Cluster finder, just gather the neighbourginp pads = precluster
[u/mrichter/AliRoot.git] / MUON / AliMUONPreClusterFinder.cxx
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18466557 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 "AliMUONPreClusterFinder.h"
19
20#include "AliLog.h"
21#include "AliMUONCluster.h"
22#include "AliMpVSegmentation.h"
23#include "TClonesArray.h"
24#include "AliMpArea.h"
25#include "TVector2.h"
26#include "AliMUONPad.h"
27#include "AliMUONDigit.h"
28
29/// \class AliMUONPreClusterFinder
30///
31/// Implementation of AliMUONVClusterFinder
32///
33/// This class simply find adjacent pads to form clusters
34///
35/// \author Laurent Aphecetche
36
37ClassImp(AliMUONPreClusterFinder)
38
39//_____________________________________________________________________________
40AliMUONPreClusterFinder::AliMUONPreClusterFinder()
41: AliMUONVClusterFinder(),
42 fClusters(0x0),
43 fSegmentations(0x0),
44 fDigits(0x0),
45 fDetElemId(0)
46{
47 /// ctor
48 for ( Int_t i = 0; i < 2; ++i )
49 {
50 fPads[i] = 0x0;
51 }
52}
53
54//_____________________________________________________________________________
55AliMUONPreClusterFinder::~AliMUONPreClusterFinder()
56{
57 /// dtor : note we're owner of the pads and the clusters, but not of
58 /// the remaining objects (digits, segmentations)
59 delete fClusters;
60 for ( Int_t i = 0; i < 2; ++i )
61 {
62 delete fPads[i];
63 }
64}
65
66//_____________________________________________________________________________
67Bool_t
68AliMUONPreClusterFinder::UsePad(const AliMUONPad& pad)
69{
70 /// Add a pad to the list of pads to be considered
71 if ( pad.DetElemId() != fDetElemId )
72 {
73 AliError(Form("Cannot add pad from DE %d to this cluster finder which is "
74 "currently dealing with DE %d",pad.DetElemId(),fDetElemId));
75 return kFALSE;
76 }
77
78 new ((*fPads[pad.Cathode()])[fPads[pad.Cathode()]->GetLast()+1]) AliMUONPad(pad);
79 // FIXME: should set the ClusterId of that new pad to be -1
80 return kTRUE;
81}
82
83//_____________________________________________________________________________
84Bool_t
85AliMUONPreClusterFinder::Prepare(const AliMpVSegmentation* segmentations[2],
86 TClonesArray* digits[2])
87// FIXME : add area on which to look for clusters here.
88{
89 /// Prepare for clustering, by giving access to segmentations and digit lists
90
91 fSegmentations = segmentations;
92 fDigits = digits;
93
94 delete fClusters;
95 fClusters = new TClonesArray("AliMUONCluster");
96 for ( Int_t i = 0; i < 2; ++i )
97 {
98 delete fPads[i];
99 fPads[i] = new TClonesArray("AliMUONPad");
100 }
101
102 fDetElemId = -1;
103
104 // Converts digits into pads
105 for ( Int_t cathode = 0; cathode < 2; ++cathode )
106 {
107 if ( !digits[cathode] ) continue;
108
109 AliMUONDigit* d;
110 TIter next(digits[cathode]);
111 while ( ( d = static_cast<AliMUONDigit*>(next())))
112 {
113 Int_t ix = d->PadX();
114 Int_t iy = d->PadY();
115 AliMpPad pad = fSegmentations[cathode]->PadByIndices(AliMpIntPair(ix,iy));
116 TClonesArray& padArray = *(fPads[cathode]);
117 if ( fDetElemId == -1 )
118 {
119 fDetElemId = d->DetElemId();
120 }
121 else
122 {
123 if ( d->DetElemId() != fDetElemId )
124 {
125 AliError("Something is seriously wrong with DE. Aborting clustering");
126 return kFALSE;
127 }
128 }
129
130 AliMUONPad mpad(fDetElemId,cathode,
131 ix,iy,pad.Position().X(),pad.Position().Y(),
132 pad.Dimensions().X(),pad.Dimensions().Y(),
133 d->Signal());
134 if ( d->IsSaturated() ) mpad.SetSaturated(kTRUE);
135 new (padArray[padArray.GetLast()+1]) AliMUONPad(mpad);
136 }
137 }
138 if ( fPads[0]->GetLast() < 0 && fPads[1]->GetLast() < 0 )
139 {
140 // no pad at all, nothing to do...
141 return kFALSE;
142 }
143
144 return kTRUE;
145}
146
147//_____________________________________________________________________________
148void
149AliMUONPreClusterFinder::AddPad(AliMUONCluster& cluster, AliMUONPad* pad)
150{
151 /// Add a pad to a cluster
152 cluster.AddPad(*pad);
153
154 Int_t cathode = pad->Cathode();
155 TClonesArray& padArray = *fPads[cathode];
156 padArray.Remove(pad);
157 padArray.Compress();
158 TIter next(&padArray);
159 AliMUONPad* testPad;
160
161 while ( ( testPad = static_cast<AliMUONPad*>(next())))
162 {
163 if ( AliMUONPad::AreNeighbours(*testPad,*pad) )
164 {
165 AddPad(cluster,testPad);
166 }
167 }
168}
169
170//_____________________________________________________________________________
171Bool_t
172AreOverlapping(const AliMUONPad& pad, const AliMUONCluster& cluster)
173{
174 /// Whether the pad overlaps with the cluster
175
176 static Double_t precision = 1E-4; // cm
177 static TVector2 precisionAdjustment(precision,precision);//-precision,-precision);
178 for ( Int_t i = 0; i < cluster.Multiplicity(); ++i )
179 {
180 AliMUONPad* testPad = cluster.Pad(i);
181 // Note: we use negative precision numbers, meaning
182 // the area of the pads will be *increased* by these small numbers
183 // prior to check the overlap by the AreOverlapping method,
184 // so pads touching only by the corners will be considered as
185 // overlapping.
186 if ( AliMUONPad::AreOverlapping(*testPad,pad,precisionAdjustment) )
187 {
188 return kTRUE;
189 }
190 }
191 return kFALSE;
192}
193
194//_____________________________________________________________________________
195AliMUONCluster*
196AliMUONPreClusterFinder::NextCluster()
197{
198 /// Builds the next cluster, and returns it.
199
200 // Start a new cluster
201 Int_t id = fClusters->GetLast()+1;
202 AliMUONCluster* cluster = new ((*fClusters)[id]) AliMUONCluster;
203 cluster->SetUniqueID(id);
204
205 AliMUONPad* pad = static_cast<AliMUONPad*>(fPads[0]->First());
206
207 if (!pad) // protection against no pad in first cathode, which might happen
208 {
209 // try other cathode
210 pad = static_cast<AliMUONPad*>(fPads[1]->First());
211 if (!pad)
212 {
213 // we are done.
214 return 0x0;
215 }
216 // Builds (recursively) a cluster on second cathode only
217 AddPad(*cluster,pad);
218 }
219 else
220 {
221 // Builds (recursively) a cluster on first cathode only
222 AddPad(*cluster,pad);
223
224 // On the 2nd cathode, only add pads overlapping with the current cluster
225 TClonesArray& padArray = *fPads[1];
226 TIter next(&padArray);
227 AliMUONPad* testPad;
228
229 while ( ( testPad = static_cast<AliMUONPad*>(next())))
230 {
231 if ( AreOverlapping(*testPad,*cluster) )
232 {
233 AddPad(*cluster,testPad);
234 }
235 }
236 }
237
238 if ( cluster->Multiplicity() <= 1 )
239 {
240 if ( cluster->Multiplicity() == 0 )
241 {
242 // no pad is suspicious
243 AliWarning("Got an empty cluster...");
244 }
245 // else only 1 pad (not suspicious, but kind of useless, probably noise)
246 // so we remove it from our list
247 fClusters->Remove(cluster);
248 fClusters->Compress();
249 // then proceed further
250 return NextCluster();
251 }
252
253 return cluster;
254}