lsst::afw::math::Chebyshev1Function1< ReturnT > Class Template Reference

1-dimensional weighted sum of Chebyshev polynomials of the first kind. More...

#include <FunctionLibrary.h>

Inheritance diagram for lsst::afw::math::Chebyshev1Function1< ReturnT >:

Public Types
typedef Function1< ReturnT >::Ptr	Function1Ptr
Public Types inherited from lsst::afw::math::Function1< ReturnT >
typedef boost::shared_ptr < Function1< 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
	Chebyshev1Function1 (unsigned int order, double minX=-1, double maxX=1)
	Construct a Chebyshev polynomial of specified order and range. More...
	Chebyshev1Function1 (std::vector< double > params, double minX=-1, double maxX=1)
	Construct a Chebyshev polynomial with specified parameters and range. More...
virtual	~Chebyshev1Function1 ()
virtual Function1Ptr	clone () const
	Return a pointer to a deep copy of this function. More...
double	getMinX () const
	Get minimum allowed x. More...
double	getMaxX () const
	Get maximum allowed x. More...
unsigned int	getOrder () const
	Get the polynomial order. More...
virtual bool	isLinearCombination () const
	Is the function a linear combination of its parameters? More...
virtual ReturnT	operator() (double x) const
virtual std::string	toString (std::string const &prefix) const
	Return a string representation of the function. More...
Public Member Functions inherited from lsst::afw::math::Function1< ReturnT >
	Function1 (unsigned int nParams)
	Construct a Function1 given the number of function parameters. More...
	Function1 (std::vector< double > const &params)
	Construct a Function1 given the function parameters. More...
virtual	~Function1 ()
virtual void	computeCache (int const n)
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...
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 bool	isPersistable () const
	Return true if this particular object can be persisted using afw::table::io. More...
virtual	~Persistable ()

Protected Member Functions
	Chebyshev1Function1 ()
Protected Member Functions inherited from lsst::afw::math::Function1< ReturnT >
	Function1 ()
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
virtual std::string	getPersistenceName () const
	Return the unique name used to persist this object and look up its factory. More...
virtual void	write (OutputArchiveHandle &handle) const
	Write the object to one or more catalogs. More...
	Persistable ()
	Persistable (Persistable const &other)
void	operator= (Persistable const &other)

Private Member Functions
void	_initialize (double minX, double maxX)
	initialize private constants More...
template<class Archive >
void	serialize (Archive &ar, unsigned int const)

Private Attributes
double	_minX
	minimum allowed x More...
double	_maxX
	maximum allowed x More...
double	_scale
	x' = (x + _offset) * _scale More...
double	_offset
	x' = (x + _offset) * _scale More...
unsigned int	_order
	polynomial order More...

Friends
class	boost::serialization::access

Additional Inherited Members
Static Public Member Functions inherited from lsst::afw::table::io::PersistableFacade< Function1< ReturnT > >
static boost::shared_ptr < Function1< ReturnT > >	readFits (fits::Fits &fitsfile)
	Read an object from an already open FITS object. More...
static boost::shared_ptr < Function1< ReturnT > >	readFits (std::string const &fileName, int hdu=0)
	Read an object from a regular FITS file. More...
static boost::shared_ptr < Function1< 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::Chebyshev1Function1< ReturnT >

1-dimensional weighted sum of Chebyshev polynomials of the first kind.

f(x) = c0 T0(x') + c1 T1(x') + c2 T2(x') + ... = c0 + c1 T1(x') + c2 T2(x') + ... where:

• Tn(x) is the nth Chebyshev function of the first kind: T0(x) = 1 T1(x) = 2 Tn+1(x) = 2xTn(x) + Tn-1(x)
• x' is x offset and scaled to range [-1, 1] as x ranges over [minX, maxX]

The function argument must be in the range [minX, maxX].

Definition at line 669 of file FunctionLibrary.h.

Member Typedef Documentation

template<typename ReturnT >

typedef Function1<ReturnT>::Ptr lsst::afw::math::Chebyshev1Function1< ReturnT >::Function1Ptr

Definition at line 671 of file FunctionLibrary.h.

Constructor & Destructor Documentation

template<typename ReturnT >

lsst::afw::math::Chebyshev1Function1< ReturnT >::Chebyshev1Function1 ( unsigned int  order, double  minX = -1, double  maxX = 1  )

inlineexplicit

Construct a Chebyshev polynomial of specified order and range.

The parameters are initialized to zero.

Parameters

order	order of polynomial (0 for constant)
minX	minimum allowed x
maxX	maximum allowed x

Definition at line 678 of file FunctionLibrary.h.

        :
            Function1<ReturnT>(order + 1)
        {
            _initialize(minX, maxX);
        }

template<typename ReturnT >

lsst::afw::math::Chebyshev1Function1< ReturnT >::Chebyshev1Function1 ( std::vector< double >  params, double  minX = -1, double  maxX = 1  )

inlineexplicit

Construct a Chebyshev polynomial with specified parameters and range.

The order of the polynomial is set to the length of the params vector.

Exceptions

lsst::pex::exceptions::InvalidParameterError

if params is empty

Parameters

params	polynomial coefficients
minX	minimum allowed x
maxX	maximum allowed x

Definition at line 695 of file FunctionLibrary.h.

        :
            Function1<ReturnT>(params)
        {
            if (params.size() < 1) {
                throw LSST_EXCEPT(lsst::pex::exceptions::InvalidParameterError,
                                  "Chebyshev1Function1 called with empty vector");
            }
            _initialize(minX, maxX);
        }

template<typename ReturnT >

virtual lsst::afw::math::Chebyshev1Function1< ReturnT >::~Chebyshev1Function1 ( )

inlinevirtual

Definition at line 709 of file FunctionLibrary.h.

{}

template<typename ReturnT >

lsst::afw::math::Chebyshev1Function1< ReturnT >::Chebyshev1Function1 ( )

inlineexplicitprotected

Definition at line 780 of file FunctionLibrary.h.

                                       : Function1<ReturnT>(1),
            _minX(0.0), _maxX(0.0), _scale(1.0), _offset(0.0), _order(0) {}

Member Function Documentation

template<typename ReturnT >

void lsst::afw::math::Chebyshev1Function1< ReturnT >::_initialize ( double  minX, double  maxX  )

inlineprivate

initialize private constants

Definition at line 770 of file FunctionLibrary.h.

                                                   {
            _minX = minX;
            _maxX = maxX;
            _scale = 2.0 / (_maxX - _minX);
            _offset = -(_minX + _maxX) * 0.5;
            _order = this->getNParameters() - 1;
        }

template<typename ReturnT >

virtual Function1Ptr lsst::afw::math::Chebyshev1Function1< 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 concrete subclass must override this method.

Returns

a pointer to a deep copy of the function

Implements lsst::afw::math::Function1< ReturnT >.

Definition at line 711 of file FunctionLibrary.h.

                                           {
            return Function1Ptr(new Chebyshev1Function1(this->_params, _minX, _maxX));
        }

template<typename ReturnT >

double lsst::afw::math::Chebyshev1Function1< ReturnT >::getMaxX ( ) const

inline

Get maximum allowed x.

Definition at line 723 of file FunctionLibrary.h.

{ return _maxX; };

template<typename ReturnT >

double lsst::afw::math::Chebyshev1Function1< ReturnT >::getMinX ( ) const

inline

Get minimum allowed x.

Definition at line 718 of file FunctionLibrary.h.

{ return _minX; };

template<typename ReturnT >

unsigned int lsst::afw::math::Chebyshev1Function1< ReturnT >::getOrder ( ) const

inline

Get the polynomial order.

Definition at line 728 of file FunctionLibrary.h.

{ return this->getNParameters() - 1; };

template<typename ReturnT >

virtual bool lsst::afw::math::Chebyshev1Function1< ReturnT >::isLinearCombination ( ) const

inlinevirtual

Is the function a linear combination of its parameters?

Returns

true if the function can be expressed as: sum over i of parameter_i * function_i(args)

Warning

: subclasses must override if true.

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

Definition at line 730 of file FunctionLibrary.h.

{ return true; };

template<typename ReturnT >

virtual ReturnT lsst::afw::math::Chebyshev1Function1< ReturnT >::operator() ( double  x ) const

inlinevirtual

Implements lsst::afw::math::Function1< ReturnT >.

Definition at line 732 of file FunctionLibrary.h.

                                                    {
            double xPrime = (x + _offset) * _scale;
            
            // Clenshaw function for solving the Chebyshev polynomial
            // Non-recursive version from Kresimir Cosic
            int const order = _order;
            if (order == 0) {
                return this->_params[0];
            } else if (order == 1) {
                return this->_params[0] + (this->_params[1] * xPrime);
            }
            double cshPrev = this->_params[order];
            double csh = (2 * xPrime * this->_params[order]) + this->_params[order-1];
            for (int i = order - 2; i > 0; --i) {
                double cshNext = (2 * xPrime * csh) + this->_params[i] - cshPrev;
                cshPrev = csh;
                csh = cshNext;
            }
            return (xPrime * csh) + this->_params[0] - cshPrev;
        }

template<typename ReturnT >

template<class Archive >

void lsst::afw::math::Chebyshev1Function1< ReturnT >::serialize ( Archive &  ar, unsigned int  const  )

inlineprivate

Definition at line 786 of file FunctionLibrary.h.

                                                        {
            ar & make_nvp("fn1", boost::serialization::base_object<Function1<ReturnT> >(*this));
            ar & make_nvp("minX", this->_minX);
            ar & make_nvp("minX", this->_minX);
            ar & make_nvp("maxX", this->_maxX);
            ar & make_nvp("scale", this->_scale);
            ar & make_nvp("offset", this->_offset);
            ar & make_nvp("maxInd", this->_order);
        }

template<typename ReturnT >

virtual std::string lsst::afw::math::Chebyshev1Function1< 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::Function1< ReturnT >.

Definition at line 753 of file FunctionLibrary.h.

                                                                  {
            std::ostringstream os;
            os << "Chebyshev1Function1 [" << _minX << ", " << _maxX << "]: ";
            os << Function1<ReturnT>::toString(prefix);
            return os.str();
        }

Friends And Related Function Documentation

template<typename ReturnT >

friend class boost::serialization::access

friend

Definition at line 784 of file FunctionLibrary.h.

Member Data Documentation

template<typename ReturnT >

double lsst::afw::math::Chebyshev1Function1< ReturnT >::_maxX

private

maximum allowed x

Definition at line 762 of file FunctionLibrary.h.

template<typename ReturnT >

double lsst::afw::math::Chebyshev1Function1< ReturnT >::_minX

private

minimum allowed x

Definition at line 761 of file FunctionLibrary.h.

template<typename ReturnT >

double lsst::afw::math::Chebyshev1Function1< ReturnT >::_offset

private

x' = (x + _offset) * _scale

Definition at line 764 of file FunctionLibrary.h.

template<typename ReturnT >

unsigned int lsst::afw::math::Chebyshev1Function1< ReturnT >::_order

private

polynomial order

Definition at line 765 of file FunctionLibrary.h.

template<typename ReturnT >

double lsst::afw::math::Chebyshev1Function1< ReturnT >::_scale

private

x' = (x + _offset) * _scale

Definition at line 763 of file FunctionLibrary.h.

---

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