/cvmfs/atlas.cern.ch/repo/sw/ASG/AnalysisBase/2.4.31/GeoPrimitives/GeoPrimitives/CLHEPtoEigenEulerAnglesConverters.h

/*
 * eigen_migration
 * main.cpp
 *
 *  Created on: Feb 4, 2014
 *      Author: rbianchi <Riccardo.Maria.Bianchi@cern.ch>
 *
 */

#ifndef _GEOPRIMITIVES_CLHEPTOEIGENEULERANGLESCONVERTERS_H
#define _GEOPRIMITIVES_CLHEPTOEIGENEULERANGLESCONVERTERS_H

#include "GeoPrimitives/GeoPrimitives.h"

#include <math.h> // for M_PI definition



namespace Amg {


inline Amg::Vector3D convert_CLHEPPhiThetaPsi_to_EigenEulerAngles(Amg::Vector3D clhep_angles, int convention = 0)
{
    Amg::Vector3D eigen_angles;

    // using Z-X-Z convention (CLHEP): (2,0,2) == "Z,X,Z". // DEFAULT
    if (convention == 0) {
        eigen_angles(2) = -clhep_angles(0); // Phi-->Z
        eigen_angles(1) = -clhep_angles(1); // Theta-->X
        eigen_angles(0) = -clhep_angles(2); // Psi-->Z
    }
    // using Z-Y-Z convention: (2,1,2) == "Z,Y,Z"
    else {
        eigen_angles(0) = -0.5 * clhep_angles(0); // Phi-->Z
        eigen_angles(1) = clhep_angles(1); // Theta-->Y
        eigen_angles(2) = clhep_angles(2); // Psi-->Z
    }

    return eigen_angles;
}

inline Amg::Vector3D convert_EigenEulerAngles_to_CLHEPPhiThetaPsi(Amg::Vector3D eigen_angles, int convention = 0)
{
    Amg::Vector3D clhep_angles;

    double phi;
    double theta;
    double psi;

    // using Z-X-Z convention: (2,0,2) == "Z,X,Z".  // DEFAULT
    if (convention == 0) {
        phi   = -eigen_angles(2); // Z-->Phi
        theta = -eigen_angles(1); // X-->Theta
        psi   = -eigen_angles(0); // Z-->Psi
    }
    // using Z-Y-Z convention: (2,1,2) == "Z,Y,Z"
    else {
        phi   = -2 * eigen_angles(0); // Z-->Phi
        theta = eigen_angles(1); // Y-->Theta
        psi   = eigen_angles(2); // Z-->Psi
    }

    clhep_angles(0) = phi;
    clhep_angles(1) = theta;
    clhep_angles(2) = psi;

    return clhep_angles;

}


} // end of namespace Amg


#endif

---