lsst::gauss2d::Covariance Class Reference

A representation of a 2D Gaussian with x and y standard deviations and a covariance value. More...

#include <ellipse.h>

Inheritance diagram for lsst::gauss2d::Covariance:

Public Member Functions
	Covariance (double sigma_x_sq=0, double sigma_y_sq=0, double cov_xy=0)
	Construct a new Covariance object.
	Covariance (const Ellipse &ell)
	Construct a covariance using values from an ellipse instance.
void	convolve (const Covariance &cov)
	Convolve with another covariance, adding the values of each parameter to this.
double	get_sigma_x_sq () const
	Get the square of sigma_x.
double	get_sigma_y_sq () const
	Get the square of sigma_y.
double	get_cov_xy () const
	Get the covariance.
std::array< double, 3 >	get_xyc () const
	Get the array of sigma_x^2, sigma_y^2, covariance.
std::shared_ptr< Covariance >	make_convolution (const Covariance &cov) const
	Return the convolution of this with another covariance.
std::unique_ptr< Covariance >	make_convolution_uniq (const Covariance &cov) const
	Same as make_convolution(), but returning a unique_ptr.
void	set (const Ellipse &ellipse)
	Set values from an ellipse instance.
void	set (double sigma_x_sq=0, double sigma_y_sq=0, double cov_xy=0)
	Set all values at once.
void	set_sigma_x_sq (double sigma_x_sq)
	Set the square of sigma_x.
void	set_sigma_y_sq (double sigma_y_sq)
	Set the square of sigma_y.
void	set_cov_xy (double cov_xy)
	Set the off-diagonal (covariance) term.
void	set_xyc (const std::array< double, 3 > &xyc)
	Set sigma_x_sq, sigma_y_sq and cov_xy from an array ref.
std::string	repr (bool name_keywords=false, std::string_view namespace_separator=Object::CC_NAMESPACE_SEPARATOR) const override
std::string	str () const override
	Return a brief, human-readable string representation of this.
bool	operator== (const Covariance &other) const
bool	operator!= (const Covariance &other) const

Static Public Member Functions
static void	check (double sigma_x_sq, double sigma_y_sq, double cov_xy)
	Check whether the supplied values are valid, throwing if not.
Static Public Member Functions inherited from lsst::gauss2d::Object
static std::string_view	null_str (const std::string_view &namespace_separator)

Friends
std::ostream &	operator<< (std::ostream &out, const Covariance &obj)

Additional Inherited Members
Static Public Attributes inherited from lsst::gauss2d::Object
static constexpr std::string_view	CC_NAMESPACE_SEPARATOR = "::"
	The C++ namespace separator.
static constexpr std::string_view	NULL_STR_GENERAL = "None"
static constexpr std::string_view	PY_NAMESPACE_SEPARATOR = "."

Detailed Description

A representation of a 2D Gaussian with x and y standard deviations and a covariance value.

This ellipse representation is intended for intermediate calculations and does not use an abstract Data class.

Note

The covariance is equal to sigma_x*sigma_y*rho, where -1 < rho < 1. Covariance values implying rho values outside this range are invalid.

Constructor & Destructor Documentation

Covariance()

lsst::gauss2d::Covariance::Covariance ( double sigma_x_sq = 0, double sigma_y_sq = 0, double cov_xy = 0 )

explicit

Construct a new Covariance object.

Parameters

sigma_x_sq	The value of sigma_x^2
sigma_y_sq	The value of sigma_y^2
cov_xy	The value of the covariance

Member Function Documentation

make_convolution()

std::shared_ptr< Covariance > lsst::gauss2d::Covariance::make_convolution

(

const Covariance &

cov

)

const

Return the convolution of this with another covariance.

Convolution simply sums the values of each respective parameter.

Parameters

cov	The covariance to convolve with.

Returns

A new covariance with values set to the convolution.

repr()

std::string lsst::gauss2d::Covariance::repr ( bool name_keywords = false, std::string_view namespace_separator = Object::CC_NAMESPACE_SEPARATOR ) const

overridevirtual

Return a full, callable string representation of this.

Parameters

name_keywords	Whether to prefix arguments with "{name}=", where name is the arg name in the header (as with keyword arguments in Python).
namespace_separator	The string to use to delimit namespaces, i.e. :: in C++ and . in Python.

Returns

A callable string representation of this, which should return an an identical object to this.

Note

The representation with name_keywords=false must be callable in C++. The representation with name_keywords=true should be callable in Python, if there are any bindings.

Implements lsst::gauss2d::Object.

str()

std::string lsst::gauss2d::Covariance::str ( ) const

overridevirtual

Return a brief, human-readable string representation of this.

Implements lsst::gauss2d::Object.

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

• include/lsst/gauss2d/ellipse.h
• src/ellipse.cc