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geant4/source/externals/clhep/src/ThreeVector.cc
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2020-12-04 12:30:43 +01:00

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// -*- C++ -*-
// ---------------------------------------------------------------------------
//
// This file is a part of the CLHEP - a Class Library for High Energy Physics.
//
// This is the implementation of the Hep3Vector class.
//
// See also ThreeVectorR.cc for implementation of Hep3Vector methods which
// would couple in all the HepRotation methods.
//
#include "CLHEP/Vector/ThreeVector.h"
#include "CLHEP/Units/PhysicalConstants.h"
#include <cmath>
#include <iostream>
namespace CLHEP {
void Hep3Vector::setMag(double ma) {
double factor = mag();
if (factor == 0) {
std::cerr << "Hep3Vector::setMag() - "
<< "zero vector can't be stretched" << std::endl;
}else{
factor = ma/factor;
setX(x()*factor);
setY(y()*factor);
setZ(z()*factor);
}
}
Hep3Vector & Hep3Vector::rotateUz(const Hep3Vector& NewUzVector) {
// NewUzVector must be normalized !
double u1 = NewUzVector.x();
double u2 = NewUzVector.y();
double u3 = NewUzVector.z();
double up = u1*u1 + u2*u2;
if (up > 0) {
up = std::sqrt(up);
double px = (u1 * u3 * x() - u2 * y()) / up + u1 * z();
double py = (u2 * u3 * x() + u1 * y()) / up + u2 * z();
double pz = -up * x() + u3 * z();
set(px, py, pz);
} else if (u3 < 0.) {
setX(-x());
setZ(-z());
} // phi=0 teta=pi
return *this;
}
double Hep3Vector::pseudoRapidity() const {
double m1 = mag();
if ( m1== 0 ) return 0.0;
if ( m1== z() ) return 1.0E72;
if ( m1== -z() ) return -1.0E72;
return 0.5*std::log( (m1+z())/(m1-z()) );
}
std::ostream & operator<< (std::ostream & os, const Hep3Vector & v) {
return os << "(" << v.x() << "," << v.y() << "," << v.z() << ")";
}
void ZMinput3doubles ( std::istream & is, const char * type,
double & x, double & y, double & z );
std::istream & operator>>(std::istream & is, Hep3Vector & v) {
double x, y, z;
ZMinput3doubles ( is, "Hep3Vector", x, y, z );
v.set(x, y, z);
return is;
} // operator>>()
const Hep3Vector HepXHat(1.0, 0.0, 0.0);
const Hep3Vector HepYHat(0.0, 1.0, 0.0);
const Hep3Vector HepZHat(0.0, 0.0, 1.0);
//-------------------
//
// New methods introduced when ZOOM PhysicsVectors was merged in:
//
//-------------------
Hep3Vector & Hep3Vector::rotateX (double phi1) {
double sinphi = std::sin(phi1);
double cosphi = std::cos(phi1);
double ty = y() * cosphi - z() * sinphi;
double tz = z() * cosphi + y() * sinphi;
setY(ty);
setZ(tz);
return *this;
} /* rotateX */
Hep3Vector & Hep3Vector::rotateY (double phi1) {
double sinphi = std::sin(phi1);
double cosphi = std::cos(phi1);
double tx = x() * cosphi + z() * sinphi;
double tz = z() * cosphi - x() * sinphi;
setX(tx);
setZ(tz);
return *this;
} /* rotateY */
Hep3Vector & Hep3Vector::rotateZ (double phi1) {
double sinphi = std::sin(phi1);
double cosphi = std::cos(phi1);
double tx = x() * cosphi - y() * sinphi;
double ty = y() * cosphi + x() * sinphi;
setX(tx);
setY(ty);
return *this;
} /* rotateZ */
bool Hep3Vector::isNear(const Hep3Vector & v, double epsilon) const {
double limit = dot(v)*epsilon*epsilon;
return ( (*this - v).mag2() <= limit );
} /* isNear() */
double Hep3Vector::howNear(const Hep3Vector & v ) const {
// | V1 - V2 | **2 / V1 dot V2, up to 1
double d = (*this - v).mag2();
double vdv = dot(v);
if ( (vdv > 0) && (d < vdv) ) {
return std::sqrt (d/vdv);
} else if ( (vdv == 0) && (d == 0) ) {
return 0;
} else {
return 1;
}
} /* howNear */
double Hep3Vector::deltaPhi (const Hep3Vector & v2) const {
double dphi = v2.getPhi() - getPhi();
if ( dphi > CLHEP::pi ) {
dphi -= CLHEP::twopi;
} else if ( dphi <= -CLHEP::pi ) {
dphi += CLHEP::twopi;
}
return dphi;
} /* deltaPhi */
double Hep3Vector::deltaR ( const Hep3Vector & v ) const {
double a = eta() - v.eta();
double b = deltaPhi(v);
return std::sqrt ( a*a + b*b );
} /* deltaR */
double Hep3Vector::cosTheta(const Hep3Vector & q) const {
double arg;
double ptot2 = mag2()*q.mag2();
if(ptot2 <= 0) {
arg = 0.0;
}else{
arg = dot(q)/std::sqrt(ptot2);
if(arg > 1.0) arg = 1.0;
if(arg < -1.0) arg = -1.0;
}
return arg;
}
double Hep3Vector::cos2Theta(const Hep3Vector & q) const {
double arg;
double ptot2 = mag2();
double qtot2 = q.mag2();
if ( ptot2 == 0 || qtot2 == 0 ) {
arg = 1.0;
}else{
double pdq = dot(q);
arg = (pdq/ptot2) * (pdq/qtot2);
// More naive methods overflow on vectors which can be squared
// but can't be raised to the 4th power.
if(arg > 1.0) arg = 1.0;
}
return arg;
}
void Hep3Vector::setEta (double eta1) {
double phi1 = 0;
double r1;
if ( (x() == 0) && (y() == 0) ) {
if (z() == 0) {
std::cerr << "Hep3Vector::setEta() - "
<< "Attempt to set eta of zero vector -- vector is unchanged"
<< std::endl;
return;
}
std::cerr << "Hep3Vector::setEta() - "
<< "Attempt to set eta of vector along Z axis -- will use phi = 0"
<< std::endl;
r1 = std::fabs(z());
} else {
r1 = getR();
phi1 = getPhi();
}
double tanHalfTheta = std::exp ( -eta1 );
double cosTheta1 =
(1 - tanHalfTheta*tanHalfTheta) / (1 + tanHalfTheta*tanHalfTheta);
double rho1 = r1*std::sqrt(1 - cosTheta1*cosTheta1);
setZ(r1 * cosTheta1);
setY(rho1 * std::sin (phi1));
setX(rho1 * std::cos (phi1));
return;
}
void Hep3Vector::setCylTheta (double theta1) {
// In cylindrical coords, set theta while keeping rho and phi fixed
if ( (x() == 0) && (y() == 0) ) {
if (z() == 0) {
std::cerr << "Hep3Vector::setCylTheta() - "
<< "Attempt to set cylTheta of zero vector -- vector is unchanged"
<< std::endl;
return;
}
if (theta1 == 0) {
setZ(std::fabs(z()));
return;
}
if (theta1 == CLHEP::pi) {
setZ(-std::fabs(z()));
return;
}
std::cerr << "Hep3Vector::setCylTheta() - "
<< "Attempt set cylindrical theta of vector along Z axis "
<< "to a non-trivial value, while keeping rho fixed -- "
<< "will return zero vector" << std::endl;
setZ(0.0);
return;
}
if ( (theta1 < 0) || (theta1 > CLHEP::pi) ) {
std::cerr << "Hep3Vector::setCylTheta() - "
<< "Setting Cyl theta of a vector based on a value not in [0, PI]"
<< std::endl;
// No special return needed if warning is ignored.
}
double phi1 (getPhi());
double rho1 = getRho();
if ( (theta1 == 0) || (theta1 == CLHEP::pi) ) {
std::cerr << "Hep3Vector::setCylTheta() - "
<< "Attempt to set cylindrical theta to 0 or PI "
<< "while keeping rho fixed -- infinite Z will be computed"
<< std::endl;
setZ((theta1==0) ? 1.0E72 : -1.0E72);
return;
}
setZ(rho1 / std::tan (theta1));
setY(rho1 * std::sin (phi1));
setX(rho1 * std::cos (phi1));
} /* setCylTheta */
void Hep3Vector::setCylEta (double eta1) {
// In cylindrical coords, set eta while keeping rho and phi fixed
double theta1 = 2 * std::atan ( std::exp (-eta1) );
//-| The remaining code is similar to setCylTheta, The reason for
//-| using a copy is so as to be able to change the messages in the
//-| ZMthrows to say eta rather than theta. Besides, we assumedly
//-| need not check for theta of 0 or PI.
if ( (x() == 0) && (y() == 0) ) {
if (z() == 0) {
std::cerr << "Hep3Vector::setCylEta() - "
<< "Attempt to set cylEta of zero vector -- vector is unchanged"
<< std::endl;
return;
}
if (theta1 == 0) {
setZ(std::fabs(z()));
return;
}
if (theta1 == CLHEP::pi) {
setZ(-std::fabs(z()));
return;
}
std::cerr << "Hep3Vector::setCylEta() - "
<< "Attempt set cylindrical eta of vector along Z axis "
<< "to a non-trivial value, while keeping rho fixed -- "
<< "will return zero vector" << std::endl;
setZ(0.0);
return;
}
double phi1 (getPhi());
double rho1 = getRho();
setZ(rho1 / std::tan (theta1));
setY(rho1 * std::sin (phi1));
setX(rho1 * std::cos (phi1));
} /* setCylEta */
Hep3Vector operator/ ( const Hep3Vector & v1, double c ) {
// if (c == 0) {
// std::cerr << "Hep3Vector::operator/ () - "
// << "Attempt to divide vector by 0 -- "
// << "will produce infinities and/or NANs" << std::endl;
// }
return v1 * (1.0/c);
} /* v / c */
Hep3Vector & Hep3Vector::operator/= (double c) {
// if (c == 0) {
// std::cerr << "Hep3Vector::operator/ () - "
// << "Attempt to do vector /= 0 -- "
// << "division by zero would produce infinite or NAN components"
// << std::endl;
// }
*this *= 1.0/c;
return *this;
}
double Hep3Vector::tolerance = Hep3Vector::ToleranceTicks * 2.22045e-16;
} // namespace CLHEP