git://git.uio.no / u / mrichter / AliRoot.git / blame
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1 | /////////////////////////////////////////////////////////////////////////// |
| 2 | // | |
| 3 | // Copyright 2010 | |
| 4 | // | |
| 5 | // This file is part of starlight. | |
| 6 | // | |
| 7 | // starlight is free software: you can redistribute it and/or modify | |
| 8 | // it under the terms of the GNU General Public License as published by | |
| 9 | // the Free Software Foundation, either version 3 of the License, or | |
| 10 | // (at your option) any later version. | |
| 11 | // | |
| 12 | // starlight is distributed in the hope that it will be useful, | |
| 13 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 14 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 15 | // GNU General Public License for more details. | |
| 16 | // | |
| 17 | // You should have received a copy of the GNU General Public License | |
| 18 | // along with starlight. If not, see <http://www.gnu.org/licenses/>. | |
| 19 | // | |
| 20 | /////////////////////////////////////////////////////////////////////////// | |
| 21 | // | |
| 22 | // File and Version Information: | |
| 23 | // $Rev:: $: revision of last commit | |
| 24 | // $Author:: $: author of last commit | |
| 25 | // $Date:: $: date of last commit | |
| 26 | // | |
| 27 | // Description: | |
| 28 | // | |
| 29 | // | |
| 30 | // | |
| 31 | /////////////////////////////////////////////////////////////////////////// | |
| 32 | ||
| 33 | ||
| 34 | #ifndef LORENTZVECTOR_H | |
| 35 | #define LORENTZVECTOR_H | |
| 36 | ||
| 37 | ||
| 38 | #include "vector3.h" | |
| 39 | #include <vector> | |
| 40 | ||
| 41 | ||
| 42 | class lorentzVector | |
| 43 | { | |
| 44 | public: | |
| 45 | ||
| 46 | lorentzVector(); | |
| 47 | virtual ~lorentzVector(); | |
| 48 | ||
| 49 | lorentzVector(double x, double y, double z, double t); | |
| 50 | //lorentzVector(double px, double py, double pz, double e); | |
| 51 | ||
| 52 | void SetXYZT(double x, double y, double z, double t); | |
| 53 | void SetPxPyPzE(double px, double py, double pz, double e) { SetXYZT(px, py, pz, e); }; | |
| 54 | ||
| 55 | double GetPx() const { return fSpaceVec.GetVector()[0]; } | |
| 56 | double GetPy() const { return fSpaceVec.GetVector()[1]; } | |
| 57 | double GetPz() const { return fSpaceVec.GetVector()[2]; } | |
| 58 | double GetE() const { return fTime; } | |
| 59 | ||
| 60 | lorentzVector& operator +=(const lorentzVector& vec) | |
| 61 | { | |
| 62 | fSpaceVec += vec.fSpaceVec; | |
| 63 | fTime += vec.fTime; | |
| 64 | return *this; | |
| 65 | } | |
| 66 | lorentzVector& operator -=(const lorentzVector& vec) | |
| 67 | { | |
| 68 | fSpaceVec -= vec.fSpaceVec; | |
| 69 | fTime -= vec.fTime; | |
| 70 | return *this; | |
| 71 | } | |
| 72 | ||
| 73 | double M2() const { return fTime * fTime - fSpaceVec.Mag2(); } | |
| 74 | double M () const | |
| 75 | { | |
| 76 | const double mag2 = M2(); | |
| 77 | return (mag2 < 0) ? -sqrt(-mag2) : sqrt(mag2); | |
| 78 | } | |
| 79 | ||
| 80 | vector3 BoostVector() const | |
| 81 | { return vector3(fSpaceVec.X() / fTime, fSpaceVec.Y() / fTime, fSpaceVec.Z() / fTime); } | |
| 82 | void Boost(const vector3& beta) | |
| 83 | { | |
| 84 | const double beta2 = beta.Mag2(); | |
| 85 | const double gamma = 1 / sqrt(1 - beta2); | |
| 86 | const double betaTimesMom = beta.X() * fSpaceVec.X() + beta.Y() * fSpaceVec.Y() + beta.Z() * fSpaceVec.Z(); | |
| 87 | const double gamma2 = (beta2 > 0) ? (gamma - 1) / beta2 : 0; | |
| 88 | SetXYZT(fSpaceVec.X() + gamma2 * betaTimesMom * beta.X() + gamma * beta.X() * fTime, | |
| 89 | fSpaceVec.Y() + gamma2 * betaTimesMom * beta.Y() + gamma * beta.Y() * fTime, | |
| 90 | fSpaceVec.Z() + gamma2 * betaTimesMom * beta.Z() + gamma * beta.Z() * fTime, | |
| 91 | gamma * (fTime + betaTimesMom)); | |
| 92 | } | |
| 93 | ||
| 94 | friend std::ostream& operator << (std::ostream& out, | |
| 95 | const lorentzVector& vec) | |
| 96 | { | |
| 97 | out << "(" << vec.GetPx() << ", " << vec.GetPy() << ", " << vec.GetPz() | |
| 98 | << "; " << vec.GetE() << ")"; | |
| 99 | return out; | |
| 100 | } | |
| 101 | ||
| 102 | private: | |
| 103 | ||
| 104 | vector3 fSpaceVec; | |
| 105 | double fTime; | |
| 106 | ||
| 107 | }; | |
| 108 | ||
| 109 | ||
| 110 | #endif // LORENTZVECTOR_H |