Added function GetEstimatedCrossPoint to evaluate most probable track

point in the x-z plane for the case of row cross tracklet

diff --git a/TRD/AliTRDseedV1.cxx b/TRD/AliTRDseedV1.cxx
index fd53b09399eba2e5a26ae952875a6ee589e188a2..3061dcd826838582246031483ba42f7c66ff596b 100644 (file)
--- a/TRD/AliTRDseedV1.cxx
+++ b/TRD/AliTRDseedV1.cxx
@@ -497,6 +497,47 @@ Float_t AliTRDseedV1::GetCharge(Bool_t useOutliers)
   return qt;
 }
 
+//____________________________________________________________________
+Bool_t AliTRDseedV1::GetEstimatedCrossPoint(Float_t &x, Float_t &z) const
+{
+// Algorithm to estimate cross point in the x-z plane for pad row cross tracklets.
+// Returns true in case of success.
+  if(!IsRowCross()) return kFALSE;
+
+  x=0.; z=0.;
+  AliTRDcluster *c(NULL);
+  // Find radial range for first row
+  Float_t x1[] = {0., 1.e3};
+  for(int ic=0; ic<kNtb; ic++){
+    if(!(c=fClusters[ic])) continue;
+    if(!c->IsInChamber()) continue;
+    if(c->GetX() <= x1[1]) x1[1] = c->GetX();
+    if(c->GetX() >= x1[0]) x1[0] = c->GetX();
+    z=c->GetZ();
+  }
+  if((x1[0] - x1[1])<1.e-5) return kFALSE;
+
+  // Find radial range for second row
+  Bool_t kZ(kFALSE);
+  Float_t x2[] = {0., 1.e3};
+  for(int ic=kNtb; ic<kNclusters; ic++){
+    if(!(c=fClusters[ic])) continue;
+    if(!c->IsInChamber()) continue;
+    if(c->GetX() <= x2[1]) x2[1] = c->GetX();
+    if(c->GetX() >= x2[0]) x2[0] = c->GetX();
+    if(!kZ){
+      z+=c->GetZ();
+      z*=0.5;
+      kZ=kTRUE;
+    }
+  }
+  if((x2[0] - x2[1])<1.e-5) return kFALSE;
+
+  // Find intersection of the 2 radial regions
+  x = 0.5*((x1[0]+x1[1] > x2[0]+x2[1]) ? (x1[1]+x2[0]) : (x1[0]+x2[1]));
+  return kTRUE;
+}
+
 //____________________________________________________________________
 Float_t AliTRDseedV1::GetdQdl(Int_t ic, Float_t *dl) const
 {

diff --git a/TRD/AliTRDseedV1.h b/TRD/AliTRDseedV1.h
index 2277f1dcc1eac8bdd30c52d961b4fad36e0bb600..f2cac2d9b01649801753a448905494b3e4d84894 100644 (file)
--- a/TRD/AliTRDseedV1.h
+++ b/TRD/AliTRDseedV1.h
@@ -129,6 +129,7 @@ public:
   void      GetCalibParam(Float_t &exb, Float_t &vd, Float_t &t0, Float_t &s2, Float_t &dl, Float_t &dt) const    { 
               exb = fExB; vd = fVD; t0 = fT0; s2 = fS2PRF; dl = fDiffL; dt = fDiffT;}
   AliTRDcluster*  GetClusters(Int_t i) const               { return i<0 || i>=kNclusters ? NULL: fClusters[i];}
+  Bool_t    GetEstimatedCrossPoint(Float_t &x, Float_t &z) const;
   Int_t     GetIndexes(Int_t i) const{ return i<0 || i>=kNclusters ? -1 : fIndexes[i];}
   Int_t     GetLabels(Int_t i) const { return fLabels[i];}  
   Float_t   GetMomentum(Float_t *err = NULL) const;