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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 <TRandom.h> | |
30 | ||
31 | #include "AliGausCorr.h" | |
32 | ||
33 | ClassImp(AliGausCorr) | |
34 | ||
35 | //_______________________________________________________________________ | |
36 | AliGausCorr::AliGausCorr(): | |
37 | fSize(0), | |
38 | fCv(0) | |
39 | { | |
40 | // | |
41 | // Default constructor | |
42 | // | |
43 | } | |
44 | ||
45 | //_______________________________________________________________________ | |
46 | AliGausCorr::AliGausCorr(const TMatrixD & vec, Int_t size): | |
47 | fSize(size), | |
48 | fCv(new TMatrixD(fSize,fSize)) | |
49 | { | |
50 | // | |
51 | // Standard constructor | |
52 | // | |
53 | for(Int_t j=0;j<fSize;j++){ | |
54 | double accum = 0; | |
55 | for(Int_t k=0;k<j;k++){ | |
56 | accum += (*fCv)(j,k)* (*fCv)(j,k); | |
57 | } | |
58 | (*fCv)(j,j)=TMath::Sqrt(TMath::Abs(vec(j,j)-accum)); | |
59 | for(Int_t i=j+1;i<fSize;i++){ | |
60 | accum = 0; | |
61 | for(Int_t k=0;k<j;k++){ | |
62 | accum+=(*fCv)(i,k)* (*fCv)(j,k); | |
63 | } | |
64 | (*fCv)(i,j) = (vec(i,j)-accum) / (*fCv)(j,j); | |
65 | } | |
66 | } | |
67 | } | |
68 | ||
69 | //_______________________________________________________________________ | |
70 | AliGausCorr::AliGausCorr(const AliGausCorr & tgcorr): | |
71 | TObject(tgcorr), | |
72 | fSize(tgcorr.fSize), | |
73 | fCv(new TMatrixD(fSize,fSize)) | |
74 | { | |
75 | // | |
76 | // Copy contructor | |
77 | // | |
78 | for(Int_t i=0;i<fSize;i++){ | |
79 | for(Int_t j=0;j<fSize;j++)(*fCv)(i,j)=(*tgcorr.fCv)(i,j); | |
80 | } | |
81 | } | |
82 | ||
83 | //_______________________________________________________________________ | |
84 | AliGausCorr::~AliGausCorr() | |
85 | { | |
86 | // Destructor | |
87 | delete fCv; | |
88 | } | |
89 | ||
90 | //_______________________________________________________________________ | |
91 | void AliGausCorr::GetGaussN(TArrayD &vec) const | |
92 | { | |
93 | // return fSize correlated gaussian numbers | |
94 | ||
95 | TArrayD tmpv(fSize); | |
96 | ||
97 | for(Int_t i=0; i<fSize; i++){ | |
98 | Double_t x, y, z; | |
99 | do { | |
100 | y = gRandom->Rndm(); | |
101 | } while (!y); | |
102 | z = gRandom->Rndm(); | |
103 | x = z * 6.283185; | |
104 | tmpv[i] = TMath::Sin(x)*TMath::Sqrt(-2*TMath::Log(y)); | |
105 | } | |
106 | ||
107 | for(Int_t i=0;i<fSize;i++){ | |
108 | vec[i]=0; | |
109 | for(Int_t j=0;j<=i;j++)vec[i] += (*fCv)(i,j)* tmpv[j]; | |
110 | } | |
111 | ||
112 | } | |
113 | ||
114 | //_______________________________________________________________________ | |
115 | void AliGausCorr::PrintCv() const | |
116 | { | |
117 | // Printout of the "square root" cov. matrix | |
118 | printf("\n AliGausCorr - triangular matrix \n"); | |
119 | for(Int_t i=0; i<fSize;i++){ | |
120 | for(Int_t j=0;j<(fSize-1);j++){ | |
121 | if(j==0){ | |
122 | printf("| %12.4f ",(*fCv)(i,j)); | |
123 | } | |
124 | else { | |
125 | printf(" %12.4f ",(*fCv)(i,j)); | |
126 | } | |
127 | } | |
128 | printf(" %12.4f | \n",(*fCv)(i,fSize-1)); | |
129 | } | |
130 | printf("\n"); | |
131 | } | |
132 | ||
133 | //_______________________________________________________________________ | |
134 | AliGausCorr & AliGausCorr::operator=(const AliGausCorr & tgcorr) | |
135 | { | |
136 | if(&tgcorr != this && tgcorr.fSize!=fSize){ | |
137 | if(fCv)delete fCv; | |
138 | fSize = tgcorr.fSize; | |
139 | fCv = new TMatrixD(fSize,fSize); | |
140 | } | |
141 | if(&tgcorr != this){ | |
142 | for(Int_t i=0;i<fSize;i++){ | |
143 | for(Int_t j=0;j<fSize;j++)(*fCv)(i,j)=(*tgcorr.fCv)(i,j); | |
144 | } | |
145 | } | |
146 | ||
147 | return *this; | |
148 | } |