Added some extra CF plots and changed binning for a few histograms (kathrin) anddded...

[u/mrichter/AliRoot.git] / STEER / AliVParticle.cxx

diff --git a/STEER/AliVParticle.cxx b/STEER/AliVParticle.cxx
index 56effb0537f4a43a4cf0d1eeedb23057fe3e7305..b0e37e27c95a9803364ee5793fa16ba9f1010302 100644 (file)
--- a/STEER/AliVParticle.cxx
+++ b/STEER/AliVParticle.cxx
@@ -21,6 +21,7 @@
 //-------------------------------------------------------------------------
 
 #include "AliVParticle.h"
+#include "TMath.h"
 
 ClassImp(AliVParticle)
 
@@ -34,3 +35,81 @@ AliVParticle& AliVParticle::operator=(const AliVParticle& vPart)
   
   return *this; 
 }
+
+Bool_t AliVParticle::Local2GlobalMomentum(Double_t p[3], Double_t alpha) const {
+  //----------------------------------------------------------------
+  // This function performs local->global transformation of the
+  // track momentum.
+  // When called, the arguments are:
+  //    p[0] = 1/pt * charge of the track;
+  //    p[1] = sine of local azim. angle of the track momentum;
+  //    p[2] = tangent of the track momentum dip angle;
+  //   alpha - rotation angle. 
+  // The result is returned as:
+  //    p[0] = px
+  //    p[1] = py
+  //    p[2] = pz
+  // Results for (nearly) straight tracks are meaningless !
+  //----------------------------------------------------------------
+  if (TMath::Abs(p[0])<=kAlmost0) return kFALSE;
+  if (TMath::Abs(p[1])> kAlmost1) return kFALSE;
+
+  Double_t pt=1./TMath::Abs(p[0]);
+  Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha);
+  Double_t r=TMath::Sqrt((1. - p[1])*(1. + p[1]));
+  p[0]=pt*(r*cs - p[1]*sn); p[1]=pt*(p[1]*cs + r*sn); p[2]=pt*p[2];
+
+  return kTRUE;
+}
+
+Bool_t AliVParticle::Local2GlobalPosition(Double_t r[3], Double_t alpha) const {
+  //----------------------------------------------------------------
+  // This function performs local->global transformation of the
+  // track position.
+  // When called, the arguments are:
+  //    r[0] = local x
+  //    r[1] = local y
+  //    r[2] = local z
+  //   alpha - rotation angle. 
+  // The result is returned as:
+  //    r[0] = global x
+  //    r[1] = global y
+  //    r[2] = global z
+  //----------------------------------------------------------------
+  Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha), x=r[0];
+  r[0]=x*cs - r[1]*sn; r[1]=x*sn + r[1]*cs;
+
+  return kTRUE;
+}
+
+Bool_t AliVParticle::Global2LocalMomentum(Double_t p[3], Short_t charge, Double_t &alpha) const {
+  //----------------------------------------------------------------
+  // This function performs global->local transformation of the
+  // track momentum.
+  // When called, the arguments are:
+  //    p[0] = px
+  //    p[1] = py
+  //    p[2] = pz
+  //   charge - of the track
+  //   alpha - rotation angle. 
+  // The result is returned as:
+  //    p[0] = 1/pt * charge of the track;
+  //    p[1] = sine of local azim. angle of the track momentum;
+  //    p[2] = tangent of the track momentum dip angle;
+  // Results for (nearly) straight tracks are meaningless !
+  //----------------------------------------------------------------
+  double pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
+  if (pt == 0.) return kFALSE;
+  alpha = TMath::Pi() + TMath::ATan2(-p[1], -p[0]);
+  
+  p[0] = 1./pt * (float)charge;
+  p[1] = 0.;
+  p[2] = p[2]/pt;
+
+  return kTRUE;
+}
+
+Bool_t AliVParticle::Global2LocalPosition(Double_t r[3], Double_t alpha) const {
+  return Local2GlobalPosition(r, -alpha);
+}
+