Adding calibration object for the sharing efficiency
[u/mrichter/AliRoot.git] / FMD / AliFMDESDRevertexer.cxx
CommitLineData
50b9d194 1#include <AliFMDESDRevertexer.h>
2#include <AliFMDGeometry.h>
3#include <AliESDFMD.h>
4
5//____________________________________________________________________
6AliFMDESDRevertexer::AliFMDESDRevertexer()
7{
8 AliFMDGeometry* geom = AliFMDGeometry::Instance();
9 geom->Init();
10 geom->InitTransforms();
11}
12
13//____________________________________________________________________
14Bool_t
15AliFMDESDRevertexer::Revertex(AliESDFMD* fmdEsd, Double_t vz)
16{
17 if (!fmdEsd) return kFALSE;
18
19 Bool_t ret = kTRUE;
20 for (UShort_t det = 1; det <= 3; det++) {
21 UShort_t nrng = (det == 1 ? 1 : 2);
22 for (UShort_t ir = 0; ir < nrng; ir++) {
23 Char_t rng = (ir == 0 ? 'I' : 'O');
24 UShort_t nsec = (ir == 0 ? 20 : 40);
25 UShort_t nstr = (ir == 0 ? 512 : 256);
26 for (UShort_t str = 0; str < nstr; str++) {
27 Double_t phi, r, theta, oldTheta;
28 Double_t eta = AliESDFMD::kInvalidEta;
29 Double_t oldEta = fmdEsd->Eta(det, rng, sec, str);
30 Double_t oldTheta = Eta2Theta(oldEta);
31 Bool_t ret1 = PhysicalCoordinates(det, rng, 0, str, vz,
32 eta, phi, r, theta));
33 fmdEsd->SetEta(det, rng, sec, str, eta);
34
35 if (!ret1) {
36 // If the was an error, then there's no reason to go on with
37 // this strip-ring. Note, that the eta is correctly set to
38 // AliESDFMD::kInvalidMult.
39 AliWarning(Form("Failed to calculate eta, phi for "
40 "FMD%d%c[%02d,%03d] with v_z=%9.4f"
41 det, rng, 0, str, vz));
42 ret = kFALSE;
43 continue;
44 }
45
46 Double_t corr = TMath::Abs(TMath::Cos(theta));
47 if (fmdEsd->IsAngleCorrected())
48 corr /= TMath::Abs(TMath::Cos(oldTheta));
49 for (UShort_t sec = 0; sec < nsec; sec++) {
50 Double_t mult = fmdEsd->Multiplicity(det, rng, sec, str);
51 fmdEsd->SetMultiplicity(det, rng, sec, str, corr * mult);
52 }
53 }
54 }
55 }
56
57 return ret;
58}
59
60//____________________________________________________________________
61Double_t
62AliFMDESDRevertexer::Eta2Theta(Double_t eta) const
63{
64 return 2 * TMath::ATan(TMath::Exp(-eta));
65}
66
67
68//____________________________________________________________________
69Bool_t
70AliFMDESDRevertexer::PhysicalCoordinates(UShort_t det,
71 Char_t rng,
72 UShort_t sec,
73 UShort_t str,
74 Double_t vz,
75 Double_t& eta,
76 Double_t& phi,
77 Double_t& r,
78 Double_t& theta) const
79{
80 // Get the eta and phi of a digit
81 //
82 // Get geometry.
83 AliFMDGeometry* geom = AliFMDGeometry::Instance();
84 Double_t x=0, y=0, z=0;
85 geom->Detector2XYZ(det, rng, sec, str, x, y, z);
86
87 // Check that the conversion succeeded
88 if (x == 0 && y == 0 && z == 0) return kFALSE;
89
90 // Correct for vertex offset.
8161c5f7 91 z -= vz;
50b9d194 92 phi = TMath::ATan2(y, x);
93 r = TMath::Sqrt(y * y + x * x);
94 theta = TMath::ATan2(r, z);
95 eta = -TMath::Log(TMath::Tan(theta / 2));
96
97 return kTRUE;
98}
99
100