[5] | 1 | #ifndef INLINE_MATHS |
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| 2 | #define INLINE_MATHS |
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| 3 | |
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| 4 | // This file is distributed with FastJet under the terms of the GNU |
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| 5 | // General Public License (v2). Permission to do so has been granted |
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| 6 | // by Lars Sonnenschein and the D0 collaboration (see COPYING for |
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| 7 | // details) |
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| 8 | // |
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| 9 | // History of changes in FastJet compared tothe original version of |
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| 10 | // inline_math.h |
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| 11 | // |
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| 12 | // 2011-12-13 Gregory Soyez <soyez@fastjet.fr> |
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| 13 | // |
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| 14 | // * added license information |
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| 15 | // |
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| 16 | // 2011-10-06 Gregory Soyez <soyez@fastjet.fr> |
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| 17 | // |
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| 18 | // * put the code in the fastjet::d0runi namespace |
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| 19 | |
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| 20 | #include <cmath> |
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| 21 | #include <cerrno> |
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| 22 | #include <fastjet/internal/base.hh> |
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| 23 | |
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| 24 | FASTJET_BEGIN_NAMESPACE |
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| 25 | |
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| 26 | //using namespace std; |
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| 27 | |
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| 28 | namespace d0runi{ |
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| 29 | namespace inline_maths { |
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| 30 | |
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| 31 | const double PI = fabs(acos(-1.)); |
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| 32 | |
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| 33 | const double TWOPI = 2*PI; |
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| 34 | |
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| 35 | |
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| 36 | inline double sqr(double a) { |
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| 37 | return a*a; |
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| 38 | } |
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| 39 | |
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| 40 | |
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| 41 | |
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| 42 | inline double min(double a, double b) { |
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| 43 | return (a < b) ? a : b; |
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| 44 | } |
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| 45 | |
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| 46 | |
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| 47 | |
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| 48 | inline double delta_phi(double phi1, double phi2) { |
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| 49 | double dphi = min( double(fabs(phi1-phi2)), double(2.*PI-fabs(phi1-phi2)) ); |
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| 50 | return (phi1 < phi2) ? -dphi : dphi; |
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| 51 | } |
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| 52 | |
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| 53 | |
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| 54 | |
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| 55 | inline double phi(double px, double py) { |
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| 56 | return atan2(py, px); |
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| 57 | } |
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| 58 | |
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| 59 | |
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| 60 | |
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| 61 | inline double y(double E, double pz) { |
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| 62 | errno=0; |
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| 63 | double y; |
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| 64 | //cout << "inline_maths: "; |
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| 65 | if (fabs(E-pz) == 0.) { |
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| 66 | // cout << "Error in header mathe.h: division by 0 in function y!" << " p=" << p << " pz=" << pz << endl; |
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| 67 | // exit(721); |
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| 68 | errno=721; |
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| 69 | y = 99999.; |
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| 70 | } |
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| 71 | else { |
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| 72 | y = 0.5*log((E+pz)/(E-pz)); |
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| 73 | } |
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| 74 | //cout << "y: E=" << E << " pz=" << pz << " y=" << y << endl; |
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| 75 | return y; |
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| 76 | } |
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| 77 | |
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| 78 | |
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| 79 | |
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| 80 | |
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| 81 | inline double eta(double p, double pz) { |
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| 82 | errno=0; |
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| 83 | double eta; |
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| 84 | //cout << "inline_maths: "; |
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| 85 | if (fabs(p-pz) == 0.) { |
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| 86 | // cout << "Error in header mathe.h: division by 0 in function eta!" << " p=" << p << " pz=" << pz << endl; |
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| 87 | // exit(721); |
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| 88 | errno=721; |
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| 89 | eta = 99999.; |
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| 90 | } |
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| 91 | else { |
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| 92 | eta = 0.5*log((p+pz)/(p-pz)); |
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| 93 | } |
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| 94 | //cout << "eta: p=" << p << " pz=" << pz << " eta=" << eta << endl; |
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| 95 | return eta; |
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| 96 | } |
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| 97 | |
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| 98 | |
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| 99 | |
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| 100 | |
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| 101 | inline double eta(double px, double py, double pz) { |
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| 102 | errno=0; |
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| 103 | double eta; |
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| 104 | //cout << "inline_maths: "; |
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| 105 | double p = sqrt(px*px+py*py+pz*pz); |
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| 106 | if (fabs(p-pz) == 0.) { |
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| 107 | // cout << "Error in header mathe.h: division by 0 in function eta!" << " p=" << p << " pz=" << pz << endl; |
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| 108 | // exit(721); |
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| 109 | errno=721; |
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| 110 | eta = 99999.; |
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| 111 | } |
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| 112 | else { |
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| 113 | eta = 0.5*log((p+pz)/(p-pz)); |
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| 114 | } |
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| 115 | //cout << "eta: p=" << p << " pz=" << pz << " eta=" << eta << endl; |
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| 116 | return eta; |
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| 117 | } |
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| 118 | |
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| 119 | |
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| 120 | |
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| 121 | inline double eta(double theta) { |
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| 122 | double eta = -log(tan(theta/2.)); |
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| 123 | |
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| 124 | return eta; |
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| 125 | } |
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| 126 | |
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| 127 | |
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| 128 | inline double theta(double eta) { |
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| 129 | double theta = 2.*atan(exp(-eta)); |
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| 130 | |
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| 131 | return theta; |
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| 132 | } |
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| 133 | |
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| 134 | inline double theta(double px, double py, double pz) { |
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| 135 | double Eta = eta(px, py, pz); |
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| 136 | double theta = 2.*atan(exp(-Eta)); |
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| 137 | |
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| 138 | return theta; |
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| 139 | } |
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| 140 | |
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| 141 | |
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| 142 | |
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| 143 | } //end usename inline_maths |
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| 144 | } //end usename d0runi |
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| 145 | |
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| 146 | FASTJET_END_NAMESPACE |
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| 147 | |
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| 148 | |
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| 149 | #endif |
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