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50b9d194 | 1 | #ifndef ALIFMDESDREVERTEXER_H |
2 | #define ALIFMDESDREVERTEXER_H | |
3 | # include <Rtypes.h> | |
4 | class ::AliESDFMD; | |
5 | ||
6 | // | |
7 | // Class to recaculate quantities in an AliESDFMD object based on new | |
8 | // a value for the z-coordinate of the primary interaction point. | |
9 | // | |
10 | // This allows us, in case we get a better determination of the | |
11 | // z-coordinate of the primary interaction, to recalibrate the signals | |
12 | // in the FMD ESD object, without having to redo the reconstruction. | |
13 | // | |
14 | class AliFMDESDRevertexer | |
15 | { | |
16 | public: | |
17 | /** | |
18 | * Constructor | |
19 | * | |
20 | */ | |
21 | AliFMDESDRevertexer(); | |
22 | /** | |
23 | * Destructor | |
24 | * | |
25 | */ | |
26 | virtual ~AliFMDESDRevertexer() {} | |
27 | /** | |
28 | * Revertex the passed ESD. The passed ESD object will be modified | |
29 | * directly. | |
30 | * | |
31 | * @param fmdEsd ESD object to revertex. | |
32 | * @param vz New Z coordinate of primary vertex. | |
33 | * | |
34 | * @return @c true on success, @c false failure. | |
35 | */ | |
36 | Bool_t Revertex(AliESDFMD* fmdEsd, Double_t vz) const; | |
37 | ||
38 | /** | |
39 | * Calculate the physical coordinates (@a eta, @a phi) corresponding | |
40 | * to the detector coordinates (@a det, @a rng, @a sec, @a str). | |
41 | * | |
42 | * @param det The detector identifier | |
43 | * @param rng The ring identifier | |
44 | * @param sec The sector identifier | |
45 | * @param str The strip identifier | |
46 | * @param vz The z coordinate of the current primary interation vertex | |
47 | * @param eta On return, the psuedo-rapidity | |
48 | * @param phi On return, the azimuthal angle | |
49 | * @param r On return, the radius | |
50 | * @param theta On return, the polar angle | |
51 | */ | |
52 | Bool_t PhysicalCoordinates(UShort_t det, | |
53 | Char_t rng, | |
54 | UShort_t sec, | |
55 | UShort_t str, | |
56 | Double_t vz, | |
57 | Double_t& eta, | |
58 | Double_t& phi, | |
59 | Double_t& r, | |
60 | Double_t& theta) const; | |
61 | ||
62 | /** | |
63 | * Calculate the polar angle @f$ \theta@f$ corresponding to the | |
64 | * psuedo-rapidity @f$ \eta@f$ | |
65 | * | |
66 | * @param eta Psuedo rapidity @f$ \eta=-\log[\tan(\theta/2)]@f$ | |
67 | * | |
e5571b63 | 68 | * @return Polar angle @f$ \theta=2\tan^{-1}[\exp(-\eta)]@f$ |
50b9d194 | 69 | */ |
70 | Double_t Eta2Theta(Double_t eta) const; | |
71 | protected: | |
72 | }; | |
73 | ||
74 | # ifndef __CINT__ | |
75 | # ifndef ALIFMDGEOMETRY_H | |
76 | # include <AliFMDGeometry.h> | |
77 | # endif | |
78 | # ifndef ALIESDFMD_H | |
79 | # include <AliESDFMD.h> | |
80 | # endif | |
81 | ||
82 | //____________________________________________________________________ | |
83 | inline | |
84 | AliFMDESDRevertexer::AliFMDESDRevertexer() | |
85 | { | |
86 | // Constructor | |
87 | AliFMDGeometry* geom = AliFMDGeometry::Instance(); | |
88 | geom->Init(); | |
89 | geom->InitTransformations(); | |
90 | } | |
91 | ||
92 | //____________________________________________________________________ | |
93 | inline Bool_t | |
94 | AliFMDESDRevertexer::Revertex(AliESDFMD* fmdEsd, Double_t vz) const | |
95 | { | |
96 | // Revertex the passed ESD. The passed ESD object will be modified | |
97 | // directly. | |
98 | // | |
99 | // Parameters: | |
100 | // fmdEsd ESD object to revertex. | |
101 | // vz New Z coordinate of primary vertex. | |
102 | // | |
103 | // Return: | |
104 | // kTRUE on success, kFALSE failure. | |
105 | if (!fmdEsd) return kFALSE; | |
106 | ||
107 | Bool_t ret = kTRUE; | |
108 | const UShort_t sec0 = 0; | |
109 | for (UShort_t det = 1; det <= 3; det++) { | |
110 | UShort_t nrng = (det == 1 ? 1 : 2); | |
111 | for (UShort_t ir = 0; ir < nrng; ir++) { | |
112 | Char_t rng = (ir == 0 ? 'I' : 'O'); | |
113 | UShort_t nsec = (ir == 0 ? 20 : 40); | |
114 | UShort_t nstr = (ir == 0 ? 512 : 256); | |
115 | for (UShort_t str = 0; str < nstr; str++) { | |
116 | Double_t phi, r, theta; | |
117 | Double_t eta = AliESDFMD::kInvalidEta; | |
118 | Double_t oldEta = fmdEsd->Eta(det, rng, 0u, str); | |
119 | Double_t oldTheta = Eta2Theta(oldEta); | |
120 | Bool_t ret1 = PhysicalCoordinates(det, rng, sec0, str, vz, | |
121 | eta, phi, r, theta); | |
122 | fmdEsd->SetEta(det, rng, sec0, str, eta); | |
123 | ||
124 | if (!ret1) { | |
125 | // If the was an error, then there's no reason to go on with | |
126 | // this strip-ring. Note, that the eta is correctly set to | |
127 | // AliESDFMD::kInvalidMult. | |
128 | ret = kFALSE; | |
129 | continue; | |
130 | } | |
131 | ||
f70f588a | 132 | Double_t corr = 1; |
50b9d194 | 133 | if (fmdEsd->IsAngleCorrected()) |
f70f588a | 134 | corr = TMath::Abs(TMath::Cos(theta) / TMath::Cos(oldTheta)); |
50b9d194 | 135 | for (UShort_t sec = 0; sec < nsec; sec++) { |
136 | Double_t mult = fmdEsd->Multiplicity(det, rng, sec, str); | |
137 | fmdEsd->SetMultiplicity(det, rng, sec, str, corr * mult); | |
138 | } | |
139 | } | |
140 | } | |
141 | } | |
142 | ||
143 | return ret; | |
144 | } | |
145 | ||
146 | //____________________________________________________________________ | |
147 | inline Double_t | |
148 | AliFMDESDRevertexer::Eta2Theta(Double_t eta) const | |
149 | { | |
150 | // Calculate the polar angle @f$ \theta@f$ corresponding to the | |
151 | // psuedo-rapidity @f$ \eta@f$ | |
152 | // | |
153 | // Parameters: | |
154 | // eta Psuedo rapidity @f$ \eta=-\log[\tan(\theta/2)]@f$ | |
155 | // Return: | |
e5571b63 | 156 | // Polar angle @f$ \theta=2\atan[\exp(-\eta)]@f$ |
50b9d194 | 157 | return 2 * TMath::ATan(TMath::Exp(-eta)); |
158 | } | |
159 | ||
160 | ||
161 | //____________________________________________________________________ | |
162 | inline Bool_t | |
163 | AliFMDESDRevertexer::PhysicalCoordinates(UShort_t det, | |
164 | Char_t rng, | |
165 | UShort_t sec, | |
166 | UShort_t str, | |
167 | Double_t vz, | |
168 | Double_t& eta, | |
169 | Double_t& phi, | |
170 | Double_t& r, | |
171 | Double_t& theta) const | |
172 | { | |
173 | // Calculate the physical coordinates (@a eta, @a phi) corresponding | |
174 | // to the detector coordinates (@a det, @a rng, @a sec, @a str). | |
175 | // | |
176 | // Parameters: | |
177 | // det The detector identifier | |
178 | // rng The ring identifier | |
179 | // sec The sector identifier | |
180 | // str The strip identifier | |
181 | // vz The z coordinate of the current primary interation vertex | |
182 | // eta On return, the psuedo-rapidity | |
183 | // phi On return, the azimuthal angle | |
184 | // r On return, the radius | |
185 | // phi On return, the polar angle | |
186 | AliFMDGeometry* geom = AliFMDGeometry::Instance(); | |
187 | Double_t x=0, y=0, z=0; | |
188 | geom->Detector2XYZ(det, rng, sec, str, x, y, z); | |
189 | ||
190 | // Check that the conversion succeeded | |
191 | if (x == 0 && y == 0 && z == 0) return kFALSE; | |
192 | ||
193 | // Correct for vertex offset. | |
8161c5f7 | 194 | z -= vz; |
50b9d194 | 195 | phi = TMath::ATan2(y, x); |
196 | r = TMath::Sqrt(y * y + x * x); | |
197 | theta = TMath::ATan2(r, z); | |
198 | eta = -TMath::Log(TMath::Tan(theta / 2)); | |
199 | ||
200 | return kTRUE; | |
201 | } | |
202 | # endif // __CINT__ | |
203 | #endif | |
204 | // | |
205 | // Local Variables: | |
206 | // mode: C++ | |
207 | // End: | |
208 | // | |
209 | ||
210 | ||
211 |