meanx("mean1", "mean of gaussian x", 2);
35  RooRealVar meany("mean2", "mean of gaussian y", -2);
36  RooRealVar sigmax("sigmax", "width of gaussian x", 1);
37  RooRealVar sigmay("sigmay", "width of gaussian y", 5);
38
39  RooGaussian gaussx("gaussx", "gaussian PDF", x, meanx, sigmax);
40  RooGaussian gaussy("gaussy", "gaussian PDF", y, meany, sigmay);
41
42  // C o n s t r u c t u n c o r r e l a t e d p r o d u c t p d f
43  // -------------------------------------------------------------------
44
45  // Multiply gaussx and gaussy into a two-dimensional pdf gaussxy
46  RooProdPdf gaussxy("gaussxy", "gaussx*gaussy", RooArgList(gaussx, gaussy));
47
48  // S a m p l e p d f , p l o t p r o j e c t i o n o n x a n d y
49  // ---------------------------------------------------------------------------
50
51  // Generate 10000 events in x and y from gaussxy
52  RooDataSet *data = gaussxy.generate(RooArgSet(x, y), 10000);
53
54  // Plot x distribution of data and projection of gaussxy on x = Int(dy) gaussxy(x,y)
55  RooPlot *xframe = x.frame(Title("X projection of gauss(x)*gauss(y)"));
56  data->plotOn(xframe);
57  gaussxy.plotOn(xframe);
58
59  // Plot x distribution of data and projection of gaussxy on y = Int(dx) gaussxy(x,y)
60  RooPlot *yframe = y.frame(Title("Y projection of gauss(x)*gauss(y)"));
61  data->plotOn(yframe);
62  gaussxy.plotOn(yframe);
63
64  // Make canvas and draw RooPlots
65  TCanvas *c = new TCanvas("rf304_uncorrprod", "rf304_uncorrprod", 800, 400);
66  c->Divide(2);
67  c->cd(1);
69  xframe->GetYaxis()->SetTitleOffset(1.4);
70  xframe->Draw();
71  c->cd(2);
73  yframe->GetYaxis()->SetTitleOffset(1.4);
74  yframe->Draw();
75 }
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
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
TCanvas.h
RooDataSet.h
rf304_uncorrprod
Definition: rf304_uncorrprod.py:1
RooProdPdf.h
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
y
Double_t y[n]
Definition: legend1.C:17
RooRealVar.h
TCanvas
The Canvas class.
Definition: TCanvas.h:23
TAxis.h
RooDataSet
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
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
RooProdPdf
RooProdPdf is an efficient implementation of a product of PDFs of the form.
Definition: RooProdPdf.h:37
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