1 #include <AliFMDESDRevertexer.h>
2 #include <AliFMDGeometry.h>
5 //____________________________________________________________________
6 AliFMDESDRevertexer::AliFMDESDRevertexer()
8 AliFMDGeometry* geom = AliFMDGeometry::Instance();
10 geom->InitTransforms();
13 //____________________________________________________________________
15 AliFMDESDRevertexer::Revertex(AliESDFMD* fmdEsd, Double_t vz)
17 if (!fmdEsd) return kFALSE;
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,
33 fmdEsd->SetEta(det, rng, sec, str, eta);
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));
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);
60 //____________________________________________________________________
62 AliFMDESDRevertexer::Eta2Theta(Double_t eta) const
64 return 2 * TMath::ATan(TMath::Exp(-eta));
68 //____________________________________________________________________
70 AliFMDESDRevertexer::PhysicalCoordinates(UShort_t det,
78 Double_t& theta) const
80 // Get the eta and phi of a digit
83 AliFMDGeometry* geom = AliFMDGeometry::Instance();
84 Double_t x=0, y=0, z=0;
85 geom->Detector2XYZ(det, rng, sec, str, x, y, z);
87 // Check that the conversion succeeded
88 if (x == 0 && y == 0 && z == 0) return kFALSE;
90 // Correct for vertex offset.
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));