Basic (certainly too much) cluster finder based on center-of-gravity

(Laurent)

diff --git a/MUON/AliMUONClusterFinderCOG.cxx b/MUON/AliMUONClusterFinderCOG.cxx
new file mode 100644 (file)
index 0000000..33f079c
--- /dev/null
+++ b/MUON/AliMUONClusterFinderCOG.cxx
@@ -0,0 +1,177 @@
+/**************************************************************************
+* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+*                                                                        *
+* Author: The ALICE Off-line Project.                                    *
+* Contributors are mentioned in the code where appropriate.              *
+*                                                                        *
+* Permission to use, copy, modify and distribute this software and its   *
+* documentation strictly for non-commercial purposes is hereby granted   *
+* without fee, provided that the above copyright notice appears in all   *
+* copies and that both the copyright notice and this permission notice   *
+* appear in the supporting documentation. The authors make no claims     *
+* about the suitability of this software for any purpose. It is          *
+* provided "as is" without express or implied warranty.                  *
+**************************************************************************/
+
+// $Id$
+
+#include "AliMUONClusterFinderCOG.h"
+
+#include "AliLog.h"
+#include "AliMUONCluster.h"
+#include "AliMUONDigit.h"
+#include "AliMUONPad.h"
+#include "AliMUONPreClusterFinder.h"
+#include "AliMpArea.h"
+#include "TClonesArray.h"
+#include "TVector2.h"
+
+/// \class AliMUONClusterFinderCOG
+///
+/// A very basic (and mostly useless, probably) cluster finder.
+/// 
+/// We use AliMUONPreClusterFinder to actually build the cluster,
+/// and then we simply use center-of-gravity to get the coordinates
+/// of the cluster.
+/// Only point to note is that we compute separately both
+/// cathodes when doing, in order to take the positions from the 
+/// direction with the better resolution.
+///
+/// \author Laurent Aphecetche
+
+/// \nocond CLASSIMP
+ClassImp(AliMUONClusterFinderCOG)
+/// \endcond
+
+//_____________________________________________________________________________
+AliMUONClusterFinderCOG::AliMUONClusterFinderCOG()
+: AliMUONVClusterFinder(),
+fPreClusterFinder(0x0)
+{
+  /// ctor
+}
+
+//_____________________________________________________________________________
+AliMUONClusterFinderCOG::~AliMUONClusterFinderCOG()
+{
+  /// dtor
+  delete fPreClusterFinder;
+}
+
+//_____________________________________________________________________________
+Bool_t 
+AliMUONClusterFinderCOG::Prepare(const AliMpVSegmentation* segmentations[2],
+                                       TClonesArray* digits[2])
+{
+  /// Prepare for clustering
+  
+  // Find out the DetElemId
+  Int_t detElemId(-1);
+  
+  for ( Int_t i = 0; i < 2; ++i )
+  {
+    AliMUONDigit* d = static_cast<AliMUONDigit*>(digits[i]->First());
+    if (d)
+    {
+      detElemId = d->DetElemId();
+      break;
+    }
+  }
+  
+  if ( detElemId < 0 )
+  {
+    AliWarning("Could not find DE. Probably no digits at all ?");
+    return kFALSE;
+  }
+  
+  delete fPreClusterFinder;
+  fPreClusterFinder = new AliMUONPreClusterFinder;
+  return fPreClusterFinder->Prepare(segmentations,digits);
+}
+
+//_____________________________________________________________________________
+AliMUONCluster* 
+AliMUONClusterFinderCOG::NextCluster()
+{
+  /// Get next cluster
+  
+  if ( !fPreClusterFinder ) return 0x0;
+  AliMUONCluster* cluster = fPreClusterFinder->NextCluster();
+  if ( cluster )
+  {
+    ComputePosition(*cluster);
+
+    if ( cluster->Charge() < 7 )
+    {
+      // skip that one
+      return NextCluster();
+    }    
+  }
+  return cluster;
+}
+
+//_____________________________________________________________________________
+void 
+AliMUONClusterFinderCOG::ComputePosition(AliMUONCluster& cluster)
+{
+  /// Compute a first estimate of cluster position by a basic center-of-gravity
+  
+  Double_t xmin = 1E9;
+  Double_t ymin = 1E9;
+  Double_t xmax = -1E9;
+  Double_t ymax = -1E9;
+  
+  Double_t x[] = { 0.0, 0.0 };
+  Double_t y[] = { 0.0, 0.0 };
+  
+  Double_t xsize[] = { 0.0, 0.0 } ;
+  Double_t ysize[] = { 0.0, 0.0 } ;
+  
+  for ( Int_t cathode = 0; cathode < 2; ++cathode )
+  {
+    for ( Int_t i = 0; i < cluster.Multiplicity(); ++i )
+    {
+      AliMUONPad* pad = cluster.Pad(i);
+      TVector2 padPosition = pad->Position();
+      AliMpArea area(pad->Position(),pad->Dimensions());
+      xmin = std::min(area.LeftBorder(),xmin);
+      xmax = std::max(area.RightBorder(),xmax);
+      ymin = std::min(area.DownBorder(),ymin);
+      ymax = std::max(area.UpBorder(),ymax);
+      if ( cathode == pad->Cathode() )
+      {
+        x[cathode] += padPosition.X()*pad->Charge();
+        y[cathode] += padPosition.Y()*pad->Charge();
+        xsize[cathode] += pad->Dimensions().X();
+        ysize[cathode] += pad->Dimensions().Y();
+      }
+    }
+    if ( cluster.Charge(cathode) )
+    {
+      x[cathode] /= cluster.Charge(cathode);
+      y[cathode] /= cluster.Charge(cathode);
+    }
+    if ( cluster.Multiplicity(cathode) )
+    {
+      xsize[cathode] /= cluster.Multiplicity(cathode);
+      ysize[cathode] /= cluster.Multiplicity(cathode);
+    }
+  }
+  
+  Double_t xCOG = 0;
+  Double_t yCOG = 0;
+
+  // take the positions from the direction with the better resolution
+  xCOG = ( xsize[0] < xsize[1] ) ? x[0] : x[1];
+  yCOG = ( ysize[0] < ysize[1] ) ? y[0] : y[1];
+  
+  AliDebug(1,Form("Cluster mult %d (x,y)=(%e,%e) boundaries=(xmin,ymin,xmax,ymax)=(%e,%e,%e,%e)"
+                  " (x0,y0,x1,y1)=(%e,%e,%e,%e) ",
+                  cluster.Multiplicity(),xCOG,yCOG,xmin,ymin,xmax,ymax,
+                  x[0],y[0],x[1],y[1]));
+  
+  cluster.SetPosition(TVector2(xCOG,yCOG),cluster.Pad(0)->Dimensions()); // FIXME: what to put as an error here ?
+}
+
+
+

diff --git a/MUON/AliMUONClusterFinderCOG.h b/MUON/AliMUONClusterFinderCOG.h
new file mode 100644 (file)
index 0000000..51d9edd
--- /dev/null
+++ b/MUON/AliMUONClusterFinderCOG.h
@@ -0,0 +1,43 @@
+#ifndef ALIMUONCLUSTERFINDERCOG_H
+#define ALIMUONCLUSTERFINDERCOG_H
+
+/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+* See cxx source for full Copyright notice                               */
+
+// $Id$
+
+/// \ingroup rec
+/// \class AliMUONClusterFinderCOG
+/// \brief A very basic (and mostly useless, probably) cluster finder
+/// 
+// Author Laurent Aphecetche, Subatech
+
+#ifndef AliMUONVCLUSTERFINDER_H
+#  include "AliMUONVClusterFinder.h"
+#endif
+
+class AliMUONMathieson;
+
+class AliMUONClusterFinderCOG : public AliMUONVClusterFinder
+{
+public:
+  AliMUONClusterFinderCOG();
+  virtual ~AliMUONClusterFinderCOG();
+  
+  virtual Bool_t Prepare(const AliMpVSegmentation* segmentations[2],
+                         TClonesArray* digits[2]);
+  
+  virtual AliMUONCluster* NextCluster();
+  
+private:
+  AliMUONClusterFinderCOG(const AliMUONClusterFinderCOG& rhs);
+  AliMUONClusterFinderCOG& operator=(const AliMUONClusterFinderCOG& rhs);
+  void ComputePosition(AliMUONCluster& cluster);
+
+private:
+    AliMUONVClusterFinder* fPreClusterFinder; ///< the preclustering we use
+
+  ClassDef(AliMUONClusterFinderCOG,1) // 
+};
+
+#endif