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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 | ||
fb17acd4 | 16 | /* $Header$ */ |
8918e700 | 17 | |
18 | #include "AliLegoGenerator.h" | |
19 | #include "AliRun.h" | |
20 | ||
21 | ClassImp(AliLegoGenerator) | |
22 | ||
e2afb3b6 | 23 | //_______________________________________________________________________ |
24 | AliLegoGenerator::AliLegoGenerator(): | |
25 | fRadMin(0), | |
26 | fRadMax(0), | |
27 | fZMax(0), | |
28 | fNCoor1(0), | |
29 | fNCoor2(0), | |
30 | fCoor1Min(0), | |
31 | fCoor1Max(0), | |
32 | fCoor2Min(0), | |
33 | fCoor2Max(0), | |
34 | fCoor1Bin(-1), | |
35 | fCoor2Bin(-1), | |
36 | fCurCoor1(0), | |
37 | fCurCoor2(0) | |
34915916 | 38 | { |
39 | // | |
40 | // Default Constructor | |
41 | // | |
42 | SetName("Lego"); | |
34915916 | 43 | } |
44 | ||
e2afb3b6 | 45 | //_______________________________________________________________________ |
34915916 | 46 | AliLegoGenerator::AliLegoGenerator(Int_t nc1, Float_t c1min, |
e2afb3b6 | 47 | Float_t c1max, Int_t nc2, |
48 | Float_t c2min, Float_t c2max, | |
49 | Float_t rmin, Float_t rmax, Float_t zmax): | |
50 | AliGenerator(0), | |
51 | fRadMin(rmin), | |
52 | fRadMax(rmax), | |
53 | fZMax(zmax), | |
54 | fNCoor1(nc1), | |
55 | fNCoor2(nc2), | |
56 | fCoor1Min(0), | |
57 | fCoor1Max(0), | |
58 | fCoor2Min(0), | |
59 | fCoor2Max(0), | |
60 | fCoor1Bin(nc1), | |
61 | fCoor2Bin(-1), | |
62 | fCurCoor1(0), | |
63 | fCurCoor2(0) | |
8918e700 | 64 | { |
ef42d733 | 65 | // |
66 | // Standard generator for Lego rays | |
67 | // | |
e2afb3b6 | 68 | SetName("Lego"); |
34915916 | 69 | SetCoor1Range(nc1, c1min, c1max); |
70 | SetCoor2Range(nc2, c2min, c2max); | |
8918e700 | 71 | } |
72 | ||
e2afb3b6 | 73 | //_______________________________________________________________________ |
8918e700 | 74 | void AliLegoGenerator::Generate() |
75 | { | |
e2afb3b6 | 76 | // Create a geantino with kinematics corresponding to the current bins |
77 | // Here: Coor1 = theta | |
78 | // Coor2 = phi. | |
79 | ||
8918e700 | 80 | // |
81 | // Rootinos are 0 | |
82 | const Int_t kMpart = 0; | |
83 | Float_t orig[3], pmom[3]; | |
84 | Float_t t, cost, sint, cosp, sinp; | |
34915916 | 85 | if (fCoor1Bin==-1) fCoor1Bin=fNCoor1; |
8918e700 | 86 | // Prepare for next step |
34915916 | 87 | if(fCoor1Bin>=fNCoor1-1) |
88 | if(fCoor2Bin>=fNCoor2-1) { | |
8918e700 | 89 | Warning("Generate","End of Lego Generation"); |
90 | return; | |
91 | } else { | |
34915916 | 92 | fCoor2Bin++; |
93 | printf("Generating rays in phi bin:%d\n",fCoor2Bin); | |
94 | fCoor1Bin=0; | |
95 | } else fCoor1Bin++; | |
96 | ||
97 | fCurCoor1 = (fCoor1Min+(fCoor1Bin+0.5)*(fCoor1Max-fCoor1Min)/fNCoor1); | |
98 | fCurCoor2 = (fCoor2Min+(fCoor2Bin+0.5)*(fCoor2Max-fCoor2Min)/fNCoor2); | |
99 | cost = TMath::Cos(fCurCoor1 * TMath::Pi()/180.); | |
100 | sint = TMath::Sin(fCurCoor1 * TMath::Pi()/180.); | |
101 | cosp = TMath::Cos(fCurCoor2 * TMath::Pi()/180.); | |
102 | sinp = TMath::Sin(fCurCoor2 * TMath::Pi()/180.); | |
8918e700 | 103 | |
104 | pmom[0] = cosp*sint; | |
105 | pmom[1] = sinp*sint; | |
106 | pmom[2] = cost; | |
107 | ||
108 | // --- Where to start | |
109 | orig[0] = orig[1] = orig[2] = 0; | |
110 | Float_t dalicz = 3000; | |
111 | if (fRadMin > 0) { | |
34915916 | 112 | t = PropagateCylinder(orig,pmom,fRadMin,dalicz); |
113 | orig[0] = pmom[0]*t; | |
114 | orig[1] = pmom[1]*t; | |
115 | orig[2] = pmom[2]*t; | |
116 | if (TMath::Abs(orig[2]) > fZMax) return; | |
8918e700 | 117 | } |
118 | ||
119 | Float_t polar[3]={0.,0.,0.}; | |
120 | Int_t ntr; | |
9e1a0ddb | 121 | gAlice->SetTrack(1, -1, kMpart, pmom, orig, polar, 0, kPPrimary, ntr); |
34915916 | 122 | |
8918e700 | 123 | } |
124 | ||
e2afb3b6 | 125 | //_______________________________________________________________________ |
126 | Float_t AliLegoGenerator::PropagateCylinder(Float_t *x, Float_t *v, Float_t r, | |
127 | Float_t z) | |
8918e700 | 128 | { |
e2afb3b6 | 129 | // |
130 | // Propagate to cylinder from inside | |
131 | // | |
8918e700 | 132 | Double_t hnorm, sz, t, t1, t2, t3, sr; |
133 | Double_t d[3]; | |
134 | const Float_t kSmall = 1e-8; | |
135 | const Float_t kSmall2 = kSmall*kSmall; | |
136 | ||
137 | // ---> Find intesection with Z planes | |
138 | d[0] = v[0]; | |
139 | d[1] = v[1]; | |
140 | d[2] = v[2]; | |
141 | hnorm = TMath::Sqrt(1/(d[0]*d[0]+d[1]*d[1]+d[2]*d[2])); | |
142 | d[0] *= hnorm; | |
143 | d[1] *= hnorm; | |
144 | d[2] *= hnorm; | |
145 | if (d[2] > kSmall) sz = (z-x[2])/d[2]; | |
146 | else if (d[2] < -kSmall) sz = -(z+x[2])/d[2]; | |
147 | else sz = 1.e10; // ---> Direction parallel to X-Y, no intersection | |
148 | ||
149 | // ---> Intersection with cylinders | |
150 | // Intersection point (x,y,z) | |
151 | // (x,y,z) is on track : x=X(1)+t*D(1) | |
152 | // y=X(2)+t*D(2) | |
153 | // z=X(3)+t*D(3) | |
154 | // (x,y,z) is on cylinder : x**2 + y**2 = R**2 | |
155 | // | |
156 | // (D(1)**2+D(2)**2)*t**2 | |
157 | // +2.*(X(1)*D(1)+X(2)*D(2))*t | |
158 | // +X(1)**2+X(2)**2-R**2=0 | |
159 | // ---> Solve second degree equation | |
160 | t1 = d[0]*d[0] + d[1]*d[1]; | |
161 | if (t1 <= kSmall2) { | |
162 | t = sz; // ---> Track parallel to the z-axis, take distance to planes | |
163 | } else { | |
164 | t2 = x[0]*d[0] + x[1]*d[1]; | |
165 | t3 = x[0]*x[0] + x[1]*x[1]; | |
166 | // ---> It should be positive, but there may be numerical problems | |
34915916 | 167 | sr = (-t2 +TMath::Sqrt(TMath::Max(t2*t2-(t3-r*r)*t1,0.)))/t1; |
8918e700 | 168 | // ---> Find minimum distance between planes and cylinder |
169 | t = TMath::Min(sz,sr); | |
170 | } | |
171 | return t; | |
172 | } | |
173 | ||
34915916 | 174 |