Public Member Functions | Protected Attributes
Emittance Class Reference

Class for emittance statistics. More...

#include <trajectorydiagnostics.hpp>

Inheritance diagram for Emittance:
EmittanceConv

List of all members.

Public Member Functions

 Emittance ()
 Default constructor for emittance statistics.
 Emittance (const std::vector< double > &x, const std::vector< double > &xp, const std::vector< double > &I)
 Constructor for emittance statistics from trajectory diagnostic data columns x, xp and current I.
 Emittance (const std::vector< double > &x, const std::vector< double > &xp)
 Constructor for emittance statistics from trajectory diagnostic data columns x, xp, assuming even weights.
 Emittance (size_t xsize, size_t xpsize, const double range[4], const std::vector< double > &I)
 Constructor for emittance statistics from trajectory diagnostic data in mesh form.
double xave (void) const
 Return average position (center location) of emittance distribution.
double xpave (void) const
 Return average angle (center location) of emittance distribution.
double alpha (void) const
 Return $\alpha$ of emittance distribution.
double beta (void) const
 Return $\beta$ of emittance distribution.
double gamma (void) const
 Return $\gamma$ of emittance distribution.
double epsilon (void) const
 Return rms emittance.
double angle (void) const
 Return angle of fitted rms ellipse.
double rmajor (void) const
 Return major radius of fitted rms ellipse.
double rminor (void) const
 Return minor radius of fitted rms ellipse.
void debug_print (std::ostream &os) const
 Print debugging information to os.

Protected Attributes

double _Isum
double _xave
double _xpave
double _x2
double _xp2
double _xxp
double _alpha
double _beta
double _gamma
double _epsilon
double _angle
double _rmajor
double _rminor

Detailed Description

Class for emittance statistics.

Emittance class does a statistical analysis on the particle distribution and it calculates averages $ <x> $ and $ <x'> $ and the expectation values $ <x^2> $, $ <x'^2> $ and $ <x x'> $. From these it calculates the rms-emittance

\[ \epsilon = \sqrt{ <x^2><x'^2> - <x x'>^2 } \]

and the Twiss parameters

\[ \alpha = \frac{-<x x'>}{\epsilon}, \beta = \frac{<x^2>}{\epsilon}, \gamma = \frac{<x'^2>}{\epsilon} \]

In addition to these physical values, the class calculates the angle of the ellipse

\[ \theta = \frac{1}{2} \arctan2{\left( -2\alpha, \beta - \gamma \right)} \]

and the half-axis lengths

\[ r_1 = \sqrt{\frac{\epsilon}{2}} ( \sqrt{H+1} + \sqrt{H-1} ) \]

\[ r_2 = \sqrt{\frac{\epsilon}{2}} ( \sqrt{H+1} - \sqrt{H-1} ), \]

where

\[ H = \frac{\beta + \gamma}{2} \]


Constructor & Destructor Documentation

Default constructor for emittance statistics.

Emittance::Emittance ( const std::vector< double > &  x,
const std::vector< double > &  xp,
const std::vector< double > &  I 
)

Constructor for emittance statistics from trajectory diagnostic data columns x, xp and current I.

Emittance::Emittance ( const std::vector< double > &  x,
const std::vector< double > &  xp 
)

Constructor for emittance statistics from trajectory diagnostic data columns x, xp, assuming even weights.

Emittance::Emittance ( size_t  xsize,
size_t  xpsize,
const double  range[4],
const std::vector< double > &  I 
)

Constructor for emittance statistics from trajectory diagnostic data in mesh form.

The mesh has integer dimensions of (xsize, xpsize) and has the extents defined by range, where range = (xmin, xpmin, xmax, xpmax). Current data at each mesh node is given by vector I, where data is stored in x major order (I[xindex+xpindex*xsize]).


Member Function Documentation

double Emittance::alpha ( void  ) const [inline]

Return $\alpha$ of emittance distribution.

double Emittance::angle ( void  ) const [inline]

Return angle of fitted rms ellipse.

double Emittance::beta ( void  ) const [inline]

Return $\beta$ of emittance distribution.

void Emittance::debug_print ( std::ostream &  os) const

Print debugging information to os.

double Emittance::epsilon ( void  ) const [inline]

Return rms emittance.

double Emittance::gamma ( void  ) const [inline]

Return $\gamma$ of emittance distribution.

double Emittance::rmajor ( void  ) const [inline]

Return major radius of fitted rms ellipse.

double Emittance::rminor ( void  ) const [inline]

Return minor radius of fitted rms ellipse.

double Emittance::xave ( void  ) const [inline]

Return average position (center location) of emittance distribution.

double Emittance::xpave ( void  ) const [inline]

Return average angle (center location) of emittance distribution.


Member Data Documentation

double Emittance::_alpha [protected]
double Emittance::_angle [protected]
double Emittance::_beta [protected]
double Emittance::_epsilon [protected]
double Emittance::_gamma [protected]
double Emittance::_Isum [protected]
double Emittance::_rmajor [protected]
double Emittance::_rminor [protected]
double Emittance::_x2 [protected]
double Emittance::_xave [protected]
double Emittance::_xp2 [protected]
double Emittance::_xpave [protected]
double Emittance::_xxp [protected]

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