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Reference Guide
RooDecay.cxx
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1/*****************************************************************************
2 * Project: RooFit *
3 * Package: RooFitModels *
4 * @(#)root/roofit:$Id$
5 * Authors: *
6 * WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu *
7 * DK, David Kirkby, UC Irvine, dkirkby@uci.edu *
8 * *
9 * Copyright (c) 2000-2005, Regents of the University of California *
10 * and Stanford University. All rights reserved. *
11 * *
12 * Redistribution and use in source and binary forms, *
13 * with or without modification, are permitted according to the terms *
14 * listed in LICENSE (http://roofit.sourceforge.net/license.txt) *
15 *****************************************************************************/
16
17/** \class RooDecay
18 \ingroup Roofit
19
20Single or double sided decay function that can be analytically convolved
21with any RooResolutionModel implementation
22**/
23
24#include "RooFit.h"
25
26#include "Riostream.h"
27#include "Riostream.h"
28#include "RooDecay.h"
29#include "RooRealVar.h"
30#include "RooRandom.h"
31
32#include "TError.h"
33
34using namespace std;
35
37
38////////////////////////////////////////////////////////////////////////////////
39/// Constructor
40
41RooDecay::RooDecay(const char *name, const char *title,
42 RooRealVar& t, RooAbsReal& tau,
43 const RooResolutionModel& model, DecayType type) :
44 RooAbsAnaConvPdf(name,title,model,t),
45 _t("t","time",this,t),
46 _tau("tau","decay time",this,tau),
47 _type(type)
48{
49 switch(type) {
50 case SingleSided:
51 _basisExp = declareBasis("exp(-@0/@1)",tau) ;
52 break ;
53 case Flipped:
54 _basisExp = declareBasis("exp(@0/@1)",tau) ;
55 break ;
56 case DoubleSided:
57 _basisExp = declareBasis("exp(-abs(@0)/@1)",tau) ;
58 break ;
59 }
60}
61
62////////////////////////////////////////////////////////////////////////////////
63/// Copy constructor
64
65RooDecay::RooDecay(const RooDecay& other, const char* name) :
67 _t("t",this,other._t),
68 _tau("tau",this,other._tau),
69 _type(other._type),
70 _basisExp(other._basisExp)
71{
72}
73
74////////////////////////////////////////////////////////////////////////////////
75/// Destructor
76
78{
79}
80
81////////////////////////////////////////////////////////////////////////////////
82
84{
85 return 1 ;
86}
87
88////////////////////////////////////////////////////////////////////////////////
89
90Int_t RooDecay::getGenerator(const RooArgSet& directVars, RooArgSet &generateVars, Bool_t /*staticInitOK*/) const
91{
92 if (matchArgs(directVars,generateVars,_t)) return 1 ;
93 return 0 ;
94}
95
96////////////////////////////////////////////////////////////////////////////////
97
99{
100 R__ASSERT(code==1) ;
101
102 // Generate delta-t dependent
103 while(1) {
105 Double_t tval(0) ;
106
107 switch(_type) {
108 case SingleSided:
109 tval = -_tau*log(rand);
110 break ;
111 case Flipped:
112 tval= +_tau*log(rand);
113 break ;
114 case DoubleSided:
115 tval = (rand<=0.5) ? -_tau*log(2*rand) : +_tau*log(2*(rand-0.5)) ;
116 break ;
117 }
118
119 if (tval<_t.max() && tval>_t.min()) {
120 _t = tval ;
121 break ;
122 }
123 }
124}
int Int_t
Definition: RtypesCore.h:41
bool Bool_t
Definition: RtypesCore.h:59
double Double_t
Definition: RtypesCore.h:55
#define ClassImp(name)
Definition: Rtypes.h:365
#define R__ASSERT(e)
Definition: TError.h:96
char name[80]
Definition: TGX11.cxx:109
int type
Definition: TGX11.cxx:120
double log(double)
RooAbsAnaConvPdf is the base class for PDFs that represent a physics model that can be analytically c...
Int_t declareBasis(const char *expression, const RooArgList &params)
Declare a basis function for use in this physics model.
RooAbsReal is the common abstract base class for objects that represent a real value and implements f...
Definition: RooAbsReal.h:53
Bool_t matchArgs(const RooArgSet &allDeps, RooArgSet &numDeps, const RooArgProxy &a) const
Utility function for use in getAnalyticalIntegral().
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:28
Single or double sided decay function that can be analytically convolved with any RooResolutionModel ...
Definition: RooDecay.h:22
RooDecay()
Definition: RooDecay.h:28
@ DoubleSided
Definition: RooDecay.h:25
@ SingleSided
Definition: RooDecay.h:25
@ Flipped
Definition: RooDecay.h:25
virtual ~RooDecay()
Destructor.
Definition: RooDecay.cxx:77
Int_t _basisExp
Definition: RooDecay.h:45
RooRealProxy _t
Definition: RooDecay.h:42
virtual Double_t coefficient(Int_t basisIndex) const
Definition: RooDecay.cxx:83
void generateEvent(Int_t code)
Interface for generation of an event using the algorithm corresponding to the specified code.
Definition: RooDecay.cxx:98
RooRealProxy _tau
Definition: RooDecay.h:43
DecayType _type
Definition: RooDecay.h:44
Int_t getGenerator(const RooArgSet &directVars, RooArgSet &generateVars, Bool_t staticInitOK=kTRUE) const
Load generatedVars with the subset of directVars that we can generate events for, and return a code t...
Definition: RooDecay.cxx:90
static Double_t uniform(TRandom *generator=randomGenerator())
Return a number uniformly distributed from (0,1)
Definition: RooRandom.cxx:84
Double_t min(const char *rname=0) const
Definition: RooRealProxy.h:56
Double_t max(const char *rname=0) const
Definition: RooRealProxy.h:57
RooRealVar represents a fundamental (non-derived) real valued object.
Definition: RooRealVar.h:36