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a9e2aefa | 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 | /* | |
17 | $Log$ | |
18 | Revision 1.1.2.3 2000/06/09 21:03:09 morsch | |
19 | Make includes consistent with new file structure. | |
20 | ||
21 | Revision 1.1.2.2 2000/06/09 12:58:05 gosset | |
22 | Removed comment beginnings in Log sections of .cxx files | |
23 | Suppressed most violations of coding rules | |
24 | ||
25 | Revision 1.1.2.1 2000/06/07 14:44:53 gosset | |
26 | Addition of files for track reconstruction in C++ | |
27 | */ | |
28 | ||
29 | //__________________________________________________________________________ | |
30 | // | |
31 | // Track parameters in ALICE dimuon spectrometer | |
32 | //__________________________________________________________________________ | |
33 | ||
34 | #include <iostream.h> | |
35 | ||
36 | #include "AliCallf77.h" | |
37 | #include "AliMUON.h" | |
38 | #include "AliMUONHitForRec.h" | |
39 | #include "AliMUONSegment.h" | |
40 | #include "AliMUONTrackParam.h" | |
41 | #include "AliMUONChamber.h" | |
42 | #include "AliRun.h" | |
43 | ||
44 | ClassImp(AliMUONTrackParam) // Class implementation in ROOT context | |
45 | ||
46 | #ifndef WIN32 | |
47 | # define reco_ghelix reco_ghelix_ | |
48 | #else | |
49 | # define reco_ghelix RECO_GHELIX | |
50 | #endif | |
51 | ||
52 | extern "C" | |
53 | { | |
54 | void type_of_call reco_ghelix(Double_t &Charge, Double_t &StepLength, Double_t *VGeant3, Double_t *VGeant3New); | |
55 | } | |
56 | ||
57 | // Inline functions for Get and Set: inline removed because it does not work !!!! | |
58 | Double_t AliMUONTrackParam::GetInverseBendingMomentum(void) { | |
59 | // Get fInverseBendingMomentum | |
60 | return fInverseBendingMomentum;} | |
61 | void AliMUONTrackParam::SetInverseBendingMomentum(Double_t InverseBendingMomentum) { | |
62 | // Set fInverseBendingMomentum | |
63 | fInverseBendingMomentum = InverseBendingMomentum;} | |
64 | Double_t AliMUONTrackParam::GetBendingSlope(void) { | |
65 | // Get fBendingSlope | |
66 | return fBendingSlope;} | |
67 | void AliMUONTrackParam::SetBendingSlope(Double_t BendingSlope) { | |
68 | // Set fBendingSlope | |
69 | fBendingSlope = BendingSlope;} | |
70 | Double_t AliMUONTrackParam::GetNonBendingSlope(void) { | |
71 | // Get fNonBendingSlope | |
72 | return fNonBendingSlope;} | |
73 | void AliMUONTrackParam::SetNonBendingSlope(Double_t NonBendingSlope) { | |
74 | // Set fNonBendingSlope | |
75 | fNonBendingSlope = NonBendingSlope;} | |
76 | Double_t AliMUONTrackParam::GetZ(void) { | |
77 | // Get fZ | |
78 | return fZ;} | |
79 | void AliMUONTrackParam::SetZ(Double_t Z) { | |
80 | // Set fZ | |
81 | fZ = Z;} | |
82 | Double_t AliMUONTrackParam::GetBendingCoor(void) { | |
83 | // Get fBendingCoor | |
84 | return fBendingCoor;} | |
85 | void AliMUONTrackParam::SetBendingCoor(Double_t BendingCoor) { | |
86 | // Set fBendingCoor | |
87 | fBendingCoor = BendingCoor;} | |
88 | Double_t AliMUONTrackParam::GetNonBendingCoor(void) { | |
89 | // Get fNonBendingCoor | |
90 | return fNonBendingCoor;} | |
91 | void AliMUONTrackParam::SetNonBendingCoor(Double_t NonBendingCoor) { | |
92 | // Set fNonBendingCoor | |
93 | fNonBendingCoor = NonBendingCoor;} | |
94 | ||
95 | //__________________________________________________________________________ | |
96 | void AliMUONTrackParam::ExtrapToZ(Double_t Z) | |
97 | { | |
98 | // Track parameter extrapolation to the plane at "Z". | |
99 | // On return, the track parameters resulting from the extrapolation | |
100 | // replace the current track parameters. | |
101 | // Use "reco_ghelix" which should be replaced by something else !!!! | |
102 | if (this->fZ == Z) return; // nothing to be done if same Z | |
103 | Double_t forwardBackward; // +1 if forward, -1 if backward | |
104 | if (Z > this->fZ) forwardBackward = 1.0; | |
105 | else forwardBackward = -1.0; | |
106 | Double_t temp, vGeant3[7], vGeant3New[7]; // 7 in parameter ???? | |
107 | Int_t iGeant3, stepNumber; | |
108 | Int_t maxStepNumber = 5000; // in parameter ???? | |
109 | // For safety: return kTRUE or kFALSE ???? | |
110 | // Parameter vector for calling GHELIX in Geant3 | |
111 | SetGeant3Parameters(vGeant3, forwardBackward); | |
112 | // For use of reco_ghelix...: invert X and Y, PX/PTOT and PY/PTOT !!!! | |
113 | temp = vGeant3[0]; vGeant3[0] = vGeant3[1]; vGeant3[1] = temp; | |
114 | temp = vGeant3[3]; vGeant3[3] = vGeant3[4]; vGeant3[4] = temp; | |
115 | // charge must be changed with momentum for backward motion | |
116 | Double_t charge = | |
117 | forwardBackward * TMath::Sign(Double_t(1.0), this->fInverseBendingMomentum); | |
118 | Double_t stepLength = 6.0; // in parameter ???? | |
119 | // Extrapolation loop | |
120 | stepNumber = 0; | |
121 | while (((forwardBackward * (vGeant3[2] - Z)) <= 0.0) && | |
122 | (stepNumber < maxStepNumber)) { | |
123 | stepNumber++; | |
124 | // call Geant3 "ghelix" subroutine through a copy in "reco_muon.F": | |
125 | // the true function should be called, but how ???? and remove prototyping ... | |
126 | reco_ghelix(charge, stepLength, vGeant3, vGeant3New); | |
127 | if ((forwardBackward * (vGeant3New[2] - Z)) > 0.0) break; // one is beyond Z | |
128 | // better use TArray ???? | |
129 | for (iGeant3 = 0; iGeant3 < 7; iGeant3++) | |
130 | {vGeant3[iGeant3] = vGeant3New[iGeant3];} | |
131 | } | |
132 | // check maxStepNumber ???? | |
133 | // For use of reco_ghelix...: | |
134 | // invert back X and Y, PX/PTOT and PY/PTOT, both for vGeant3 and vGeant3New !!!! | |
135 | temp = vGeant3[0]; vGeant3[0] = vGeant3[1]; vGeant3[1] = temp; | |
136 | temp = vGeant3New[0]; vGeant3New[0] = vGeant3New[1]; vGeant3New[1] = temp; | |
137 | temp = vGeant3[3]; vGeant3[3] = vGeant3[4]; vGeant3[4] = temp; | |
138 | temp = vGeant3New[3]; vGeant3New[3] = vGeant3New[4]; vGeant3New[4] = temp; | |
139 | // Interpolation back to exact Z (2nd order) | |
140 | // should be in function ???? using TArray ???? | |
141 | Double_t dZ12 = vGeant3New[2] - vGeant3[2]; // 1->2 | |
142 | Double_t dZ1i = Z - vGeant3[2]; // 1-i | |
143 | Double_t dZi2 = vGeant3New[2] - Z; // i->2 | |
144 | Double_t xPrime = (vGeant3New[0] - vGeant3[0]) / dZ12; | |
145 | Double_t xSecond = | |
146 | ((vGeant3New[3] / vGeant3New[5]) - (vGeant3[3] / vGeant3[5])) / dZ12; | |
147 | Double_t yPrime = (vGeant3New[1] - vGeant3[1]) / dZ12; | |
148 | Double_t ySecond = | |
149 | ((vGeant3New[4] / vGeant3New[5]) - (vGeant3[4] / vGeant3[5])) / dZ12; | |
150 | vGeant3[0] = vGeant3[0] + xPrime * dZ1i - 0.5 * xSecond * dZ1i * dZi2; // X | |
151 | vGeant3[1] = vGeant3[1] + yPrime * dZ1i - 0.5 * ySecond * dZ1i * dZi2; // Y | |
152 | vGeant3[2] = Z; // Z | |
153 | Double_t xPrimeI = xPrime - 0.5 * xSecond * (dZi2 - dZ1i); | |
154 | Double_t yPrimeI = yPrime - 0.5 * ySecond * (dZi2 - dZ1i); | |
155 | vGeant3[5] = | |
156 | 1.0 / TMath::Sqrt(1.0 + xPrimeI * xPrimeI + yPrimeI * yPrimeI); // PZ/PTOT | |
157 | vGeant3[3] = xPrimeI * vGeant3[5]; // PX/PTOT | |
158 | vGeant3[4] = yPrimeI * vGeant3[5]; // PY/PTOT | |
159 | // Track parameters from Geant3 parameters | |
160 | GetFromGeant3Parameters(vGeant3, charge); | |
161 | } | |
162 | ||
163 | //__________________________________________________________________________ | |
164 | void AliMUONTrackParam::SetGeant3Parameters(Double_t *VGeant3, Double_t ForwardBackward) | |
165 | { | |
166 | // Set vector of Geant3 parameters pointed to by "VGeant3" | |
167 | // from track parameters in current AliMUONTrackParam. | |
168 | // Since AliMUONTrackParam is only geometry, one uses "ForwardBackward" | |
169 | // to know whether the particle is going forward (+1) or backward (-1). | |
170 | VGeant3[0] = this->fNonBendingCoor; // X | |
171 | VGeant3[1] = this->fBendingCoor; // Y | |
172 | VGeant3[2] = this->fZ; // Z | |
173 | Double_t pYZ = TMath::Abs(1.0 / this->fInverseBendingMomentum); | |
174 | Double_t pZ = | |
175 | pYZ / TMath::Sqrt(1.0 + this->fBendingSlope * this->fBendingSlope); | |
176 | VGeant3[6] = | |
177 | TMath::Sqrt(pYZ * pYZ + | |
178 | pZ * pZ * this->fNonBendingSlope * this->fNonBendingSlope); // PTOT | |
179 | VGeant3[5] = ForwardBackward * pZ / VGeant3[6]; // PZ/PTOT | |
180 | VGeant3[3] = this->fNonBendingSlope * VGeant3[5]; // PX/PTOT | |
181 | VGeant3[4] = this->fBendingSlope * VGeant3[5]; // PY/PTOT | |
182 | } | |
183 | ||
184 | //__________________________________________________________________________ | |
185 | void AliMUONTrackParam::GetFromGeant3Parameters(Double_t *VGeant3, Double_t Charge) | |
186 | { | |
187 | // Get track parameters in current AliMUONTrackParam | |
188 | // from Geant3 parameters pointed to by "VGeant3". | |
189 | // "InverseBendingMomentum" is signed with "Charge". | |
190 | this->fNonBendingCoor = VGeant3[0]; // X | |
191 | this->fBendingCoor = VGeant3[1]; // Y | |
192 | this->fZ = VGeant3[2]; // Z | |
193 | Double_t pYZ = VGeant3[6] * TMath::Sqrt(1.0 - VGeant3[3] * VGeant3[3]); | |
194 | this->fInverseBendingMomentum = Charge / pYZ; | |
195 | this->fBendingSlope = VGeant3[4] / VGeant3[5]; | |
196 | this->fNonBendingSlope = VGeant3[3] / VGeant3[5]; | |
197 | } | |
198 | ||
199 | //__________________________________________________________________________ | |
200 | void AliMUONTrackParam::ExtrapToStation(Int_t Station, AliMUONTrackParam *TrackParam) | |
201 | { | |
202 | // Track parameters extrapolated from current track parameters ("this") | |
203 | // to both chambers of the station(0..) "Station" | |
204 | // are returned in the array (dimension 2) of track parameters | |
205 | // pointed to by "TrackParam" (index 0 and 1 for first and second chambers). | |
206 | Double_t extZ[2], z1, z2; | |
207 | Int_t i1, i2; | |
208 | AliMUON *pMUON = (AliMUON*) gAlice->GetModule("MUON"); // necessary ???? | |
209 | // range of Station to be checked ???? | |
210 | z1 = (&(pMUON->Chamber(2 * Station)))->Z(); // Z of first chamber | |
211 | z2 = (&(pMUON->Chamber(2 * Station + 1)))->Z(); // Z of second chamber | |
212 | // First and second Z to extrapolate at | |
213 | if ((z1 > this->fZ) && (z2 > this->fZ)) {i1 = 0; i2 = 1;} | |
214 | else if ((z1 < this->fZ) && (z2 < this->fZ)) {i1 = 1; i2 = 0;} | |
215 | else { | |
216 | cout << "ERROR in AliMUONTrackParam::CreateExtrapSegmentInStation" << endl; | |
217 | cout << "Starting Z (" << this->fZ << ") in between z1 (" << z1 << | |
218 | ") and z2 (" << z2 << ") of station(0..) " << Station << endl; | |
219 | } | |
220 | extZ[i1] = z1; | |
221 | extZ[i2] = z2; | |
222 | // copy of track parameters | |
223 | TrackParam[i1] = *this; | |
224 | // first extrapolation | |
225 | (&(TrackParam[i1]))->ExtrapToZ(extZ[0]); | |
226 | TrackParam[i2] = TrackParam[i1]; | |
227 | // second extrapolation | |
228 | (&(TrackParam[i2]))->ExtrapToZ(extZ[1]); | |
229 | return; | |
230 | } | |
231 |