Power law spectral model class. More...

#include <GModelSpectralPlaw.hpp>

Inheritance diagram for GModelSpectralPlaw:

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

	GModelSpectralPlaw (const std::string &type, const std::string &prefactor, const std::string &index, const std::string &pivot)
	Model type and parameter name constructor. More...

	GModelSpectralPlaw (const double &prefactor, const double &index, const GEnergy &pivot)
	Parameter constructor. More...

	GModelSpectralPlaw (const GXmlElement &xml)
	XML constructor. More...

	GModelSpectralPlaw (const GModelSpectralPlaw &model)
	Copy constructor. More...

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

virtual GModelSpectralPlaw &	operator= (const GModelSpectralPlaw &model)
	Assignment operator. More...

virtual void	clear (void)
	Clear spectral power law model. More...

virtual GModelSpectralPlaw *	clone (void) const
	Clone spectral power law model. More...

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

virtual std::string	type (void) const
	Return model type. More...

virtual double	eval (const GEnergy &srcEng, const GTime &srcTime=GTime(), const bool &gradients=false) const
	Evaluate function. More...

virtual double	flux (const GEnergy &emin, const GEnergy &emax) const
	Returns model photon flux between emin, emax More...

virtual double	eflux (const GEnergy &emin, const GEnergy &emax) const
	Returns model energy flux between emin, emax More...

virtual GEnergy	mc (const GEnergy &emin, const GEnergy &emax, const GTime &time, GRan &ran) const
	Returns Monte Carlo energy between [emin, emax]. More...

virtual void	read (const GXmlElement &xml)
	Read model from XML element. More...

virtual void	write (GXmlElement &xml) const
	Write model into XML element. More...

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

void	type (const std::string &type)
	Set model type. More...

double	prefactor (void) const
	Return pre factor. More...

double	index (void) const
	Return power law index. More...

GEnergy	pivot (void) const
	Return pivot energy. More...

void	prefactor (const double &prefactor)
	Set pre factor. More...

void	index (const double &index)
	Set power law index. More...

void	pivot (const GEnergy &pivot)
	Set pivot energy. More...

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

	GModelSpectral (const GModelSpectral &model)
	Copy constructor. More...

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

virtual GModelSpectral &	operator= (const GModelSpectral &model)
	Assignment operator. More...

virtual GModelPar &	operator[] (const int &index)
	Returns model parameter. More...

virtual const GModelPar &	operator[] (const int &index) const
	Returns model parameter (const version) More...

virtual GModelPar &	operator[] (const std::string &name)
	Returns reference to model parameter. More...

virtual const GModelPar &	operator[] (const std::string &name) const
	Returns reference to model parameter (const version) More...

GModelPar &	at (const int &index)
	Returns model parameter. More...

const GModelPar &	at (const int &index) const
	Returns model parameter (const version) More...

bool	has_par (const std::string &name) const
	Checks if parameter name exists. More...

int	size (void) const
	Return number of parameters. More...

void	autoscale (void)
	Autoscale parameters. More...

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

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

void	copy_members (const GModelSpectralPlaw &model)
	Copy class members. More...

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

void	update_eval_cache (const GEnergy &energy) const
	Update eval precomputation cache. More...

void	update_mc_cache (const GEnergy &emin, const GEnergy &emax) const
	Update Monte Carlo pre computation cache. More...

Protected Member Functions inherited from GModelSpectral
void	init_members (void)
	Initialise class members. More...

void	copy_members (const GModelSpectral &model)
	Copy class members. More...

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

Protected Attributes
std::string	m_type
	Model type. More...

GModelPar	m_norm
	Normalization factor. More...

GModelPar	m_index
	Spectral index. More...

GModelPar	m_pivot
	Pivot energy. More...

GEnergy	m_last_energy
	Last energy value. More...

double	m_last_norm
	Last norm parameter. More...

double	m_last_index
	Last index parameter. More...

double	m_last_pivot
	Last pivot parameter. More...

double	m_last_e_norm
	Last E/Epivot value. More...

double	m_last_log_e_norm
	Last ln(E/Epivot) value. More...

double	m_last_power
	Last power value. More...

double	m_mc_emin
	Minimum energy. More...

double	m_mc_emax
	Maximum energy. More...

double	m_mc_exponent
	Exponent (index+1) More...

double	m_mc_pow_emin
	Power of minimum energy. More...

double	m_mc_pow_ewidth
	Power of energy width. More...

Protected Attributes inherited from GModelSpectral
std::vector< GModelPar * >	m_pars
	Parameter pointers. More...

Detailed Description

Power law spectral model class.

This class implements a power law spectrum. The model is defined by

\[ S_{\rm E}(E | t) = {\tt m\_norm} \left( \frac{E}{\tt m\_pivot} \right)^{\tt m\_index} \]

where

\({\tt m\_norm}\) is the normalization or prefactor,
\({\tt m\_index}\) is the spectral index, and
\({\tt m\_pivot}\) is the pivot energy.

Definition at line 59 of file GModelSpectralPlaw.hpp.

Constructor & Destructor Documentation

GModelSpectralPlaw::GModelSpectralPlaw ( void )

Void constructor.

Definition at line 76 of file GModelSpectralPlaw.cpp.

References init_members().

Referenced by clone().

GModelSpectralPlaw::GModelSpectralPlaw	(	const std::string &	type,
		const std::string &	prefactor,
		const std::string &	index,
		const std::string &	pivot
	)

Model type and parameter name constructor.

Parameters

[in]	type	Model type.
[in]	prefactor	Name of prefactor parameter.
[in]	index	Name of index parameter.
[in]	pivot	Name of pivot parameter.

Definition at line 94 of file GModelSpectralPlaw.cpp.

References init_members(), m_index, m_norm, m_pivot, m_type, GOptimizerPar::name(), and type().

GModelSpectralPlaw::GModelSpectralPlaw	(	const double &	prefactor,
		const double &	index,
		const GEnergy &	pivot
	)

Parameter constructor.

Parameters

[in]	prefactor	Power law pre factor (ph/cm2/s/MeV).
[in]	index	Power law index.
[in]	pivot	Pivot energy.

Constructs a spectral power law using the model parameters

power law prefactor (ph/cm2/s/MeV)
spectral index
pivot energy.

Definition at line 128 of file GModelSpectralPlaw.cpp.

References GModelSpectral::autoscale(), init_members(), m_index, m_norm, m_pivot, GEnergy::MeV(), and GOptimizerPar::value().

GModelSpectralPlaw::GModelSpectralPlaw ( const GXmlElement & xml )

explicit

XML constructor.

Parameters

[in] xml XML element containing position information.

Constructs a power law spectral model by extracting information from an XML element. See the read() method for more information about the expected structure of the XML element.

Definition at line 158 of file GModelSpectralPlaw.cpp.

References init_members(), and read().

GModelSpectralPlaw::GModelSpectralPlaw ( const GModelSpectralPlaw & model )

Copy constructor.

Parameters

[in] model Spectral power law model.

Definition at line 176 of file GModelSpectralPlaw.cpp.

References copy_members(), and init_members().

GModelSpectralPlaw::~GModelSpectralPlaw ( void )

virtual

Destructor.

Definition at line 193 of file GModelSpectralPlaw.cpp.

References free_members().

Member Function Documentation

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

inlinevirtual

Return class name.

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

Implements GModelSpectral.

Definition at line 143 of file GModelSpectralPlaw.hpp.

void GModelSpectralPlaw::clear ( void )

virtual

Clear spectral power law model.

Implements GModelSpectral.

Definition at line 248 of file GModelSpectralPlaw.cpp.

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

GModelSpectralPlaw * GModelSpectralPlaw::clone ( void ) const

virtual

Clone spectral power law model.

Returns: Pointer to deep copy of spectral power law model.

Implements GModelSpectral.

Definition at line 268 of file GModelSpectralPlaw.cpp.

References GModelSpectralPlaw().

void GModelSpectralPlaw::copy_members ( const GModelSpectralPlaw & model )

protected

Copy class members.

Parameters

[in] model GModelSpectralPlaw members which should be copied.

Definition at line 663 of file GModelSpectralPlaw.cpp.

References m_index, m_last_e_norm, m_last_energy, m_last_index, m_last_log_e_norm, m_last_norm, m_last_pivot, m_last_power, m_mc_emax, m_mc_emin, m_mc_exponent, m_mc_pow_emin, m_mc_pow_ewidth, m_norm, GModelSpectral::m_pars, m_pivot, and m_type.

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

double GModelSpectralPlaw::eflux	(	const GEnergy &	emin,
		const GEnergy &	emax
	)		const

virtual

Returns model energy flux between emin, emax

Parameters

[in]	emin	Minimum photon energy.
[in]	emax	Maximum photon energy.

Returns: Energy flux (erg/cm2/s).

Computes

\[ \int_{\tt emin}^{\tt emax} S_{\rm E}(E | t) E \, dE \]

where

[emin, emax] is an energy interval, and
\(S_{\rm E}(E | t)\) is the spectral model (ph/cm2/s/MeV). The integration is done analytically.

Implements GModelSpectral.

Definition at line 422 of file GModelSpectralPlaw.cpp.

References m_index, m_norm, m_pivot, GEnergy::MeV(), gammalib::MeV2erg, gammalib::plaw_energy_flux(), and GOptimizerPar::value().

double GModelSpectralPlaw::eval	(	const GEnergy &	srcEng,
		const GTime &	srcTime = `GTime()`,
		const bool &	gradients = `false`
	)		const

virtual

Evaluate function.

Parameters

[in]	srcEng	True photon energy.
[in]	srcTime	True photon arrival time.
[in]	gradients	Compute gradients?

Returns: Model value (ph/cm2/s/MeV).

Evaluates

\[ S_{\rm E}(E | t) = {\tt m\_norm} \left( \frac{E}{\tt m\_pivot} \right)^{\tt m\_index} \]

where

\({\tt m\_norm}\) is the normalization or prefactor,
\({\tt m\_index}\) is the spectral index, and
\({\tt m\_pivot}\) is the pivot energy.

If the gradients flag is true the method will also compute the partial derivatives of the model with respect to the parameters using

\[ \frac{\delta S_{\rm E}(E | t)}{\delta {\tt m\_norm}} = \frac{S_{\rm E}(E | t)}{{\tt m\_norm}} \]

\[ \frac{\delta S_{\rm E}(E | t)}{\delta {\tt m\_index}} = S_{\rm E}(E | t) \, \ln(E/{\tt m_pivot}) \]

\[ \frac{\delta S_{\rm E}(E | t)}{\delta {\tt m\_pivot}} = -S_{\rm E}(E | t) \, \left( \frac{{\tt m\_index}}{{\tt m\_pivot}} \right) \]

Todo:: The method expects that energy!=0. Otherwise Inf or NaN may result.

Implements GModelSpectral.

Definition at line 316 of file GModelSpectralPlaw.cpp.

References GOptimizerPar::factor_gradient(), GOptimizerPar::factor_value(), G_EVAL, GOptimizerPar::is_free(), gammalib::is_infinite(), gammalib::is_notanumber(), m_index, m_last_index, m_last_log_e_norm, m_last_power, m_norm, GModelSpectral::m_pars, m_pivot, GEnergy::print(), GTime::print(), GOptimizerPar::scale(), gammalib::str(), update_eval_cache(), GOptimizerPar::value(), and gammalib::warning().

double GModelSpectralPlaw::flux	(	const GEnergy &	emin,
		const GEnergy &	emax
	)		const

virtual

Returns model photon flux between emin, emax

Parameters

[in]	emin	Minimum photon energy.
[in]	emax	Maximum photon energy.

Returns: Photon flux (ph/cm2/s).

Computes

\[ \int_{\tt emin}^{\tt emax} S_{\rm E}(E | t) dE \]

where

[emin, emax] is an energy interval, and
\(S_{\rm E}(E | t)\) is the spectral model (ph/cm2/s/MeV). The integration is done analytically.

Implements GModelSpectral.

Definition at line 381 of file GModelSpectralPlaw.cpp.

References m_index, m_norm, m_pivot, GEnergy::MeV(), gammalib::plaw_photon_flux(), and GOptimizerPar::value().

void GModelSpectralPlaw::free_members ( void )

protected

Delete class members.

Definition at line 701 of file GModelSpectralPlaw.cpp.

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

double GModelSpectralPlaw::index ( void ) const

inline

Return power law index.

Returns: Power law index.

Returns the power law index.

Definition at line 215 of file GModelSpectralPlaw.hpp.

References m_index, and GOptimizerPar::value().

Referenced by mc(), read(), GCOMIaq::set(), update_eval_cache(), update_mc_cache(), and write().

void GModelSpectralPlaw::index ( const double & index )

inline

Set power law index.

Parameters

[in] index Power law index.

Sets the power law index.

Definition at line 229 of file GModelSpectralPlaw.hpp.

References m_index, and GOptimizerPar::value().

void GModelSpectralPlaw::init_members ( void )

protected

Initialise class members.

Definition at line 595 of file GModelSpectralPlaw.cpp.

References GEnergy::clear(), GOptimizerPar::clear(), GOptimizerPar::fix(), GOptimizerPar::free(), GOptimizerPar::gradient(), GOptimizerPar::has_grad(), m_index, m_last_e_norm, m_last_energy, m_last_index, m_last_log_e_norm, m_last_norm, m_last_pivot, m_last_power, m_mc_emax, m_mc_emin, m_mc_exponent, m_mc_pow_emin, m_mc_pow_ewidth, m_norm, GModelSpectral::m_pars, m_pivot, m_type, GOptimizerPar::min(), GOptimizerPar::name(), GOptimizerPar::range(), GOptimizerPar::scale(), GOptimizerPar::unit(), and GOptimizerPar::value().

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

GEnergy GModelSpectralPlaw::mc	(	const GEnergy &	emin,
		const GEnergy &	emax,
		const GTime &	time,
		GRan &	ran
	)		const

virtual

Returns Monte Carlo energy between [emin, emax].

Parameters

[in]	emin	Minimum photon energy.
[in]	emax	Maximum photon energy.
[in]	time	True photon arrival time.
[in,out]	ran	Random number generator.

Returns: Energy.

Returns Monte Carlo energy by randomly drawing from a power law.

Implements GModelSpectral.

Definition at line 459 of file GModelSpectralPlaw.cpp.

References gammalib::check_energy_interval(), exp(), G_MC, index(), log(), m_mc_exponent, m_mc_pow_emin, m_mc_pow_ewidth, GEnergy::MeV(), GRan::uniform(), and update_mc_cache().

GModelSpectralPlaw & GModelSpectralPlaw::operator= ( const GModelSpectralPlaw & model )

virtual

Assignment operator.

Parameters

[in] model Spectral power law model.

Returns: Spectral power law model.

Definition at line 215 of file GModelSpectralPlaw.cpp.

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

GEnergy GModelSpectralPlaw::pivot ( void ) const

inline

Return pivot energy.

Returns: Pivot energy.

Returns the pivot energy.

Definition at line 244 of file GModelSpectralPlaw.hpp.

References m_pivot, GEnergy::MeV(), and GOptimizerPar::value().

Referenced by read(), update_eval_cache(), and write().

void GModelSpectralPlaw::pivot ( const GEnergy & pivot )

inline

Set pivot energy.

Parameters

[in] pivot Pivot energy.

Sets the pivot energy.

Definition at line 260 of file GModelSpectralPlaw.hpp.

References m_pivot, GEnergy::MeV(), and GOptimizerPar::value().

double GModelSpectralPlaw::prefactor ( void ) const

inline

Return pre factor.

Returns: Pre factor (ph/cm2/s/MeV).

Returns the pre factor.

Definition at line 186 of file GModelSpectralPlaw.hpp.

References m_norm, and GOptimizerPar::value().

void GModelSpectralPlaw::prefactor ( const double & prefactor )

inline

Set pre factor.

Parameters

[in] prefactor Pre factor (ph/cm2/s/MeV).

Sets the pre factor.

Definition at line 200 of file GModelSpectralPlaw.hpp.

References m_norm, and GOptimizerPar::value().

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

virtual

Print powerlaw information.

Parameters

[in] chatter Chattiness (defaults to NORMAL).

Returns: String containing model information.

Implements GModelSpectral.

Definition at line 561 of file GModelSpectralPlaw.cpp.

References GModelSpectral::m_pars, gammalib::parformat(), SILENT, GModelSpectral::size(), and gammalib::str().

void GModelSpectralPlaw::read ( const GXmlElement & xml )

virtual

Read model from XML element.

Parameters

[in] xml XML element.

Reads the spectral information from an XML element.

Implements GModelSpectral.

Definition at line 508 of file GModelSpectralPlaw.cpp.

References G_READ, index(), m_index, m_norm, m_pivot, GOptimizerPar::name(), norm(), pivot(), GModelPar::read(), gammalib::xml_check_parnum(), and gammalib::xml_get_par().

Referenced by GModelSpectralPlaw().

std::string GModelSpectralPlaw::type ( void ) const

inlinevirtual

Return model type.

Returns: Model type.

Returns the type of the spectral power law model.

Implements GModelSpectral.

Definition at line 157 of file GModelSpectralPlaw.hpp.

References m_type.

Referenced by GModelSpectralPlaw(), type(), and write().

void GModelSpectralPlaw::type ( const std::string & type )

inline

Set model type.

Parameters

[in] type Model type.

Set the type of the spectral power law model.

Definition at line 171 of file GModelSpectralPlaw.hpp.

References m_type, and type().

void GModelSpectralPlaw::update_eval_cache ( const GEnergy & energy ) const

protected

Update eval precomputation cache.

Parameters

[in] energy Energy.

Updates the precomputation cache for eval() method.

Definition at line 715 of file GModelSpectralPlaw.cpp.

References index(), log(), m_index, m_last_e_norm, m_last_energy, m_last_index, m_last_log_e_norm, m_last_pivot, m_last_power, m_pivot, GEnergy::MeV(), pivot(), pow(), and GOptimizerPar::value().

Referenced by eval().

void GModelSpectralPlaw::update_mc_cache	(	const GEnergy &	emin,
		const GEnergy &	emax
	)		const

protected

Update Monte Carlo pre computation cache.

Parameters

[in]	emin	Minimum photon energy.
[in]	emax	Maximum photon energy.

Updates the precomputation cache for Monte Carlo simulations.

Definition at line 754 of file GModelSpectralPlaw.cpp.

References index(), log(), m_mc_emax, m_mc_emin, m_mc_exponent, m_mc_pow_emin, m_mc_pow_ewidth, GEnergy::MeV(), and pow().

Referenced by mc().

void GModelSpectralPlaw::write ( GXmlElement & xml ) const

virtual

Write model into XML element.

Parameters

[in] xml XML element.

Writes the spectral information into an XML element.

Implements GModelSpectral.

Definition at line 535 of file GModelSpectralPlaw.cpp.

References G_WRITE, index(), m_index, m_norm, m_pivot, GOptimizerPar::name(), norm(), pivot(), type(), GModelPar::write(), gammalib::xml_check_type(), and gammalib::xml_need_par().

Member Data Documentation

GModelPar GModelSpectralPlaw::m_index

protected

Spectral index.

Definition at line 118 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), eflux(), eval(), flux(), GModelSpectralPlaw(), index(), init_members(), read(), update_eval_cache(), and write().

double GModelSpectralPlaw::m_last_e_norm

mutableprotected

Last E/Epivot value.

Definition at line 126 of file GModelSpectralPlaw.hpp.

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

GEnergy GModelSpectralPlaw::m_last_energy

mutableprotected

Last energy value.

Definition at line 122 of file GModelSpectralPlaw.hpp.

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

double GModelSpectralPlaw::m_last_index

mutableprotected

Last index parameter.

Definition at line 124 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), eval(), init_members(), and update_eval_cache().

double GModelSpectralPlaw::m_last_log_e_norm

mutableprotected

Last ln(E/Epivot) value.

Definition at line 127 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), eval(), init_members(), and update_eval_cache().

double GModelSpectralPlaw::m_last_norm

mutableprotected

Last norm parameter.

Definition at line 123 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), and init_members().

double GModelSpectralPlaw::m_last_pivot

mutableprotected

Last pivot parameter.

Definition at line 125 of file GModelSpectralPlaw.hpp.

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

double GModelSpectralPlaw::m_last_power

mutableprotected

Last power value.

Definition at line 128 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), eval(), init_members(), and update_eval_cache().

double GModelSpectralPlaw::m_mc_emax

mutableprotected

Maximum energy.

Definition at line 130 of file GModelSpectralPlaw.hpp.

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

double GModelSpectralPlaw::m_mc_emin

mutableprotected

Minimum energy.

Definition at line 129 of file GModelSpectralPlaw.hpp.

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

double GModelSpectralPlaw::m_mc_exponent

mutableprotected

Exponent (index+1)

Definition at line 131 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), init_members(), mc(), and update_mc_cache().

double GModelSpectralPlaw::m_mc_pow_emin

mutableprotected

Power of minimum energy.

Definition at line 132 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), init_members(), mc(), and update_mc_cache().

double GModelSpectralPlaw::m_mc_pow_ewidth

mutableprotected

Power of energy width.

Definition at line 133 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), init_members(), mc(), and update_mc_cache().

GModelPar GModelSpectralPlaw::m_norm

protected

Normalization factor.

Definition at line 117 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), eflux(), eval(), flux(), GModelSpectralPlaw(), init_members(), prefactor(), read(), and write().

GModelPar GModelSpectralPlaw::m_pivot

protected

Pivot energy.

Definition at line 119 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), eflux(), eval(), flux(), GModelSpectralPlaw(), init_members(), pivot(), read(), update_eval_cache(), and write().

std::string GModelSpectralPlaw::m_type

protected

Model type.

Definition at line 116 of file GModelSpectralPlaw.hpp.

Referenced by copy_members(), GModelSpectralPlaw(), init_members(), and type().

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

include/GModelSpectralPlaw.hpp
src/model/GModelSpectralPlaw.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation