]>
Commit | Line | Data |
---|---|---|
1 | /************************************************************************** | |
2 | * Copyright(c) 2001-2002, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
7 | * Permission to use, copy, modify and distribute this software and its * | |
8 | * documentation strictly for non-commercial purposes is hereby granted * | |
9 | * without fee, provided that the above copyright notice appears in all * | |
10 | * copies and that both the copyright notice and this permission notice * | |
11 | * appear in the supporting documentation. The authors make no claims * | |
12 | * about the suitability of this software for any purpose. It is * | |
13 | * provided "as is" without express or implied warranty. * | |
14 | **************************************************************************/ | |
15 | ||
16 | /* $Id$ */ | |
17 | ||
18 | //////////////////////////////////////////////////////////////////////// | |
19 | // Class used to generate correlated gaussian numbers with mean | |
20 | // zero and known covariance matrix. | |
21 | // Adapted from the Fortran code in Cernlib V122 (corset, corgen) | |
22 | // F. James, Monte Carlo theory and practice, | |
23 | // Rep. Prog. Phys. 43 (1980) 1145-1189. | |
24 | // M.Masera 15.03.2001 9:30 - modified on 26.02.2002 17:40 | |
25 | //////////////////////////////////////////////////////////////////////// | |
26 | ||
27 | #include <Riostream.h> | |
28 | #include <TArrayD.h> | |
29 | #include <TMath.h> | |
30 | #include <TRandom.h> | |
31 | ||
32 | #include "AliGausCorr.h" | |
33 | ||
34 | ClassImp(AliGausCorr) | |
35 | ||
36 | //_______________________________________________________________________ | |
37 | AliGausCorr::AliGausCorr(): | |
38 | fSize(0), | |
39 | fCv(0) | |
40 | { | |
41 | // | |
42 | // Default constructor | |
43 | // | |
44 | } | |
45 | ||
46 | //_______________________________________________________________________ | |
47 | AliGausCorr::AliGausCorr(const TMatrixD & vec, Int_t size): | |
48 | fSize(size), | |
49 | fCv(new TMatrixD(fSize,fSize)) | |
50 | { | |
51 | // | |
52 | // Standard constructor | |
53 | // | |
54 | for(Int_t j=0;j<fSize;j++){ | |
55 | double accum = 0; | |
56 | for(Int_t k=0;k<j;k++){ | |
57 | accum += (*fCv)(j,k)* (*fCv)(j,k); | |
58 | } | |
59 | (*fCv)(j,j)=TMath::Sqrt(TMath::Abs(vec(j,j)-accum)); | |
60 | for(Int_t i=j+1;i<fSize;i++){ | |
61 | accum = 0; | |
62 | for(Int_t k=0;k<j;k++){ | |
63 | accum+=(*fCv)(i,k)* (*fCv)(j,k); | |
64 | } | |
65 | (*fCv)(i,j) = (vec(i,j)-accum) / (*fCv)(j,j); | |
66 | } | |
67 | } | |
68 | } | |
69 | ||
70 | //_______________________________________________________________________ | |
71 | AliGausCorr::AliGausCorr(const AliGausCorr & tgcorr): | |
72 | TObject(tgcorr), | |
73 | fSize(tgcorr.fSize), | |
74 | fCv(new TMatrixD(fSize,fSize)) | |
75 | { | |
76 | // | |
77 | // Copy contructor | |
78 | // | |
79 | for(Int_t i=0;i<fSize;i++){ | |
80 | for(Int_t j=0;j<fSize;j++)(*fCv)(i,j)=(*tgcorr.fCv)(i,j); | |
81 | } | |
82 | } | |
83 | ||
84 | //_______________________________________________________________________ | |
85 | AliGausCorr::~AliGausCorr() | |
86 | { | |
87 | // Destructor | |
88 | delete fCv; | |
89 | } | |
90 | ||
91 | //_______________________________________________________________________ | |
92 | void AliGausCorr::GetGaussN(TArrayD &vec) const | |
93 | { | |
94 | // return fSize correlated gaussian numbers | |
95 | ||
96 | TArrayD tmpv(fSize); | |
97 | ||
98 | for(Int_t i=0; i<fSize; i++){ | |
99 | Double_t x, y, z; | |
100 | do { | |
101 | y = gRandom->Rndm(); | |
102 | } while (!y); | |
103 | z = gRandom->Rndm(); | |
104 | x = z * 6.283185; | |
105 | tmpv[i] = TMath::Sin(x)*TMath::Sqrt(-2*TMath::Log(y)); | |
106 | } | |
107 | ||
108 | for(Int_t i=0;i<fSize;i++){ | |
109 | vec[i]=0; | |
110 | for(Int_t j=0;j<=i;j++)vec[i] += (*fCv)(i,j)* tmpv[j]; | |
111 | } | |
112 | ||
113 | } | |
114 | ||
115 | //_______________________________________________________________________ | |
116 | void AliGausCorr::PrintCv() const | |
117 | { | |
118 | // Printout of the "square root" cov. matrix | |
119 | printf("\n AliGausCorr - triangular matrix \n"); | |
120 | for(Int_t i=0; i<fSize;i++){ | |
121 | for(Int_t j=0;j<(fSize-1);j++){ | |
122 | if(j==0){ | |
123 | printf("| %12.4f ",(*fCv)(i,j)); | |
124 | } | |
125 | else { | |
126 | printf(" %12.4f ",(*fCv)(i,j)); | |
127 | } | |
128 | } | |
129 | printf(" %12.4f | \n",(*fCv)(i,fSize-1)); | |
130 | } | |
131 | printf("\n"); | |
132 | } | |
133 | ||
134 | //_______________________________________________________________________ | |
135 | AliGausCorr & AliGausCorr::operator=(const AliGausCorr & tgcorr) | |
136 | { | |
137 | // Assignment operator | |
138 | if(&tgcorr != this && tgcorr.fSize!=fSize){ | |
139 | if(fCv)delete fCv; | |
140 | fSize = tgcorr.fSize; | |
141 | fCv = new TMatrixD(fSize,fSize); | |
142 | } | |
143 | if(&tgcorr != this){ | |
144 | for(Int_t i=0;i<fSize;i++){ | |
145 | for(Int_t j=0;j<fSize;j++)(*fCv)(i,j)=(*tgcorr.fCv)(i,j); | |
146 | } | |
147 | } | |
148 | ||
149 | return *this; | |
150 | } |