lsst::afw::math::GaussianFunction2< ReturnT > Class Template Reference

2-dimensional Gaussian More...

#include <FunctionLibrary.h>

Inheritance diagram for lsst::afw::math::GaussianFunction2< ReturnT >:

Public Types
typedef Function2< ReturnT >::Ptr	Function2Ptr
Public Types inherited from lsst::afw::math::Function2< ReturnT >
typedef boost::shared_ptr < Function2< ReturnT > >	Ptr
Public Types inherited from lsst::daf::base::Citizen
enum	{ magicSentinel = 0xdeadbeef }
typedef unsigned long	memId
	Type of the block's ID. More...
typedef memId(*	memNewCallback )(const memId cid)
	A function used to register a callback. More...
typedef memId(*	memCallback )(const Citizen *ptr)

Public Member Functions
	GaussianFunction2 (double sigma1, double sigma2, double angle=0.0)
	Construct a 2-dimensional Gaussian function. More...
virtual	~GaussianFunction2 ()
virtual Function2Ptr	clone () const
	Return a pointer to a deep copy of this function. More...
virtual ReturnT	operator() (double x, double y) const
virtual std::string	toString (std::string const &prefix) const
	Return a string representation of the function. More...
virtual bool	isPersistable () const
	Return true if this particular object can be persisted using afw::table::io. More...
Public Member Functions inherited from lsst::afw::math::Function2< ReturnT >
	Function2 (unsigned int nParams)
	Construct a Function2 given the number of function parameters. More...
	Function2 (std::vector< double > const &params)
	Construct a Function2 given the function parameters. More...
virtual	~Function2 ()
virtual std::vector< double >	getDFuncDParameters (double, double) const
Public Member Functions inherited from lsst::afw::math::Function< ReturnT >
	Function (unsigned int nParams)
	Construct a Function given the number of function parameters. More...
	Function (std::vector< double > const &params)
	Construct a Function given the function parameters. More...
virtual	~Function ()
unsigned int	getNParameters () const
	Return the number of function parameters. More...
virtual double	getParameter (unsigned int ind) const
	Get one function parameter without range checking. More...
std::vector< double > const &	getParameters () const
	Return all function parameters. More...
virtual bool	isLinearCombination () const
	Is the function a linear combination of its parameters? More...
void	setParameter (unsigned int ind, double newValue)
	Set one function parameter without range checking. More...
void	setParameters (std::vector< double > const &params)
	Set all function parameters. More...
Public Member Functions inherited from lsst::daf::base::Citizen
	Citizen (const std::type_info &)
	Citizen (Citizen const &)
	~Citizen ()
Citizen &	operator= (Citizen const &)
std::string	repr () const
	Return a string representation of a Citizen. More...
void	markPersistent (void)
	Mark a Citizen as persistent and not destroyed until process end. More...
memId	getId () const
	Return the Citizen's ID. More...
Public Member Functions inherited from lsst::afw::table::io::Persistable
void	writeFits (std::string const &fileName, std::string const &mode="w") const
	Write the object to a regular FITS file. More...
void	writeFits (fits::MemFileManager &manager, std::string const &mode="w") const
	Write the object to a FITS image in memory. More...
void	writeFits (fits::Fits &fitsfile) const
	Write the object to an already-open FITS object. More...
virtual	~Persistable ()

Protected Member Functions
virtual std::string	getPersistenceName () const
	Return the unique name used to persist this object and look up its factory. More...
virtual void	write (afw::table::io::OutputArchiveHandle &handle) const
	Write the object to one or more catalogs. More...
	GaussianFunction2 ()
Protected Member Functions inherited from lsst::afw::math::Function2< ReturnT >
	Function2 ()
Protected Member Functions inherited from lsst::afw::math::Function< ReturnT >
virtual std::string	getPythonModule () const
	Return the fully-qualified Python module that should be imported to guarantee that its factory is registered. More...
	Function ()
Protected Member Functions inherited from lsst::afw::table::io::Persistable
	Persistable ()
	Persistable (Persistable const &other)
void	operator= (Persistable const &other)

Private Member Functions
void	_updateCache () const
	Update cached values. More...
template<class Archive >
void	serialize (Archive &ar, unsigned int const version)

Private Attributes
const double	_multFac
	precomputed scale factor More...
double	_angle
	cached angle More...
double	_sinAngle
	cached sin(angle) More...
double	_cosAngle
	cached cos(angle) More...

Friends
class	boost::serialization::access

Additional Inherited Members
Static Public Member Functions inherited from lsst::afw::table::io::PersistableFacade< Function2< ReturnT > >
static boost::shared_ptr < Function2< ReturnT > >	readFits (fits::Fits &fitsfile)
	Read an object from an already open FITS object. More...
static boost::shared_ptr < Function2< ReturnT > >	readFits (std::string const &fileName, int hdu=0)
	Read an object from a regular FITS file. More...
static boost::shared_ptr < Function2< ReturnT > >	readFits (fits::MemFileManager &manager, int hdu=0)
	Read an object from a FITS file in memory. More...
Static Public Member Functions inherited from lsst::daf::base::Citizen
static bool	hasBeenCorrupted ()
	Check all allocated blocks for corruption. More...
static memId	getNextMemId ()
	Return the memId of the next object to be allocated. More...
static int	init ()
	Called once when the memory system is being initialised. More...
static int	census (int, memId startingMemId=0)
	How many active Citizens are there? More...
static void	census (std::ostream &stream, memId startingMemId=0)
	Print a list of all active Citizens to stream, sorted by ID. More...
static const std::vector < const Citizen * > *	census ()
	Return a (newly allocated) std::vector of active Citizens sorted by ID. More...
static memId	setNewCallbackId (memId id)
	Call the NewCallback when block is allocated. More...
static memId	setDeleteCallbackId (memId id)
	Call the current DeleteCallback when block is deleted. More...
static memNewCallback	setNewCallback (memNewCallback func)
	Set the NewCallback function. More...
static memCallback	setDeleteCallback (memCallback func)
	Set the DeleteCallback function. More...
static memCallback	setCorruptionCallback (memCallback func)
	Set the CorruptionCallback function. More...
Static Public Member Functions inherited from lsst::afw::table::io::PersistableFacade< Function< ReturnT > >
static boost::shared_ptr < Function< ReturnT > >	readFits (fits::Fits &fitsfile)
	Read an object from an already open FITS object. More...
static boost::shared_ptr < Function< ReturnT > >	readFits (std::string const &fileName, int hdu=0)
	Read an object from a regular FITS file. More...
static boost::shared_ptr < Function< ReturnT > >	readFits (fits::MemFileManager &manager, int hdu=0)
	Read an object from a FITS file in memory. More...
Protected Types inherited from lsst::afw::table::io::Persistable
typedef io::OutputArchiveHandle	OutputArchiveHandle
Protected Attributes inherited from lsst::afw::math::Function< ReturnT >
std::vector< double >	_params
bool	_isCacheValid

Detailed Description

template<typename ReturnT>
class lsst::afw::math::GaussianFunction2< ReturnT >

2-dimensional Gaussian

f(x,y) = A e^((-pos1^2 / 2 sigma1^2) - (pos2^2 / 2 sigma2^2)) where:

• A = 1 / (2 pi sigma1 sigma2)
• pos1 = cos(angle) x + sin(angle) y
• pos2 = -sin(angle) x + cos(angle) y coefficients c0 = sigma1, c1 = sigma2, c2 = angle

Note

if sigma1 > sigma2 then angle is the angle of the major axis

Definition at line 246 of file FunctionLibrary.h.

Member Typedef Documentation

template<typename ReturnT >

typedef Function2<ReturnT>::Ptr lsst::afw::math::GaussianFunction2< ReturnT >::Function2Ptr

Definition at line 248 of file FunctionLibrary.h.

Constructor & Destructor Documentation

template<typename ReturnT >

lsst::afw::math::GaussianFunction2< ReturnT >::GaussianFunction2 ( double  sigma1, double  sigma2, double  angle = 0.0  )

inlineexplicit

Construct a 2-dimensional Gaussian function.

Parameters

sigma1	sigma along the pos1 axis
sigma2	sigma along the pos2 axis
angle	angle of pos1 axis, in rad (along x=0, y=pi/2)

Definition at line 253 of file FunctionLibrary.h.

        :
            Function2<ReturnT>(3),
            _multFac(1.0 / (lsst::afw::geom::TWOPI))
        {
            this->_params[0] = sigma1;
            this->_params[1] = sigma2;
            this->_params[2] = angle;
            _updateCache();
        }

template<typename ReturnT >

virtual lsst::afw::math::GaussianFunction2< ReturnT >::~GaussianFunction2 ( )

inlinevirtual

Definition at line 267 of file FunctionLibrary.h.

{}

template<typename ReturnT >

lsst::afw::math::GaussianFunction2< ReturnT >::GaussianFunction2 ( )

inlineexplicitprotected

Definition at line 330 of file FunctionLibrary.h.

                                     : Function2<ReturnT>(3), _multFac(1.0 / (lsst::afw::geom::TWOPI)), _angle(0.0),
            _sinAngle(0.0), _cosAngle(1.0) {}

Member Function Documentation

template<typename ReturnT >

void lsst::afw::math::GaussianFunction2< ReturnT >::_updateCache ( ) const

inlineprivate

Update cached values.

sin(angle) and cos(angle) are cached to speed computation and angle is cached so one can check if an update is required

The current design is to have operator() update the cache if needed. An alternate design is to update the cache when the parameters are set, not test in operator(). The main advantage to updating in operator() is safety and simplicity. The test is performed in one place, and it is the place where it matters the most. In contrast, there are multiple member functions to set parameters, and all must be overloaded to update the cache; miss one and the function silently misbehaves. There are trade-offs, of course. Testing the cache in operator() slows down operator() slightly. The overhead is small, but the function is typically evaulated more often than its parameters are changed.

Definition at line 318 of file FunctionLibrary.h.

                                  {
            _angle = this->_params[2];
            _sinAngle = std::sin(_angle);
            _cosAngle = std::cos(_angle);
        }

template<typename ReturnT >

virtual Function2Ptr lsst::afw::math::GaussianFunction2< ReturnT >::clone ( ) const

inlinevirtual

Return a pointer to a deep copy of this function.

This function exists instead of a copy constructor so one can obtain a copy of an actual function instead of a useless copy of the base class.

Every non-virtual function must override this method.

Returns

a pointer to a deep copy of the function

Implements lsst::afw::math::Function2< ReturnT >.

Definition at line 269 of file FunctionLibrary.h.

                                           {
            return Function2Ptr(new GaussianFunction2(this->_params[0], this->_params[1], this->_params[2]));
        }

template<typename ReturnT >

virtual std::string lsst::afw::math::GaussianFunction2< ReturnT >::getPersistenceName ( ) const

protectedvirtual

Return the unique name used to persist this object and look up its factory.

Must be less than ArchiveIndexSchema::MAX_NAME_LENGTH characters.

Reimplemented from lsst::afw::table::io::Persistable.

template<typename ReturnT >

virtual bool lsst::afw::math::GaussianFunction2< ReturnT >::isPersistable ( ) const

inlinevirtual

Return true if this particular object can be persisted using afw::table::io.

Reimplemented from lsst::afw::table::io::Persistable.

Definition at line 292 of file FunctionLibrary.h.

{ return true; }

template<typename ReturnT >

virtual ReturnT lsst::afw::math::GaussianFunction2< ReturnT >::operator() ( double  x, double  y  ) const

inlinevirtual

Implements lsst::afw::math::Function2< ReturnT >.

Definition at line 273 of file FunctionLibrary.h.

                                                              {
            if (_angle != this->_params[2]) {
                _updateCache();
            }
            double pos1 = ( _cosAngle * x) + (_sinAngle * y);
            double pos2 = (-_sinAngle * x) + (_cosAngle * y);
            return static_cast<ReturnT> (
                (_multFac / (this->_params[0] * this->_params[1])) *
                std::exp(- ((pos1 * pos1) / (2.0 * this->_params[0] * this->_params[0]))
                         - ((pos2 * pos2) / (2.0 * this->_params[1] * this->_params[1]))));
        }

template<typename ReturnT >

template<class Archive >

void lsst::afw::math::GaussianFunction2< ReturnT >::serialize ( Archive &  ar, unsigned int const  version  )

inlineprivate

Definition at line 336 of file FunctionLibrary.h.

                                                                {
            ar & make_nvp("fn2", boost::serialization::base_object<Function2<ReturnT> >(*this));
            ar & make_nvp("angle", this->_angle);
            ar & make_nvp("sinAngle", this->_sinAngle);
            ar & make_nvp("cosAngle", this->_cosAngle);
        }

template<typename ReturnT >

virtual std::string lsst::afw::math::GaussianFunction2< ReturnT >::toString ( std::string const &  ) const

inlinevirtual

Return a string representation of the function.

Returns

a string representation of the function

Reimplemented from lsst::afw::math::Function2< ReturnT >.

Definition at line 285 of file FunctionLibrary.h.

                                                                  {
            std::ostringstream os;
            os << "GaussianFunction2: ";
            os << Function2<ReturnT>::toString(prefix);
            return os.str();
        }

template<typename ReturnT >

virtual void lsst::afw::math::GaussianFunction2< ReturnT >::write ( afw::table::io::OutputArchiveHandle &  handle ) const

protectedvirtual

Write the object to one or more catalogs.

The handle object passed to this function provides an interface for adding new catalogs and adding nested objects to the same archive (while checking for duplicates). See OutputArchiveHandle for more information.

Reimplemented from lsst::afw::table::io::Persistable.

Friends And Related Function Documentation

template<typename ReturnT >

friend class boost::serialization::access

friend

Definition at line 334 of file FunctionLibrary.h.

Member Data Documentation

template<typename ReturnT >

double lsst::afw::math::GaussianFunction2< ReturnT >::_angle

mutableprivate

cached angle

Definition at line 324 of file FunctionLibrary.h.

template<typename ReturnT >

double lsst::afw::math::GaussianFunction2< ReturnT >::_cosAngle

mutableprivate

cached cos(angle)

Definition at line 326 of file FunctionLibrary.h.

template<typename ReturnT >

const double lsst::afw::math::GaussianFunction2< ReturnT >::_multFac

private

precomputed scale factor

Definition at line 323 of file FunctionLibrary.h.

template<typename ReturnT >

double lsst::afw::math::GaussianFunction2< ReturnT >::_sinAngle

mutableprivate

cached sin(angle)

Definition at line 325 of file FunctionLibrary.h.

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

• /home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/include/lsst/afw/math/FunctionLibrary.h