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[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
16/*
17$Log$
18*/
19
20#include "AliFastMuonTrackingRes.h"
21#include "AliMUONFastTracking.h"
22#include <TRandom.h>
23#include <TF1.h>
24
25ClassImp(AliFastMuonTrackingRes)
26
27
28AliFastMuonTrackingRes::AliFastMuonTrackingRes() :
29 AliFastResponse("Resolution", "Muon Tracking Resolution")
30{
31 SetBackground();
32}
33
34void AliFastMuonTrackingRes::Init()
35{
36 fFastTracking = AliMUONFastTracking::Instance();
37 fFastTracking->Init(fBackground);
38}
39
40
41
42void AliFastMuonTrackingRes::Evaluate(Float_t p, Float_t theta , Float_t phi,
43 Float_t& pS, Float_t& thetaS, Float_t& phiS)
44{
45
46 Double_t meanp = fFastTracking->MeanP (p, theta, phi, Int_t(fCharge));
47 Double_t sigmap = fFastTracking->SigmaP (p, theta, phi, Int_t(fCharge));
48 Double_t sigma1p = fFastTracking->Sigma1P(p, theta, phi, Int_t(fCharge));
49 Double_t normg2 = fFastTracking->NormG2 (p, theta, phi, Int_t(fCharge));
50 Double_t meang2 = fFastTracking->MeanG2 (p, theta, phi, Int_t(fCharge));
51 Double_t sigmag2 = fFastTracking->SigmaG2(p, theta, phi, Int_t(fCharge));
52
53 Int_t ip,itheta,iphi;
54 TF1* fitp = fFastTracking->GetFitP();
55
56 fFastTracking->GetIpIthetaIphi(p, theta, phi, Int_t(fCharge), ip, itheta, iphi);
57 if (sigmap == 0) {
58 printf ("WARNING!!! sigmap=0: ");
59 printf ("ip= %d itheta = %d iphi = %d ", ip, itheta, iphi);
60 printf ("p= %f theta = %f phi = %f\n", p, theta, phi);
61 }
62
63 fitp->SetParameters(meanp,sigmap,sigma1p,normg2,meang2,sigmag2);
64
65 Double_t meantheta = fFastTracking->MeanTheta (p, theta, phi, Int_t(fCharge));
66 Double_t sigmatheta = fFastTracking->SigmaTheta(p, theta, phi, Int_t(fCharge));
67 Double_t meanphi = fFastTracking->MeanPhi (p, theta, phi, Int_t(fCharge));
68 Double_t sigmaphi = fFastTracking->SigmaPhi (p, theta, phi, Int_t(fCharge));
69
70 // Components different from ip=0 have the RMS bigger than mean
71 Float_t ptp[3] = { 1.219576,-0.354764,-0.690117 };
72 Float_t ptph[3] = { 0.977522, 0.016269, 0.023158 };
73 Float_t pphp[3] = { 1.303256,-0.464847,-0.869322 };
74
75 // Smeared momentum
76 pS = p + fitp->GetRandom();
77 Float_t dp = pS - p;
78
79 // Smeared phi
80 if (ip==0) sigmaphi *= pphp[0] + pphp[1] * dp + pphp[2] * dp*dp;
81 phiS = phi + gRandom->Gaus(meanphi, sigmaphi);
82 Float_t dphi = phiS - phi;
83 // Smeared theta
84 if (ip==0) sigmatheta *= ptp[0] + ptp[1] * dp + ptp[2] * dp*dp;
85 if (ip==0) sigmatheta *= ptph[0] + ptph[1] * dphi + ptph[2] * dphi*dphi;
86 thetaS = theta + gRandom->Gaus(meantheta,sigmatheta);
87}
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