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edc97986 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-2003, 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 | **************************************************************************/ | |
090026bf | 15 | |
16 | /* $Id$ */ | |
17 | ||
edc97986 | 18 | /////////////////////////////////////////////////////////////////// |
19 | // // | |
20 | // A straight line is coded as a point (3 Double_t) and // | |
21 | // 3 direction cosines // | |
22 | // // | |
23 | /////////////////////////////////////////////////////////////////// | |
090026bf | 24 | |
edc97986 | 25 | #include <Riostream.h> |
26 | #include <TTree.h> | |
090026bf | 27 | #include <TMath.h> |
28 | ||
edc97986 | 29 | #include "AliStrLine.h" |
30 | ||
31 | ClassImp(AliStrLine) | |
32 | ||
33 | //________________________________________________________ | |
fe12e09c | 34 | AliStrLine::AliStrLine() : |
35 | TObject(), | |
36 | fTpar(0), | |
37 | fDebug(0) | |
38 | { | |
edc97986 | 39 | // Default constructor |
40 | for(Int_t i=0;i<3;i++) { | |
41 | fP0[i] = 0.; | |
42 | fCd[i] = 0.; | |
43 | } | |
edc97986 | 44 | } |
45 | ||
46 | //________________________________________________________ | |
fe12e09c | 47 | AliStrLine::AliStrLine(Double_t *point, Double_t *cd,Bool_t twopoints) : |
48 | TObject(), | |
49 | fTpar(0), | |
50 | fDebug(0) | |
51 | { | |
edc97986 | 52 | // Standard constructor |
24a0c65f | 53 | // if twopoints is true: point and cd are the 3D coordinates of |
54 | // two points defininig the straight line | |
55 | // if twopoint is false: point represents the 3D coordinates of a point | |
56 | // belonging to the straight line and cd is the | |
57 | // direction in space | |
58 | if(twopoints){ | |
59 | InitTwoPoints(point,cd); | |
60 | } | |
61 | else { | |
62 | InitDirection(point,cd); | |
63 | } | |
64 | } | |
65 | ||
2c9641ee | 66 | //________________________________________________________ |
67 | AliStrLine::AliStrLine(Float_t *pointf, Float_t *cdf,Bool_t twopoints) : | |
68 | TObject(), | |
69 | fTpar(0), | |
70 | fDebug(0) | |
71 | { | |
72 | // Standard constructor - with float arguments | |
73 | // if twopoints is true: point and cd are the 3D coordinates of | |
74 | // two points defininig the straight line | |
75 | // if twopoint is false: point represents the 3D coordinates of a point | |
76 | // belonging to the straight line and cd is the | |
77 | // direction in space | |
78 | Double_t point[3]; | |
79 | Double_t cd[3]; | |
80 | for(Int_t i=0;i<3;i++){ | |
81 | point[i] = pointf[i]; | |
82 | cd[i] = cdf[i]; | |
83 | } | |
84 | if(twopoints){ | |
85 | InitTwoPoints(point,cd); | |
86 | } | |
87 | else { | |
88 | InitDirection(point,cd); | |
89 | } | |
90 | } | |
24a0c65f | 91 | |
92 | //________________________________________________________ | |
93 | void AliStrLine::InitDirection(Double_t *point, Double_t *cd){ | |
94 | // Initialization from a point and a direction | |
edc97986 | 95 | Double_t norm = 0.; |
96 | for(Int_t i=0;i<3;i++)norm+=cd[i]*cd[i]; | |
97 | if(norm) { | |
98 | norm = TMath::Sqrt(norm); | |
99 | for(Int_t i=0;i<3;i++) cd[i]/=norm; | |
100 | } | |
101 | else { | |
102 | Error("AliStrLine","Null direction cosines!!!"); | |
103 | } | |
104 | SetP0(point); | |
105 | SetCd(cd); | |
106 | fTpar = 0.; | |
107 | SetDebug(); | |
108 | } | |
109 | ||
24a0c65f | 110 | //________________________________________________________ |
111 | void AliStrLine::InitTwoPoints(Double_t *pA, Double_t *pB){ | |
112 | // Initialization from the coordinates of two | |
113 | // points in the space | |
114 | Double_t cd[3]; | |
115 | for(Int_t i=0;i<3;i++)cd[i] = pB[i]-pA[i]; | |
116 | InitDirection(pA,cd); | |
117 | } | |
118 | ||
edc97986 | 119 | //________________________________________________________ |
120 | AliStrLine::~AliStrLine() { | |
121 | // destructor | |
122 | } | |
123 | ||
124 | //________________________________________________________ | |
125 | void AliStrLine::PrintStatus() const { | |
126 | // Print current status | |
127 | cout <<"=======================================================\n"; | |
128 | cout <<"Direction cosines: "; | |
129 | for(Int_t i=0;i<3;i++)cout <<fCd[i]<<"; "; | |
130 | cout <<endl; | |
131 | cout <<"Known point: "; | |
132 | for(Int_t i=0;i<3;i++)cout <<fP0[i]<<"; "; | |
133 | cout <<endl; | |
134 | cout <<"Current value for the parameter: "<<fTpar<<endl; | |
135 | cout <<" Debug flag: "<<fDebug<<endl; | |
136 | } | |
137 | ||
138 | //________________________________________________________ | |
139 | Int_t AliStrLine::IsParallelTo(AliStrLine *line) const { | |
140 | // returns 1 if lines are parallel, 0 if not paralel | |
141 | Double_t cd2[3]; | |
142 | line->GetCd(cd2); | |
143 | Double_t vecpx=fCd[1]*cd2[2]-fCd[2]*cd2[1]; | |
144 | if(vecpx!=0) return 0; | |
145 | Double_t vecpy=-fCd[0]*cd2[2]+fCd[2]*cd2[0]; | |
146 | if(vecpy!=0) return 0; | |
147 | Double_t vecpz=fCd[0]*cd2[1]-fCd[1]*cd2[0]; | |
148 | if(vecpz!=0) return 0; | |
149 | return 1; | |
150 | } | |
151 | //________________________________________________________ | |
152 | Int_t AliStrLine::Crossrphi(AliStrLine *line){ | |
153 | // Cross 2 lines in the X-Y plane | |
154 | Double_t p2[3]; | |
155 | Double_t cd2[3]; | |
156 | line->GetP0(p2); | |
157 | line->GetCd(cd2); | |
158 | Double_t a=fCd[0]; | |
159 | Double_t b=-cd2[0]; | |
160 | Double_t c=p2[0]-fP0[0]; | |
161 | Double_t d=fCd[1]; | |
162 | Double_t e=-cd2[1]; | |
163 | Double_t f=p2[1]-fP0[1]; | |
164 | Double_t deno = a*e-b*d; | |
165 | Int_t retcode = 0; | |
166 | if(deno != 0.) { | |
167 | fTpar = (c*e-b*f)/deno; | |
168 | } | |
169 | else { | |
170 | retcode = -1; | |
171 | } | |
172 | return retcode; | |
173 | } | |
174 | ||
175 | //________________________________________________________ | |
176 | Int_t AliStrLine::CrossPoints(AliStrLine *line, Double_t *point1, Double_t *point2){ | |
177 | // Looks for the crossing point estimated starting from the | |
178 | // DCA segment | |
179 | Double_t p2[3]; | |
180 | Double_t cd2[3]; | |
181 | line->GetP0(p2); | |
182 | line->GetCd(cd2); | |
183 | Int_t i; | |
184 | Double_t k1 = 0; | |
185 | for(i=0;i<3;i++)k1+=(fP0[i]-p2[i])*fCd[i]; | |
186 | Double_t k2 = 0; | |
187 | for(i=0;i<3;i++)k2+=(fP0[i]-p2[i])*cd2[i]; | |
188 | Double_t a11 = 0; | |
189 | for(i=0;i<3;i++)a11+=fCd[i]*cd2[i]; | |
190 | Double_t a22 = -a11; | |
191 | Double_t a21 = 0; | |
192 | for(i=0;i<3;i++)a21+=cd2[i]*cd2[i]; | |
193 | Double_t a12 = 0; | |
194 | for(i=0;i<3;i++)a12-=fCd[i]*fCd[i]; | |
195 | Double_t deno = a11*a22-a21*a12; | |
196 | if(deno == 0.) return -1; | |
197 | fTpar = (a11*k2-a21*k1) / deno; | |
198 | Double_t par2 = (k1*a22-k2*a12) / deno; | |
199 | line->SetPar(par2); | |
200 | GetCurrentPoint(point1); | |
201 | line->GetCurrentPoint(point2); | |
202 | return 0; | |
203 | } | |
204 | //________________________________________________________________ | |
205 | Int_t AliStrLine::Cross(AliStrLine *line, Double_t *point){ | |
206 | ||
207 | //Finds intersection between lines | |
208 | Double_t point1[3]; | |
209 | Double_t point2[3]; | |
210 | Int_t retcod=CrossPoints(line,point1,point2); | |
211 | if(retcod==0){ | |
212 | for(Int_t i=0;i<3;i++)point[i]=(point1[i]+point2[i])/2.; | |
213 | return 0; | |
214 | }else{ | |
215 | return -1; | |
216 | } | |
217 | } | |
218 | ||
219 | //___________________________________________________________ | |
2c9641ee | 220 | Double_t AliStrLine::GetDCA(AliStrLine *line) const{ |
edc97986 | 221 | //Returns the distance of closest approach between two lines |
222 | Double_t p2[3]; | |
223 | Double_t cd2[3]; | |
224 | line->GetP0(p2); | |
225 | line->GetCd(cd2); | |
226 | Int_t i; | |
227 | Int_t ispar=IsParallelTo(line); | |
228 | if(ispar){ | |
229 | Double_t dist1q=0,dist2=0,mod=0; | |
230 | for(i=0;i<3;i++){ | |
231 | dist1q+=(fP0[i]-p2[i])*(fP0[i]-p2[i]); | |
232 | dist2+=(fP0[i]-p2[i])*fCd[i]; | |
233 | mod+=fCd[i]*fCd[i]; | |
234 | } | |
235 | if(mod!=0){ | |
236 | dist2/=mod; | |
237 | return TMath::Sqrt(dist1q-dist2*dist2); | |
238 | }else{return -1;} | |
239 | }else{ | |
240 | Double_t perp[3]; | |
241 | perp[0]=fCd[1]*cd2[2]-fCd[2]*cd2[1]; | |
242 | perp[1]=-fCd[0]*cd2[2]+fCd[2]*cd2[0]; | |
243 | perp[2]=fCd[0]*cd2[1]-fCd[1]*cd2[0]; | |
244 | Double_t mod=0,dist=0; | |
245 | for(i=0;i<3;i++){ | |
246 | mod+=perp[i]*perp[i]; | |
247 | dist+=(fP0[i]-p2[i])*perp[i]; | |
248 | } | |
249 | mod=sqrt(mod); | |
250 | if(mod!=0){ | |
251 | dist/=mod; | |
252 | return TMath::Abs(dist); | |
253 | }else{return -1;} | |
254 | } | |
255 | } | |
256 | //________________________________________________________ | |
257 | void AliStrLine::GetCurrentPoint(Double_t *point) const { | |
258 | // Fills the array point with the current value on the line | |
259 | for(Int_t i=0;i<3;i++)point[i]=fP0[i]+fCd[i]*fTpar; | |
260 | } | |
2c9641ee | 261 | |
262 | //________________________________________________________ | |
263 | Double_t AliStrLine::GetDistFromPoint(Double_t *point) const { | |
264 | // computes distance from point | |
265 | AliStrLine tmp(point,(Double_t *)fCd,kFALSE); | |
266 | return this->GetDCA(&tmp); | |
267 | } |