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91509ec6 | 1 | // $Id$ |
2 | ||
3 | /*! | |
4 | ||
5 | \page README_rec Reconstruction | |
6 | ||
b1fea02e | 7 | The reconstruction is a multistage process, driven by the AliMUONTracker and AliMUONReconstructor classes |
8 | via the AliReconstruction class, which is divided into three parts: | |
9 | - the digitization of the electronic response, | |
10 | - the clustering of the digits to locate the crossing point of the muon with the chamber, | |
11 | - the tracking to reconstruct the trajectory of the muon in the spectrometer from which we can extract the kinematics. | |
91509ec6 | 12 | |
b1fea02e | 13 | All the adjustable options and parameters used to tune the different part of the reconstruction are handled by the class AliMUONRecoParam. |
91509ec6 | 14 | |
91509ec6 | 15 | |
b1fea02e | 16 | \section rec_s1 Digitization |
91509ec6 | 17 | |
b1fea02e | 18 | - We read the RAW data, convert them (convert them back for simulated data) to digit (object inheriting from AliMUONVDigit |
19 | stored into containers inheriting from AliMUONVDigitStore). This conversion is performed by the class AliMUONDigitMaker. | |
20 | - We calibrate the digits, via AliMUONDigitCalibrator, by subtracting pedestals and multiplying by gains. All the calibration parameters | |
21 | (pedestals, gains, capacitances and HV) are read from the OCDB and stored into AliMUONCalibrationData objects. | |
22 | - We create the status of the digit (e.g. pedestal higher than maximum or HV switched off), using AliMUONPadStatusMaker. | |
23 | - We create the status map for each digit, i.e the global status (good/bad) of that digit and of its neighbords, using AliMUONPadStatusMapMaker. | |
24 | - Calibrated digits might be saved (back) to TreeD in MUON.Digits.root file. | |
fd3ef136 | 25 | |
fd3ef136 | 26 | |
b1fea02e | 27 | \section rec_s2 Clustering |
28 | ||
29 | - We convert the digits having a positive charge into pads (AliMUONPad objects), which also contain information about the digit geometrical | |
30 | position. | |
31 | - We loop over pads in the bending and non-bending planes of the DE to form groups of contiguous pads. We then merge the overlapping groups | |
32 | of pads from both cathodes to build the pre-clusters that are the objects to be clusterized. | |
33 | - We unfold each pre-cluster in order to extract the number and the position of individual clusters merged in it (complex pre-clusters are | |
a2d5f607 | 34 | made of a superimposition of signals from muon, from physical background (e.g. hadrons) and from electronic noise). |
35 | - We finally determine the MC label: take the one of the simulated track that contribute the most to the total charge of the 2 (bending and the | |
36 | non bending) pads located below the cluster position. This is possible only if we perform the reconstruction from simulated digits (which contain | |
37 | the list of MC track contributions). We set it to -1 when reconstructing from raw data or in case of failure. | |
b1fea02e | 38 | |
39 | Several versions of pre-clustering are available, all inheriting from AliMUONVClusterFinder, with different ways to loop over pads to form | |
40 | pre-clusters: | |
41 | - AliMUONPreClusterFinder | |
42 | - AliMUONPreClusterFinderV2 | |
43 | - AliMUONPreClusterFinderV3 | |
44 | ||
45 | Several version of clustering are available, all inheriting from AliMUONVClusterFinder, with different degrees of complexity: | |
46 | - AliMUONClusterFinderCOG simply compute the Center Of Gravity of the charge distribution in the pre-cluster. | |
47 | - AliMUONClusterFinderSimpleFit simply fit the charge distribution with a single 2D Mathieson function. | |
48 | - AliMUONClusterFinderMLEM uses the Maximum Likelihood Expectation Minimization algorithm. | |
49 | This is a recursive procedure which determines the number and the approximate position of clusters into the pre-cluster that are needed | |
50 | to reproduce the whole charge distribution. It assumes that the charge distribution of each single cluster follow a 2D Mathieson function. | |
51 | If the estimated number of clusters is too high (>3), the pre-cluster is split into several groups of 1-2 or 3 clusters selected having | |
52 | the minimum total coupling to all the other clusters into the pre-cluster. Each group of clusters is then fitted with a sum of 2D Mathieson | |
53 | functions to extract their exact position. | |
54 | - AliMUONClusterFinderPeakCOG is a simplified version of the MLEM clusterizer, without splitting and computing the Center Of Gravity of the | |
55 | local charge distribution to extract the position of every clusters found in the pre-cluster. | |
56 | - AliMUONClusterFinderPeakFit is another simplified version of the MLEM clusterizer again without splitting. The pre-cluster is fitted with | |
57 | a sum of 2D Mathieson if it contains less than 3 clusters or we switch to the above COG method. | |
58 | ||
59 | The cluster recontruction is driven by the class AliMUONSimpleClusterServer, inheriting from AliMUONVClusterServer. | |
60 | It can be performed either before or during the tracking. In the first case, all the chambers are fully clusterized and the clusters (objects | |
61 | inheriting from AliMUONVCluster stored into containers inheriting from AliMUONVClusterStore) are saved to TreeR in Muon.RecPoints.root file. | |
62 | We use the class AliMUONLegacyClusterServer (also inheriting from AliMUONVClusterServer) read back the TreeR and provide clusters to the tracking. | |
63 | In the second case, we clusterize the chambers only in the region where we are looking for new clusters to be attached to the track candidates. | |
64 | This makes the clustering faster but the clusters cannot be saved to the TreeR. | |
65 | ||
66 | ||
67 | \section rec_s3 Tracking | |
68 | ||
69 | The MUON code provides two different algorithms to reconstruct the muon trajectory. In both cases the general tracking procedure is the same, | |
70 | the only difference being the way the track parameters are computed from the cluster positions. The "Original" algorithm perform a fit of the | |
71 | track parameters using the MINUIT package of Root, while the "Kalman" algorithm compute them using analytical formulae. The classes driving | |
72 | the tracking are AliMUONTrackReconstructor and AliMUONTrackReconstructorK for the "Original" and the "Kalman" algorithms respectively, | |
73 | both inheriting from AliMUONVTrackReconstructor. The reconstructed muon tracks are objects of the class AliMUONTrack. | |
74 | ||
75 | The general tracking procedure is as follow: | |
76 | - Build primary track candidates using clusters on station 4 and 5: Make all combination of clusters between the two chambers of station 5(4). | |
a2d5f607 | 77 | For each combination compute the local position and impact parameter of the tracklet at vertex and estimate its bending momentum given the averaged |
78 | magnetic field inside the dipole and assuming that the track is coming from the vertex. Also compute the corresponding error and covariances of | |
79 | these parameters. Then select pairs for which the estimated bending momentum and the non-bending impact parameter at vertex are within given limits | |
80 | taking into account the errors. Extrapolate the primary track candidates to station 4(5), look for at least one compatible cluster to validate them | |
81 | and recompute the track parameters and covariances. | |
82 | - Remove the identical track candidates (i.e. the ones sharing exactly the same clusters), and the ones whose bending momentum and non-bending | |
83 | impact parameter at vertex are out of given limits taking into account the errors. | |
4c29c3c5 | 84 | - Propagate the track to stations 3, 2 then 1. At each station, ask the "ClusterServer" to provide clusters in the region of interest defined in |
a2d5f607 | 85 | the reconstruction parameters. Select the one(s) compatible with the track and recompute the track parameters and covariances. Remove the track if |
86 | no good cluster is found or if its re-computed bending momentum and non-bending impact parameter at vertex are out of given limits taking into | |
87 | account the errors. | |
4c29c3c5 | 88 | - Remove the connected tracks (i.e. the ones sharing one cluster or more in stations 3, 4 or 5) keeping the one with the largest number of cluster |
a2d5f607 | 89 | or the one with the lowest chi2 in case of equality. Then recompute the track parameters and covariances at each attached cluster (using the |
90 | so-called Smoother algorithm in the case of the "Kalman" tracking). | |
91 | - Find the MC label from the label of each attached cluster (if available): more than 50% of clusters must share the same label, including 1 before | |
92 | and 1 after the dipole. Set it to -1 when reconstructing real data or in case of failure. | |
b1fea02e | 93 | - The reconstructed tracks are finally matched with the trigger tracks (reconstructed from the local response of the trigger) to identify the |
94 | muon(s) that made the trigger. | |
95 | ||
96 | The new clusters to be attached to the track are selected according to their local chi2 (i.e. their transverse position relatively to the track, | |
a2d5f607 | 97 | normalized by the convolution of the cluster resolution with the resolution of the track extrapolated to the cluster location). |
4c29c3c5 | 98 | If several compatible clusters are found on the same chamber, the track candidate is duplicated to consider all the possibilities. |
b1fea02e | 99 | |
100 | The last part of the tracking is the extrapolation of the reconstructed tracks to the vertex of the collision. The vertex position is measured | |
101 | by the SPD (the Silicon Pixel layers of the ITS Detector). In order to be able to perform any kind of muon analysis, we need to compute the track | |
102 | parameters assuming the muon has been produced in the initial collision as well as the track parameters in the vertex plane. The first set of | |
103 | parameters is obtained by correcting for energy loss and multiple Coulomb scattering in the front absorber (we force the track to come from the | |
104 | exact vertex position (x,y,z) by using the Branson correction), while the second one is obtained by correcting for energy loss only. | |
105 | ||
106 | The final results of the reconstruction - from which we will perform the physical analyses, compute detector efficiencies and perform calibration | |
107 | checks - are stored in objects of the class AliESDMuonTrack and saved in AliESD.root file. Three kinds of track can be saved: a tracker track | |
108 | matched with a trigger track, a tracker track alone and a trigger track alone (unused data members are set to default in the last two cases). | |
109 | The complete list of MUON data saved into ESD is given in section @ref rec_s5. | |
110 | ||
111 | ||
112 | \section rec_s4 How to tune the muon reconstruction | |
113 | ||
4c29c3c5 | 114 | Several options and adjustable parameters allow to tune the entire reconstruction. They are stored in the OCDB in the directory MUON/Calib/RecoParam. |
115 | However, it is possible to customize the parameters by adding the following lines in the reconstruction macro (runReconstruction.C): | |
b1fea02e | 116 | \verbatim |
117 | AliMUONRecoParam *muonRecoParam = AliMUONRecoParam::Get...Param(); | |
fd3ef136 | 118 | muonRecoParam->Use...(); |
119 | muonRecoParam->Set...(); | |
120 | ... | |
4c29c3c5 | 121 | MuonRec->SetRecoParam("MUON",muonRecoParam); |
b1fea02e | 122 | \endverbatim |
123 | ||
124 | Three sets of default parameters are available: | |
125 | - <code>GetLowFluxParam()</code>: parameters for p-p collisions | |
126 | - <code>GetHighFluxParam()</code>: parameters for Pb-Pb collisions | |
127 | - <code>GetCosmicParam()</code>: parameters for cosmic runs | |
128 | ||
4c29c3c5 | 129 | Every option/parameter can be set one by one. Here is the complete list of available setters: |
b1fea02e | 130 | - <code>SetCalibrationMode("mode")</code>: set the calibration mode: NOGAIN (only do pedestal subtraction), |
131 | GAIN (do pedestal subtraction and apply gain correction, but with a single capacitance value for all channels), | |
132 | GAINCONSTANTCAPA (as GAIN, but with a channel-dependent capacitance value). | |
133 | - <code>SetClusteringMode("mode")</code>: set the clustering (pre-clustering) mode: NOCLUSTERING, PRECLUSTER, PRECLUSTERV2, PRECLUSTERV3, COG, | |
134 | SIMPLEFIT, SIMPLEFITV3, MLEM:DRAW, MLEM, MLEMV2, MLEMV3. | |
135 | - <code>SetTrackingMode("mode")</code>: Set the tracking mode: ORIGINAL, KALMAN. | |
136 | - <code>CombineClusterTrackReco(flag)</code>: switch on/off the combined cluster/track reconstruction | |
137 | - <code>SaveFullClusterInESD(flag, % of event)</code>: save all cluster info (including pads) in ESD, for the given percentage of events | |
138 | (100% by default) | |
a2d5f607 | 139 | - <code>SelectOnTrackSlope(flag)</code>: switch to select tracks on their slope instead of impact parameter at vertex and/or bending momentum. |
b1fea02e | 140 | - <code>SetMinBendingMomentum(value)</code>: set the minimum acceptable value (GeV/c) of track momentum in bending plane |
141 | - <code>SetMaxBendingMomentum(value)</code>: set the maximum acceptable value (GeV/c) of track momentum in bending plane | |
a2d5f607 | 142 | - <code>SetMaxNonBendingSlope(value)</code>: set the maximum value of the track slope in non bending plane (used when selecting on track slope). |
143 | - <code>SetMaxBendingSlope(value)</code>: set the maximum value of the track slope in non bending plane (used when selecting on track slope). | |
144 | - <code>SetNonBendingVertexDispersion(value)</code>: set the vertex dispersion (cm) in non bending plane (used for the original tracking and to | |
145 | select track on their non-bending impact parameter at vertex). | |
146 | - <code>SetBendingVertexDispersion(value)</code>: set the vertex dispersion (cm) in bending plane (used for the original tracking, to compute the | |
147 | error on the estimated bending momentum at the very begining and to select track on their bending impact parameter at vertex (used when B=0)). | |
b1fea02e | 148 | - <code>SetMaxNonBendingDistanceToTrack(value)</code>: set the maximum distance to the track to search for compatible cluster(s) in non bending |
a2d5f607 | 149 | direction. This value is convoluted with both the track and the cluster resolutions to define the region of interest. |
b1fea02e | 150 | - <code>SetMaxBendingDistanceToTrack(value)</code>: set the maximum distance to the track to search for compatible cluster(s) in bending direction |
a2d5f607 | 151 | This value is convoluted with both the track and the cluster resolutions to define the region of interest. |
b1fea02e | 152 | - <code>SetSigmaCutForTracking(value)</code>: set the cut in sigma to apply on cluster (local chi2) and track (global chi2) during tracking |
153 | - <code>ImproveTracks(flag, sigma cut)</code>: recompute the local chi2 of each cluster with the final track parameters and removed the ones that | |
a2d5f607 | 154 | do not pass a new quality cut. The track is removed if we do not end with at least one good cluster per requested station and two clusters in |
155 | station 4 and 5 together whatever they are requested or not. | |
b1fea02e | 156 | - <code>ImproveTracks(flag)</code>: same as above using the default quality cut |
157 | - <code>SetSigmaCutForTrigger(value)</code>: set the cut in sigma to apply on track during trigger hit pattern search | |
158 | - <code>SetStripCutForTrigger(value)</code>: set the cut in strips to apply on trigger track during trigger chamber efficiency | |
159 | - <code>SetMaxStripAreaForTrigger(value)</code>: set the maximum search area in strips to apply on trigger track during trigger chamber efficiency | |
160 | - <code>SetMaxNormChi2MatchTrigger(value)</code>: set the maximum normalized chi2 for tracker/trigger track matching | |
161 | - <code>TrackAllTracks(flag)</code>: consider all the clusters passing the sigma cut (duplicate the track) or only the best one | |
a2d5f607 | 162 | - <code>RecoverTracks(flag)</code>: during the tracking procedure, if no cluster is found in station 1 or 2, we try it again after having removed |
163 | (if possible with respect to the condition to keep at least 1 cluster per requested station) the worst cluster attached in the previous station | |
164 | (assuming it was a cluster from background). | |
b1fea02e | 165 | - <code>MakeTrackCandidatesFast(flag)</code>: make the primary track candidates formed by cluster on stations 4 and 5 assuming there is no |
166 | magnetic field in that region to speed up the reconstruction. | |
167 | - <code>MakeMoreTrackCandidates(Bool_t flag)</code>: make the primary track candidate using 1 cluster on station 4 and 1 cluster on station 5 | |
168 | instead of starting from 2 clusters in the same station. | |
169 | - <code>ComplementTracks(Bool_t flag)</code>: look for potentially missing cluster to be attached to the track (a track may contain up to 2 | |
170 | clusters per chamber do to the superimposition of DE, while the tracking procedure is done in such a way that only 1 can be attached). | |
4c29c3c5 | 171 | - <code>RemoveConnectedTracksInSt12(Bool_t flag)</code>: extend the definition of connected tracks to be removed at the end of the tracking |
a2d5f607 | 172 | procedure to the ones sharing one cluster on more in any station, including stations 1 and 2. |
b1fea02e | 173 | - <code>UseSmoother(Bool_t flag)</code>: use or not the smoother to recompute the track parameters at each attached cluster |
174 | (used for Kalman tracking only) | |
175 | - <code>UseChamber(Int_t iCh, Bool_t flag)</code>: set the chambers to be used (disable the clustering if the chamber is not used). | |
176 | - <code>RequestStation(Int_t iSt, Bool_t flag)</code>: impose/release the condition "at least 1 cluster per station" for that station. | |
de487b6e | 177 | - <code>BypassSt45(Bool_t st4, Bool_t st5)</code>: make the primary track candidate from the trigger track instead of using stations 4 and/or 5. |
4c29c3c5 | 178 | - <code>SetHVSt12Limits(float low, float high)</code>: Set Low and High threshold for St12 HV |
179 | - <code>SetHVSt345Limits(float low, float high)</code>: Set Low and High threshold for St345 HV | |
180 | - <code>SetPedMeanLimits(float low, float high)</code>: Set Low and High threshold for pedestal mean | |
181 | - <code>SetPedSigmaLimits(float low, float high)</code>: Set Low and High threshold for pedestal sigma | |
182 | - <code>SetGainA1Limits(float low, float high)</code>: Set Low and High threshold for gain a0 term | |
183 | - <code>SetGainA2Limits(float low, float high)</code>: Set Low and High threshold for gain a1 term | |
184 | - <code>SetGainThresLimits(float low, float high)</code>: Set Low and High threshold for gain threshold term | |
185 | - <code>SetPadGoodnessMask(UInt_t mask)</code>: Set the goodness mask (see AliMUONPadStatusMapMaker) | |
186 | - <code>ChargeSigmaCut(Double_t value)</code>: Number of sigma cut we must apply when cutting on adc-ped | |
187 | - <code>SetDefaultNonBendingReso(Int_t iCh, Double_t val)</code>: Set the default non bending resolution of chamber iCh | |
188 | - <code>SetDefaultBendingReso(Int_t iCh, Double_t val)</code>: Set the default bending resolution of chamber iCh | |
a2d5f607 | 189 | - <code>SetMaxTriggerTracks(Int_t val)</code>: Set the maximum number of trigger tracks above which the tracking is cancelled |
190 | - <code>SetMaxTrackCandidates(Int_t val)</code>: Set the maximum number of track candidates above which the tracking abort | |
b1fea02e | 191 | |
192 | We can use the method Print("FULL") to printout all the parameters and options set in the class AliMUONRecoParam. | |
193 | ||
e1fe98be | 194 | RecoParams can be put into OCDB using the MakeMUONSingleRecoParam.C or MakeMUONRecoParamArray.C macros. |
b1fea02e | 195 | |
196 | \section rec_s5 ESD content | |
197 | ||
4c29c3c5 | 198 | Three kinds of track can be saved in ESD: a tracker track matched with a trigger track, a tracker track alone and a trigger track alone (unused |
a2d5f607 | 199 | data members are set to default values in the last two cases). These tracks are stored in objects of the class AliESDMuonTrack. Two methods can be |
200 | used to know the content of an ESD track: | |
201 | - <code>ContainTrackerData()</code>: Return kTRUE if the track contain tracker data | |
202 | - <code>ContainTriggerData()</code>: Return kTRUE if the track contain trigger data | |
203 | ||
204 | The AliESDMuonTrack objects contain: | |
b1fea02e | 205 | - Tracker track parameters (x, theta_x, y, theta_y, 1/p_yz) at vertex (x=x_vtx; y=y_vtx) |
206 | - Tracker track parameters in the vertex plane | |
207 | - Tracker track parameters at first cluster | |
208 | - Tracker track parameter covariances at first cluster | |
a2d5f607 | 209 | - Tracker track global informations (track ID, chi2, number of clusters, cluster map, MC label if any) |
b1fea02e | 210 | - TClonesArray of associated clusters stored in AliESDMuonCluster objects |
a2d5f607 | 211 | - Trigger track informations (local trigger decision, strip pattern, hit pattern, ...) |
b1fea02e | 212 | - Chi2 of tracker/trigger track matching |
213 | ||
a2d5f607 | 214 | The AliESDMuonCluster objects contain: |
b1fea02e | 215 | - Cluster ID providing information about the location of the cluster (chamber ID and DE ID) |
216 | - Cluster position (x,y,z) | |
217 | - Cluster resolution (sigma_x,sigma_y) | |
b1fea02e | 218 | - Charge |
219 | - Chi2 | |
a2d5f607 | 220 | - MC label if any |
221 | - TClonesArray of associated pads stored in AliESDMuonPad objects for a given fraction of events | |
b1fea02e | 222 | |
a2d5f607 | 223 | The AliESDMuonPad objects contain: |
b1fea02e | 224 | - Digit ID providing information about the location of the digit (DE ID, Manu ID, Manu channel and cathode) |
225 | - Raw charge (ADC value) | |
226 | - Calibrated charge | |
a2d5f607 | 227 | - One saturation bit and one calibration bit to say whether it is saturated/calibrated or not |
b1fea02e | 228 | |
229 | ||
230 | \section rec_s6 Conversion between MUON/ESD objects | |
231 | ||
a2d5f607 | 232 | Every conversion between MUON objects (AliMUONVDigit/AliMUONVCluster/AliMUONTrack) and ESD objects |
b1fea02e | 233 | (AliESDMuonPad/AliESDMuonCluster/AliESDMuonTrack) is done by the class AliMUONESDInterface. There are 2 ways of using this class: |
234 | ||
235 | 1) Using the static methods to convert the objects one by one (and possibly put them into the provided store): | |
236 | - Get track parameters at vertex, at DCA, ...: | |
237 | \verbatim | |
238 | ... | |
4c29c3c5 | 239 | AliESDMuonTrack* esdTrack = esd->GetMuonTrack(iTrack); |
b1fea02e | 240 | AliMUONTrackParam param; |
241 | AliMUONESDInterface::GetParamAtVertex(*esdTrack, param); | |
242 | \endverbatim | |
243 | ||
244 | - Convert an AliMUONVDigit to an AliESDMuonPad: | |
245 | \verbatim | |
246 | ... | |
247 | AliMUONVDigit *digit = ...; | |
248 | AliESDMuonPad esdPad; | |
249 | AliMUONESDInterface::MUONToESD(*digit, esdPad); | |
250 | \endverbatim | |
251 | ||
252 | - Convert an AliMUONLocalTrigger to a ghost AliESDMuonTrack (containing only trigger informations): | |
253 | \verbatim | |
254 | ... | |
255 | AliMUONLocalTrigger* locTrg = ...; | |
a2d5f607 | 256 | AliMUONTriggerTrack* triggerTrack = ...; |
b1fea02e | 257 | AliESDMuonTrack esdTrack; |
a2d5f607 | 258 | AliMUONESDInterface::MUONToESD(*locTrg, esdTrack, trackId, triggerTrack); |
b1fea02e | 259 | \endverbatim |
260 | ||
261 | - Convert an AliESDMuonTrack to an AliMUONTrack: | |
262 | \verbatim | |
263 | ... | |
4c29c3c5 | 264 | AliESDMuonTrack* esdTrack = esd->GetMuonTrack(iTrack); |
b1fea02e | 265 | AliMUONTrack track; |
266 | AliMUONESDInterface::ESDToMUON(*esdTrack, track); | |
267 | \endverbatim | |
268 | ||
4c29c3c5 | 269 | - Add an AliESDMuonTrack (converted into AliMUONTrack object) into an AliMUONVTrackStore: |
b1fea02e | 270 | \verbatim |
271 | ... | |
4c29c3c5 | 272 | AliESDMuonTrack* esdTrack = esd->GetMuonTrack(iTrack); |
b1fea02e | 273 | AliMUONVTrackStore *trackStore = AliMUONESDInteface::NewTrackStore(); |
4c29c3c5 | 274 | AliMUONTrack* trackInStore = AliMUONESDInterface::Add(*esdTrack, *trackStore); |
b1fea02e | 275 | \endverbatim |
276 | ||
277 | 2) Loading an entire ESDEvent and using the finders and/or the iterators to access the corresponding MUON objects: | |
278 | - First load the ESD event: | |
279 | \verbatim | |
280 | AliMUONESDInterface esdInterface; | |
281 | esdInterface.LoadEvent(*esd); | |
282 | \endverbatim | |
283 | ||
284 | - Get the track store: | |
285 | \verbatim | |
286 | AliMUONVTrackStore* trackStore = esdInterface.GetTracks(); | |
287 | \endverbatim | |
288 | ||
289 | - Access the number of digits in a particular cluster: | |
290 | \verbatim | |
291 | Int_t nDigits = esdInterface.GetNDigitsInCluster(clusterId); | |
292 | \endverbatim | |
293 | ||
294 | - Find a particular digit using its ID: | |
295 | \verbatim | |
296 | AliMUONVDigit *digit = esdInterface.FindDigit(digitId); | |
297 | \endverbatim | |
298 | ||
299 | - Find a particular cluster in a given track using their IDs: | |
300 | \verbatim | |
301 | AliMUONVCluster* cluster = esdInterface.FindCluster(trackId, clusterId); | |
302 | \endverbatim | |
303 | ||
304 | - Iterate over all clusters of a particular track using an iterator: | |
305 | \verbatim | |
306 | TIterator* nextCluster = esdInterface.CreateClusterIterator(trackId); | |
307 | while ((cluster = static_cast<AliMUONVCluster*>(nextCluster()))) {...} | |
308 | \endverbatim | |
309 | ||
310 | Note: You can change (via static method) the type of the store this class is using: | |
311 | \verbatim | |
312 | AliMUONESDInterface::UseTrackStore("name"); | |
313 | AliMUONESDInterface::UseClusterStore("name"); | |
314 | AliMUONESDInterface::UseDigitStore("name"); | |
315 | AliMUONESDInterface::UseTriggerStore("name"); | |
316 | \endverbatim | |
317 | ||
318 | ||
319 | \section rec_s7 ESD cluster/track refitting | |
320 | ||
321 | We can re-clusterize and re-track the clusters/tracks stored into the ESD by using the class AliMUONRefitter. This class gets the MUON objects | |
322 | to be refitted from an instance of AliMUONESDInterface (see section @ref rec_s6), then uses the reconstruction framework to refit the | |
323 | objects. The reconstruction parameters are still set via the class AliMUONRecoParam (see section @ref rec_s5). The initial data are not changed. | |
a2d5f607 | 324 | Results are stored into new MUON objects. The aim of the refitting is to be able to study effects of changing the reconstruction parameter, the |
325 | calibration parameters or the alignment without re-running the entire reconstruction. | |
fd3ef136 | 326 | |
b1fea02e | 327 | To use this class we first have to connect it to the ESD interface containing MUON objects: |
328 | \verbatim | |
329 | AliMUONRefitter refitter; | |
330 | refitter.Connect(&esdInterface); | |
331 | \endverbatim | |
fd3ef136 | 332 | |
b1fea02e | 333 | We can then: |
334 | - Re-clusterize the ESD clusters using the attached ESD pads (several new clusters can be reconstructed per ESD cluster): | |
335 | \verbatim | |
336 | AliMUONVClusterStore* clusterStore = refitter.ReClusterize(iTrack, iCluster); | |
337 | AliMUONVClusterStore* clusterStore = refitter.ReClusterize(clusterId); | |
338 | \endverbatim | |
339 | ||
340 | - Re-fit the ESD tracks using the attached ESD clusters: | |
341 | \verbatim | |
342 | AliMUONTrack* track = refitter.RetrackFromClusters(iTrack); | |
343 | AliMUONVTrackStore* trackStore = refitter.ReconstructFromClusters(); | |
344 | \endverbatim | |
345 | ||
346 | - Reconstruct the ESD tracks from ESD pads (i.e. re-clusterize the attached clusters). Consider all the combination of clusters and return only | |
347 | the best one: | |
348 | \verbatim | |
349 | AliMUONTrack* track = refitter.RetrackFromDigits(iTrack); | |
350 | AliMUONVTrackStore* trackStore = refitter.ReconstructFromDigits(); | |
351 | \endverbatim | |
fd3ef136 | 352 | |
b1fea02e | 353 | The macro MUONRefit.C is an example of using this class. The results are stored in a new AliESDs.root file. |
fd3ef136 | 354 | |
91509ec6 | 355 | |
aa36dc36 | 356 | This chapter is defined in the READMErec.txt file. |
91509ec6 | 357 | |
358 | */ |