Bugfix (C.Cheshkov)
[u/mrichter/AliRoot.git] / FASTSIM / AliFastMuonTrackingRes.cxx
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6255180c 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
d53fc881 16/*
17$Log$
041f7f97 18Revision 1.5 2003/08/13 17:37:29 hristov
19Bug fix (Alpha)
20
de4a225a 21Revision 1.4 2003/08/05 16:14:20 morsch
22Some problems with too big fluctuations corrected. (A. de Falco)
23
d53fc881 24Revision 1.1 2003/01/06 10:13:09 morsch
25First commit.
26
27*/
6255180c 28
041f7f97 29// Implementation of AliFastResponse for the Muon Spectrometer resolution.
30// The response depends on the charge of the muon and
31// the background level.
32// The class uses the instance of an object of type AliMUONFastTracking to
33// obtain the smearing parameters.
34// Author: andreas.morsch@cern.ch
35
6255180c 36#include "AliFastMuonTrackingRes.h"
37#include "AliMUONFastTracking.h"
38#include <TRandom.h>
39#include <TF1.h>
40
41ClassImp(AliFastMuonTrackingRes)
42
43
44AliFastMuonTrackingRes::AliFastMuonTrackingRes() :
45 AliFastResponse("Resolution", "Muon Tracking Resolution")
46{
041f7f97 47// Deafault constructor
6255180c 48 SetBackground();
49}
50
51void AliFastMuonTrackingRes::Init()
52{
041f7f97 53// Initialisation
6255180c 54 fFastTracking = AliMUONFastTracking::Instance();
55 fFastTracking->Init(fBackground);
56}
57
58
59
60void AliFastMuonTrackingRes::Evaluate(Float_t p, Float_t theta , Float_t phi,
61 Float_t& pS, Float_t& thetaS, Float_t& phiS)
62{
041f7f97 63//
64// Evaluate Gaussian smearing from given kinematics
65//
6255180c 66
67 Double_t meanp = fFastTracking->MeanP (p, theta, phi, Int_t(fCharge));
68 Double_t sigmap = fFastTracking->SigmaP (p, theta, phi, Int_t(fCharge));
69 Double_t sigma1p = fFastTracking->Sigma1P(p, theta, phi, Int_t(fCharge));
70 Double_t normg2 = fFastTracking->NormG2 (p, theta, phi, Int_t(fCharge));
71 Double_t meang2 = fFastTracking->MeanG2 (p, theta, phi, Int_t(fCharge));
72 Double_t sigmag2 = fFastTracking->SigmaG2(p, theta, phi, Int_t(fCharge));
73
74 Int_t ip,itheta,iphi;
6255180c 75 fFastTracking->GetIpIthetaIphi(p, theta, phi, Int_t(fCharge), ip, itheta, iphi);
d53fc881 76 TF1* fitp = fFastTracking->GetFitP(ip,itheta,iphi);
77
78 Float_t curmeanp = fitp->GetParameter(0);
79 Float_t cursigmap = fitp->GetParameter(1);
80 Float_t cursigma1p = fitp->GetParameter(2);
81 Float_t curnormg2 = fitp->GetParameter(3);
82 Float_t curmeang2 = fitp->GetParameter(4);
83 Float_t cursigmag2 = fitp->GetParameter(5);
84 if (curmeanp != meanp || cursigmap != sigmap || cursigma1p != sigma1p ||
85 curnormg2 != normg2 || curmeang2 != meang2 || cursigmag2 != sigmag2){
86 printf ("Setting new parameters for ip=%d itheta=%d iphi=%d\n",ip,itheta,iphi);
87 fitp->SetParameters(meanp,sigmap,sigma1p,normg2,meang2,sigmag2);
6255180c 88 }
6255180c 89
90 Double_t meantheta = fFastTracking->MeanTheta (p, theta, phi, Int_t(fCharge));
91 Double_t sigmatheta = fFastTracking->SigmaTheta(p, theta, phi, Int_t(fCharge));
92 Double_t meanphi = fFastTracking->MeanPhi (p, theta, phi, Int_t(fCharge));
93 Double_t sigmaphi = fFastTracking->SigmaPhi (p, theta, phi, Int_t(fCharge));
d53fc881 94
de4a225a 95 if (sigmatheta<0 || sigmaphi<0)
d53fc881 96 printf ("bin %d %d %d sigmatheta = %f, sigmaphi = %f\n",
97 ip,itheta,iphi,sigmatheta,sigmaphi);
6255180c 98 // Components different from ip=0 have the RMS bigger than mean
99 Float_t ptp[3] = { 1.219576,-0.354764,-0.690117 };
100 Float_t ptph[3] = { 0.977522, 0.016269, 0.023158 };
101 Float_t pphp[3] = { 1.303256,-0.464847,-0.869322 };
102
103 // Smeared momentum
d53fc881 104 pS = -1.;
105 // Float_t dpmax = 5. + ip * 2.5;
106 // Float_t dpmax = 5. + ip * 2;
107 Float_t dpmax;
108 if (sigmag2<999.) dpmax = 5. * (sigmap + sigmag2);
109 else dpmax = 5. * sigmap;
110 Float_t dp = 100;
111 while (pS<0 || TMath::Abs(dp)>dpmax) {
112 pS = p + fitp->GetRandom();
113 dp = pS - p;
114 }
6255180c 115 // Smeared phi
d53fc881 116 Float_t sigmaphiold=sigmaphi;
6255180c 117 if (ip==0) sigmaphi *= pphp[0] + pphp[1] * dp + pphp[2] * dp*dp;
d53fc881 118 if (sigmaphi<0.5 * sigmaphiold) sigmaphi = 0.5 * sigmaphiold;
119 if (sigmaphi>2. * sigmaphiold) sigmaphi = 2. * sigmaphiold;
6255180c 120 phiS = phi + gRandom->Gaus(meanphi, sigmaphi);
121 Float_t dphi = phiS - phi;
122 // Smeared theta
d53fc881 123 Float_t sigmathetaold=sigmatheta;
6255180c 124 if (ip==0) sigmatheta *= ptp[0] + ptp[1] * dp + ptp[2] * dp*dp;
125 if (ip==0) sigmatheta *= ptph[0] + ptph[1] * dphi + ptph[2] * dphi*dphi;
d53fc881 126 if (sigmatheta<0.5 * sigmathetaold) sigmatheta = 0.5 * sigmathetaold;
127 if (sigmatheta>2. * sigmathetaold) sigmatheta = 2. * sigmathetaold;
6255180c 128 thetaS = theta + gRandom->Gaus(meantheta,sigmatheta);
129}
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