CTA performance table background class. More...

#include <GCTABackgroundPerfTable.hpp>

Inheritance diagram for GCTABackgroundPerfTable:

Classes
class	integrand

Public Member Functions
	GCTABackgroundPerfTable (void)
	Void constructor. More...

	GCTABackgroundPerfTable (const GFilename &filename)
	File constructor. More...

	GCTABackgroundPerfTable (const GCTABackgroundPerfTable &bgd)
	Copy constructor. More...

virtual	~GCTABackgroundPerfTable (void)
	Destructor. More...

virtual double	operator() (const double &logE, const double &detx, const double &dety) const
	Return background rate in units of events MeV \(^{-1}\) s \(^{-1}\) sr \(^{-1}\). More...

GCTABackgroundPerfTable &	operator= (const GCTABackgroundPerfTable &bgd)
	Assignment operator. More...

void	clear (void)
	Clear background. More...

GCTABackgroundPerfTable *	clone (void) const
	Clone background. More...

std::string	classname (void) const
	Return class name. More...

void	load (const GFilename &filename)
	Load background from performance table. More...

GFilename	filename (void) const
	Return filename. More...

GCTAInstDir	mc (const GEnergy &energy, const GTime &time, GRan &ran) const
	Returns MC instrument direction. More...

const GModelSpectralNodes &	spectrum (void) const
	Get response cube spectrum. More...

double	rate_ebin (const GCTAInstDir &dir, const GEnergy &emin, const GEnergy &emax) const
	Returns background rate integrated over energy interval in units of events s \(^{-1}\) sr \(^{-1}\). More...

std::string	print (const GChatter &chatter=NORMAL) const
	Print background information. More...

int	size (void) const
	Return number of node energies in response. More...

void	sigma (const double &sigma)
	Set sigma for offset angle dependence. More...

const double &	sigma (void) const
	Return sigma for offset angle dependence. More...

Public Member Functions inherited from GCTABackground
	GCTABackground (void)
	Void constructor. More...

	GCTABackground (const GCTABackground &bgd)
	Copy constructor. More...

virtual	~GCTABackground (void)
	Destructor. More...

GCTABackground &	operator= (const GCTABackground &bgd)
	Assignment operator. More...

Public Member Functions inherited from GBase
virtual	~GBase (void)
	Destructor. More...

Private Member Functions
void	init_members (void)
	Initialise class members. More...

void	copy_members (const GCTABackgroundPerfTable &bgd)
	Copy class members. More...

void	free_members (void)
	Delete class members. More...

double	solidangle (void) const
	Returns integral over radial model (in steradians) More...

void	init_mc_cache (void) const
	Initialise Monte Carlo cache. More...

double	rate (const double &logE) const
	Return background rate for a given energy (events/s/MeV/sr) More...

Private Attributes
GFilename	m_filename
	Name of background response file. More...

GEnergies	m_energy
	Vector of energies. More...

GNodeArray	m_log10_energy
	log10(E) nodes for background interpolation More...

std::vector< double >	m_background
	Background rate. More...

std::vector< double >	m_log_background
	log(background rate) More...

double	m_sigma
	Sigma for offset angle computation (0=none) More...

GModelSpectralNodes	m_mc_spectrum
	Background spectrum. More...

Additional Inherited Members
Protected Member Functions inherited from GCTABackground
void	init_members (void)
	Initialise class members. More...

void	copy_members (const GCTABackground &bgd)
	Copy class members. More...

void	free_members (void)
	Delete class members. More...

Detailed Description

CTA performance table background class.

Definition at line 47 of file GCTABackgroundPerfTable.hpp.

Constructor & Destructor Documentation

GCTABackgroundPerfTable::GCTABackgroundPerfTable ( void )

Void constructor.

Definition at line 63 of file GCTABackgroundPerfTable.cpp.

References init_members().

Referenced by clone().

GCTABackgroundPerfTable::GCTABackgroundPerfTable ( const GFilename & filename )

explicit

File constructor.

Parameters

[in] filename Performance table file name.

Construct instance by loading the background information from a performance table.

Definition at line 81 of file GCTABackgroundPerfTable.cpp.

References init_members(), and load().

GCTABackgroundPerfTable::GCTABackgroundPerfTable ( const GCTABackgroundPerfTable & bgd )

Copy constructor.

Parameters

[in] bgd Background.

Definition at line 100 of file GCTABackgroundPerfTable.cpp.

References copy_members(), and init_members().

GCTABackgroundPerfTable::~GCTABackgroundPerfTable ( void )

virtual

Destructor.

Definition at line 117 of file GCTABackgroundPerfTable.cpp.

References free_members().

Member Function Documentation

std::string GCTABackgroundPerfTable::classname ( void ) const

inlinevirtual

Return class name.

Returns: String containing the class name ("GCTABackgroundPerfTable").

Implements GCTABackground.

Definition at line 127 of file GCTABackgroundPerfTable.hpp.

void GCTABackgroundPerfTable::clear ( void )

virtual

Clear background.

This method properly resets the background to an initial state.

Implements GCTABackground.

Definition at line 210 of file GCTABackgroundPerfTable.cpp.

References GCTABackground::free_members(), free_members(), GCTABackground::init_members(), and init_members().

GCTABackgroundPerfTable * GCTABackgroundPerfTable::clone ( void ) const

virtual

Clone background.

Returns: Pointer to deep copy of background.

Implements GCTABackground.

Definition at line 230 of file GCTABackgroundPerfTable.cpp.

References GCTABackgroundPerfTable().

void GCTABackgroundPerfTable::copy_members ( const GCTABackgroundPerfTable & bgd )

private

Copy class members.

Parameters

[in] bgd Background.

Definition at line 553 of file GCTABackgroundPerfTable.cpp.

References m_background, m_energy, m_filename, m_log10_energy, m_log_background, m_mc_spectrum, and m_sigma.

Referenced by GCTABackgroundPerfTable(), and operator=().

GFilename GCTABackgroundPerfTable::filename ( void ) const

inlinevirtual

Return filename.

Returns: Returns filename from which the background was loaded.

Implements GCTABackground.

Definition at line 139 of file GCTABackgroundPerfTable.hpp.

References m_filename.

Referenced by load().

void GCTABackgroundPerfTable::free_members ( void )

private

Delete class members.

Definition at line 574 of file GCTABackgroundPerfTable.cpp.

Referenced by clear(), operator=(), and ~GCTABackgroundPerfTable().

void GCTABackgroundPerfTable::init_mc_cache ( void ) const

private

Initialise Monte Carlo cache.

Todo:

Verify assumption made about the solid angles of the response table elements.

Add optional sampling on a finer spatial grid.

Definition at line 629 of file GCTABackgroundPerfTable.cpp.

References GModelSpectralNodes::append(), GModelSpectralNodes::clear(), m_background, m_energy, m_mc_spectrum, size(), and solidangle().

Referenced by spectrum().

void GCTABackgroundPerfTable::init_members ( void )

private

Initialise class members.

Definition at line 530 of file GCTABackgroundPerfTable.cpp.

References GNodeArray::clear(), GEnergies::clear(), GFilename::clear(), GModelSpectralNodes::clear(), m_background, m_energy, m_filename, m_log10_energy, m_log_background, m_mc_spectrum, and m_sigma.

Referenced by clear(), GCTABackgroundPerfTable(), and operator=().

void GCTABackgroundPerfTable::load ( const GFilename & filename )

virtual

Load background from performance table.

Parameters

[in] filename Performance table file name.

Exceptions

GException::file_open_error File could not be opened for read access.

Loads the background information from a performance table.

Implements GCTABackground.

Definition at line 246 of file GCTABackgroundPerfTable.cpp.

References GNodeArray::append(), GEnergies::append(), GNodeArray::clear(), GEnergies::clear(), cos(), gammalib::deg2rad, filename(), G_LOAD, log(), GEnergy::log10TeV(), m_background, m_energy, m_filename, m_log10_energy, m_log_background, pow(), solidangle(), gammalib::split(), gammalib::strip_whitespace(), gammalib::todouble(), gammalib::twopi, and GFilename::url().

Referenced by GCTABackgroundPerfTable().

GCTAInstDir GCTABackgroundPerfTable::mc	(	const GEnergy &	energy,
		const GTime &	time,
		GRan &	ran
	)		const

virtual

Returns MC instrument direction.

Parameters

[in]	energy	Photon energy.
[in]	time	Photon arrival time.
[in,out]	ran	Random number generator.

Returns: CTA instrument direction.

Implements GCTABackground.

Definition at line 334 of file GCTABackgroundPerfTable.cpp.

References cos(), gammalib::deg2rad, GCTAInstDir::detx(), GCTAInstDir::dety(), exp(), sigma(), sin(), sqrt(), gammalib::twopi, and GRan::uniform().

double GCTABackgroundPerfTable::operator()	(	const double &	logE,
		const double &	detx,
		const double &	dety
	)		const

virtual

Return background rate in units of events MeV \(^{-1}\) s \(^{-1}\) sr \(^{-1}\).

Parameters

[in]	logE	Log10 of the true photon energy (TeV).
[in]	detx	Tangential coordinate in nominal system (rad).
[in]	dety	Tangential coordinate in nominal system (rad).

Returns: Background rate (events MeV \(^{-1}\) s \(^{-1}\) sr \(^{-1}\)).

Returns the background rate for a given energy and detector coordinates. The rate is given per ontime. The method assures that the background rate never becomes negative.

If the performance table contains less than 2 nodes an empty value is returned.

Implements GCTABackground.

Definition at line 179 of file GCTABackgroundPerfTable.cpp.

References exp(), m_sigma, gammalib::rad2deg, rate(), and sqrt().

GCTABackgroundPerfTable & GCTABackgroundPerfTable::operator= ( const GCTABackgroundPerfTable & bgd )

Assignment operator.

Parameters

[in] bgd Background.

Returns: Background.

Definition at line 139 of file GCTABackgroundPerfTable.cpp.

References copy_members(), free_members(), init_members(), and GCTABackground::operator=().

std::string GCTABackgroundPerfTable::print ( const GChatter & chatter = NORMAL ) const

virtual

Print background information.

Parameters

[in] chatter Chattiness.

Returns: String containing background information.

Implements GCTABackground.

Definition at line 478 of file GCTABackgroundPerfTable.cpp.

References GEnergies::append(), m_energy, m_filename, m_sigma, gammalib::parformat(), SILENT, size(), and gammalib::str().

double GCTABackgroundPerfTable::rate ( const double & logE ) const

private

Return background rate for a given energy (events/s/MeV/sr)

Parameters

[in] logE Log10 of the true photon energy (TeV).

Returns: Background rate (events/s/MeV/sr)

Definition at line 661 of file GCTABackgroundPerfTable.cpp.

References exp(), GNodeArray::interpolate(), m_background, m_log10_energy, m_log_background, and size().

Referenced by operator()(), and rate_ebin().

double GCTABackgroundPerfTable::rate_ebin	(	const GCTAInstDir &	dir,
		const GEnergy &	emin,
		const GEnergy &	emax
	)		const

virtual

Returns background rate integrated over energy interval in units of events s \(^{-1}\) sr \(^{-1}\).

Parameters

[in]	dir	Instrument direction.
[in]	emin	Minimum energy of energy interval.
[in]	emax	Maximum energy of energy interval.

Returns: Integrated background count rate (events s \(^{-1}\) sr \(^{-1}\)).

Returns the background count rate for a given instrument direction that is integrated over a specified energy interval. The rate is given per ontime.

If the energy interval is not positive, a zero background rate is returned.

Implements GCTABackground.

Definition at line 399 of file GCTABackgroundPerfTable.cpp.

References exp(), GEnergy::log10TeV(), m_background, m_energy, m_sigma, GEnergy::MeV(), gammalib::plaw_integral(), gammalib::rad2deg, rate(), size(), and GCTAInstDir::theta().

void GCTABackgroundPerfTable::sigma ( const double & sigma )

inline

Set sigma for offset angle dependence.

Parameters

[in] sigma Sigma for offset angle dependence.

Sets the sigma parameter for the offset angle dependence of the effective area. If sigma is 0, no offset angle dependency will be assumed. By default, sigma = 3.

Definition at line 168 of file GCTABackgroundPerfTable.hpp.

References m_sigma, and sigma().

Referenced by GCTAResponseIrf::read().

const double & GCTABackgroundPerfTable::sigma ( void ) const

inline

Return sigma for offset angle dependence.

Returns: Sigma for offset angle dependence.

Definition at line 181 of file GCTABackgroundPerfTable.hpp.

References m_sigma.

Referenced by mc(), sigma(), and solidangle().

int GCTABackgroundPerfTable::size ( void ) const

inline

Return number of node energies in response.

Returns: Number of node energies.

Definition at line 152 of file GCTABackgroundPerfTable.hpp.

References m_energy, and GEnergies::size().

Referenced by init_mc_cache(), print(), rate(), and rate_ebin().

double GCTABackgroundPerfTable::solidangle ( void ) const

private

Returns integral over radial model (in steradians)

Computes

\[\Omega = 2 \pi \int_0^{\pi} \sin \theta f(\theta) d\theta\]

where

\[f(\theta) = \exp \left(-\frac{1}{2} \left( \frac{\theta^2}{\sigma} \right)^2 \right)\]

\(\theta\) is the offset angle (in degrees), and \(\sigma\) is the Gaussian width (in degrees \(^2\)).

The integration is performed numerically, and the upper integration bound \(\pi\) is set to \(\sqrt(10 \sigma)\) to reduce inaccuracies in the numerical integration.

Definition at line 598 of file GCTABackgroundPerfTable.cpp.

References gammalib::deg2rad, gammalib::pi, GIntegral::romberg(), sigma(), sqrt(), and gammalib::twopi.

Referenced by init_mc_cache(), and load().

const GModelSpectralNodes & GCTABackgroundPerfTable::spectrum ( void ) const

inlinevirtual

Get response cube spectrum.