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RooRandom.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 *
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 /**
18 \file RooRandom.cxx
19 \class RooRandom
20 \ingroup Roofitcore
21 
22 This class provides a static interface for generating random numbers.
23 By default a private copy of TRandom3 is used to generate all random numbers.
24 **/
25 #include <cassert>
26 
27 #include "RooFit.h"
28 
29 #include "RooRandom.h"
30 #include "RooRandom.h"
32 
33 #include "TRandom3.h"
34 
35 using namespace std;
36 
38  ;
39 
40 
44 
45 ////////////////////////////////////////////////////////////////////////////////
46 
49 
50 ////////////////////////////////////////////////////////////////////////////////
51 /// Return a pointer to a singleton random-number generator
52 /// implementation. Creates the object the first time it is called.
53 
55 {
56  if (!_theGenerator) _theGenerator= new TRandom3();
57  return _theGenerator;
58 }
59 
60 
61 ////////////////////////////////////////////////////////////////////////////////
62 /// set the random number generator; takes ownership of the object passed as parameter
63 
65 {
66  if (_theGenerator) delete _theGenerator;
67  _theGenerator = gen;
68 }
69 
70 ////////////////////////////////////////////////////////////////////////////////
71 /// Return a pointer to a singleton quasi-random generator
72 /// implementation. Creates the object the first time it is called.
73 
75 {
76  if(!_theQuasiGenerator) _theQuasiGenerator= new RooQuasiRandomGenerator();
77  return _theQuasiGenerator;
78 }
79 
80 
81 ////////////////////////////////////////////////////////////////////////////////
82 /// Return a number uniformly distributed from (0,1)
83 
85 {
86  return generator->Rndm();
87 }
88 
89 
90 ////////////////////////////////////////////////////////////////////////////////
91 /// Fill the vector provided with random numbers uniformly distributed from (0,1)
92 
93 void RooRandom::uniform(UInt_t dimension, Double_t vector[], TRandom *generator)
94 {
95  generator->RndmArray(dimension, vector);
96 }
97 
98 
99 ////////////////////////////////////////////////////////////////////////////////
100 /// Return an integer uniformly distributed from [0,n-1]
101 
103 {
104  return generator->Integer(n);
105 }
106 
107 
108 ////////////////////////////////////////////////////////////////////////////////
109 /// Return a Gaussian random variable with mean 0 and variance 1.
110 
112 {
113  return generator->Gaus();
114 }
115 
116 
117 ////////////////////////////////////////////////////////////////////////////////
118 /// Return a quasi-random number in the range (0,1) using the
119 /// Niederreiter base 2 generator described in Bratley, Fox, Niederreiter,
120 /// ACM Trans. Model. Comp. Sim. 2, 195 (1992).
121 
123 {
124  return generator->generate(dimension,vector);
125 }
Random number generator class based on M.
Definition: TRandom3.h:27
static Double_t gaussian(TRandom *generator=randomGenerator())
Return a Gaussian random variable with mean 0 and variance 1.
Definition: RooRandom.cxx:111
virtual Double_t Gaus(Double_t mean=0, Double_t sigma=1)
Samples a random number from the standard Normal (Gaussian) Distribution with the given mean and sigm...
Definition: TRandom.cxx:235
virtual void RndmArray(Int_t n, Float_t *array)
Return an array of n random numbers uniformly distributed in ]0,1].
Definition: TRandom.cxx:548
static UInt_t integer(UInt_t max, TRandom *generator=randomGenerator())
Return an integer uniformly distributed from [0,n-1].
Definition: RooRandom.cxx:102
bool Bool_t
Definition: RtypesCore.h:59
static Bool_t quasi(UInt_t dimension, Double_t vector[], RooQuasiRandomGenerator *generator=quasiGenerator())
Return a quasi-random number in the range (0,1) using the Niederreiter base 2 generator described in ...
Definition: RooRandom.cxx:122
STL namespace.
This is the base class for the ROOT Random number generators.
Definition: TRandom.h:27
virtual UInt_t Integer(UInt_t imax)
Returns a random integer on [ 0, imax-1 ].
Definition: TRandom.cxx:320
Bool_t generate(UInt_t dimension, Double_t vector[])
Generate the next number in the sequence for the specified dimension.
static TRandom * randomGenerator()
Return a pointer to a singleton random-number generator implementation.
Definition: RooRandom.cxx:54
static RooQuasiRandomGenerator * quasiGenerator()
Return a pointer to a singleton quasi-random generator implementation.
Definition: RooRandom.cxx:74
static void setRandomGenerator(TRandom *gen)
set the random number generator; takes ownership of the object passed as parameter ...
Definition: RooRandom.cxx:64
virtual Double_t Rndm()
Machine independent random number generator.
Definition: TRandom.cxx:512
This class provides a static interface for generating random numbers.
Definition: RooRandom.h:24
unsigned int UInt_t
Definition: RtypesCore.h:42
static struct Guard guard
Definition: RooRandom.h:48
static TRandom * _theGenerator
Definition: RooRandom.h:43
#define ClassImp(name)
Definition: Rtypes.h:336
static Double_t uniform(TRandom *generator=randomGenerator())
Return a number uniformly distributed from (0,1)
Definition: RooRandom.cxx:84
double Double_t
Definition: RtypesCore.h:55
static RooQuasiRandomGenerator * _theQuasiGenerator
Definition: RooRandom.h:44
This class generates the quasi-random (aka "low discrepancy") sequence for dimensions up to 12 using ...
const Int_t n
Definition: legend1.C:16