 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"
22using namespace RooFit;
23
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}
#define c(i)
Definition: RSha256.hxx:101
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
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
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
Plain Gaussian p.d.f.
Definition: RooGaussian.h:24
A RooPlot is a plot frame and a container for graphics objects within that frame.
Definition: RooPlot.h:44
TAxis * GetYaxis() const
Definition: RooPlot.cxx:1263
virtual void Draw(Option_t *options=0)
Draw this plot and all of the elements it contains.
Definition: RooPlot.cxx:691
RooProdPdf is an efficient implementation of a product of PDFs of the form.
Definition: RooProdPdf.h:37
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:39
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition: TAttAxis.cxx:293
The Canvas class.
Definition: TCanvas.h:23
Double_t y[n]
Definition: legend1.C:17
Double_t x[n]
Definition: legend1.C:17
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
const char * Title
Definition: TXMLSetup.cxx:68