| 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // $Id: G4CascadeSampler.icc,v 1.2 2010/05/21 18:26:16 mkelsey Exp $ |
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| 26 | // GEANT4 tag: $Name: geant4-09-04-beta-cand-01 $ |
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| 27 | // |
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| 28 | // 20100506 M. Kelsey -- Move functionity of G4CascadeChannel here, |
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| 29 | // use as base class to G4CascadeFunctions<T>. |
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| 30 | // 20100512 M. Kelsey -- Move implementation to .icc with templating |
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| 31 | |
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| 32 | #include "G4CascadeSampler.hh" |
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| 33 | #include "Randomize.hh" |
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| 34 | #include <vector> |
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| 35 | |
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| 36 | |
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| 37 | template <int NBINS, int NMULT> inline |
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| 38 | G4double G4CascadeSampler<NBINS,NMULT>:: |
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| 39 | findCrossSection(double ke, |
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| 40 | const G4double (&xsec)[energyBins]) const { |
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| 41 | return interpolator.interpolate(ke, xsec); |
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| 42 | } |
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| 43 | |
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| 44 | template <int NBINS, int NMULT> inline |
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| 45 | G4int G4CascadeSampler<NBINS,NMULT>:: |
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| 46 | findMultiplicity(G4double ke, |
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| 47 | const G4double xmult[][energyBins]) const { |
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| 48 | fillSigmaBuffer(ke, xmult); |
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| 49 | return sampleFlat() + 2; // Convert array index to actual mult (2 to 7) |
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| 50 | } |
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| 51 | |
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| 52 | template <int NBINS, int NMULT> inline |
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| 53 | G4int G4CascadeSampler<NBINS,NMULT>:: |
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| 54 | findFinalStateIndex(G4int mult, G4double ke, const G4int index[], |
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| 55 | const G4double xsec[][energyBins]) const { |
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| 56 | G4int start = index[mult-2]; |
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| 57 | G4int stop = index[mult-1]; |
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| 58 | if (stop-start <= 1) return start; // Avoid unnecessary work |
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| 59 | |
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| 60 | fillSigmaBuffer(ke, xsec, start, stop); |
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| 61 | return sampleFlat(); |
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| 62 | } |
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| 63 | |
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| 64 | // Optional start/stop arguments default to multiplicity arrays |
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| 65 | template <int NBINS, int NMULT> inline |
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| 66 | void G4CascadeSampler<NBINS,NMULT>:: |
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| 67 | fillSigmaBuffer(G4double ke, const G4double x[][energyBins], |
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| 68 | G4int startBin, G4int stopBin) const { |
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| 69 | sigmaBuf.clear(); |
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| 70 | if (stopBin-startBin <= 1) return; // Avoid unnecessary work |
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| 71 | |
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| 72 | // NOTE: push_back() must be used to ensure that size() gets set! |
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| 73 | sigmaBuf.reserve(stopBin-startBin); |
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| 74 | for(G4int m = startBin; m < stopBin; m++) |
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| 75 | sigmaBuf.push_back(interpolator.interpolate(ke, x[m])); |
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| 76 | } |
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| 77 | |
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| 78 | |
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| 79 | template <int NBINS, int NMULT> inline |
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| 80 | G4int G4CascadeSampler<NBINS,NMULT>::sampleFlat() const { |
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| 81 | G4int nbins = sigmaBuf.size(); |
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| 82 | if (nbins <= 1) return 0; // Avoid unnecessary work |
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| 83 | |
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| 84 | #ifdef G4CASCADE_DEBUG_SAMPLER |
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| 85 | G4cout << "G4CascadeSampler::sampleFlat() has " << nbins << "bins:" << G4endl; |
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| 86 | for (G4int sbi=0; sbi<nbins; sbi++) G4cout << " " << sigmaBuf[sbi]; |
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| 87 | G4cout << G4endl; |
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| 88 | #endif |
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| 89 | |
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| 90 | G4int i; |
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| 91 | G4double fsum = 0.; |
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| 92 | for (i = 0; i < nbins; i++) fsum += sigmaBuf[i]; |
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| 93 | #ifdef G4CASCADE_DEBUG_SAMPLER |
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| 94 | G4cout << " buffer total (fsum) " << fsum; |
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| 95 | #endif |
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| 96 | fsum *= G4UniformRand(); |
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| 97 | #ifdef G4CASCADE_DEBUG_SAMPLER |
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| 98 | G4cout << " *random-scale " << fsum << G4endl; |
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| 99 | #endif |
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| 100 | |
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| 101 | G4double partialSum = 0.0; |
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| 102 | for (i = 0; i < nbins; i++) { |
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| 103 | partialSum += sigmaBuf[i]; |
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| 104 | if (fsum < partialSum) return i; // Breaks out of loop automatically |
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| 105 | } |
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| 106 | |
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| 107 | return 0; // Is this right? Shouldn't it return maximum, not minimum? |
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| 108 | } |
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