CTA 2D background class. More...

#include <GCTABackground2D.hpp>

Inheritance diagram for GCTABackground2D:

Public Member Functions
	GCTABackground2D (void)
	Void constructor. More...

	GCTABackground2D (const GFilename &filename)
	File constructor. More...

	GCTABackground2D (const GCTABackground2D &bgd)
	Copy constructor. More...

virtual	~GCTABackground2D (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...

GCTABackground2D &	operator= (const GCTABackground2D &bgd)
	Assignment operator. More...

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

GCTABackground2D *	clone (void) const
	Clone background. More...

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

void	load (const GFilename &filename)
	Load background from FITS file. 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...

bool	is_valid (void) const
	Return validity of background model. More...

const GCTAResponseTable &	table (void) const
	Return response table. More...

void	table (const GCTAResponseTable &table)
	Assign response table. More...

void	read (const GFitsTable &table)
	Read background from FITS table. More...

void	write (GFitsBinTable &table) const
	Write background into FITS table. More...

void	save (const GFilename &filename, const bool &clobber=false) const
	Save background into FITS file. 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 GCTABackground2D &bgd)
	Copy class members. More...

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

void	set_members (void)
	Set members from background table. More...

int	index (const int &itheta, const int &iebin) const
	Return background rate bin index. More...

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

void	init_mc_max_rate (void) const
	Initialise array of maximum background rate. More...

double	solid_angle (const double &detx1, const double &dety1, const double &detx2, const double &dety2, const double &detx3, const double &dety3) const
	Compute solid angle of pixel wedge. More...

double	rate (const int &iebin, const double &theta) const
	Return background rate for a given energy bin and offset angle value (events/s/MeV/sr) More...

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

GCTAResponseTable	m_background
	Background response table. More...

GEnergies	m_energy
	Vector of energies. More...

int	m_inx_theta
	THETA axis index. More...

int	m_inx_energy
	Energy axis index. More...

int	m_inx_bgd
	Background index. More...

int	m_num_theta
	Number of THETA bins. More...

int	m_num_energy
	Number of energy bins. More...

int	m_num [2]
	Array of number of bins. More...

double	m_theta_min
	THETA minimum (radians) More...

double	m_theta_max
	THETA maximum (radians) More...

double	m_logE_min
	Log10(E/TeV) minimum. More...

double	m_logE_max
	Log10(E/TeV) maximum. More...

std::vector< double >	m_mc_max
	Maximum background rate. More...

GModelSpectralNodes	m_mc_spectrum
	Response cube 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 2D background class.

Definition at line 53 of file GCTABackground2D.hpp.

Constructor & Destructor Documentation

GCTABackground2D::GCTABackground2D ( void )

Void constructor.

Constructs empty background.

Definition at line 69 of file GCTABackground2D.cpp.

References init_members().

Referenced by clone().

GCTABackground2D::GCTABackground2D ( const GFilename & filename )

explicit

File constructor.

Parameters

[in] filename FITS file name.

Constructs background from a FITS file.

Definition at line 86 of file GCTABackground2D.cpp.

References init_members(), and load().

GCTABackground2D::GCTABackground2D ( const GCTABackground2D & bgd )

Copy constructor.

Parameters

[in] bgd Background.

Constructs background by copying from another background.

Definition at line 107 of file GCTABackground2D.cpp.

References copy_members(), and init_members().

GCTABackground2D::~GCTABackground2D ( void )

virtual

Destructor.

Destructs background.

Definition at line 126 of file GCTABackground2D.cpp.

References free_members().

Member Function Documentation

std::string GCTABackground2D::classname ( void ) const

inlinevirtual

Return class name.

Returns: String containing the class name ("GCTABackground2D").

Implements GCTABackground.

Definition at line 135 of file GCTABackground2D.hpp.

void GCTABackground2D::clear ( void )

virtual

Clear background.

Clears background.

Implements GCTABackground.

Definition at line 255 of file GCTABackground2D.cpp.

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

GCTABackground2D * GCTABackground2D::clone ( void ) const

virtual

Clone background.

Returns: Deep copy of background.

Returns a pointer to a deep copy of the background.

Implements GCTABackground.

Definition at line 277 of file GCTABackground2D.cpp.

References GCTABackground2D().

void GCTABackground2D::copy_members ( const GCTABackground2D & bgd )

private

Copy class members.

Parameters

[in] bgd Background.

Definition at line 753 of file GCTABackground2D.cpp.

References m_background, m_energy, m_filename, m_inx_bgd, m_inx_energy, m_inx_theta, m_logE_max, m_logE_min, m_mc_max, m_mc_spectrum, m_num, m_num_energy, m_num_theta, m_theta_max, and m_theta_min.

Referenced by GCTABackground2D(), and operator=().

GFilename GCTABackground2D::filename ( void ) const

inlinevirtual

Return filename.

Returns: Returns filename from which the background was loaded.

Implements GCTABackground.

Definition at line 147 of file GCTABackground2D.hpp.

References m_filename.

Referenced by load().

void GCTABackground2D::free_members ( void )

private

Delete class members.

Definition at line 783 of file GCTABackground2D.cpp.

Referenced by clear(), operator=(), and ~GCTABackground2D().

int GCTABackground2D::index	(	const int &	itheta,
		const int &	iebin
	)		const

private

Return background rate bin index.

Parameters

[in]	itheta	THETA index.
[in]	iebin	Energy index.

Returns: Background rate bin index.

Returns the background rate bin index independent of the ordering.

Definition at line 869 of file GCTABackground2D.cpp.

References m_inx_energy, m_inx_theta, and m_num.

Referenced by init_mc_max_rate(), and rate().

void GCTABackground2D::init_mc_cache ( void ) const

private

Initialise Monte Carlo cache.

Exceptions

GException::invalid_value Background response table was empty.

Initialises the cache for Monte Carlo sampling.

Definition at line 893 of file GCTABackground2D.cpp.

References GModelSpectralNodes::append(), GCTAResponseTable::axis_hi(), GCTAResponseTable::axis_hi_unit(), GCTAResponseTable::axis_lo(), GCTAResponseTable::axis_lo_unit(), GModelSpectralNodes::clear(), GEnergies::extend(), G_INIT_MC_CACHE, init_mc_max_rate(), m_background, m_energy, m_inx_energy, m_mc_max, m_mc_spectrum, m_num_energy, m_num_theta, m_theta_max, GModelSpectralNodes::nodes(), GEnergies::remove(), GEnergies::size(), and solid_angle().

Referenced by mc(), and spectrum().

void GCTABackground2D::init_mc_max_rate ( void ) const

private

Initialise array of maximum background rate.

Initialises the array m_mc_max that holds the maximum background rate for each energy of the background model.

Definition at line 1036 of file GCTABackground2D.cpp.

References index(), m_background, m_inx_bgd, m_mc_max, m_num_energy, m_num_theta, and rate().

Referenced by init_mc_cache().

void GCTABackground2D::init_members ( void )

private

Initialise class members.

Definition at line 721 of file GCTABackground2D.cpp.

References GCTAResponseTable::clear(), GEnergies::clear(), GFilename::clear(), GModelSpectralNodes::clear(), m_background, m_energy, m_filename, m_inx_bgd, m_inx_energy, m_inx_theta, m_logE_max, m_logE_min, m_mc_max, m_mc_spectrum, m_num, m_num_energy, m_num_theta, m_theta_max, and m_theta_min.

Referenced by clear(), GCTABackground2D(), and operator=().

bool GCTABackground2D::is_valid ( void ) const

inline

Return validity of background model.

Returns: True if background model is valid.

Definition at line 177 of file GCTABackground2D.hpp.

References GCTAResponseTable::axes(), and m_background.

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

void GCTABackground2D::load ( const GFilename & filename )

virtual

Load background from FITS file.

Parameters

[in] filename FITS file name.

Loads the background from a FITS file.

If no extension name is given the method scans the HDUCLASS keywords of all extensions and loads the background from the first extension for which HDUCLAS4=BKG_2D.

Otherwise, the background will be loaded from the BKG extension.

Implements GCTABackground.

Definition at line 368 of file GCTABackground2D.cpp.

References GFits::close(), GFilename::extname(), gammalib::extname_cta_background2d, filename(), gammalib::gadf_hduclas4(), m_filename, read(), table(), and GFits::table().

Referenced by GCTABackground2D().

GCTAInstDir GCTABackground2D::mc	(	const GEnergy &	energy,
		const GTime &	time,
		GRan &	ran
	)		const

virtual

Returns MC instrument direction.

Parameters

[in]	energy	Event energy.
[in]	time	Event trigger time.
[in,out]	ran	Random number generator.

Returns: CTA instrument direction.

Returns a Monte Carlo simulated instrument direction for a given energy and event trigger time. The simulation is done using a rejection method that makes use of the background rate access operator. This assures that the simulation is consistent with the background rate interpolation that is done by the access operator.

Implements GCTABackground.

Definition at line 461 of file GCTABackground2D.cpp.

References GCTAResponseTable::axis_nodes(), GCTAInstDir::detx(), GCTAInstDir::dety(), GModelSpectralNodes::energy(), G_MC, init_mc_cache(), GNodeArray::inx_left(), GNodeArray::inx_right(), GEnergy::log10TeV(), m_background, m_inx_energy, m_mc_max, m_mc_spectrum, m_theta_max, GModelSpectralNodes::nodes(), operator()(), GEnergy::print(), gammalib::rad2deg, GNodeArray::set_value(), gammalib::str(), GRan::uniform(), and gammalib::warning().

double GCTABackground2D::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 X coordinate in nominal system (radians).
[in]	dety	Tangential Y coordinate in nominal system (radians).

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 operator computes the offset angle

\[\theta = \sqrt{ {\rm DETX}^2 + {\rm DETY}^2 }\]

and interpolates linearly in \(\theta\) and logarithmically in energy.

The operator assures that the background rate never becomes negative. For invalid background models or detector coordinates outside the range covered by the response cube, the operator returns a rate of zero.

Implements GCTABackground.

Definition at line 194 of file GCTABackground2D.cpp.

References GCTAResponseTable::axis_nodes(), exp(), GNodeArray::inx_left(), GNodeArray::inx_right(), is_valid(), log(), m_background, m_inx_energy, m_theta_max, m_theta_min, rate(), GNodeArray::set_value(), sqrt(), GNodeArray::wgt_left(), and GNodeArray::wgt_right().

Referenced by mc().

GCTABackground2D & GCTABackground2D::operator= ( const GCTABackground2D & bgd )

Assignment operator.

Parameters

[in] bgd Background.

Returns: Background.

Assigns background.

Definition at line 150 of file GCTABackground2D.cpp.

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

std::string GCTABackground2D::print ( const GChatter & chatter = NORMAL ) const

virtual

Print background information.

Parameters

[in] chatter Chattiness.

Returns: String containing background information.

Implements GCTABackground.

Definition at line 660 of file GCTABackground2D.cpp.

References GCTAResponseTable::axis_hi(), GCTAResponseTable::axis_lo(), is_valid(), m_background, m_filename, m_inx_energy, m_inx_theta, m_num_energy, m_num_theta, gammalib::parformat(), SILENT, and gammalib::str().

double GCTABackground2D::rate	(	const int &	iebin,
		const double &	theta
	)		const

private

Return background rate for a given energy bin and offset angle value (events/s/MeV/sr)

Parameters

[in]	iebin	Energy index.
[in]	theta	Offset angle in nominal system (radians).

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

Definition at line 1149 of file GCTABackground2D.cpp.

References GCTAResponseTable::axis_nodes(), index(), GNodeArray::inx_left(), GNodeArray::inx_right(), m_background, m_inx_bgd, m_inx_theta, GNodeArray::set_value(), GNodeArray::wgt_left(), and GNodeArray::wgt_right().

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

double GCTABackground2D::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 576 of file GCTABackground2D.cpp.

References GCTAInstDir::detx(), GCTAInstDir::dety(), is_valid(), GEnergy::log10TeV(), m_energy, m_theta_max, m_theta_min, GEnergy::MeV(), gammalib::plaw_integral(), rate(), GEnergies::size(), and sqrt().

void GCTABackground2D::read ( const GFitsTable & table )

Read background from FITS table.

Parameters

[in] table FITS table.

Reads the background form the FITS table. The following column names are mandatory:

THETA_LO - THETA lower bin boundaries
THETA_HI - THETA upper bin boundaries
ENERG_LO - Energy lower bin boundaries
ENERG_HI - Energy upper bin boundaries
BKG      - Background template

The data are stored in the m_background member. The THETA axis will be set to radians, the energy axis will be set to log10. The data are expected to be given in unit of events per MeV, second and steradian, where the time is the real ontime.

This method ignores all column names that are not the mandatory column names in the FITS table.

Definition at line 305 of file GCTABackground2D.cpp.

References GCTAResponseTable::clear(), GFitsTable::clone(), m_background, GFitsTable::ncols(), GCTAResponseTable::read(), GFitsTable::remove(), and set_members().

Referenced by load().

void GCTABackground2D::save	(	const GFilename &	filename,
		const bool &	clobber = `false`
	)		const

Save background into FITS file.

Parameters

[in]	filename	Background table FITS file name.
[in]	clobber	Overwrite existing file?

Saves background into a FITS file. If a file with the given filename does not yet exist it will be created, otherwise the method opens the existing file. The method will create a (or replace an existing) background extension. The extension name can be specified as part of the filename, or if no extension name is given, is assumed to be BKG.

An existing file will only be modified if the clobber flag is set to true.

Definition at line 413 of file GCTABackground2D.cpp.

References GFitsHDU::extname(), GFilename::extname(), gammalib::extname_cta_background2d, GFits::remove(), table(), GFilename::url(), and write().

void GCTABackground2D::set_members ( void )

private

Set members from background table.

Exceptions

GException::invalid_value Response table is not three-dimensional.

Set class members based on the background table. The THETA axis will be set to radians, the energy axis will be set to log10.

Definition at line 799 of file GCTABackground2D.cpp.

Referenced by read(), and table().

double GCTABackground2D::solid_angle	(	const double &	detx1,
		const double &	dety1,
		const double &	detx2,
		const double &	dety2,
		const double &	detx3,
		const double &	dety3
	)		const

private

Compute solid angle of pixel wedge.

Parameters

[in]	detx1	DETX of first edge.
[in]	dety1	DETY of first edge.
[in]	detx2	DETX of second edge.
[in]	dety2	DETY of second edge.
[in]	detx3	DETX of third edge.
[in]	dety3	DETY of third edge.

Returns: Solid angle (steradians).

Estimate the solid angle subtended by 3 coordinates using Huilier's theorem.

Below, the definiton of the pixel cornes and sides are shown as used within the code.

        a12
    1---------2
    |        / 
    |       /  
    |      /   
    |     /    
 a13|    /a23
    |   / 
    |  / 
    | /
    |/

Definition at line 1106 of file GCTABackground2D.cpp.

References atan(), gammalib::atan2(), GSkyDir::dist(), gammalib::pihalf, GSkyDir::radec(), sqrt(), and tan().

Referenced by init_mc_cache().

const GModelSpectralNodes & GCTABackground2D::spectrum ( void ) const

inlinevirtual

Get response cube spectrum.

Returns: Response cube spectrum.

Returns the response cube spectrum.

Implements GCTABackground.

Definition at line 162 of file GCTABackground2D.hpp.

References init_mc_cache(), m_mc_spectrum, and GModelSpectralNodes::nodes().

const GCTAResponseTable & GCTABackground2D::table ( void ) const

inline

Return response table.

Returns: Response table.

Definition at line 189 of file GCTABackground2D.hpp.

References m_background.

Referenced by load(), save(), and table().

void GCTABackground2D::table ( const GCTAResponseTable & table )

inline

Assign response table.

Parameters

[in] table Response table.

Definition at line 201 of file GCTABackground2D.hpp.

References m_background, set_members(), and table().

void GCTABackground2D::write ( GFitsBinTable & table ) const

Write background into FITS table.

Parameters

[in] table FITS binary table.

Writes background into a FITS binary table.

Todo:: Add necessary keywords.

Definition at line 345 of file GCTABackground2D.cpp.

References m_background, and GCTAResponseTable::write().

Referenced by save().

Member Data Documentation

GCTAResponseTable GCTABackground2D::m_background

private

Background response table.

Definition at line 110 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_mc_max_rate(), init_members(), is_valid(), mc(), operator()(), print(), rate(), read(), set_members(), table(), and write().

GEnergies GCTABackground2D::m_energy

private

Vector of energies.

Definition at line 111 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_members(), rate_ebin(), and set_members().

GFilename GCTABackground2D::m_filename

private

Name of background response file.

Definition at line 109 of file GCTABackground2D.hpp.

Referenced by copy_members(), filename(), init_members(), load(), and print().

int GCTABackground2D::m_inx_bgd

private

Background index.

Definition at line 114 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_max_rate(), init_members(), rate(), and set_members().

int GCTABackground2D::m_inx_energy

private

Energy axis index.

Definition at line 113 of file GCTABackground2D.hpp.

Referenced by copy_members(), index(), init_mc_cache(), init_members(), mc(), operator()(), print(), and set_members().

int GCTABackground2D::m_inx_theta

private

THETA axis index.

Definition at line 112 of file GCTABackground2D.hpp.

Referenced by copy_members(), index(), init_members(), print(), rate(), and set_members().

double GCTABackground2D::m_logE_max

private

Log10(E/TeV) maximum.

Definition at line 121 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_members(), and set_members().

double GCTABackground2D::m_logE_min

private

Log10(E/TeV) minimum.

Definition at line 120 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_members(), and set_members().

std::vector<double> GCTABackground2D::m_mc_max

mutableprivate

Maximum background rate.

Definition at line 124 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_mc_max_rate(), init_members(), and mc().

GModelSpectralNodes GCTABackground2D::m_mc_spectrum

mutableprivate

Response cube spectrum.

Definition at line 125 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_members(), mc(), and spectrum().

int GCTABackground2D::m_num[2]

private

Array of number of bins.

Definition at line 117 of file GCTABackground2D.hpp.

Referenced by copy_members(), index(), init_members(), and set_members().

int GCTABackground2D::m_num_energy

private

Number of energy bins.

Definition at line 116 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_mc_max_rate(), init_members(), print(), and set_members().

int GCTABackground2D::m_num_theta

private

Number of THETA bins.

Definition at line 115 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_mc_max_rate(), init_members(), print(), and set_members().

double GCTABackground2D::m_theta_max

private

THETA maximum (radians)

Definition at line 119 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_mc_cache(), init_members(), mc(), operator()(), rate_ebin(), and set_members().

double GCTABackground2D::m_theta_min

private

THETA minimum (radians)

Definition at line 118 of file GCTABackground2D.hpp.

Referenced by copy_members(), init_members(), operator()(), rate_ebin(), and set_members().

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

inst/cta/include/GCTABackground2D.hpp
inst/cta/src/GCTABackground2D.cpp

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation