correct.C
[u/mrichter/AliRoot.git] / MUON / AliMUONPreClusterFinderV2.cxx
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c13ab450 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// $Id$
17
18#include "AliMUONPreClusterFinderV2.h"
19
20#include "AliLog.h"
21#include "AliMUONCluster.h"
22#include "AliMpVSegmentation.h"
6e97fbb8 23#include "AliMpPad.h"
c13ab450 24#include "TClonesArray.h"
25#include "TVector2.h"
26#include "AliMUONPad.h"
27#include "AliMUONVDigit.h"
28#include "AliMUONVDigitStore.h"
29
3d1463c8 30//-----------------------------------------------------------------------------
c13ab450 31/// \class AliMUONPreClusterFinderV2
32///
33/// Implementation of AliMUONVClusterFinder
34///
35/// This one ressembles the preclustering stage in the original ClusterFinderAZ
36///
37/// \author Laurent Aphecetche
3d1463c8 38//-----------------------------------------------------------------------------
c13ab450 39
40ClassImp(AliMUONPreClusterFinderV2)
41
42//_____________________________________________________________________________
43AliMUONPreClusterFinderV2::AliMUONPreClusterFinderV2()
44: AliMUONVClusterFinder(),
45 fClusters(0x0),
72dae9ff 46 fkSegmentations(0x0),
24935e58 47 fPads(0x0),
c13ab450 48 fDetElemId(0)
49{
50 /// ctor
c13ab450 51}
52
53//_____________________________________________________________________________
54AliMUONPreClusterFinderV2::~AliMUONPreClusterFinderV2()
55{
24935e58 56 /// dtor : note we're owner of the clusters, but not of the pads
c13ab450 57 delete fClusters;
c13ab450 58}
59
60//_____________________________________________________________________________
61Bool_t
62AliMUONPreClusterFinderV2::UsePad(const AliMUONPad& pad)
63{
64 /// Add a pad to the list of pads to be considered
65 if ( pad.DetElemId() != fDetElemId )
66 {
67 AliError(Form("Cannot add pad from DE %d to this cluster finder which is "
68 "currently dealing with DE %d",pad.DetElemId(),fDetElemId));
69 return kFALSE;
70 }
71
72 new ((*fPads[pad.Cathode()])[fPads[pad.Cathode()]->GetLast()+1]) AliMUONPad(pad);
73 // FIXME: should set the ClusterId of that new pad to be -1
74 return kTRUE;
75}
76
77//_____________________________________________________________________________
78Bool_t
24935e58 79AliMUONPreClusterFinderV2::Prepare(Int_t detElemId,
80 TClonesArray* pads[2],
81 const AliMpArea& area,
82 const AliMpVSegmentation* seg[2])
c13ab450 83{
84 /// Prepare for clustering, by giving access to segmentations and digit lists
85
24935e58 86 if ( area.IsValid() )
c13ab450 87 {
24935e58 88 AliError("Handling of area not yet implemented for this class. Please check");
c13ab450 89 }
90
24935e58 91 delete fClusters;
92 fClusters = new TClonesArray("AliMUONCluster");
93
94 fPads = pads;
72dae9ff 95 fkSegmentations = seg;
c13ab450 96
24935e58 97 fDetElemId = detElemId;
c13ab450 98
c13ab450 99 if ( fPads[0]->GetLast() < 0 && fPads[1]->GetLast() < 0 )
100 {
101 // no pad at all, nothing to do...
102 return kFALSE;
103 }
104
105 return kTRUE;
106}
107
108//_____________________________________________________________________________
109void
110AliMUONPreClusterFinderV2::AddPad(AliMUONCluster& cluster, AliMUONPad* pad)
111{
112 /// Add a pad to a cluster
113
114 cluster.AddPad(*pad);
115 pad->SetClusterId(cluster.GetUniqueID());
116
117 Int_t cathode = pad->Cathode();
118 TClonesArray& padArray = *fPads[cathode];
119 padArray.Remove(pad);
120 TIter next(&padArray);
121
122 // Check neighbours
123 TObjArray neighbours;
168e9c4d 124 AliMpPad p = fkSegmentations[pad->Cathode()]->PadByIndices(pad->Ix(),pad->Iy(),kTRUE);
72dae9ff 125 Int_t nn = fkSegmentations[pad->Cathode()]->GetNeighbours(p,neighbours);
c13ab450 126 for (Int_t in = 0; in < nn; ++in)
127 {
bf0d3528 128 AliMpPad* p1 = static_cast<AliMpPad*>(neighbours.At(in));
c13ab450 129
bf0d3528 130 TIter next2(&padArray);
c13ab450 131 AliMUONPad* p2;
132
bf0d3528 133 while ( ( p2 = static_cast<AliMUONPad*>(next2()) ) )
c13ab450 134 {
168e9c4d 135 if ( !p2->IsUsed() && p2->Ix()==p1->GetIx()
136 && p2->Iy() == p1->GetIy() &&
c13ab450 137 p2->Cathode() == pad->Cathode() )
138 {
139 AddPad(cluster,p2);
140 }
141 }
142 } // for (Int_t in = 0;
143}
144
145namespace
146{
147//_____________________________________________________________________________
148Bool_t
149AreOverlapping(const AliMUONPad& pad, const AliMUONCluster& cluster)
150{
151 /// Whether the pad overlaps with the cluster
152
153 static Double_t precision = 1E-4; // cm
154 static TVector2 precisionAdjustment(precision,precision);//-precision,-precision);
155 for ( Int_t i = 0; i < cluster.Multiplicity(); ++i )
156 {
157 AliMUONPad* testPad = cluster.Pad(i);
158 // Note: we use negative precision numbers, meaning
159 // the area of the pads will be *increased* by these small numbers
160 // prior to check the overlap by the AreOverlapping method,
161 // so pads touching only by the corners will be considered as
162 // overlapping.
163 if ( AliMUONPad::AreOverlapping(*testPad,pad,precisionAdjustment) )
164 {
165 return kTRUE;
166 }
167 }
168 return kFALSE;
169}
170}
171
172//_____________________________________________________________________________
173AliMUONCluster*
174AliMUONPreClusterFinderV2::NextCluster()
175{
176 /// Builds the next cluster, and returns it.
177
178 // Start a new cluster
179 Int_t id = fClusters->GetLast()+1;
180 AliMUONCluster* cluster = new ((*fClusters)[id]) AliMUONCluster;
181 cluster->SetUniqueID(id);
182
183 AliMUONPad* pad;
184 TIter next(fPads[0]);
94bf739c 185 while ( ( pad = static_cast<AliMUONPad*>(next())) && pad->IsUsed() ) {}
c13ab450 186
187 if (!pad) // protection against no pad in first cathode, which might happen
188 {
189 // try other cathode
bf0d3528 190 TIter next2(fPads[1]);
94bf739c 191 while ( ( pad = static_cast<AliMUONPad*>(next2())) && pad->IsUsed() ) {}
c13ab450 192 if (!pad)
193 {
194 // we are done.
195 return 0x0;
196 }
197 // Builds (recursively) a cluster on second cathode only
198 AddPad(*cluster,pad);
199 }
200 else
201 {
202 // Builds (recursively) a cluster on first cathode only
203
204 AddPad(*cluster,pad);
205
206 // On the 2nd cathode, only add pads overlapping with the current cluster
207 TIter next1(fPads[1]);
208 AliMUONPad* testPad;
209
210 while ( ( testPad = static_cast<AliMUONPad*>(next1())))
211 {
212 if ( !testPad->IsUsed() && AreOverlapping(*testPad,*cluster) )
213 {
214 AddPad(*cluster,testPad);
215 }
216 }
217 }
218
219 if ( cluster->Multiplicity() <= 1 )
220 {
221 if ( cluster->Multiplicity() == 0 )
222 {
223 // no pad is suspicious
224 AliWarning("Got an empty cluster...");
225 }
226 // else only 1 pad (not suspicious, but kind of useless, probably noise)
227 // so we remove it from our list
228 fClusters->Remove(cluster);
229 fClusters->Compress();
230 // then proceed further
231 return NextCluster();
232 }
233
234 return cluster;
235}