1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
19 // Generates n particles with in the same phi angle, varies theta
20 // in equidistant intervals
21 // This class is intended to use for studies of TPC response
22 // via merging with background event.
23 // Note that for a given theta pt and p are not independent
24 // Range for only one variable (pt or p) should be given.
25 // Based on the AliGenBox class written by andreas.morsch@cern.ch
27 // Comments and suggestions: Jiri.Chudoba@cern.ch
33 #include "AliGenThetaSlice.h"
36 ClassImp(AliGenThetaSlice)
38 //_____________________________________________________________________________
39 AliGenThetaSlice::AliGenThetaSlice()
44 // Default constructor
48 //_____________________________________________________________________________
49 AliGenThetaSlice::AliGenThetaSlice(Int_t npart)
54 // Standard constructor
57 fTitle = "Particle generator - const. phi, slices in theta";
60 //_____________________________________________________________________________
62 void AliGenThetaSlice::Generate()
65 // Generate one trigger
68 Float_t polar[3]= {0,0,0};
73 Double_t pmom, theta, phi, pt;
76 if (fNpart == 0) return;
78 for (j=0;j<3;j++) origin[j]=fOrigin[j];
80 if(fVertexSmear==kPerEvent) {
83 origin[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
84 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
87 time += fOsigma[2]/TMath::Ccgs()*
88 TMath::Cos(2*random[0]*TMath::Pi())*
89 TMath::Sqrt(-2*TMath::Log(random[1]));
91 Float_t thetaInterval = 0.;
93 thetaInterval = (fThetaMax-fThetaMin)/(fNpart-1);
96 phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
97 for(i=0;i<fNpart;i++) {
99 theta=fThetaMin+i*thetaInterval;
100 if(TestBit(kMomentumRange)) {
101 pmom=fPMin+random[0]*(fPMax-fPMin);
102 pt=pmom*TMath::Sin(theta);
104 pt=fPtMin+random[0]*(fPtMax-fPtMin);
105 pmom=pt/TMath::Sin(theta);
107 p[0] = pt*TMath::Cos(phi);
108 p[1] = pt*TMath::Sin(phi);
109 p[2] = pmom*TMath::Cos(theta);
111 if(fVertexSmear==kPerTrack) {
114 origin[j]=fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
115 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
118 time = fTimeOrigin + fOsigma[2]/TMath::Ccgs()*
119 TMath::Cos(2*random[0]*TMath::Pi())*
120 TMath::Sqrt(-2*TMath::Log(random[1]));
122 PushTrack(fTrackIt,-1,fIpart,p,origin,polar,time,kPPrimary,nt);
126 //_____________________________________________________________________________
128 void AliGenThetaSlice::Init()
130 // Initialisation, check consistency of selected ranges
131 if(TestBit(kPtRange)&&TestBit(kMomentumRange))
132 Fatal("Init","You should not set the momentum range and the pt range!\n");
133 if((!TestBit(kPtRange))&&(!TestBit(kMomentumRange)))
134 Fatal("Init","You should set either the momentum or the pt range!\n");