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RooEffGenContext.cxx
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1/*****************************************************************************
2 * Project: RooFit *
3 * Package: RooFitCore *
4 * @(#)root/roofitcore:$Id$
5 * Authors: *
6 * GR, Gerhard Raven, NIKHEF/VU, Gerhard.Raven@nikhf.nl *
7 * *
8 * Copyright (c) 2005, NIKHEF. All rights reserved. *
9 * *
10 * Redistribution and use in source and binary forms, *
11 * with or without modification, are permitted according to the terms *
12 * listed in LICENSE (http://roofit.sourceforge.net/license.txt) *
13 *****************************************************************************/
14
15
16/**
17\file RooEffGenContext.cxx
18\class RooEffGenContext
19\ingroup Roofitcore
20
21RooEffGenContext is a specialized generator context for p.d.fs represented
22by class RooEffProd, which are p.d.fs multiplied with an efficiency function.
23This generator context generates events from such products by first
24generating events from a dedicated generator context of the input p.d.f.
25and applying an extra rejection step based on the efficiency function.
26**/
27
28#include <memory>
29
30#include "RooFit.h"
31#include "RooEffGenContext.h"
32#include "RooAbsPdf.h"
33#include "RooRandom.h"
34
35using namespace std;
36
38
39////////////////////////////////////////////////////////////////////////////////
40/// Constructor of generator context for RooEffProd products
41
43 const RooAbsPdf& pdf, const RooAbsReal& eff,
44 const RooArgSet &vars,
45 const RooDataSet *prototype, const RooArgSet* auxProto,
46 Bool_t verbose, const RooArgSet* /*forceDirect*/) :
47 RooAbsGenContext(model, vars, prototype, auxProto, verbose), _maxEff(0.)
48{
49 RooArgSet x(eff,eff.GetName());
50 _cloneSet = static_cast<RooArgSet*>(x.snapshot(kTRUE));
51 _eff = dynamic_cast<RooAbsReal*>(_cloneSet->find(eff.GetName()));
52 _generator = pdf.genContext(vars, prototype, auxProto, verbose);
53 _vars = static_cast<RooArgSet*>(vars.snapshot(kTRUE));
54}
55
56////////////////////////////////////////////////////////////////////////////////
57/// Destructor
58
60{
61 delete _generator;
62 delete _cloneSet;
63 delete _vars;
64}
65
66////////////////////////////////////////////////////////////////////////////////
67/// One-time initialization of generator.
68
70{
72 _generator->initGenerator(theEvent);
73
74 // Check if PDF supports maximum finding
75 Int_t code = _eff->getMaxVal(*_vars);
76 if (!code) {
77 _maxEff = 1.;
78 } else {
79 _maxEff = _eff->maxVal(code);
80 }
81}
82
83////////////////////////////////////////////////////////////////////////////////
84/// Generate one event. Generate an event from the p.d.f and
85/// then perform an accept/reject sampling based on the efficiency
86/// function
87
89{
90 while (true) {
91 _generator->generateEvent(theEvent, remaining);
92 double val = _eff->getVal();
93 if (val > _maxEff && !_eff->getMaxVal(*_vars)) {
94 coutE(Generation) << ClassName() << "::" << GetName()
95 << ":generateEvent: value of efficiency is larger than assumed maximum of 1." << std::endl;
96 continue;
97 }
98 if (val > RooRandom::uniform() * _maxEff) {
99 break;
100 }
101 }
102}
#define coutE(a)
Definition: RooMsgService.h:33
int Int_t
Definition: RtypesCore.h:43
bool Bool_t
Definition: RtypesCore.h:61
const Bool_t kTRUE
Definition: RtypesCore.h:89
#define ClassImp(name)
Definition: Rtypes.h:361
Bool_t recursiveRedirectServers(const RooAbsCollection &newServerList, Bool_t mustReplaceAll=kFALSE, Bool_t nameChange=kFALSE, Bool_t recurseInNewSet=kTRUE)
Definition: RooAbsArg.cxx:1064
RooAbsArg * find(const char *name) const
Find object with given name in list.
RooAbsGenContext is the abstract base class for generator contexts of RooAbsPdf objects.
virtual void initGenerator(const RooArgSet &theEvent)
Interface function to initialize context for generation for given set of observables.
virtual void generateEvent(RooArgSet &theEvent, Int_t remaining)=0
virtual RooAbsGenContext * genContext(const RooArgSet &vars, const RooDataSet *prototype=0, const RooArgSet *auxProto=0, Bool_t verbose=kFALSE) const
Interface function to create a generator context from a p.d.f.
Definition: RooAbsPdf.cxx:1998
RooAbsReal is the common abstract base class for objects that represent a real value and implements f...
Definition: RooAbsReal.h:60
Double_t getVal(const RooArgSet *normalisationSet=nullptr) const
Evaluate object.
Definition: RooAbsReal.h:90
virtual Double_t maxVal(Int_t code) const
Return maximum value for set of observables identified by code assigned in getMaxVal.
virtual Int_t getMaxVal(const RooArgSet &vars) const
Advertise capability to determine maximum value of function for given set of observables.
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:28
RooArgSet * snapshot(bool deepCopy=true) const
Use RooAbsCollection::snapshot(), but return as RooArgSet.
Definition: RooArgSet.h:126
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
RooEffGenContext is a specialized generator context for p.d.fs represented by class RooEffProd,...
RooArgSet * _cloneSet
void initGenerator(const RooArgSet &theEvent)
One-time initialization of generator.
virtual ~RooEffGenContext()
Destructor.
RooEffGenContext(const RooAbsPdf &model, const RooAbsPdf &pdf, const RooAbsReal &eff, const RooArgSet &vars, const RooDataSet *prototype=0, const RooArgSet *auxProto=0, Bool_t verbose=kFALSE, const RooArgSet *forceDirect=0)
Constructor of generator context for RooEffProd products.
RooAbsGenContext * _generator
RooAbsReal * _eff
void generateEvent(RooArgSet &theEvent, Int_t remaining)
Generate one event.
static Double_t uniform(TRandom *generator=randomGenerator())
Return a number uniformly distributed from (0,1)
Definition: RooRandom.cxx:83
virtual const char * GetName() const
Returns name of object.
Definition: TNamed.h:47
virtual const char * ClassName() const
Returns name of class to which the object belongs.
Definition: TObject.cxx:128
Double_t x[n]
Definition: legend1.C:17
@ Generation
Definition: RooGlobalFunc.h:67