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8918e700 | 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 1.16 2000/05/26 08:35:03 fca | |
19 | Move the check on z after z has been retrieved | |
20 | ||
21 | Revision 1.15 2000/05/16 13:10:40 fca | |
22 | New method IsNewTrack and fix for a problem in Father-Daughter relations | |
23 | ||
24 | Revision 1.14 2000/04/27 10:38:21 fca | |
25 | Correct termination of Lego Run and introduce Lego getter in AliRun | |
26 | ||
27 | Revision 1.13 2000/04/26 10:17:31 fca | |
28 | Changes in Lego for G4 compatibility | |
29 | ||
30 | Revision 1.12 2000/04/07 11:12:33 fca | |
31 | G4 compatibility changes | |
32 | ||
33 | Revision 1.11 2000/03/22 13:42:26 fca | |
34 | SetGenerator does not replace an existing generator, ResetGenerator does | |
35 | ||
36 | Revision 1.10 2000/02/23 16:25:22 fca | |
37 | AliVMC and AliGeant3 classes introduced | |
38 | ReadEuclid moved from AliRun to AliModule | |
39 | ||
40 | Revision 1.9 1999/12/03 10:54:01 fca | |
41 | Fix lego summary | |
42 | ||
43 | Revision 1.8 1999/10/01 09:54:33 fca | |
44 | Correct logics for Lego StepManager | |
45 | ||
46 | Revision 1.7 1999/09/29 09:24:29 fca | |
47 | Introduction of the Copyright and cvs Log | |
48 | ||
49 | */ | |
50 | ||
51 | #include "AliLegoGenerator.h" | |
52 | #include "AliRun.h" | |
53 | ||
54 | ClassImp(AliLegoGenerator) | |
55 | ||
56 | //___________________________________________ | |
57 | AliLegoGenerator::AliLegoGenerator(Int_t ntheta, Float_t themin, | |
58 | Float_t themax, Int_t nphi, | |
59 | Float_t phimin, Float_t phimax, | |
60 | Float_t rmin, Float_t rmax, Float_t zmax) : | |
61 | AliGenerator(0), fRadMin(rmin), fRadMax(rmax), fZMax(zmax), fNtheta(ntheta), | |
62 | fNphi(nphi), fThetaBin(ntheta), fPhiBin(-1), fCurTheta(0), fCurPhi(0) | |
63 | ||
64 | { | |
65 | SetPhiRange(phimin,phimax); | |
66 | SetThetaRange(themin,themax); | |
67 | SetName("Lego"); | |
68 | } | |
69 | ||
70 | ||
71 | //___________________________________________ | |
72 | void AliLegoGenerator::Generate() | |
73 | { | |
74 | // Create a geantino with kinematics corresponding to the current | |
75 | // bins in theta and phi. | |
76 | ||
77 | // | |
78 | // Rootinos are 0 | |
79 | const Int_t kMpart = 0; | |
80 | Float_t orig[3], pmom[3]; | |
81 | Float_t t, cost, sint, cosp, sinp; | |
82 | ||
83 | // Prepare for next step | |
84 | if(fThetaBin>=fNtheta-1) | |
85 | if(fPhiBin>=fNphi-1) { | |
86 | Warning("Generate","End of Lego Generation"); | |
87 | return; | |
88 | } else { | |
89 | fPhiBin++; | |
90 | printf("Generating rays in phi bin:%d\n",fPhiBin); | |
91 | fThetaBin=0; | |
92 | } else fThetaBin++; | |
93 | ||
94 | fCurTheta = (fThetaMin+(fThetaBin+0.5)*(fThetaMax-fThetaMin)/fNtheta); | |
95 | fCurPhi = (fPhiMin+(fPhiBin+0.5)*(fPhiMax-fPhiMin)/fNphi); | |
96 | cost = TMath::Cos(fCurTheta); | |
97 | sint = TMath::Sin(fCurTheta); | |
98 | cosp = TMath::Cos(fCurPhi); | |
99 | sinp = TMath::Sin(fCurPhi); | |
100 | ||
101 | pmom[0] = cosp*sint; | |
102 | pmom[1] = sinp*sint; | |
103 | pmom[2] = cost; | |
104 | ||
105 | // --- Where to start | |
106 | orig[0] = orig[1] = orig[2] = 0; | |
107 | Float_t dalicz = 3000; | |
108 | if (fRadMin > 0) { | |
109 | t = PropagateCylinder(orig,pmom,fRadMin,dalicz); | |
110 | orig[0] = pmom[0]*t; | |
111 | orig[1] = pmom[1]*t; | |
112 | orig[2] = pmom[2]*t; | |
113 | if (TMath::Abs(orig[2]) > fZMax) return; | |
114 | } | |
115 | ||
116 | Float_t polar[3]={0.,0.,0.}; | |
117 | Int_t ntr; | |
118 | gAlice->SetTrack(1, 0, kMpart, pmom, orig, polar, 0, "LEGO ray", ntr); | |
119 | ||
120 | } | |
121 | ||
122 | //___________________________________________ | |
123 | Float_t AliLegoGenerator::PropagateCylinder(Float_t *x, Float_t *v, Float_t r, Float_t z) | |
124 | { | |
125 | // Propagate to cylinder from inside | |
126 | ||
127 | Double_t hnorm, sz, t, t1, t2, t3, sr; | |
128 | Double_t d[3]; | |
129 | const Float_t kSmall = 1e-8; | |
130 | const Float_t kSmall2 = kSmall*kSmall; | |
131 | ||
132 | // ---> Find intesection with Z planes | |
133 | d[0] = v[0]; | |
134 | d[1] = v[1]; | |
135 | d[2] = v[2]; | |
136 | hnorm = TMath::Sqrt(1/(d[0]*d[0]+d[1]*d[1]+d[2]*d[2])); | |
137 | d[0] *= hnorm; | |
138 | d[1] *= hnorm; | |
139 | d[2] *= hnorm; | |
140 | if (d[2] > kSmall) sz = (z-x[2])/d[2]; | |
141 | else if (d[2] < -kSmall) sz = -(z+x[2])/d[2]; | |
142 | else sz = 1.e10; // ---> Direction parallel to X-Y, no intersection | |
143 | ||
144 | // ---> Intersection with cylinders | |
145 | // Intersection point (x,y,z) | |
146 | // (x,y,z) is on track : x=X(1)+t*D(1) | |
147 | // y=X(2)+t*D(2) | |
148 | // z=X(3)+t*D(3) | |
149 | // (x,y,z) is on cylinder : x**2 + y**2 = R**2 | |
150 | // | |
151 | // (D(1)**2+D(2)**2)*t**2 | |
152 | // +2.*(X(1)*D(1)+X(2)*D(2))*t | |
153 | // +X(1)**2+X(2)**2-R**2=0 | |
154 | // ---> Solve second degree equation | |
155 | t1 = d[0]*d[0] + d[1]*d[1]; | |
156 | if (t1 <= kSmall2) { | |
157 | t = sz; // ---> Track parallel to the z-axis, take distance to planes | |
158 | } else { | |
159 | t2 = x[0]*d[0] + x[1]*d[1]; | |
160 | t3 = x[0]*x[0] + x[1]*x[1]; | |
161 | // ---> It should be positive, but there may be numerical problems | |
162 | sr = (t2 +TMath::Sqrt(TMath::Max(t2*t2-(t3-r*r)*t1,0.)))/t1; | |
163 | // ---> Find minimum distance between planes and cylinder | |
164 | t = TMath::Min(sz,sr); | |
165 | } | |
166 | return t; | |
167 | } | |
168 |