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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 | ||
a0209ae4 | 36 | #include <TMath.h> |
37 | #include <TVector3.h> | |
51ad6848 | 38 | |
39 | #include "AliExternalTrackParam.h" | |
40 | #include "AliKalmanTrack.h" | |
41 | ||
42 | ClassImp(AliExternalTrackParam) | |
43 | ||
44 | ||
45 | //_____________________________________________________________________________ | |
90e48c0c | 46 | AliExternalTrackParam::AliExternalTrackParam() : |
47 | AliTrackParam(), | |
48 | fX(0), | |
49 | fAlpha(0) | |
51ad6848 | 50 | { |
90e48c0c | 51 | // |
52 | // default constructor | |
53 | // | |
51ad6848 | 54 | for (Int_t i = 0; i < 5; i++) fParam[i] = 0; |
55 | for (Int_t i = 0; i < 15; i++) fCovar[i] = 0; | |
56 | } | |
57 | ||
58 | //_____________________________________________________________________________ | |
59 | AliExternalTrackParam::AliExternalTrackParam(Double_t x, Double_t alpha, | |
60 | const Double_t param[5], | |
90e48c0c | 61 | const Double_t covar[15]) : |
62 | AliTrackParam(), | |
63 | fX(x), | |
64 | fAlpha(alpha) | |
51ad6848 | 65 | { |
90e48c0c | 66 | // |
67 | // create external track parameters from given arguments | |
68 | // | |
51ad6848 | 69 | for (Int_t i = 0; i < 5; i++) fParam[i] = param[i]; |
70 | for (Int_t i = 0; i < 15; i++) fCovar[i] = covar[i]; | |
71 | } | |
72 | ||
90e48c0c | 73 | //_____________________________________________________________________________ |
74 | AliExternalTrackParam::AliExternalTrackParam(const AliKalmanTrack& track) : | |
75 | fX(0), | |
76 | fAlpha(track.GetAlpha()) | |
51ad6848 | 77 | { |
78 | // | |
79 | // | |
80 | track.GetExternalParameters(fX,fParam); | |
81 | track.GetExternalCovariance(fCovar); | |
51ad6848 | 82 | } |
83 | ||
51ad6848 | 84 | //_____________________________________________________________________________ |
85 | const Double_t* AliExternalTrackParam::GetParameter() const | |
86 | { | |
87 | // get a pointer to the array of track parameters | |
88 | ||
89 | return fParam; | |
90 | } | |
91 | ||
92 | //_____________________________________________________________________________ | |
93 | const Double_t* AliExternalTrackParam::GetCovariance() const | |
94 | { | |
95 | // get a pointer to the array of the track parameter covariance matrix | |
96 | ||
97 | return fCovar; | |
98 | } | |
99 | ||
100 | //_____________________________________________________________________________ | |
101 | AliExternalTrackParam* AliExternalTrackParam::CreateExternalParam() const | |
102 | { | |
103 | // copy this instance | |
104 | ||
105 | return new AliExternalTrackParam(fX, fAlpha, fParam, fCovar); | |
106 | } | |
107 | ||
108 | //_____________________________________________________________________________ | |
109 | void AliExternalTrackParam::ResetCovariance(Double_t factor, | |
110 | Bool_t clearOffDiagonal) | |
111 | { | |
112 | // reset the covariance matrix ("forget" track history) | |
113 | ||
114 | Int_t k = 0; | |
115 | for (Int_t i = 0; i < 5; i++) { | |
116 | for (Int_t j = 0; j < i; j++) { // off diagonal elements | |
117 | if (clearOffDiagonal) { | |
118 | fCovar[k++] = 0; | |
119 | } else { | |
120 | fCovar[k++] *= factor; | |
121 | } | |
122 | } | |
123 | fCovar[k++] *= factor; // diagonal elements | |
124 | } | |
125 | } | |
126 | ||
127 | ||
128 | //_____________________________________________________________________________ | |
129 | Bool_t AliExternalTrackParam::PropagateTo(Double_t /*x*/, Double_t* /*length*/) | |
130 | { | |
131 | // Propagate the track parameters to the given x coordinate assuming vacuum. | |
132 | // If length is not NULL, the change of track length is added to it. | |
133 | // | |
134 | // NOT IMPLEMENTED for this class | |
135 | ||
136 | return kFALSE; | |
137 | } | |
138 | ||
139 | //_____________________________________________________________________________ | |
140 | Bool_t AliExternalTrackParam::RotateTo(Double_t /*alpha*/) | |
141 | { | |
142 | // Rotate the reference axis for the parametrisation to the given angle. | |
143 | // | |
144 | // NOT IMPLEMENTED for this class | |
145 | ||
146 | return kFALSE; | |
147 | } | |
148 | ||
149 | //_____________________________________________________________________________ | |
150 | Bool_t AliExternalTrackParam::CorrectForMaterial(Double_t /*dAngle*/, | |
151 | Double_t /*dPrel*/) | |
152 | { | |
153 | // Take into account material effects assuming: | |
154 | // dAngle2: mean multiple scattering angle in rad squared | |
155 | // dPrel : mean relative momentum gain (if > 0) or loss (if < 0) | |
156 | // | |
157 | // NOT IMPLEMENTED for this class | |
158 | ||
159 | return kFALSE; | |
160 | } | |
161 | ||
162 | //_____________________________________________________________________________ | |
163 | Bool_t AliExternalTrackParam::GetProlongationAt(Double_t /*x*/, | |
164 | Double_t& /*y*/, | |
165 | Double_t& /*z*/) const | |
166 | { | |
167 | // Get the local y and z coordinates at the given x value | |
168 | // | |
169 | // NOT IMPLEMENTED for this class | |
170 | ||
171 | return kFALSE; | |
172 | } | |
173 | ||
174 | //_____________________________________________________________________________ | |
175 | Double_t AliExternalTrackParam::GetXAtVertex(Double_t /*x*/, | |
176 | Double_t /*y*/) const | |
177 | { | |
178 | // Get the x coordinate at the given vertex (x,y) | |
179 | // | |
180 | // NOT IMPLEMENTED for this class | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
185 | ||
186 | //_____________________________________________________________________________ | |
187 | Double_t AliExternalTrackParam::GetPredictedChi2(const AliCluster* /*cluster*/) | |
188 | { | |
189 | // calculate the chi2 contribution of the given cluster | |
190 | // | |
191 | // NOT IMPLEMENTED for this class | |
192 | ||
193 | return -1; | |
194 | } | |
195 | ||
196 | //_____________________________________________________________________________ | |
197 | Bool_t AliExternalTrackParam::Update(const AliCluster* /*cluster*/) | |
198 | { | |
199 | // update the track parameters using the position and error | |
200 | // of the given cluster | |
201 | // | |
202 | // NOT IMPLEMENTED for this class | |
203 | ||
204 | return kFALSE; | |
205 | } | |
206 | ||
207 | ||
208 | //_____________________________________________________________________________ | |
209 | Double_t AliExternalTrackParam::SigmaPhi() const | |
210 | { | |
211 | // get the error of the azimuthal angle | |
212 | ||
213 | return TMath::Sqrt(TMath::Abs(fCovar[5] / (1. - fParam[2]*fParam[2]))); | |
214 | } | |
215 | ||
216 | //_____________________________________________________________________________ | |
217 | Double_t AliExternalTrackParam::SigmaTheta() const | |
218 | { | |
219 | // get the error of the polar angle | |
220 | ||
221 | return TMath::Sqrt(TMath::Abs(fCovar[9])) / (1. + fParam[3]*fParam[3]); | |
222 | } | |
223 | ||
224 | //_____________________________________________________________________________ | |
225 | Double_t AliExternalTrackParam::SigmaPt() const | |
226 | { | |
227 | // get the error of the transversal component of the momentum | |
228 | ||
229 | return TMath::Sqrt(fCovar[14]) / TMath::Abs(fParam[4]); | |
230 | } | |
231 | ||
232 | //_____________________________________________________________________________ | |
233 | TVector3 AliExternalTrackParam::Momentum() const | |
234 | { | |
235 | // get the momentum vector | |
236 | ||
237 | Double_t phi = TMath::ASin(fParam[2]) + fAlpha; | |
238 | Double_t pt = 1. / TMath::Abs(fParam[4]); | |
239 | return TVector3(pt * TMath::Cos(phi), | |
240 | pt * TMath::Sin(phi), | |
241 | pt * fParam[3]); | |
242 | } | |
243 | ||
244 | //_____________________________________________________________________________ | |
245 | TVector3 AliExternalTrackParam::Position() const | |
246 | { | |
247 | // get the current spatial position in global coordinates | |
248 | ||
249 | return TVector3(fX * TMath::Cos(fAlpha) - fParam[0] * TMath::Sin(fAlpha), | |
250 | fX * TMath::Sin(fAlpha) + fParam[0] * TMath::Cos(fAlpha), | |
251 | fParam[1]); | |
252 | } | |
253 | ||
254 | ||
255 | //_____________________________________________________________________________ | |
256 | void AliExternalTrackParam::Print(Option_t* /*option*/) const | |
257 | { | |
258 | // print the parameters and the covariance matrix | |
259 | ||
260 | printf("AliExternalTrackParam: x = %-12g alpha = %-12g\n", fX, fAlpha); | |
261 | printf(" parameters: %12g %12g %12g %12g %12g\n", | |
262 | fParam[0], fParam[1], fParam[2], fParam[3], fParam[4]); | |
263 | printf(" covariance: %12g\n", fCovar[0]); | |
264 | printf(" %12g %12g\n", fCovar[1], fCovar[2]); | |
265 | printf(" %12g %12g %12g\n", fCovar[3], fCovar[4], fCovar[5]); | |
266 | printf(" %12g %12g %12g %12g\n", | |
267 | fCovar[6], fCovar[7], fCovar[8], fCovar[9]); | |
268 | printf(" %12g %12g %12g %12g %12g\n", | |
269 | fCovar[10], fCovar[11], fCovar[12], fCovar[13], fCovar[14]); | |
270 | } |