G4CascadeCoalescence.cc

Go to the documentation of this file.

//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
// G4CascadeCoalescence:  Factory model for final-state interactions to
//   produce light ions from cascade nucleons.  The algorithm implemented
//   here is descirbed in Section 2.3 of the LAQGSM documentation (p. 11-12)
//   [http://lib-www.lanl.gov/la-pubs/00818645.pdf].
//
// The relative-momentum cut offs for each cluster type may be set with
// environment variables:
//  DPMAX_2CLUSTER      0.090 GeV/c for deuterons
//  DPMAX_3CLUSTER      0.108 GeV/c for tritons, He-3
//  DPMAX_4CLUSTER      0.115 GeV/c for alphas
//
// 20110917  Michael Kelsey
// 20110920  M. Kelsey -- Use environment variables to set momentum cuts for
//       tuning, replace polymorphic argument lists with use of
//       "ClusterCandidate"
// 20110922  M. Kelsey -- Follow G4InuclParticle::print(ostream&) migration
// 20110927  M. Kelsey -- Bug fix; missing <iterator> header, strtof -> strtod
// 20120822  M. Kelsey -- Move envvars to G4CascadeParameters.
// 20130314  M. Kelsey -- Restore null initializer and if-block for _TLS_.
// 20130326  M. Kelsey -- Replace _TLS_ with mutable data member buffer.
// 20170406  M. Kelsey -- Remove recursive tryCluster() calls (redundant),
//       and remove use of triedClusters registry.
 
#include "G4CascadeCoalescence.hh"
#include "G4CascadeParameters.hh"
#include "G4CollisionOutput.hh"
#include "G4InuclElementaryParticle.hh"
#include "G4InuclNuclei.hh"
#include "G4InuclParticle.hh"
#include "G4ParticleLargerBeta.hh"
#include "G4ParticleLargerEkin.hh"
#include "G4ThreeVector.hh"
#include <vector>
#include <numeric>
#include <algorithm>
#include <iterator>
 
 
// Constructor and Destructor
 
G4CascadeCoalescence::G4CascadeCoalescence(G4int verbose)
  : verboseLevel(verbose), thisFinalState(0), thisHadrons(0),
    dpMaxDoublet(G4CascadeParameters::dpMaxDoublet()),
    dpMaxTriplet(G4CascadeParameters::dpMaxTriplet()),
    dpMaxAlpha(G4CascadeParameters::dpMaxAlpha()) {}
 
G4CascadeCoalescence::~G4CascadeCoalescence() {}
 
 
// Final state particle list is modified directly
 
void G4CascadeCoalescence::FindClusters(G4CollisionOutput& finalState) {
  if (verboseLevel)
    G4cout << " >>> G4CascadeCoalescence::FindClusters()" << G4endl;
 
  thisFinalState = &finalState;     // Save pointers for use in processing
  thisHadrons = &finalState.getOutgoingParticles();
 
  if (verboseLevel>1) thisFinalState->printCollisionOutput();   // Before
 
  selectCandidates();
  createNuclei();
  removeNucleons();
 
  if (verboseLevel>1) thisFinalState->printCollisionOutput();   // After
}
 
 
// Scan list for possible nucleon clusters
 
void G4CascadeCoalescence::selectCandidates() {
  if (verboseLevel)
    G4cout << " >>> G4CascadeCoalescence::selectCandidates()" << G4endl;
 
  allClusters.clear();
  usedNucleons.clear();
 
  size_t nHad = thisHadrons->size();
  for (size_t idx1=0; idx1<nHad; idx1++) {
    if (!getHadron(idx1).nucleon()) continue;
    for (size_t idx2=idx1+1; idx2<nHad; idx2++) {
      if (!getHadron(idx2).nucleon()) continue;
      for (size_t idx3=idx2+1; idx3<nHad; idx3++) {
    if (!getHadron(idx3).nucleon()) continue;
    for (size_t idx4=idx3+1; idx4<nHad; idx4++) {
      if (!getHadron(idx4).nucleon()) continue;
      tryClusters(idx1, idx2, idx3, idx4);
    }
    tryClusters(idx1, idx2, idx3);      // If idx4 loop was empty
      }
      tryClusters(idx1, idx2);          // If idx3 loop was empty
    }
  }
 
  // All potential candidates built; report statistics
  if (verboseLevel>1) {
    G4cout << " Found " << allClusters.size() << " candidates, using "
       << usedNucleons.size() << " nucleons" << G4endl;
  }
}
 
 
// Do combinatorics of current set of four, skip nucleons already used
 
void G4CascadeCoalescence::tryClusters(size_t idx1, size_t idx2,
                       size_t idx3, size_t idx4) {
  if (nucleonUsed(idx1) || nucleonUsed(idx2) ||
      nucleonUsed(idx3) || nucleonUsed(idx4)) return;
 
  fillCluster(idx1,idx2,idx3,idx4);
  if (verboseLevel>1) reportArgs("tryClusters",thisCluster);
 
  if (goodCluster(thisCluster)) {
    allClusters.push_back(thisCluster);
    usedNucleons.insert(idx1);
    usedNucleons.insert(idx2);
    usedNucleons.insert(idx3);
    usedNucleons.insert(idx4);
  }
}
 
void 
G4CascadeCoalescence::tryClusters(size_t idx1, size_t idx2, size_t idx3) {
  if (nucleonUsed(idx1) || nucleonUsed(idx2) || nucleonUsed(idx3)) return;
 
  fillCluster(idx1,idx2,idx3);
  if (verboseLevel>1) reportArgs("tryClusters",thisCluster);
 
  if (goodCluster(thisCluster)) {
    allClusters.push_back(thisCluster);
    usedNucleons.insert(idx1);
    usedNucleons.insert(idx2);
    usedNucleons.insert(idx3);
  }
}
 
void 
G4CascadeCoalescence::tryClusters(size_t idx1, size_t idx2) {
  if (nucleonUsed(idx1) || nucleonUsed(idx2)) return;
 
  fillCluster(idx1,idx2);
  if (verboseLevel>1) reportArgs("tryClusters",thisCluster);
 
  if (goodCluster(thisCluster)) {
    allClusters.push_back(thisCluster);
    usedNucleons.insert(idx1);
    usedNucleons.insert(idx2);
  }
}
 
 
// Process list of candidate clusters into light ions
 
void G4CascadeCoalescence::createNuclei() {
  if (verboseLevel)
    G4cout << " >>> G4CascadeCoalescence::createNuclei()" << G4endl;
 
  usedNucleons.clear();
 
  for (size_t i=0; i<allClusters.size(); i++) {
    if (verboseLevel>1) G4cout << " attempting candidate #" << i << G4endl;
 
    const ClusterCandidate& cand = allClusters[i];
    if (makeLightIon(cand)) {           // Success, put ion in output
      thisFinalState->addOutgoingNucleus(thisLightIon);
      usedNucleons.insert(cand.begin(), cand.end());
    }
  }
}
 
 
// Remove nucleons indexed in "usedNucleons" from output
 
void G4CascadeCoalescence::removeNucleons() {
  if (verboseLevel>1)
    G4cout << " >>> G4CascadeCoalescence::removeNucleons()" << G4endl;
 
  // Remove nucleons from output from last to first (to preserve indexing)
  for (auto usedIter = usedNucleons.crbegin(); usedIter != usedNucleons.crend(); ++usedIter)
    thisFinalState->removeOutgoingParticle((G4int)*usedIter);
 
  usedNucleons.clear();
}
 
 
// Compute momentum of whole cluster
 
G4LorentzVector 
G4CascadeCoalescence::getClusterMomentum(const ClusterCandidate& aCluster) const {
  pCluster.set(0.,0.,0.,0.);
  for (size_t i=0; i<aCluster.size(); i++)
    pCluster += getHadron(aCluster[i]).getMomentum();
 
  return pCluster;
}
 
 
// Determine magnitude of largest momentum in CM frame
 
G4double G4CascadeCoalescence::maxDeltaP(const ClusterCandidate& aCluster) const {
  if (verboseLevel>1) reportArgs("maxDeltaP", aCluster);
 
  G4ThreeVector boost = getClusterMomentum(aCluster).boostVector();
 
  G4double dp, maxDP = -1.;
  for (size_t i=0; i<aCluster.size(); i++) {
    const G4InuclElementaryParticle& nucl = getHadron(aCluster[i]);
 
    // NOTE:  getMomentum() returns by value, event kinematics are not changed
    if ((dp = nucl.getMomentum().boost(-boost).rho()) > maxDP) maxDP = dp;
  }
 
  if (verboseLevel>1) G4cout << " maxDP = " << maxDP << G4endl;
 
  return maxDP;
}
 
 
// Compute "cluster type code" as sum of nucleon codes
 
G4int G4CascadeCoalescence::
clusterType(const ClusterCandidate& aCluster) const {
  G4int type = 0;
  for (size_t i=0; i<aCluster.size(); i++) {
    const G4InuclElementaryParticle& had = getHadron(aCluster[i]);
    type += had.nucleon() ? had.type() : 0;
  }
 
  return type;
}
 
 
// Create cluster candidate with listed indices
 
void G4CascadeCoalescence::fillCluster(size_t idx1, size_t idx2) {
  thisCluster.clear();
  thisCluster.push_back(idx1);
  thisCluster.push_back(idx2);
}
 
void G4CascadeCoalescence::fillCluster(size_t idx1, size_t idx2, size_t idx3) {
  thisCluster.clear();
  thisCluster.push_back(idx1);
  thisCluster.push_back(idx2);
  thisCluster.push_back(idx3);
}
 
void G4CascadeCoalescence::fillCluster(size_t idx1, size_t idx2, size_t idx3,
                      size_t idx4) {
  thisCluster.clear();
  thisCluster.push_back(idx1);
  thisCluster.push_back(idx2);
  thisCluster.push_back(idx3);
  thisCluster.push_back(idx4);
}
 
 
 
// Make sure all candidates in cluster are nucleons
 
bool G4CascadeCoalescence::allNucleons(const ClusterCandidate& clus) const {
  bool result = true;
  for (size_t i=0; i<clus.size(); i++)
    result &= getHadron(clus[0]).nucleon();
  return result;
}
 
 
// Determine if collection of nucleons can form a light ion
 
bool G4CascadeCoalescence::goodCluster(const ClusterCandidate& clus) const {
  if (verboseLevel>2) reportArgs("goodCluster?",clus);
 
  if (!allNucleons(clus)) return false;
 
  if (clus.size() == 2)                 // Deuterons (pn)
    return (clusterType(clus) == 3 && maxDeltaP(clus) < dpMaxDoublet);
 
  if (clus.size() == 3)                 // Tritons or He-3
    return ((clusterType(clus) == 4 || clusterType(clus) == 5)  // ppn OR pnn
        && maxDeltaP(clus) < dpMaxTriplet);
 
  if (clus.size() == 4)                 // Alphas (ppnn)
    return (clusterType(clus) == 6 && maxDeltaP(clus) < dpMaxAlpha);
 
  return false;
}
 
 
 
// Convert candidate nucleon set into output nucleus
 
bool G4CascadeCoalescence::makeLightIon(const ClusterCandidate& aCluster) {
  if (verboseLevel>1) reportArgs("makeLightIon",aCluster);
 
  thisLightIon.clear();     // Initialize nucleus buffer before filling
 
  if (aCluster.size()<2) return false;      // Sanity check
 
  G4int A = (G4int)aCluster.size();
  G4int Z = -1;
 
  G4int type = clusterType(aCluster);
  if (A==2 && type==3) Z = 1;       // Deuteron (pn)
  if (A==3 && type==5) Z = 1;       // Triton (pnn)
  if (A==3 && type==4) Z = 2;       // He-3 (ppn)
  if (A==4 && type==6) Z = 2;       // He-4/alpha (ppnn)
 
  if (Z < 0) return false;      // Invalid cluster content
 
  // NOTE:  Four-momentum will not be conserved due to binding energy
  thisLightIon.fill(getClusterMomentum(aCluster), A, Z, 0.,
            G4InuclParticle::Coalescence);
 
  if (verboseLevel>1) reportResult("makeLightIon output",thisLightIon);
  return true;
}
 
 
// Report cluster arguments for validation
 
void G4CascadeCoalescence::reportArgs(const G4String& name,
                      const ClusterCandidate& aCluster) const {
  G4cout << " >>> G4CascadeCoalescence::" << name << " ";
  std::copy(aCluster.begin(), aCluster.end(),
        std::ostream_iterator<size_t>(G4cout, " "));
  G4cout << G4endl;
 
  if (verboseLevel>2) {
    for (size_t i=0; i<aCluster.size(); i++)
      G4cout << getHadron(aCluster[i]) << G4endl;
  }
}
 
void G4CascadeCoalescence::reportResult(const G4String& name,
                    const G4InuclNuclei& nucl) const {
  G4cout << " >>> G4CascadeCoalescence::" << name << G4endl << nucl << G4endl;
}