G4AngularDistributionPP.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.          *
// ********************************************************************
//
#include "G4AngularDistributionPP.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "G4ios.hh"
 
// Initialization of static data arrays:
#include "G4AngularDistributionPPData.hh"
#include "Randomize.hh"
 
 
G4double G4AngularDistributionPP::CosTheta(G4double S, G4double m_1, G4double m_2) const
{
    G4int verboseLevel=1;
 
    G4double ek= ((S - sqr(m_1) -sqr(m_2) )/(2*m_1) - m_1 )/GeV   ;    // kinetic energy in GeV
 
    // Find energy bin
 
    G4int je1 = 0;
    G4int je2 = NENERGY - 1;
     G4int iterationsLeft=2*NENERGY +1;
    do {
      G4int midBin = (je1 + je2)/2;
      if (ek < elab[midBin])
        je2 = midBin;
      else
        je1 = midBin;
    } while ( (je2 - je1) > 1 && --iterationsLeft > 0 );    /* Loop checking, 30-Oct-2015, G.Folger */
     if ( iterationsLeft <= 0 ) {
         G4Exception("G4AngularDistributionPP", "im_r_matrix020", FatalException,
             "Problem with energy bin (elab) data");
 
     }
    //    G4int j;
    //std::abs(ek-elab[je1]) < std::abs(ek-elab[je2]) ? j = je1 : j = je2;
    G4double delab = elab[je2] - elab[je1];
 
    // Sample the angle
 
    G4double sample = G4UniformRand();
    G4int ke1 = 0;
    G4int ke2 = NANGLE - 1;
    G4double dsig = sig[je2][0] - sig[je1][0];
    G4double rc = dsig/delab;
    G4double b = sig[je1][0] - rc*elab[je1];
    G4double sigint1 = rc*ek + b;
    G4double sigint2 = 0.;
 
    if (verboseLevel > 1) G4cout << "sample=" << sample << G4endl
                                 << ek << " " << ke1 << " " << ke2 << " "
                                 << sigint1 << " " << sigint2 << G4endl;
 
    iterationsLeft= 2*NANGLE +1;
     do {
      G4int midBin = (ke1 + ke2)/2;
      dsig = sig[je2][midBin] - sig[je1][midBin];
      rc = dsig/delab;
      b = sig[je1][midBin] - rc*elab[je1];
      G4double sigint = rc*ek + b;
      if (sample < sigint) {
        ke2 = midBin;
        sigint2 = sigint;
      }
      else {
        ke1 = midBin;
        sigint1 = sigint;
      }
      if (verboseLevel > 1)G4cout << ke1 << " " << ke2 << " "
                                  << sigint1 << " " << sigint2 << G4endl;
    } while ( (ke2 - ke1) > 1 && --iterationsLeft > 0);    /* Loop checking, 30-Oct-2015, G.Folger */
     if ( iterationsLeft <= 0 ) {
         G4Exception("G4AngularDistributionPP", "im_r_matrix021", FatalException,
             "Problem with angular distribution (sig) data");
     }
 
    // sigint1 and sigint2 should be recoverable from above loop
 
    //    G4double dsig = sig[je2][ke1] - sig[je1][ke1];
    //    G4double rc = dsig/delab;
    //    G4double b = sig[je1][ke1] - rc*elab[je1];
    //    G4double sigint1 = rc*ek + b;
 
    //    G4double dsig = sig[je2][ke2] - sig[je1][ke2];
    //    G4double rc = dsig/delab;
    //    G4double b = sig[je1][ke2] - rc*elab[je1];
    //    G4double sigint2 = rc*ek + b;
 
    dsig = sigint2 - sigint1;
    rc = 1./dsig;
    b = ke1 - rc*sigint1;
    G4double kint = rc*sample + b;
    G4double theta = (0.5 + kint)*pi/180.;
 
    //    G4int k;
    //std::abs(sample-sig[j][ke1]) < std::abs(sample-sig[j][ke2]) ? k = ke1 : k = ke2;
    //    G4double theta = (0.5 + k)*pi/180.;
 
    if (verboseLevel > 1) {
      G4cout << "   energy bin " << je1 << " energy=" << elab[je1] << G4endl;
      G4cout << "   angle bin " << kint << " angle=" << theta/degree << G4endl;
    }
    G4double costh= std::cos(theta);
//    G4cout << "scattering angle hpw "<<costh<<" "<<s<<" "<<m1<<" "<<m2<<G4endl;
    return costh;
}
 
G4double G4AngularDistributionPP::Phi() const
{
    return twopi * G4UniformRand();
}