New version of AliGeVSim code. New class for flow afterburner (S.Radomski)

[u/mrichter/AliRoot.git] / EVGEN / AliGeVSimParticle.cxx

diff --git a/EVGEN/AliGeVSimParticle.cxx b/EVGEN/AliGeVSimParticle.cxx
index a69f9525d2430ac93766f05cddc2195da6f06205..311b7b8ac3b6cd05ed11fbf3188fb97b2a6fa32a 100644 (file)
--- a/EVGEN/AliGeVSimParticle.cxx
+++ b/EVGEN/AliGeVSimParticle.cxx
@@ -1,28 +1,51 @@
-
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// AliGeVSimParticle is a helper class for GeVSim (AliGenGeVSim) event generator.
+// An object of this class represents one particle type and contain 
+// information about particle type thermal parameters.
+//
+// For examples, parameters and testing macros refer to:
+// http:/home.cern.ch/radomski
+//
+// Author:
+// Sylwester Radomski,
+// GSI, March 2002
+// 
+// S.Radomski@gsi.de
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include "TMath.h"
 #include "AliGeVSimParticle.h"
 
 ClassImp(AliGeVSimParticle);
 
+////////////////////////////////////////////////////////////////////////////////////////////////////
 
-////////////////////////////////////////////////////////////////////////////
-
-AliGeVSimParticle::AliGeVSimParticle
-(Int_t pdg, Int_t n, Float_t T, Float_t dY, Float_t exp) {
-
+AliGeVSimParticle::AliGeVSimParticle(Int_t pdg, Int_t n, Float_t T, Float_t dY, Float_t exp) {
+  //
+  //  pdg - Particle type code in PDG standard (see: http://pdg.lbl.gov)
+  //  n   - Multiplicity of particle type
+  //  T   - Inverse slope parameter ("temperature")
+  //  dY  - Raridity Width (only for model 1)
+  //  exp - expansion velocity (only for model 4) 
+  
   fPDG = pdg;
   fN = n;
   fT = T;
   fSigmaY = dY;
   fExpansion = exp;
 
-  fV1 = 0.;
-  fV2 = 0.;
+  fV1[0] = fV1[1] = fV1[2] = fV1[3] = 0.;
+  fV2[0] = fV2[1] = fV2[2] = 0.;
 }
 
-////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////
 
-AliGeVSimParticle::AliGeVSimParticle
-(Int_t pdg) {
+AliGeVSimParticle::AliGeVSimParticle(Int_t pdg) {
+  //
+  //  pdg - Particle type code in PDG standard (see: http://pdg.lbl.gov)
+  // 
 
   fPDG = pdg;
   fN = 0;
@@ -30,26 +53,105 @@ AliGeVSimParticle::AliGeVSimParticle
   fSigmaY = 0.;
   fExpansion = 0.;
   
-  fV1 = 0.;
-  fV2 = 0.;
+  fV1[0] = fV1[1] = fV1[2] = fV1[3] = 0.;
+  fV2[0] = fV2[1] = fV2[2] = 0.; 
 }
 
-////////////////////////////////////////////////////////////////////////////
-
-
-
-
-
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+void AliGeVSimParticle::SetDirectedFlow(Float_t v11, Float_t v12, Float_t v13, Float_t v14) {
+  //
+  // Set Directed Flow parameters.
+  // Acctual flow coefficient is calculated as follows
+  //
+  // V1(Pt,Y) = (V11 + V12*Pt) * sign(Y) * (V13 + V14 * Y^3)
+  //
+  // where sign = 1 for Y > 0 and -1 for Y < 0
+  // 
+  // Defaults values
+  // v12 = v14 = 0
+  // v13 = 1
+  // 
+  // Note 1: In many cases it is sufficient to set v11 only.
+  // Note 2: Be carefull with parameter v14
+  // 
+
+
+  fV1[0] = v11;
+  fV1[1] = v12;
+  fV1[2] = v13;
+  fV1[3] = v14;
+}
 
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+void AliGeVSimParticle::SetEllipticFlow(Float_t v21, Float_t v22, Float_t v23) {
+  //
+  // Set Elliptic Flow parameters.
+  // Acctual flow coefficient is calculated as follows
+  //
+  // V2 = (V21 + V22 * Pt^2) * exp( -V23 * Y^2)
+  // 
+  // Default values:
+  // v22 = v23 = 0
+  //
+  // Note: In many cases it is sufficient to set v21 only
+  //
+  
+  fV2[0] = v21;
+  fV2[1] = v22;
+  fV2[2] = v23;
+}
 
+////////////////////////////////////////////////////////////////////////////////////////////////////
 
+Float_t AliGeVSimParticle::GetDirectedFlow(Float_t pt, Float_t y) {
+  //
+  // Return coefficient of a directed flow for a given pt and y.
+  // For coefficient calculation method refer to SetDirectedFlow()
+  // 
+  
+  Float_t v;
+  
+  v = (fV1[0] + fV1[1]* pt) * TMath::Sign(1.,y) *
+    (fV1[2] + fV1[3] * TMath::Abs(y*y*y) );
 
+  return v;
+}
 
+////////////////////////////////////////////////////////////////////////////////////////////////////
 
+Float_t AliGeVSimParticle::GetEllipticFlow(Float_t pt, Float_t y) {
+  //
+  // Return coefficient of a elliptic flow for a given pt and y.
+  // For coefficient calculation method refer to SetEllipticFlow()
+  // 
+    
+  return  (fV2[0] + fV2[2] * pt * pt) * TMath::Exp( -fV2[3] * y*y );
+}
 
+////////////////////////////////////////////////////////////////////////////////////////////////////
 
+Float_t AliGeVSimParticle::GetDirectedFlow() {
+  //
+  // Simplified version of GetDirectedFlow(pt,y) for backward compatibility
+  // Return fV1[0]
+  //
+  
+  return fV1[0];
+}
 
+////////////////////////////////////////////////////////////////////////////////////////////////////
+Float_t AliGeVSimParticle::GetEllipticFlow() {
+  //
+  // Simplified version of GetEllipticFlow(pt,y) for backward compatibility
+  // Return fV2[0]
+  //
+  
+  return fV2[0];
+}
 
+////////////////////////////////////////////////////////////////////////////////////////////////////