ROOT   Reference Guide
RooNumConvPdf.cxx
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1/*****************************************************************************
2 * Project: RooFit *
3 * Package: RooFitCore *
4 * @(#)root/roofitcore:$Id$
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 *
11 * *
12 * Redistribution and use in source and binary forms, *
13 * with or without modification, are permitted according to the terms *
15 *****************************************************************************/
16
17/**
18\file RooNumConvPdf.cxx
19\class RooNumConvPdf
20\ingroup Roofitcore
21
22Numeric 1-dimensional convolution operator PDF. This class can convolve any PDF
23with any other PDF using a straightforward numeric calculation of the
24convolution integral
25This class should be used as last resort as numeric convolution calculated
26this way is computationally intensive and prone to stability fitting problems.
27<b>The preferred way to compute numeric convolutions is RooFFTConvPdf</b>,
28which calculates convolutions using Fourier Transforms (requires external free
29FFTW3 package)
30RooNumConvPdf implements reasonable defaults that should convolve most
31functions reasonably well, but results strongly depend on the shape of your
32input PDFS so always check your result.
33The default integration engine for the numeric convolution is the
34adaptive Gauss-Kronrod method, which empirically seems the most robust
35for this task. You can override the convolution integration settings via
36the RooNumIntConfig object reference returned by the convIntConfig() member
37function
38By default the numeric convolution is integrated from -infinity to
39+infinity through a <pre>x -> 1/x</pre> coordinate transformation of the
40tails. For convolution with a very small bandwidth it may be
41advantageous (for both CPU consumption and stability) if the
42integration domain is limited to a finite range. The function
43setConvolutionWindow(mean,width,scale) allows to set a sliding
44window around the x value to be calculated taking a RooAbsReal
45expression for an offset and a width to be taken around the x
46value. These input expression can be RooFormulaVars or other
47function objects although the 3d 'scale' argument 'scale'
48multiplies the width RooAbsReal expression given in the 2nd
49argument, allowing for an appropriate window definition for most
50cases without need for a RooFormulaVar object: e.g. a Gaussian
51resolution PDF do setConvolutionWindow(gaussMean,gaussSigma,5)
52Note that for a 'wide' Gaussian the -inf to +inf integration
53may converge more quickly than that over a finite range!
54The default numeric precision is 1e-7, i.e. the global default for
55numeric integration but you should experiment with this value to
56see if it is sufficient for example by studying the number of function
57calls that MINUIT needs to fit your function as function of the
58convolution precision.
59**/
60
61#include "RooFit.h"
62
63#include "Riostream.h"
64#include "Riostream.h"
65#include "TH2F.h"
66#include "RooNumConvPdf.h"
67#include "RooArgList.h"
68#include "RooRealVar.h"
69#include "RooFormulaVar.h"
70#include "RooCustomizer.h"
72#include "RooNumIntFactory.h"
73#include "RooGenContext.h"
74#include "RooConvGenContext.h"
75
76
77
78using namespace std;
79
81;
82
83
84
85////////////////////////////////////////////////////////////////////////////////
86
88 _init(kFALSE),
89 _conv(0)
90{
91}
92
93
94
95
96//_____________________________________________________________________________R
97RooNumConvPdf::RooNumConvPdf(const char *name, const char *title, RooRealVar& convVar, RooAbsPdf& inPdf, RooAbsPdf& resmodel) :
98 RooAbsPdf(name,title),
99 _init(kFALSE),
100 _conv(0),
101 _origVar("!origVar","Original Convolution variable",this,convVar),
102 _origPdf("!origPdf","Original Input PDF",this,inPdf),
103 _origModel("!origModel","Original Resolution model",this,resmodel)
104{
105 // Constructor of convolution operator PDF
106 //
107 // convVar : convolution variable (on which both pdf and resmodel should depend)
108 // pdf : input 'physics' pdf
109 // resmodel : input 'resultion' pdf
110 //
111 // output is pdf(x) (X) resmodel(x) = Int [ pdf(x') resmodel (x-x') ] dx'
112 //
113}
114
115
116
117////////////////////////////////////////////////////////////////////////////////
118/// Copy constructor
119
121 RooAbsPdf(other,name),
122 _init(kFALSE),
123 _origVar("!origVar",this,other._origVar),
124 _origPdf("!origPdf",this,other._origPdf),
125 _origModel("!origModel",this,other._origModel)
126{
127 // Make temporary clone of original convolution to preserve configuration information
128 // This information will be propagated to a newly create convolution in a subsequent
129 // call to initialize()
130 if (other._conv) {
131 _conv = new RooNumConvolution(*other._conv,Form("%s_CONV",name?name:GetName())) ;
132 } else {
133 _conv = 0 ;
134 }
135}
136
137
138
139////////////////////////////////////////////////////////////////////////////////
140/// Destructor
141
143{
144 if (_init) {
145 delete _conv ;
146 }
147}
148
149
150
151////////////////////////////////////////////////////////////////////////////////
152/// Calculate and return value of p.d.f
153
155{
156 if (!_init) initialize() ;
157
158 return _conv->evaluate() ;
159}
160
161
162
163////////////////////////////////////////////////////////////////////////////////
164/// One-time initialization of object
165
167{
168 // Save pointer to any prototype convolution object (only present if this object is made through
169 // a copy constructor)
170 RooNumConvolution* protoConv = _conv ;
171
172 // Optionally pass along configuration data from prototype object
173 _conv = new RooNumConvolution(Form("%s_CONV",GetName()),GetTitle(),var(),pdf(),model(),protoConv) ;
174
175 // Delete prototype object now
176 if (protoConv) {
177 delete protoConv ;
178 }
179
180 _init = kTRUE ;
181}
182
183
184
185////////////////////////////////////////////////////////////////////////////////
186/// Return appropriate generator context for this convolved p.d.f. If both pdf and resolution
187/// model support internal generation return and optimization convolution generation context
188/// that uses a smearing algorithm. Otherwise return a standard accept/reject sampling
189/// context on the convoluted shape.
190
192 const RooArgSet* auxProto, Bool_t verbose) const
193{
194 if (!_init) initialize() ;
195
196 // Check if physics PDF and resolution model can both directly generate the convolution variable
197 RooArgSet* modelDep = _conv->model().getObservables(&vars) ;
198 modelDep->remove(_conv->var(),kTRUE,kTRUE) ;
199 Int_t numAddDep = modelDep->getSize() ;
200 delete modelDep ;
201
203 Bool_t pdfCanDir = (((RooAbsPdf&)_conv->pdf()).getGenerator(_conv->var(),dummy) != 0 && \
205 Bool_t resCanDir = (((RooAbsPdf&)_conv->model()).getGenerator(_conv->var(),dummy) !=0 &&
207
208 if (numAddDep>0 || !pdfCanDir || !resCanDir) {
209 // Any resolution model with more dependents than the convolution variable
210 // or pdf or resmodel do not support direct generation
211 return new RooGenContext(*this,vars,prototype,auxProto,verbose) ;
212 }
213
214 // Any other resolution model: use specialized generator context
215 return new RooConvGenContext(*this,vars,prototype,auxProto,verbose) ;
216}
217
218
219
220////////////////////////////////////////////////////////////////////////////////
221/// Customized printing of arguments of a RooNumConvPdf to more intuitively reflect the contents of the
222/// product operator construction
223
224void RooNumConvPdf::printMetaArgs(ostream& os) const
225{
226 os << _origPdf.arg().GetName() << "(" << _origVar.arg().GetName() << ") (*) " << _origModel.arg().GetName() << "(" << _origVar.arg().GetName() << ") " ;
227}
static RooMathCoreReg dummy
int Int_t
Definition: RtypesCore.h:41
const Bool_t kFALSE
Definition: RtypesCore.h:88
bool Bool_t
Definition: RtypesCore.h:59
double Double_t
Definition: RtypesCore.h:55
const Bool_t kTRUE
Definition: RtypesCore.h:87
#define ClassImp(name)
Definition: Rtypes.h:365
char name[80]
Definition: TGX11.cxx:109
char * Form(const char *fmt,...)
RooArgSet * getObservables(const RooArgSet &set, Bool_t valueOnly=kTRUE) const
Return the observables of this pdf given a set of observables.
Definition: RooAbsArg.h:240
Int_t getSize() const
virtual Bool_t remove(const RooAbsArg &var, Bool_t silent=kFALSE, Bool_t matchByNameOnly=kFALSE)
Remove the specified argument from our list.
RooAbsGenContext is the abstract base class for generator contexts of RooAbsPdf objects.
virtual 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: RooAbsPdf.cxx:2431
virtual Bool_t isDirectGenSafe(const RooAbsArg &arg) const
Check if given observable can be safely generated using the pdfs internal generator mechanism (if tha...
Definition: RooAbsPdf.cxx:2466
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:28
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:31
Class RooGenContext implement a universal generator context for all RooAbsPdf classes that do not hav...
Definition: RooGenContext.h:30
Numeric 1-dimensional convolution operator PDF.
Definition: RooNumConvPdf.h:26
friend class RooConvGenContext
Definition: RooNumConvPdf.h:76
virtual ~RooNumConvPdf()
Destructor.
RooRealProxy _origPdf
Definition: RooNumConvPdf.h:70
RooNumConvolution * _conv
Definition: RooNumConvPdf.h:67
virtual RooAbsGenContext * genContext(const RooArgSet &vars, const RooDataSet *prototype=0, const RooArgSet *auxProto=0, Bool_t verbose=kFALSE) const
Return appropriate generator context for this convolved p.d.f.
RooRealProxy _origModel
Definition: RooNumConvPdf.h:71
RooRealVar & var() const
Definition: RooNumConvPdf.h:52
RooRealProxy _origVar
Actual convolution calculation.
Definition: RooNumConvPdf.h:69
RooAbsReal & pdf() const
Definition: RooNumConvPdf.h:53
virtual Double_t evaluate() const
Calculate and return value of p.d.f.
RooAbsReal & model() const
Definition: RooNumConvPdf.h:54
void initialize() const
do not persist
void printMetaArgs(std::ostream &os) const
Customized printing of arguments of a RooNumConvPdf to more intuitively reflect the contents of the p...
Numeric 1-dimensional convolution operator PDF.
Double_t evaluate() const
Calculate convolution integral.
RooRealVar & var() const
RooAbsReal & model() const
RooAbsReal & pdf() const
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:35
const T & arg() const
Return reference to object held in proxy.
virtual const char * GetTitle() const
Returns title of object.
Definition: TNamed.h:48
virtual const char * GetName() const
Returns name of object.
Definition: TNamed.h:47