ECCE @ EIC Software
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
G4VHadPhaseSpaceAlgorithm.cc
Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file G4VHadPhaseSpaceAlgorithm.cc
1 //
2 // ********************************************************************
3 // * License and Disclaimer *
4 // * *
5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. *
10 // * *
11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitation of liability. *
17 // * *
18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Software license. *
24 // ********************************************************************
25 //
26 //
27 // Abstract base class for multibody uniform phase space generators.
28 // Subclasses implement a specific algorithm, such as Kopylov, GENBOD,
29 // or Makoto's NBody. Subclasses are used by G4HadDecayGenerator.
30 //
31 // Author: Michael Kelsey (SLAC) <kelsey@slac.stanford.edu>
32 
34 #include "G4HadronicException.hh"
35 #include "G4PhysicalConstants.hh"
36 #include "G4SystemOfUnits.hh"
37 #include "G4ThreeVector.hh"
38 #include "Randomize.hh"
39 #include <algorithm>
40 #include <iostream>
41 #include <iterator>
42 #include <numeric>
43 #include <vector>
44 
45 
46 
47 
48 // Two body decay with uniform angular distribution
49 
52  const std::vector<G4double>& masses,
53  std::vector<G4LorentzVector>& finalState) {
54  if (GetVerboseLevel()>1)
55  G4cout << " >>> G4HadDecayGenerator::FillTwoBody" << G4endl;
56 
57  // Initialization and sanity check
58  finalState.clear();
59  if (masses.size() != 2U) return; // Should not have been called
60 
61  // Momentum of final state (energy balance has already been checked)
62  G4double p = TwoBodyMomentum(initialMass,masses[0],masses[1]);
63  if (GetVerboseLevel()>2) G4cout << " finalState momentum = " << p << G4endl;
64 
65  finalState.resize(2); // Allows filling by index
66  finalState[0].setVectM(UniformVector(p), masses[0]);
67  finalState[1].setVectM(-finalState[0].vect(), masses[1]);
68 }
69 
70 
71 // Samples a random vector with given magnitude
72 
74  // FIXME: Should this be made a static thread-local buffer?
77  return v;
78 }