Fermi/LAT point spread function version 3 class. More...

#include <GLATPsfV3.hpp>

Inheritance diagram for GLATPsfV3:

Classes
class	base_integrand

Public Member Functions
	GLATPsfV3 (void)
	Void constructor. More...

	GLATPsfV3 (const GLATPsfV3 &psf)
	Copy constructor. More...

virtual	~GLATPsfV3 (void)
	Destructor. More...

GLATPsfV3 &	operator= (const GLATPsfV3 &psf)
	Assignment operator. More...

void	clear (void)
	Clear point spread function. More...

GLATPsfV3 *	clone (void) const
	Clone point spread function. More...

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

void	read (const GFitsTable &table)
	Read point spread function from FITS table. More...

void	write (GFits &file) const
	Write point spread function into FITS file. More...

double	psf (const double &offset, const double &logE, const double &ctheta)
	Return point spread function value. More...

int	version (void) const
	Return point spread function version number. More...

std::string	print (const GChatter &chatter=NORMAL) const
	Print point spread function. More...

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

	GLATPsfBase (const GLATPsfBase &psf)
	Copy constructor. More...

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

GLATPsfBase &	operator= (const GLATPsfBase &psf)
	Assignment operator. More...

void	read_scale (const GFitsTable &hdu)
	Read PSF scale factors from FITS table. More...

void	write_scale (GFits &file) const
	Write PSF scale factors. More...

int	size (void) const
	Return number of bins in point spread function. More...

int	nenergies (void) const
	Return number of energies in point spread function. More...

int	ncostheta (void) const
	Return number of cosine theta bins in point spread function. More...

const double &	costhetamin (void) const
	Return cosine theta minimum. More...

void	costhetamin (const double &ctheta)
	Set minimum cos(theta) angle for point spread function. More...

bool	has_phi (void) const
	Signal that point spread function has Phi dependence. More...

const bool &	front (void) const
	Signal that point spread function is for front section. More...

void	front (const bool &front)
	Set if point spread function is for front section. More...

const double &	scale_par1 (void) const
	Return first scaling parameter. More...

const double &	scale_par2 (void) const
	Return second scaling parameter. More...

const double &	scale_index (void) const
	Return scaling index. 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 GLATPsfV3 &psf)
	Copy class members. More...

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

double	eval_psf (const double &offset, const double &energy, const int &index)
	Evaluate PSF for a specific set of parameters. More...

double	integrate_psf (const double &energy, const int &index)
	Integrates PSF for a specific set of parameters. More...

void	normalize_psf (void)
	Normalize PSF for all parameters. More...

Static Private Member Functions
static double	base_fct (const double &u, const double &gamma)
	Return point spread base function value. More...

static double	base_int (const double &u, const double &gamma)
	Return approximation of point spread base function integral. More...

Private Attributes
std::vector< double >	m_ncore
	PSF ncore parameter. More...

std::vector< double >	m_ntail
	PSF ntail parameter. More...

std::vector< double >	m_score
	PSF score parameter. More...

std::vector< double >	m_stail
	PSF stail parameter. More...

std::vector< double >	m_gcore
	PSF gcore parameter. More...

std::vector< double >	m_gtail
	PSF gtail parameter. More...

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

void	copy_members (const GLATPsfBase &psf)
	Copy class members. More...

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

double	scale_factor (const double &energy) const
	Return scale factor for energy (in MeV) More...

Protected Attributes inherited from GLATPsfBase
bool	m_front
	PSF is for front section? More...

GLATResponseTable	m_rpsf_bins
	PSF energy and cos theta binning. More...

double	m_scale_par1
	PSF scaling parameter 1. More...

double	m_scale_par2
	PSF scaling parameter 2. More...

double	m_scale_index
	PSF scaling index. More...

double	m_min_ctheta
	Minimum valid cos(theta) More...

Detailed Description

Fermi/LAT point spread function version 3 class.

Version 3 of the Fermi/LAT PSF is the sum of two King model functions. In contrast to version 2, this class interpolates the distributions rather than the parameters.

This class has been inspired by code from the Fermi/LAT ScienceTools. For comparison check the file irfs/latResponse/src/Psf3.h

Definition at line 51 of file GLATPsfV3.hpp.

Constructor & Destructor Documentation

GLATPsfV3::GLATPsfV3 ( void )

Void constructor.

Definition at line 61 of file GLATPsfV3.cpp.

References init_members().

Referenced by clone().

GLATPsfV3::GLATPsfV3 ( const GLATPsfV3 & psf )

Copy constructor.

Parameters

[in] psf Point spread function.

Definition at line 76 of file GLATPsfV3.cpp.

References copy_members(), and init_members().

GLATPsfV3::~GLATPsfV3 ( void )

virtual

Destructor.

Definition at line 92 of file GLATPsfV3.cpp.

References free_members().

Member Function Documentation

double GLATPsfV3::base_fct	(	const double &	u,
		const double &	gamma
	)

staticprivate

Return point spread base function value.

Parameters

[in]	u	Function argument.
[in]	gamma	Index.

The version 3 PSF base function is given by

\[\left(1 - \frac{1}{\Gamma} \right) \left(1 + \frac{u}{\Gamma} \right)^{-\Gamma}\]

Definition at line 507 of file GLATPsfV3.cpp.

References pow().

Referenced by GLATPsfV3::base_integrand::eval(), and eval_psf().

double GLATPsfV3::base_int	(	const double &	u,
		const double &	gamma
	)

staticprivate

Return approximation of point spread base function integral.

Parameters

[in]	u	Function argument.
[in]	gamma	Index.

The version 3 PSF base function integral is approximated by

\[1 - \left(1 + \frac{u}{\Gamma} \right)^{1-\Gamma}\]

which is valid for small angles \(u\). For larger angles a numerical integration of the base function has to be performed.

Todo:: Verify that 1+u/gamma is not negative

Definition at line 534 of file GLATPsfV3.cpp.

References pow().

Referenced by integrate_psf().

std::string GLATPsfV3::classname ( void ) const

inlinevirtual

Return class name.

Returns: String containing the class name ("GLATPsfV3").

Implements GLATPsfBase.

Definition at line 130 of file GLATPsfV3.hpp.

void GLATPsfV3::clear ( void )

virtual

Clear point spread function.

Implements GLATPsfBase.

Definition at line 147 of file GLATPsfV3.cpp.

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

GLATPsfV3 * GLATPsfV3::clone ( void ) const

virtual

Clone point spread function.

Returns: Pointer to deep copy of point spread function

Implements GLATPsfBase.

Definition at line 167 of file GLATPsfV3.cpp.

References GLATPsfV3().

void GLATPsfV3::copy_members ( const GLATPsfV3 & psf )

private

Copy class members.

Parameters

[in] psf Point spread function.

Definition at line 472 of file GLATPsfV3.cpp.

References m_gcore, m_gtail, m_ncore, m_ntail, m_score, and m_stail.

Referenced by GLATPsfV3(), and operator=().

double GLATPsfV3::eval_psf	(	const double &	offset,
		const double &	energy,
		const int &	index
	)

private

Evaluate PSF for a specific set of parameters.

Parameters

[in]	offset	Offset angle (radians).
[in]	energy	Energy (MeV).
[in]	index	Parameter array index.

Evaluates PSF as function of offset angle and energy for a specific set of PSF parameters. The parameter set that is used is specified by the index parameter. The energy parameter only serves to scale the score and stail parameters of the PSF.

This method is inspired from the Fermi/LAT Science Tools method Psf3::evaluate.

Definition at line 559 of file GLATPsfV3.cpp.

References base_fct(), m_gcore, m_gtail, m_ncore, m_ntail, m_score, m_stail, psf(), and GLATPsfBase::scale_factor().

Referenced by psf().

void GLATPsfV3::free_members ( void )

private

Delete class members.

Definition at line 490 of file GLATPsfV3.cpp.

Referenced by clear(), operator=(), and ~GLATPsfV3().

void GLATPsfV3::init_members ( void )

private

Initialise class members.

Definition at line 452 of file GLATPsfV3.cpp.

References m_gcore, m_gtail, m_ncore, m_ntail, m_score, and m_stail.

Referenced by clear(), GLATPsfV3(), and operator=().

double GLATPsfV3::integrate_psf	(	const double &	energy,
		const int &	index
	)

private

Integrates PSF for a specific set of parameters.

Parameters

[in]	energy	Energy (MeV).
[in]	index	Parameter array index.

Integrates PSF for a specific set of parameters.

Compile option G_APPROXIMATE_PSF_INTEGRAL: If defined, a numerical PSF integral is only performed for energies < 120 MeV, while for larger energies the small angle approximation is used. In not defined, a numerical PSF integral is performed for all energies. This option is kept for comparison with the Fermi/LAT ScienceTools who select the integration method based on the true photon energy. As the normalization is only performed once upon loading of the PSF, CPU time is not really an issue here, and we can afford the more precise numerical integration. Note that the uncertainties of the approximation at energies near to 120 MeV reaches 0.1%.

Todo:: Implement gcore and gtail checking

Definition at line 609 of file GLATPsfV3.cpp.

References base_int(), m_gcore, m_gtail, m_ncore, m_ntail, m_score, m_stail, gammalib::pihalf, psf(), GIntegral::romberg(), GLATPsfBase::scale_factor(), and gammalib::twopi.

Referenced by normalize_psf().

void GLATPsfV3::normalize_psf ( void )

private

Normalize PSF for all parameters.

Makes sure that PSF is normalized for all parameters. We assure this by looping over all parameter nodes, integrating the PSF for each set of parameters, and dividing the NCORE parameter by the integral.

Compile option G_CHECK_PSF_NORM: If defined, checks that the PSF is normalized correctly.

Definition at line 679 of file GLATPsfV3.cpp.

References GLATResponseTable::costheta_lo(), GLATResponseTable::energy(), GLATResponseTable::index(), integrate_psf(), m_gcore, m_gtail, m_ncore, m_ntail, GLATPsfBase::m_rpsf_bins, m_score, m_stail, GLATResponseTable::ncostheta(), GLATResponseTable::nenergies(), norm(), gammalib::pihalf, GIntegral::romberg(), GLATPsfBase::scale_factor(), sum(), and gammalib::twopi.

Referenced by read().

GLATPsfV3 & GLATPsfV3::operator= ( const GLATPsfV3 & psf )

Assignment operator.

Parameters

[in] psf Point spread function.

Returns: Point spread function.

Definition at line 114 of file GLATPsfV3.cpp.

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

std::string GLATPsfV3::print ( const GChatter & chatter = NORMAL ) const

virtual

Print point spread function.

Parameters

[in] chatter Chattiness (defaults to NORMAL).

Returns: String containing point spread function information.

Implements GLATPsfBase.

Definition at line 425 of file GLATPsfV3.cpp.

References SILENT.

double GLATPsfV3::psf	(	const double &	offset,
		const double &	logE,
		const double &	ctheta
	)

virtual

Return point spread function value.

Parameters

[in]	offset	Offset angle (deg).
[in]	logE	Log10 of the true photon energy (MeV).
[in]	ctheta	Cosine of zenith angle.

Evaluates point spread function by doing a bi-linear interpolation of PSF values obtained at the 4 corners that bound the specified energy and cos(theta) value.

This method is inspired by the Fermi/LAT Science Tools method Psf3::value.

Implements GLATPsfBase.

Definition at line 382 of file GLATPsfV3.cpp.

References gammalib::deg2rad, GLATResponseTable::energies(), eval_psf(), GLATResponseTable::indices(), GLATPsfBase::m_min_ctheta, GLATPsfBase::m_rpsf_bins, GLATResponseTable::set(), and GLATResponseTable::weights().

Referenced by eval_psf(), and integrate_psf().

void GLATPsfV3::read ( const GFitsTable & table )

virtual

Read point spread function from FITS table.

Parameters

[in] table FITS table.

Exceptions

GException::invalid_argument Inconsistent response table encountered

Reads point spread function information from FITS HDU. In addition to the energy and costheta binning information, 6 columns are expected: NCORE, NTAIL, SCORE, STAIL, GCORE, and GTAIL.

The method assures that NCORE is set properly for each energy and cos(theta) bin so that the integral over the PSF amount to unity. This normalization is done by the method normalize_psf.

Implements GLATPsfBase.

Definition at line 189 of file GLATPsfV3.cpp.

References GLATResponseTable::costheta_lo(), G_READ, m_gcore, m_gtail, GLATPsfBase::m_min_ctheta, m_ncore, m_ntail, GLATPsfBase::m_rpsf_bins, m_score, m_stail, normalize_psf(), GFitsTableCol::number(), GLATResponseTable::read(), GFitsTableCol::real(), GLATPsfBase::size(), GLATResponseTable::size(), and gammalib::str().

int GLATPsfV3::version ( void ) const

inlinevirtual

Return point spread function version number.

Returns: Point spread function version number (3).

Implements GLATPsfBase.

Definition at line 142 of file GLATPsfV3.hpp.

void GLATPsfV3::write ( GFits & file ) const

virtual

Write point spread function into FITS file.

Parameters

[in] file FITS file.

Writes the PSF into the extension "RPSF" of a FITS file. This method does not check if a "RPSF" extension exists so far, it simply adds one each time it is called.

Nothing is done if the PSF size is 0.

Todo:: Check if a RPSF extension exists already in FITS file

Implements GLATPsfBase.

Definition at line 308 of file GLATPsfV3.cpp.

References GFitsTable::append(), GFits::append(), GFitsHDU::card(), GFitsHDU::extname(), GLATPsfBase::front(), m_gcore, m_gtail, m_ncore, m_ntail, GLATPsfBase::m_rpsf_bins, m_score, m_stail, GLATPsfBase::size(), GLATResponseTable::size(), and GLATResponseTable::write().

Member Data Documentation

std::vector<double> GLATPsfV3::m_gcore

private

PSF gcore parameter.

Definition at line 119 of file GLATPsfV3.hpp.

Referenced by copy_members(), eval_psf(), init_members(), integrate_psf(), normalize_psf(), read(), and write().

std::vector<double> GLATPsfV3::m_gtail

private

PSF gtail parameter.

Definition at line 120 of file GLATPsfV3.hpp.

Referenced by copy_members(), eval_psf(), init_members(), integrate_psf(), normalize_psf(), read(), and write().

std::vector<double> GLATPsfV3::m_ncore

private

PSF ncore parameter.

Definition at line 115 of file GLATPsfV3.hpp.

Referenced by copy_members(), eval_psf(), init_members(), integrate_psf(), normalize_psf(), read(), and write().

std::vector<double> GLATPsfV3::m_ntail

private

PSF ntail parameter.

Definition at line 116 of file GLATPsfV3.hpp.

Referenced by copy_members(), eval_psf(), init_members(), integrate_psf(), normalize_psf(), read(), and write().

std::vector<double> GLATPsfV3::m_score

private

PSF score parameter.

Definition at line 117 of file GLATPsfV3.hpp.

Referenced by copy_members(), eval_psf(), init_members(), integrate_psf(), normalize_psf(), read(), and write().

std::vector<double> GLATPsfV3::m_stail

private

PSF stail parameter.

Definition at line 118 of file GLATPsfV3.hpp.

Referenced by copy_members(), eval_psf(), init_members(), integrate_psf(), normalize_psf(), read(), and write().

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

inst/lat/include/GLATPsfV3.hpp
inst/lat/src/GLATPsfV3.cpp

Classes

Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation