New dsigma/dpt parameterisation for J/Psi and Upsilon based on scaled CDF data provid...
[u/mrichter/AliRoot.git] / STEER / AliLegoGenerator.cxx
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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
acd84897 16/* $Id$ */
8918e700 17
116cbefd 18//------------------------------------------------------------------------
116cbefd 19// Generic Lego generator code
5d8718b8 20// Uses geantino rays to check the material distributions and detector's
21// geometry
22// Author: A.Morsch
116cbefd 23//------------------------------------------------------------------------
24
8918e700 25#include "AliLegoGenerator.h"
26#include "AliRun.h"
5d12ce38 27#include "AliMC.h"
8918e700 28
29ClassImp(AliLegoGenerator)
30
e2afb3b6 31//_______________________________________________________________________
32AliLegoGenerator::AliLegoGenerator():
33 fRadMin(0),
34 fRadMax(0),
35 fZMax(0),
36 fNCoor1(0),
37 fNCoor2(0),
38 fCoor1Min(0),
39 fCoor1Max(0),
40 fCoor2Min(0),
41 fCoor2Max(0),
42 fCoor1Bin(-1),
43 fCoor2Bin(-1),
44 fCurCoor1(0),
45 fCurCoor2(0)
34915916 46{
47 //
48 // Default Constructor
49 //
50 SetName("Lego");
34915916 51}
52
e2afb3b6 53//_______________________________________________________________________
34915916 54AliLegoGenerator::AliLegoGenerator(Int_t nc1, Float_t c1min,
e2afb3b6 55 Float_t c1max, Int_t nc2,
56 Float_t c2min, Float_t c2max,
57 Float_t rmin, Float_t rmax, Float_t zmax):
58 AliGenerator(0),
59 fRadMin(rmin),
60 fRadMax(rmax),
61 fZMax(zmax),
62 fNCoor1(nc1),
63 fNCoor2(nc2),
64 fCoor1Min(0),
65 fCoor1Max(0),
66 fCoor2Min(0),
67 fCoor2Max(0),
68 fCoor1Bin(nc1),
69 fCoor2Bin(-1),
70 fCurCoor1(0),
71 fCurCoor2(0)
8918e700 72{
ef42d733 73 //
74 // Standard generator for Lego rays
75 //
e2afb3b6 76 SetName("Lego");
34915916 77 SetCoor1Range(nc1, c1min, c1max);
78 SetCoor2Range(nc2, c2min, c2max);
8918e700 79}
80
e2afb3b6 81//_______________________________________________________________________
8918e700 82void AliLegoGenerator::Generate()
83{
e2afb3b6 84 // Create a geantino with kinematics corresponding to the current bins
85 // Here: Coor1 = theta
86 // Coor2 = phi.
87
8918e700 88 //
89 // Rootinos are 0
90 const Int_t kMpart = 0;
91 Float_t orig[3], pmom[3];
92 Float_t t, cost, sint, cosp, sinp;
34915916 93 if (fCoor1Bin==-1) fCoor1Bin=fNCoor1;
8918e700 94 // Prepare for next step
34915916 95 if(fCoor1Bin>=fNCoor1-1)
96 if(fCoor2Bin>=fNCoor2-1) {
8918e700 97 Warning("Generate","End of Lego Generation");
98 return;
99 } else {
34915916 100 fCoor2Bin++;
101 printf("Generating rays in phi bin:%d\n",fCoor2Bin);
102 fCoor1Bin=0;
103 } else fCoor1Bin++;
104
105 fCurCoor1 = (fCoor1Min+(fCoor1Bin+0.5)*(fCoor1Max-fCoor1Min)/fNCoor1);
106 fCurCoor2 = (fCoor2Min+(fCoor2Bin+0.5)*(fCoor2Max-fCoor2Min)/fNCoor2);
107 cost = TMath::Cos(fCurCoor1 * TMath::Pi()/180.);
108 sint = TMath::Sin(fCurCoor1 * TMath::Pi()/180.);
109 cosp = TMath::Cos(fCurCoor2 * TMath::Pi()/180.);
110 sinp = TMath::Sin(fCurCoor2 * TMath::Pi()/180.);
8918e700 111
112 pmom[0] = cosp*sint;
113 pmom[1] = sinp*sint;
114 pmom[2] = cost;
115
116 // --- Where to start
117 orig[0] = orig[1] = orig[2] = 0;
118 Float_t dalicz = 3000;
119 if (fRadMin > 0) {
34915916 120 t = PropagateCylinder(orig,pmom,fRadMin,dalicz);
121 orig[0] = pmom[0]*t;
122 orig[1] = pmom[1]*t;
123 orig[2] = pmom[2]*t;
124 if (TMath::Abs(orig[2]) > fZMax) return;
8918e700 125 }
126
127 Float_t polar[3]={0.,0.,0.};
128 Int_t ntr;
5d12ce38 129 gAlice->GetMCApp()->PushTrack(1, -1, kMpart, pmom, orig, polar, 0, kPPrimary, ntr);
34915916 130
8918e700 131}
132
e2afb3b6 133//_______________________________________________________________________
134Float_t AliLegoGenerator::PropagateCylinder(Float_t *x, Float_t *v, Float_t r,
135 Float_t z)
8918e700 136{
e2afb3b6 137 //
138 // Propagate to cylinder from inside
139 //
8918e700 140 Double_t hnorm, sz, t, t1, t2, t3, sr;
141 Double_t d[3];
142 const Float_t kSmall = 1e-8;
143 const Float_t kSmall2 = kSmall*kSmall;
144
145// ---> Find intesection with Z planes
146 d[0] = v[0];
147 d[1] = v[1];
148 d[2] = v[2];
149 hnorm = TMath::Sqrt(1/(d[0]*d[0]+d[1]*d[1]+d[2]*d[2]));
150 d[0] *= hnorm;
151 d[1] *= hnorm;
152 d[2] *= hnorm;
153 if (d[2] > kSmall) sz = (z-x[2])/d[2];
154 else if (d[2] < -kSmall) sz = -(z+x[2])/d[2];
155 else sz = 1.e10; // ---> Direction parallel to X-Y, no intersection
156
157// ---> Intersection with cylinders
158// Intersection point (x,y,z)
159// (x,y,z) is on track : x=X(1)+t*D(1)
160// y=X(2)+t*D(2)
161// z=X(3)+t*D(3)
162// (x,y,z) is on cylinder : x**2 + y**2 = R**2
163//
164// (D(1)**2+D(2)**2)*t**2
165// +2.*(X(1)*D(1)+X(2)*D(2))*t
166// +X(1)**2+X(2)**2-R**2=0
167// ---> Solve second degree equation
168 t1 = d[0]*d[0] + d[1]*d[1];
169 if (t1 <= kSmall2) {
170 t = sz; // ---> Track parallel to the z-axis, take distance to planes
171 } else {
172 t2 = x[0]*d[0] + x[1]*d[1];
173 t3 = x[0]*x[0] + x[1]*x[1];
174 // ---> It should be positive, but there may be numerical problems
34915916 175 sr = (-t2 +TMath::Sqrt(TMath::Max(t2*t2-(t3-r*r)*t1,0.)))/t1;
8918e700 176 // ---> Find minimum distance between planes and cylinder
177 t = TMath::Min(sz,sr);
178 }
179 return t;
180}
181
34915916 182