Rivet::ThreeMomentum Class Reference

Specialized version of the ThreeVector with momentum functionality. More...

#include <Vector3.hh>

Inheritance diagram for Rivet::ThreeMomentum:

Public Types
using	EVector = RivetEigen::Matrix< double, N, 1 >
	Vector.

Public Member Functions
template<typename V3TYPE , typename std::enable_if< HasXYZ< V3TYPE >::value, int >::type DUMMY = 0>
	ThreeMomentum (const V3TYPE &other)
	ThreeMomentum (const Vector< 3 > &other)
	ThreeMomentum (const double px, const double py, const double pz)
double	x () const
double	x2 () const
Vector3 &	setX (double x)
double	y () const
double	y2 () const
Vector3 &	setY (double y)
double	z () const
double	z2 () const
Vector3 &	setZ (double z)
double	dot (const Vector3 &v) const
	Dot-product with another vector.
Vector3	cross (const Vector3 &v) const
	Cross-product with another vector.
double	angle (const Vector3 &v) const
	Angle in radians to another vector.
Vector3	unitVec () const
	Unit-normalized version of this vector.
Vector3	unit () const
	Synonym for unitVec.
Vector3	polarVec () const
	Polar projection of this vector into the x-y plane.
Vector3	perpVec () const
	Synonym for polarVec.
Vector3	rhoVec () const
	Synonym for polarVec.
double	polarRadius2 () const
	Square of the polar radius (.
double	perp2 () const
	Synonym for polarRadius2.
double	rho2 () const
	Synonym for polarRadius2.
double	polarRadius () const
	Polar radius.
double	perp () const
	Synonym for polarRadius.
double	rho () const
	Synonym for polarRadius.
double	azimuthalAngle (const PhiMapping mapping=ZERO_2PI) const
	Angle subtended by the vector's projection in x-y and the x-axis.
double	phi (const PhiMapping mapping=ZERO_2PI) const
	Synonym for azimuthalAngle.
double	tanTheta () const
	Tangent of the polar angle.
double	polarAngle () const
	Angle subtended by the vector and the z-axis.
double	theta () const
	Synonym for polarAngle.
double	pseudorapidity () const
	Purely geometric approximation to rapidity.
double	eta () const
	Synonym for pseudorapidity.
double	abseta () const
	Convenience shortcut for fabs(eta())
Vector3 &	operator+= (const Vector3 &v)
	In-place addition operator.
Vector3 &	operator-= (const Vector3 &v)
	In-place subtraction operator.
const double &	get (const size_t index) const
double &	get (const size_t index)
const double &	operator[] (const size_t index) const
	Direct access to vector elements by index.
double &	operator[] (const size_t index)
	Direct access to vector elements by index.
Vector< N > &	set (const size_t index, const double value)
	Set indexed value.
constexpr size_t	size () const
	Vector dimensionality.
bool	isZero (double tolerance=1E-5) const
	Check for nullness, allowing for numerical precision.
double	mod2 () const
	Calculate the modulus-squared of a vector. \( \sum_{i=1}^N x_i^2 \).
double	mod () const
	Calculate the modulus of a vector. \( \sqrt{\sum_{i=1}^N x_i^2} \).
bool	operator== (const Vector< N > &a) const
bool	operator!= (const Vector< N > &a) const
Coordinate setters
ThreeMomentum &	setPx (double px)
	Set x-component of momentum \( p_x \).
ThreeMomentum &	setPy (double py)
	Set y-component of momentum \( p_y \).
ThreeMomentum &	setPz (double pz)
	Set z-component of momentum \( p_z \).
Accessors
double	px () const
	Get x-component of momentum \( p_x \).
double	px2 () const
	Get x-squared \( p_x^2 \).
double	py () const
	Get y-component of momentum \( p_y \).
double	py2 () const
	Get y-squared \( p_y^2 \).
double	pz () const
	Get z-component of momentum \( p_z \).
double	pz2 () const
	Get z-squared \( p_z^2 \).
double	p () const
	Get the modulus of the 3-momentum.
double	p2 () const
	Get the modulus-squared of the 3-momentum.
ThreeMomentum	pTvec () const
	Calculate the transverse momentum vector \( \vec{p}_T \).
ThreeMomentum	ptvec () const
	Synonym for pTvec.
double	pT2 () const
	Calculate the squared transverse momentum \( p_T^2 \).
double	pt2 () const
	Calculate the squared transverse momentum \( p_T^2 \).
double	pT () const
	Calculate the transverse momentum \( p_T \).
double	pt () const
	Calculate the transverse momentum \( p_T \).
Arithmetic operators (needed again for covariant returns)
ThreeMomentum &	operator*= (double a)
	Multiply by a scalar.
ThreeMomentum &	operator/= (double a)
	Divide by a scalar.
ThreeMomentum &	operator+= (const ThreeMomentum &v)
	Add two 3-momenta.
ThreeMomentum &	operator-= (const ThreeMomentum &v)
	Subtract two 3-momenta.
ThreeMomentum	operator- () const
	Multiply all components by -1.

Static Public Member Functions
static Vector3	mkX ()
static Vector3	mkY ()
static Vector3	mkZ ()

Detailed Description

Specialized version of the ThreeVector with momentum functionality.

Member Function Documentation

azimuthalAngle()

double Rivet::Vector3::azimuthalAngle ( const PhiMapping  mapping = ZERO_2PI ) const

inlineinherited

Angle subtended by the vector's projection in x-y and the x-axis.

Note

Returns zero in the case of a vector with null x and y components.

Todo:

Would it be better to return NaN in the null-perp case? Or throw?!

References Rivet::Vector3::eta(), and Rivet::mapAngle().

Referenced by Rivet::FourVector::azimuthalAngle(), Rivet::deltaPhi(), Rivet::deltaPhi(), Rivet::deltaPhi(), Rivet::deltaR2(), Rivet::deltaR2(), Rivet::deltaR2(), and Rivet::Vector3::phi().

pseudorapidity()

double Rivet::Vector3::pseudorapidity ( ) const

inlineinherited

Purely geometric approximation to rapidity.

eta = -ln[ tan(theta/2) ]

Also invariant under z-boosts, equal to y for massless particles.

Implemented using the tan half-angle formula tan(theta/2) = sin(theta) / [1 + cos(theta)] = pT / (p + pz)

<

Todo:

Add [[ unlikely ]] with C++20

<

Todo:

Add [[ unlikely ]] with C++20

References Rivet::Vector3::eta(), Rivet::Vector< 3 >::mod(), and Rivet::Vector3::perp().

Referenced by Rivet::deltaEta(), Rivet::deltaEta(), Rivet::deltaEta(), Rivet::deltaR2(), Rivet::deltaR2(), Rivet::deltaR2(), Rivet::Vector3::eta(), and Rivet::FourVector::pseudorapidity().

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The documentation for this class was generated from the following file:

• /Users/chrisg/software/rivet/include/Rivet/Math/Vector3.hh