Generator for HBT
[u/mrichter/AliRoot.git] / EVGEN / AliGenHBTosl.h
CommitLineData
695dc56f 1#ifndef ALIGENHBTOSL_H
2#define ALIGENHBTOSL_H
3//__________________________________________________________
4/////////////////////////////////////////////////////////////
5// //
6// class AliGenHBTosl //
7// //
8// Genarator simulating particle correlations //
9// //
10// The main idea of the generator is to produce particles //
11// according to some distribution of two particle //
12// property. In HBT they are qout,qsie and qlong. //
13// In order to be able to generate signal that produces //
14// given two particle correlation background must be //
15// known before in order to produce the shape of signal //
16// to randomize given distribution from. //
17// //
18// The generator works as follows: //
19// 1. Coarse Background (fQCoarseBackground) is generated //
20// ade from the particles //
21// given by the external generator (variable //
22// fGenerator) by the mixing technique. //
23// 2. Coarse signal is prduced by multiplying Coarse //
24// background by a required function //
25// See method FillCoarseSignal //
26// 3. Signal is randomized out of the coarse signal //
27// histogram (two particle property). First particle //
28// is taken from the external generator, and the //
29// second one is CALCULATED on the basis of the first //
30// one and the two particle property (qout,qside,qlong)//
31// Background is made by the mixing out of the //
32// genereted signal events. //
33// This step is cotinued up to the moment signal //
34// histogram has enough statistics (data member //
35// fMinFill) //
36// See method StartSignalPass1() //
37// 4. chi is calculated for each bin (chiarray variqable) //
38// (not the chi2 because sign is important) //
39// Two particle prioperty //
40// (qout,qside,qlong) is chosen at the points that //
41// chi is the smallest. First particle is taken from //
42// the the external generator (fGenerator) and second's /
43// momenta are caclulated out of their momenta and //
44// (qout,qside,qlong). Background is updated //
45// continuesely for all the events. This step is //
46// continued until stability conditions are fullfiled //
47// or maximum number of iteration is reached. //
48// 5. The same as step 4 but events are stored. //
49// //
50////////////////////////////////////////////////////////////
51
52#include "AliGenerator.h"
53
54class TH3D;
55class AliStack;
56class TParticle;
57class TVector;
58
59class AliGenHBTosl: public AliGenerator
60{
61 public:
62 AliGenHBTosl();
63 AliGenHBTosl(Int_t n,Int_t pid = 211);
64 virtual ~AliGenHBTosl();
65
66 void Init();
67 void Generate();
68
69 void SetGenerator(AliGenerator* gen){fGenerator = gen;}
70 void SetDebug(Bool_t debug){fDebug = debug;}
71 Bool_t GetDebug() const {return fDebug;}
72
73 void Rotate(TVector3& relvector, TVector3& vector);
74 Double_t Rotate(Double_t x,Double_t y,Double_t z);
75 void SetSamplePhiRange(Float_t min,Float_t max){fSamplePhiMin = min; fSamplePhiMax = max;}
76
77 Int_t GetThreeD(TParticle* first,TParticle* second, Double_t qout, Double_t qside, Double_t qlong);
78
79
80 protected:
81
82 void GetOneD(TParticle* first, TParticle* second,Double_t qinv);
83
84 void FillCoarse();
85 void FillCoarseSignal();
86 void StartSignal();
87 void StartSignalPass1();
88 void Mix(TList* eventbuffer,TH3D* denominator,TH3D* denominator2);
89 void Mix(AliStack* stack, TH3D* numerator, TH3D* numerator2);
90 Double_t GetQInv(TParticle* f, TParticle* s);
91 void GetQOutQSideQLong(TParticle* f, TParticle* s,Double_t& out, Double_t& side, Double_t& lon);
92 Double_t GetQInvCorrTheorValue(Double_t qinv) const;
93 Double_t GetQOutQSideQLongCorrTheorValue(Double_t& out, Double_t& side, Double_t& lon) const;
94
95 Double_t Scale(TH3D* num,TH3D* den);
96 void SetTrack(TParticle* p, Int_t& ntr);
97 void SetTrack(TParticle* p, Int_t& ntr, AliStack* stack);
98
99 AliStack* RotateStack();
100 void SwapGeneratingHistograms();
101 void TestCoarseSignal();
102
103 Bool_t CheckParticle(TParticle* p, TParticle* aupair,AliStack* stack);
104 private:
105 TH3D* fQCoarseBackground;//Initial Background
106 TH3D* fQCoarseSignal;//
107 TH3D* fQSignal;
108 TH3D* fQBackground;
109
110 TH3D* fQSecondSignal;
111 TH3D* fQSecondBackground;
112
113 Float_t fQRange;
114 Int_t fQNBins;
115 AliGenerator* fGenerator;
116
117 TList* fStackBuffer;
118 Int_t fBufferSize;
119 Int_t fNBinsToScale;
120 Bool_t fDebug;
121 Bool_t fSignalShapeCreated;
122
123 Int_t fMaxIterations; //maximal nuber of iterations on startup
124 Float_t fMaxChiSquereChange;//value of ChiSqr change in %, when sturtup process in stable
125 Float_t fMaxChiSquerePerNDF;//value of the chi2 where generating histograms are considered as good
126
127
128 Double_t fQRadius;
129
130 Int_t fPID;
131 //we limit mixing to some finit phi range to make it faster
132 Float_t fSamplePhiMin;//
133 Float_t fSamplePhiMax;//
134
135 Float_t fSignalRegion;
136
137 Int_t fMinFill;
138
139 Bool_t fSwapped;
140
141 ClassDef(AliGenHBTosl,1)
142};
143#endif