1 | // Nsubjettiness Package
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2 | // Questions/Comments? jthaler@jthaler.net
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3 | //
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4 | // Copyright (c) 2011-14
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5 | // Jesse Thaler, Ken Van Tilburg, Christopher K. Vermilion, and TJ Wilkason
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6 | //
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7 | //----------------------------------------------------------------------
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8 | // This file is part of FastJet contrib.
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9 | //
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10 | // It is free software; you can redistribute it and/or modify it under
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11 | // the terms of the GNU General Public License as published by the
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12 | // Free Software Foundation; either version 2 of the License, or (at
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13 | // your option) any later version.
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14 | //
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15 | // It is distributed in the hope that it will be useful, but WITHOUT
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16 | // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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17 | // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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18 | // License for more details.
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19 | //
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20 | // You should have received a copy of the GNU General Public License
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21 | // along with this code. If not, see <http://www.gnu.org/licenses/>.
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22 | //----------------------------------------------------------------------
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23 |
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24 |
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25 | #include "MeasureFunction.hh"
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26 |
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27 | FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
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28 |
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29 | namespace contrib{
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30 |
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31 | ///////
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32 | //
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33 | // Measure Function
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34 | //
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35 | ///////
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36 |
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37 | // Return all of the necessary TauComponents for specific input particles and axes
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38 | TauComponents MeasureFunction::result(const std::vector<fastjet::PseudoJet>& particles, const std::vector<fastjet::PseudoJet>& axes) {
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39 |
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40 | std::vector<double> jetPieces(axes.size(), 0.0);
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41 | double beamPiece = 0.0;
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42 |
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43 | // Calculates the unnormalized sub-tau values, i.e. a std::vector of the contributions to tau_N of each Voronoi region (or region within R_0)
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44 | for (unsigned i = 0; i < particles.size(); i++) {
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45 |
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46 | // find minimum distance; start with beam (-1) for reference
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47 | int j_min = -1;
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48 | double minRsq;
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49 | if (_has_beam) minRsq = beam_distance_squared(particles[i]);
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50 | else minRsq = std::numeric_limits<double>::max(); // make it large value
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51 |
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52 | // check to see which axis the particle is closest to
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53 | for (unsigned j = 0; j < axes.size(); j++) {
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54 | double tempRsq = jet_distance_squared(particles[i],axes[j]); // delta R distance
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55 | if (tempRsq < minRsq) {
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56 | minRsq = tempRsq;
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57 | j_min = j;
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58 | }
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59 | }
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60 |
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61 | if (j_min == -1) {
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62 | if (_has_beam) beamPiece += beam_numerator(particles[i]);
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63 | else assert(_has_beam); // this should never happen.
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64 | } else {
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65 | jetPieces[j_min] += jet_numerator(particles[i],axes[j_min]);
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66 | }
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67 | }
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68 |
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69 | // Calculates normalization for tau and subTau if _has_denominator is true, otherwise returns 1.0 (i.e. no normalization)
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70 | double tauDen = 0.0;
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71 | if (_has_denominator) {
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72 | for (unsigned i = 0; i < particles.size(); i++) {
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73 | tauDen += denominator(particles[i]);
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74 | }
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75 | } else {
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76 | tauDen = 1.0; // if no denominator, then 1.0 for no normalization factor
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77 | }
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78 |
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79 | return TauComponents(jetPieces, beamPiece, tauDen, _has_denominator, _has_beam);
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80 | }
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81 |
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82 | } //namespace contrib
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83 |
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84 | FASTJET_END_NAMESPACE
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