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51ad6848 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, 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 | // // | |
20 | // track parameters in "external" format // | |
21 | // // | |
22 | // The track parameters are: // | |
23 | // - local y coordinate // | |
24 | // - local z coordinate // | |
25 | // - sin of azimutal angle // | |
26 | // - tan of dip angle // | |
27 | // - charge/pt // | |
28 | // The parametrisation is given at the local x coordinate fX and the // | |
29 | // azimuthal angle fAlpha. // | |
30 | // // | |
31 | // The external parametrisation can be used to exchange track parameters // | |
32 | // between different detectors. // | |
33 | // // | |
34 | /////////////////////////////////////////////////////////////////////////////// | |
35 | ||
36 | ||
37 | #include "AliExternalTrackParam.h" | |
38 | #include "AliKalmanTrack.h" | |
39 | ||
40 | ClassImp(AliExternalTrackParam) | |
41 | ||
42 | ||
43 | //_____________________________________________________________________________ | |
90e48c0c | 44 | AliExternalTrackParam::AliExternalTrackParam() : |
45 | AliTrackParam(), | |
46 | fX(0), | |
47 | fAlpha(0) | |
51ad6848 | 48 | { |
90e48c0c | 49 | // |
50 | // default constructor | |
51 | // | |
51ad6848 | 52 | for (Int_t i = 0; i < 5; i++) fParam[i] = 0; |
53 | for (Int_t i = 0; i < 15; i++) fCovar[i] = 0; | |
54 | } | |
55 | ||
56 | //_____________________________________________________________________________ | |
57 | AliExternalTrackParam::AliExternalTrackParam(Double_t x, Double_t alpha, | |
58 | const Double_t param[5], | |
90e48c0c | 59 | const Double_t covar[15]) : |
60 | AliTrackParam(), | |
61 | fX(x), | |
62 | fAlpha(alpha) | |
51ad6848 | 63 | { |
90e48c0c | 64 | // |
65 | // create external track parameters from given arguments | |
66 | // | |
51ad6848 | 67 | for (Int_t i = 0; i < 5; i++) fParam[i] = param[i]; |
68 | for (Int_t i = 0; i < 15; i++) fCovar[i] = covar[i]; | |
69 | } | |
70 | ||
90e48c0c | 71 | //_____________________________________________________________________________ |
72 | AliExternalTrackParam::AliExternalTrackParam(const AliKalmanTrack& track) : | |
73 | fX(0), | |
74 | fAlpha(track.GetAlpha()) | |
51ad6848 | 75 | { |
76 | // | |
77 | // | |
78 | track.GetExternalParameters(fX,fParam); | |
79 | track.GetExternalCovariance(fCovar); | |
51ad6848 | 80 | } |
81 | ||
51ad6848 | 82 | //_____________________________________________________________________________ |
83 | const Double_t* AliExternalTrackParam::GetParameter() const | |
84 | { | |
85 | // get a pointer to the array of track parameters | |
86 | ||
87 | return fParam; | |
88 | } | |
89 | ||
90 | //_____________________________________________________________________________ | |
91 | const Double_t* AliExternalTrackParam::GetCovariance() const | |
92 | { | |
93 | // get a pointer to the array of the track parameter covariance matrix | |
94 | ||
95 | return fCovar; | |
96 | } | |
97 | ||
98 | //_____________________________________________________________________________ | |
99 | AliExternalTrackParam* AliExternalTrackParam::CreateExternalParam() const | |
100 | { | |
101 | // copy this instance | |
102 | ||
103 | return new AliExternalTrackParam(fX, fAlpha, fParam, fCovar); | |
104 | } | |
105 | ||
106 | //_____________________________________________________________________________ | |
107 | void AliExternalTrackParam::ResetCovariance(Double_t factor, | |
108 | Bool_t clearOffDiagonal) | |
109 | { | |
110 | // reset the covariance matrix ("forget" track history) | |
111 | ||
112 | Int_t k = 0; | |
113 | for (Int_t i = 0; i < 5; i++) { | |
114 | for (Int_t j = 0; j < i; j++) { // off diagonal elements | |
115 | if (clearOffDiagonal) { | |
116 | fCovar[k++] = 0; | |
117 | } else { | |
118 | fCovar[k++] *= factor; | |
119 | } | |
120 | } | |
121 | fCovar[k++] *= factor; // diagonal elements | |
122 | } | |
123 | } | |
124 | ||
125 | ||
126 | //_____________________________________________________________________________ | |
127 | Bool_t AliExternalTrackParam::PropagateTo(Double_t /*x*/, Double_t* /*length*/) | |
128 | { | |
129 | // Propagate the track parameters to the given x coordinate assuming vacuum. | |
130 | // If length is not NULL, the change of track length is added to it. | |
131 | // | |
132 | // NOT IMPLEMENTED for this class | |
133 | ||
134 | return kFALSE; | |
135 | } | |
136 | ||
137 | //_____________________________________________________________________________ | |
138 | Bool_t AliExternalTrackParam::RotateTo(Double_t /*alpha*/) | |
139 | { | |
140 | // Rotate the reference axis for the parametrisation to the given angle. | |
141 | // | |
142 | // NOT IMPLEMENTED for this class | |
143 | ||
144 | return kFALSE; | |
145 | } | |
146 | ||
147 | //_____________________________________________________________________________ | |
148 | Bool_t AliExternalTrackParam::CorrectForMaterial(Double_t /*dAngle*/, | |
149 | Double_t /*dPrel*/) | |
150 | { | |
151 | // Take into account material effects assuming: | |
152 | // dAngle2: mean multiple scattering angle in rad squared | |
153 | // dPrel : mean relative momentum gain (if > 0) or loss (if < 0) | |
154 | // | |
155 | // NOT IMPLEMENTED for this class | |
156 | ||
157 | return kFALSE; | |
158 | } | |
159 | ||
160 | //_____________________________________________________________________________ | |
161 | Bool_t AliExternalTrackParam::GetProlongationAt(Double_t /*x*/, | |
162 | Double_t& /*y*/, | |
163 | Double_t& /*z*/) const | |
164 | { | |
165 | // Get the local y and z coordinates at the given x value | |
166 | // | |
167 | // NOT IMPLEMENTED for this class | |
168 | ||
169 | return kFALSE; | |
170 | } | |
171 | ||
172 | //_____________________________________________________________________________ | |
173 | Double_t AliExternalTrackParam::GetXAtVertex(Double_t /*x*/, | |
174 | Double_t /*y*/) const | |
175 | { | |
176 | // Get the x coordinate at the given vertex (x,y) | |
177 | // | |
178 | // NOT IMPLEMENTED for this class | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
183 | ||
184 | //_____________________________________________________________________________ | |
185 | Double_t AliExternalTrackParam::GetPredictedChi2(const AliCluster* /*cluster*/) | |
186 | { | |
187 | // calculate the chi2 contribution of the given cluster | |
188 | // | |
189 | // NOT IMPLEMENTED for this class | |
190 | ||
191 | return -1; | |
192 | } | |
193 | ||
194 | //_____________________________________________________________________________ | |
195 | Bool_t AliExternalTrackParam::Update(const AliCluster* /*cluster*/) | |
196 | { | |
197 | // update the track parameters using the position and error | |
198 | // of the given cluster | |
199 | // | |
200 | // NOT IMPLEMENTED for this class | |
201 | ||
202 | return kFALSE; | |
203 | } | |
204 | ||
205 | ||
206 | //_____________________________________________________________________________ | |
207 | Double_t AliExternalTrackParam::SigmaPhi() const | |
208 | { | |
209 | // get the error of the azimuthal angle | |
210 | ||
211 | return TMath::Sqrt(TMath::Abs(fCovar[5] / (1. - fParam[2]*fParam[2]))); | |
212 | } | |
213 | ||
214 | //_____________________________________________________________________________ | |
215 | Double_t AliExternalTrackParam::SigmaTheta() const | |
216 | { | |
217 | // get the error of the polar angle | |
218 | ||
219 | return TMath::Sqrt(TMath::Abs(fCovar[9])) / (1. + fParam[3]*fParam[3]); | |
220 | } | |
221 | ||
222 | //_____________________________________________________________________________ | |
223 | Double_t AliExternalTrackParam::SigmaPt() const | |
224 | { | |
225 | // get the error of the transversal component of the momentum | |
226 | ||
227 | return TMath::Sqrt(fCovar[14]) / TMath::Abs(fParam[4]); | |
228 | } | |
229 | ||
230 | //_____________________________________________________________________________ | |
231 | TVector3 AliExternalTrackParam::Momentum() const | |
232 | { | |
233 | // get the momentum vector | |
234 | ||
235 | Double_t phi = TMath::ASin(fParam[2]) + fAlpha; | |
236 | Double_t pt = 1. / TMath::Abs(fParam[4]); | |
237 | return TVector3(pt * TMath::Cos(phi), | |
238 | pt * TMath::Sin(phi), | |
239 | pt * fParam[3]); | |
240 | } | |
241 | ||
242 | //_____________________________________________________________________________ | |
243 | TVector3 AliExternalTrackParam::Position() const | |
244 | { | |
245 | // get the current spatial position in global coordinates | |
246 | ||
247 | return TVector3(fX * TMath::Cos(fAlpha) - fParam[0] * TMath::Sin(fAlpha), | |
248 | fX * TMath::Sin(fAlpha) + fParam[0] * TMath::Cos(fAlpha), | |
249 | fParam[1]); | |
250 | } | |
251 | ||
252 | ||
253 | //_____________________________________________________________________________ | |
254 | void AliExternalTrackParam::Print(Option_t* /*option*/) const | |
255 | { | |
256 | // print the parameters and the covariance matrix | |
257 | ||
258 | printf("AliExternalTrackParam: x = %-12g alpha = %-12g\n", fX, fAlpha); | |
259 | printf(" parameters: %12g %12g %12g %12g %12g\n", | |
260 | fParam[0], fParam[1], fParam[2], fParam[3], fParam[4]); | |
261 | printf(" covariance: %12g\n", fCovar[0]); | |
262 | printf(" %12g %12g\n", fCovar[1], fCovar[2]); | |
263 | printf(" %12g %12g %12g\n", fCovar[3], fCovar[4], fCovar[5]); | |
264 | printf(" %12g %12g %12g %12g\n", | |
265 | fCovar[6], fCovar[7], fCovar[8], fCovar[9]); | |
266 | printf(" %12g %12g %12g %12g %12g\n", | |
267 | fCovar[10], fCovar[11], fCovar[12], fCovar[13], fCovar[14]); | |
268 | } |