ROOT   Reference Guide
rf306_condpereventerrors.C
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1/// \file
2/// \ingroup tutorial_roofit
3/// \notebook
4///
5/// Multidimensional models: conditional p.d.f. with per-event errors
6///
7/// \macro_image
8/// \macro_output
9/// \macro_code
10///
11/// \date 07/2008
12/// \author Wouter Verkerke
13
14#include "RooRealVar.h"
15#include "RooDataSet.h"
16#include "RooGaussian.h"
17#include "RooConstVar.h"
18#include "RooGaussModel.h"
19#include "RooDecay.h"
20#include "RooLandau.h"
21#include "RooPlot.h"
22#include "TCanvas.h"
23#include "TAxis.h"
24#include "TH2D.h"
25using namespace RooFit;
26
28{
29 // B - p h y s i c s p d f w i t h p e r - e v e n t G a u s s i a n r e s o l u t i o n
30 // ----------------------------------------------------------------------------------------------
31
32 // Observables
33 RooRealVar dt("dt", "dt", -10, 10);
34 RooRealVar dterr("dterr", "per-event error on dt", 0.01, 10);
35
36 // Build a gaussian resolution model scaled by the per-event error = gauss(dt,bias,sigma*dterr)
37 RooRealVar bias("bias", "bias", 0, -10, 10);
38 RooRealVar sigma("sigma", "per-event error scale factor", 1, 0.1, 10);
39 RooGaussModel gm("gm1", "gauss model scaled bt per-event error", dt, bias, sigma, dterr);
40
41 // Construct decay(dt) (x) gauss1(dt|dterr)
42 RooRealVar tau("tau", "tau", 1.548);
43 RooDecay decay_gm("decay_gm", "decay", dt, tau, gm, RooDecay::DoubleSided);
44
45 // C o n s t r u c t f a k e ' e x t e r n a l ' d a t a w i t h p e r - e v e n t e r r o r
46 // ------------------------------------------------------------------------------------------------------
47
48 // Use landau p.d.f to get somewhat realistic distribution with long tail
49 RooLandau pdfDtErr("pdfDtErr", "pdfDtErr", dterr, RooConst(1), RooConst(0.25));
50 RooDataSet *expDataDterr = pdfDtErr.generate(dterr, 10000);
51
52 // S a m p l e d a t a f r o m c o n d i t i o n a l d e c a y _ g m ( d t | d t e r r )
53 // ---------------------------------------------------------------------------------------------
54
55 // Specify external dataset with dterr values to use decay_dm as conditional p.d.f.
56 RooDataSet *data = decay_gm.generate(dt, ProtoData(*expDataDterr));
57
58 // F i t c o n d i t i o n a l d e c a y _ d m ( d t | d t e r r )
59 // ---------------------------------------------------------------------
60
61 // Specify dterr as conditional observable
62 decay_gm.fitTo(*data, ConditionalObservables(dterr));
63
64 // P l o t c o n d i t i o n a l d e c a y _ d m ( d t | d t e r r )
65 // ---------------------------------------------------------------------
66
67 // Make two-dimensional plot of conditional p.d.f in (dt,dterr)
68 TH1 *hh_decay = decay_gm.createHistogram("hh_decay", dt, Binning(50), YVar(dterr, Binning(50)));
69 hh_decay->SetLineColor(kBlue);
70
71 // Plot decay_gm(dt|dterr) at various values of dterr
72 RooPlot *frame = dt.frame(Title("Slices of decay(dt|dterr) at various dterr"));
73 for (Int_t ibin = 0; ibin < 100; ibin += 20) {
74 dterr.setBin(ibin);
75 decay_gm.plotOn(frame, Normalization(5.));
76 }
77
78 // Make projection of data an dt
79 RooPlot *frame2 = dt.frame(Title("Projection of decay(dt|dterr) on dt"));
80 data->plotOn(frame2);
81
82 // Make projection of decay(dt|dterr) on dt.
83 //
84 // Instead of integrating out dterr, make a weighted average of curves
85 // at values dterr_i as given in the external dataset.
86 // (The kTRUE argument bins the data before projection to speed up the process)
88
89 // Draw all frames on canvas
90 TCanvas *c = new TCanvas("rf306_condpereventerrors", "rf306_condperventerrors", 1200, 400);
91 c->Divide(3);
92 c->cd(1);
94 hh_decay->GetZaxis()->SetTitleOffset(2.5);
95 hh_decay->Draw("surf");
96 c->cd(2);
98 frame->GetYaxis()->SetTitleOffset(1.6);
99 frame->Draw();
100 c->cd(3);
102 frame2->GetYaxis()->SetTitleOffset(1.6);
103 frame2->Draw();
104}
#define c(i)
Definition: RSha256.hxx:101
const Bool_t kTRUE
Definition: RtypesCore.h:89
@ kBlue
Definition: Rtypes.h:64
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
Calls RooPlot* plotOn(RooPlot* frame, const RooLinkedList& cmdList) const ;.
Definition: RooAbsData.cxx:546
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
Single or double sided decay function that can be analytically convolved with any RooResolutionModel ...
Definition: RooDecay.h:22
@ DoubleSided
Definition: RooDecay.h:25
Class RooGaussModel implements a RooResolutionModel that models a Gaussian distribution.
Definition: RooGaussModel.h:26
Landau distribution p.d.f.
Definition: RooLandau.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:1277
static RooPlot * frame(const RooAbsRealLValue &var, Double_t xmin, Double_t xmax, Int_t nBins)
Create a new frame for a given variable in x.
Definition: RooPlot.cxx:277
virtual void Draw(Option_t *options=0)
Draw this plot and all of the elements it contains.
Definition: RooPlot.cxx:712
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:35
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition: TAttAxis.cxx:294
virtual void SetLineColor(Color_t lcolor)
Set the line color.
Definition: TAttLine.h:40
The Canvas class.
Definition: TCanvas.h:27
The TH1 histogram class.
Definition: TH1.h:56
TAxis * GetZaxis()
Definition: TH1.h:318
virtual void Draw(Option_t *option="")
Draw this histogram with options.
Definition: TH1.cxx:2998
RooCmdArg YVar(const RooAbsRealLValue &var, const RooCmdArg &arg=RooCmdArg::none())
RooConstVar & RooConst(Double_t val)
RooCmdArg ConditionalObservables(const RooArgSet &set)
RooCmdArg ProtoData(const RooDataSet &protoData, Bool_t randomizeOrder=kFALSE, Bool_t resample=kFALSE)
RooCmdArg ProjWData(const RooAbsData &projData, Bool_t binData=kFALSE)
RooCmdArg Binning(const RooAbsBinning &binning)
RooCmdArg Normalization(Double_t scaleFactor)
const Double_t sigma
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
const char * Title
Definition: TXMLSetup.cxx:67