lsst::afw::math::LinearCombinationKernel Class Reference

A kernel that is a linear combination of fixed basis kernels. More...

#include <Kernel.h>

Inheritance diagram for lsst::afw::math::LinearCombinationKernel:

Classes
class	Factory

Public Types
using	Pixel = double
using	SpatialFunctionPtr = std::shared_ptr<lsst::afw::math::Function2<double>>
using	SpatialFunction = lsst::afw::math::Function2<double>
using	NullSpatialFunction = lsst::afw::math::NullFunction2<double>
using	kernel_fill_factor = generic_kernel_tag

Public Member Functions
	LinearCombinationKernel ()
	Construct an empty LinearCombinationKernel of size 0x0.
	LinearCombinationKernel (KernelList const &kernelList, std::vector< double > const &kernelParameters)
	Construct a spatially invariant LinearCombinationKernel.
	LinearCombinationKernel (KernelList const &kernelList, Kernel::SpatialFunction const &spatialFunction)
	Construct a spatially varying LinearCombinationKernel, where the spatial model is described by one function (that is cloned to give one per basis kernel).
	LinearCombinationKernel (KernelList const &kernelList, std::vector< Kernel::SpatialFunctionPtr > const &spatialFunctionList)
	Construct a spatially varying LinearCombinationKernel, where the spatial model is described by a list of functions (one per basis kernel).
	LinearCombinationKernel (const LinearCombinationKernel &)=delete
	LinearCombinationKernel (LinearCombinationKernel &&)=delete
LinearCombinationKernel &	operator= (const LinearCombinationKernel &)=delete
LinearCombinationKernel &	operator= (LinearCombinationKernel &&)=delete
	~LinearCombinationKernel () override=default
std::shared_ptr< Kernel >	clone () const override
	Return a pointer to a deep copy of this kernel.
std::shared_ptr< Kernel >	resized (int width, int height) const override
	Return a pointer to a clone with specified kernel dimensions.
std::vector< double >	getKernelParameters () const override
	Return the current kernel parameters.
virtual KernelList const &	getKernelList () const
	Get the fixed basis kernels.
std::vector< double >	getKernelSumList () const
	Get the sum of the pixels of each fixed basis kernel.
int	getNBasisKernels () const
	Get the number of basis kernels.
void	checkKernelList (const KernelList &kernelList) const
	Check that all kernels have the same size and center and that none are spatially varying.
bool	isDeltaFunctionBasis () const
	Return true if all basis kernels are instances of DeltaFunctionKernel.
std::shared_ptr< Kernel >	refactor () const
	Refactor the kernel as a linear combination of N bases where N is the number of parameters for the spatial model.
std::string	toString (std::string const &prefix="") const override
	Return a string representation of the kernel.
bool	isPersistable () const noexcept override
	Return true if this particular object can be persisted using afw::table::io.
double	computeImage (lsst::afw::image::Image< Pixel > &image, bool doNormalize, double x=0.0, double y=0.0) const
	Compute an image (pixellized representation of the kernel) in place.
lsst::geom::Extent2I const	getDimensions () const
	Return the Kernel's dimensions (width, height)
void	setDimensions (lsst::geom::Extent2I dims)
void	setWidth (int width)
void	setHeight (int height)
int	getWidth () const
	Return the Kernel's width.
int	getHeight () const
	Return the Kernel's height.
lsst::geom::Point2I	getCtr () const
	Return index of kernel's center.
lsst::geom::Box2I	getBBox () const
	return parent bounding box, with XY0 = -center
unsigned int	getNKernelParameters () const
	Return the number of kernel parameters (0 if none)
int	getNSpatialParameters () const
	Return the number of spatial parameters (0 if not spatially varying)
SpatialFunctionPtr	getSpatialFunction (unsigned int index) const
	Return a clone of the specified spatial function (one component of the spatial model)
std::vector< SpatialFunctionPtr >	getSpatialFunctionList () const
	Return a list of clones of the spatial functions.
virtual double	getKernelParameter (unsigned int i) const
	Return a particular Kernel Parameter (no bounds checking).
lsst::geom::Box2I	growBBox (lsst::geom::Box2I const &bbox) const
	Given a bounding box for pixels one wishes to compute by convolving an image with this kernel, return the bounding box of pixels that must be accessed on the image to be convolved.
lsst::geom::Box2I	shrinkBBox (lsst::geom::Box2I const &bbox) const
	Given a bounding box for an image one wishes to convolve with this kernel, return the bounding box for the region of pixels that can be computed.
void	setCtr (lsst::geom::Point2I ctr)
	Set index of kernel's center.
std::vector< std::vector< double > >	getSpatialParameters () const
	Return the spatial parameters parameters (an empty vector if not spatially varying)
bool	isSpatiallyVarying () const
	Return true iff the kernel is spatially varying (has a spatial function)
void	setKernelParameters (std::vector< double > const &params)
	Set the kernel parameters of a spatially invariant kernel.
void	setKernelParameters (std::pair< double, double > const &params)
	Set the kernel parameters of a 2-component spatially invariant kernel.
void	setSpatialParameters (const std::vector< std::vector< double > > params)
	Set the parameters of all spatial functions.
void	computeKernelParametersFromSpatialModel (std::vector< double > &kernelParams, double x, double y) const
	Compute the kernel parameters at a specified point.
virtual void	computeCache (int const)
	Compute a cache of Kernel values, if desired.
virtual int	getCacheSize () const
	Get the current size of the kernel cache (0 if none or if caches not supported)
void	writeFits (std::string const &fileName, std::string const &mode="w") const
	Write the object to a regular FITS file.
void	writeFits (fits::MemFileManager &manager, std::string const &mode="w") const
	Write the object to a FITS image in memory.
void	writeFits (fits::Fits &fitsfile) const
	Write the object to an already-open FITS object.

Static Public Member Functions
static std::shared_ptr< LinearCombinationKernel >	readFits (fits::Fits &fitsfile)
	Read an object from an already open FITS object.
static std::shared_ptr< LinearCombinationKernel >	readFits (std::string const &fileName, int hdu=fits::DEFAULT_HDU)
	Read an object from a regular FITS file.
static std::shared_ptr< LinearCombinationKernel >	readFits (fits::MemFileManager &manager, int hdu=fits::DEFAULT_HDU)
	Read an object from a FITS file in memory.
static std::shared_ptr< LinearCombinationKernel >	dynamicCast (std::shared_ptr< Persistable > const &ptr)
	Dynamically cast a shared_ptr.
static std::shared_ptr< Kernel >	readFits (fits::Fits &fitsfile)
	Read an object from an already open FITS object.
static std::shared_ptr< Kernel >	readFits (std::string const &fileName, int hdu=fits::DEFAULT_HDU)
	Read an object from a regular FITS file.
static std::shared_ptr< Kernel >	readFits (fits::MemFileManager &manager, int hdu=fits::DEFAULT_HDU)
	Read an object from a FITS file in memory.
static std::shared_ptr< Kernel >	dynamicCast (std::shared_ptr< Persistable > const &ptr)
	Dynamically cast a shared_ptr.

Protected Types
using	OutputArchiveHandle = io::OutputArchiveHandle

Protected Member Functions
double	doComputeImage (lsst::afw::image::Image< Pixel > &image, bool doNormalize) const override
	Low-level version of computeImage.
std::string	getPersistenceName () const override
	Return the unique name used to persist this object and look up its factory.
void	write (OutputArchiveHandle &handle) const override
	Write the object to one or more catalogs.
void	setKernelParameter (unsigned int ind, double value) const override
	Set one kernel parameter.
std::string	getPythonModule () const override
	Return the fully-qualified Python module that should be imported to guarantee that its factory is registered.
void	setKernelParametersFromSpatialModel (double x, double y) const
	Set the kernel parameters from the spatial model (if any).

Protected Attributes
std::vector< SpatialFunctionPtr >	_spatialFunctionList

Detailed Description

A kernel that is a linear combination of fixed basis kernels.

Convolution may be performed by first convolving the image with each fixed kernel, then adding the resulting images using the (possibly spatially varying) kernel coefficients.

The basis kernels are cloned (deep copied) so you may safely modify your own copies.

Warnings:

• This class does not normalize the individual basis kernels; they are used "as is".

Definition at line 703 of file Kernel.h.

Member Typedef Documentation

kernel_fill_factor

using lsst::afw::math::Kernel::kernel_fill_factor = generic_kernel_tag

inherited

Definition at line 118 of file Kernel.h.

NullSpatialFunction

using lsst::afw::math::Kernel::NullSpatialFunction = lsst::afw::math::NullFunction2<double>

inherited

Definition at line 115 of file Kernel.h.

OutputArchiveHandle

using lsst::afw::table::io::Persistable::OutputArchiveHandle = io::OutputArchiveHandle

protectedinherited

Definition at line 108 of file Persistable.h.

Pixel

using lsst::afw::math::Kernel::Pixel = double

inherited

Definition at line 112 of file Kernel.h.

SpatialFunction

using lsst::afw::math::Kernel::SpatialFunction = lsst::afw::math::Function2<double>

inherited

Definition at line 114 of file Kernel.h.

SpatialFunctionPtr

using lsst::afw::math::Kernel::SpatialFunctionPtr = std::shared_ptr<lsst::afw::math::Function2<double>>

inherited

Definition at line 113 of file Kernel.h.

Constructor & Destructor Documentation

LinearCombinationKernel() [1/6]

lsst::afw::math::LinearCombinationKernel::LinearCombinationKernel ( )

explicit

Construct an empty LinearCombinationKernel of size 0x0.

Definition at line 48 of file LinearCombinationKernel.cc.

        : Kernel(),
          _kernelList(),
          _kernelImagePtrList(),
          _kernelSumList(),
          _kernelParams(),
          _isDeltaFunctionBasis(false) {}

LinearCombinationKernel() [2/6]

lsst::afw::math::LinearCombinationKernel::LinearCombinationKernel ( KernelList const & kernelList, std::vector< double > const & kernelParameters )

explicit

Construct a spatially invariant LinearCombinationKernel.

Parameters

kernelList	list of (shared pointers to const) basis kernels
kernelParameters	kernel coefficients

Definition at line 56 of file LinearCombinationKernel.cc.

        : Kernel(kernelList[0]->getWidth(), kernelList[0]->getHeight(), kernelList.size()),
          _kernelList(),
          _kernelImagePtrList(),
          _kernelSumList(),
          _kernelParams(kernelParameters),
          _isDeltaFunctionBasis(false) {
    if (kernelList.size() != kernelParameters.size()) {
        std::ostringstream os;
        os << "kernelList.size() = " << kernelList.size() << " != " << kernelParameters.size() << " = "
           << "kernelParameters.size()";
        throw LSST_EXCEPT(pexExcept::InvalidParameterError, os.str());
    }
    checkKernelList(kernelList);
    _setKernelList(kernelList);
}

LinearCombinationKernel() [3/6]

lsst::afw::math::LinearCombinationKernel::LinearCombinationKernel ( KernelList const & kernelList, Kernel::SpatialFunction const & spatialFunction )

explicit

Construct a spatially varying LinearCombinationKernel, where the spatial model is described by one function (that is cloned to give one per basis kernel).

Parameters

kernelList	list of (shared pointers to const) basis kernels
spatialFunction	spatial function; one deep copy is made for each basis kernel

Definition at line 74 of file LinearCombinationKernel.cc.

        : Kernel(kernelList[0]->getWidth(), kernelList[0]->getHeight(), kernelList.size(), spatialFunction),
          _kernelList(),
          _kernelImagePtrList(),
          _kernelSumList(),
          _kernelParams(std::vector<double>(kernelList.size())),
          _isDeltaFunctionBasis(false) {
    checkKernelList(kernelList);
    _setKernelList(kernelList);
}

LinearCombinationKernel() [4/6]

lsst::afw::math::LinearCombinationKernel::LinearCombinationKernel ( KernelList const & kernelList, std::vector< Kernel::SpatialFunctionPtr > const & spatialFunctionList )

explicit

Construct a spatially varying LinearCombinationKernel, where the spatial model is described by a list of functions (one per basis kernel).

Parameters

kernelList	list of (shared pointers to const) kernels
spatialFunctionList	list of spatial functions, one per basis kernel

Exceptions

lsst::pex::exceptions::InvalidParameterError

if the length of spatialFunctionList != # kernels

Definition at line 86 of file LinearCombinationKernel.cc.

        : Kernel(kernelList[0]->getWidth(), kernelList[0]->getHeight(), spatialFunctionList),
          _kernelList(),
          _kernelImagePtrList(),
          _kernelSumList(),
          _kernelParams(std::vector<double>(kernelList.size())),
          _isDeltaFunctionBasis(false) {
    if (kernelList.size() != spatialFunctionList.size()) {
        std::ostringstream os;
        os << "kernelList.size() = " << kernelList.size() << " != " << spatialFunctionList.size() << " = "
           << "spatialFunctionList.size()";
        throw LSST_EXCEPT(pexExcept::InvalidParameterError, os.str());
    }
    checkKernelList(kernelList);
    _setKernelList(kernelList);
}

LinearCombinationKernel() [5/6]

lsst::afw::math::LinearCombinationKernel::LinearCombinationKernel ( const LinearCombinationKernel & )

delete

LinearCombinationKernel() [6/6]

lsst::afw::math::LinearCombinationKernel::LinearCombinationKernel ( LinearCombinationKernel && )

delete

~LinearCombinationKernel()

lsst::afw::math::LinearCombinationKernel::~LinearCombinationKernel ( )

overridedefault

Member Function Documentation

checkKernelList()

void lsst::afw::math::LinearCombinationKernel::checkKernelList

(

const KernelList &

kernelList

)

const

Check that all kernels have the same size and center and that none are spatially varying.

Exceptions

lsst::pex::exceptions::InvalidParameterError

if the check fails

Definition at line 132 of file LinearCombinationKernel.cc.

                                                                                {
    if (kernelList.size() < 1) {
        throw LSST_EXCEPT(pexExcept::InvalidParameterError, "kernelList has no elements");
    }
 
    lsst::geom::Extent2I const dim0 = kernelList[0]->getDimensions();
    lsst::geom::Point2I const ctr0 = kernelList[0]->getCtr();
 
    for (unsigned int ii = 0; ii < kernelList.size(); ++ii) {
        if (kernelList[ii]->getDimensions() != dim0) {
            throw LSST_EXCEPT(pexExcept::InvalidParameterError,
                              (boost::format("kernel %d has different size than kernel 0") % ii).str());
        }
        if (kernelList[ii]->getCtr() != ctr0) {
            throw LSST_EXCEPT(pexExcept::InvalidParameterError,
                              (boost::format("kernel %d has different center than kernel 0") % ii).str());
        }
        if (kernelList[ii]->isSpatiallyVarying()) {
            throw LSST_EXCEPT(pexExcept::InvalidParameterError,
                              (boost::format("kernel %d is spatially varying") % ii).str());
        }
    }
}

clone()

std::shared_ptr< Kernel > lsst::afw::math::LinearCombinationKernel::clone ( ) const

overridevirtual

Return a pointer to a deep copy of this kernel.

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

Every kernel subclass must override this method.

Returns

a pointer to a deep copy of the kernel

Implements lsst::afw::math::Kernel.

Definition at line 104 of file LinearCombinationKernel.cc.

                                                           {
    std::shared_ptr<Kernel> retPtr;
    if (this->isSpatiallyVarying()) {
        retPtr.reset(new LinearCombinationKernel(this->_kernelList, this->_spatialFunctionList));
    } else {
        retPtr.reset(new LinearCombinationKernel(this->_kernelList, this->_kernelParams));
    }
    retPtr->setCtr(this->getCtr());
    return retPtr;
}

computeCache()

virtual void lsst::afw::math::Kernel::computeCache ( int const )

inlinevirtualinherited

Compute a cache of Kernel values, if desired.

Warning

: few kernel classes actually support this, in which case this is a no-op and getCacheSize always returns 0.

Reimplemented in lsst::afw::math::SeparableKernel.

Definition at line 397 of file Kernel.h.

      {}

computeImage()

double lsst::afw::math::Kernel::computeImage ( lsst::afw::image::Image< Pixel > & image, bool doNormalize, double x = 0.0, double y = 0.0 ) const

inherited

Compute an image (pixellized representation of the kernel) in place.

Parameters

image	image whose pixels are to be set (output); xy0 of the image will be set to -kernel.getCtr()
doNormalize	normalize the image (so sum is 1)?
x	x (column position) at which to compute spatial function
y	y (row position) at which to compute spatial function

Returns

The kernel sum

Exceptions

lsst::pex::exceptions::InvalidParameterError	if the image is the wrong size
lsst::pex::exceptions::OverflowError	if doNormalize is true and the kernel sum is exactly 0

Note

computeNewImage has been retired; it doesn't need to be a member

Definition at line 76 of file Kernel.cc.

                                                                                                {
    if (image.getDimensions() != this->getDimensions()) {
        std::ostringstream os;
        os << "image dimensions = ( " << image.getWidth() << ", " << image.getHeight() << ") != ("
           << this->getWidth() << ", " << this->getHeight() << ") = kernel dimensions";
        throw LSST_EXCEPT(pexExcept::InvalidParameterError, os.str());
    }
    image.setXY0(-_ctrX, -_ctrY);
    if (this->isSpatiallyVarying()) {
        this->setKernelParametersFromSpatialModel(x, y);
    }
    return doComputeImage(image, doNormalize);
}

computeKernelParametersFromSpatialModel()

void lsst::afw::math::Kernel::computeKernelParametersFromSpatialModel ( std::vector< double > & kernelParams, double x, double y ) const

inherited

Compute the kernel parameters at a specified point.

Warning: this is a low-level function that assumes kernelParams is the right length. It will fail in unpredictable ways if that condition is not met.

Definition at line 135 of file Kernel.cc.

                                                                     {
    std::vector<double>::iterator paramIter = kernelParams.begin();
    std::vector<SpatialFunctionPtr>::const_iterator funcIter = _spatialFunctionList.begin();
    for (; funcIter != _spatialFunctionList.end(); ++funcIter, ++paramIter) {
        *paramIter = (*(*funcIter))(x, y);
    }
}

doComputeImage()

double lsst::afw::math::LinearCombinationKernel::doComputeImage ( lsst::afw::image::Image< Pixel > & image, bool doNormalize ) const

overrideprotectedvirtual

Low-level version of computeImage.

Before this is called the image dimensions are checked, the image's xy0 is set and the kernel's parameters are set. This routine sets the pixels, including normalization if requested.

Parameters

image	image whose pixels are to be set (output)
doNormalize	normalize the image (so sum is 1)?

Returns

The kernel sum

Implements lsst::afw::math::Kernel.

Definition at line 247 of file LinearCombinationKernel.cc.

                                                                                               {
    image = 0.0;
    double imSum = 0.0;
    std::vector<std::shared_ptr<image::Image<Pixel>>>::const_iterator kImPtrIter =
            _kernelImagePtrList.begin();
    std::vector<double>::const_iterator kSumIter = _kernelSumList.begin();
    std::vector<double>::const_iterator kParIter = _kernelParams.begin();
    for (; kImPtrIter != _kernelImagePtrList.end(); ++kImPtrIter, ++kSumIter, ++kParIter) {
        image.scaledPlus(*kParIter, **kImPtrIter);
        imSum += (*kSumIter) * (*kParIter);
    }
 
    if (doNormalize) {
        if (imSum == 0) {
            throw LSST_EXCEPT(pexExcept::OverflowError, "Cannot normalize; kernel sum is 0");
        }
        image /= imSum;
        imSum = 1;
    }
 
    return imSum;
}

dynamicCast() [1/2]

template std::shared_ptr< meas::extensions::psfex::PsfexPsf > lsst::afw::table::io::PersistableFacade< LinearCombinationKernel >::dynamicCast ( std::shared_ptr< Persistable > const & ptr )

staticinherited

Dynamically cast a shared_ptr.

Dynamically cast a shared pointer and raise on failure.

You must provide an explicit template instantiation in the .cc file for each class that inherits from PersistableFacade. Designed to work around RTTI issues on macOS with hidden symbols;

Exceptions

lsst::pex::exceptions::LogicError

if the cast fails

param[in] ptr The pointer to be cast.

Returns

The cast pointer.

Exceptions

lsst::pex::exceptions::TypeError

If the dynamic cast fails.

Definition at line 218 of file Persistable.cc.

dynamicCast() [2/2]

template std::shared_ptr< meas::extensions::psfex::PsfexPsf > lsst::afw::table::io::PersistableFacade< Kernel >::dynamicCast ( std::shared_ptr< Persistable > const & ptr )

staticinherited

Dynamically cast a shared_ptr.

Dynamically cast a shared pointer and raise on failure.

You must provide an explicit template instantiation in the .cc file for each class that inherits from PersistableFacade. Designed to work around RTTI issues on macOS with hidden symbols;

Exceptions

lsst::pex::exceptions::LogicError

if the cast fails

param[in] ptr The pointer to be cast.

Returns

The cast pointer.

Exceptions

lsst::pex::exceptions::TypeError

If the dynamic cast fails.

Definition at line 218 of file Persistable.cc.

getBBox()

lsst::geom::Box2I lsst::afw::math::Kernel::getBBox ( ) const

inlineinherited

return parent bounding box, with XY0 = -center

Definition at line 239 of file Kernel.h.

                                         {
        return lsst::geom::Box2I(lsst::geom::Point2I(-_ctrX, -_ctrY), lsst::geom::Extent2I(_width, _height));
    }

getCacheSize()

virtual int lsst::afw::math::Kernel::getCacheSize ( ) const

inlinevirtualinherited

Get the current size of the kernel cache (0 if none or if caches not supported)

Reimplemented in lsst::afw::math::SeparableKernel.

Definition at line 403 of file Kernel.h.

{ return 0; };

getCtr()

lsst::geom::Point2I lsst::afw::math::Kernel::getCtr ( ) const

inlineinherited

Return index of kernel's center.

Definition at line 234 of file Kernel.h.

{ return lsst::geom::Point2I(_ctrX, _ctrY); }

getDimensions()

lsst::geom::Extent2I const lsst::afw::math::Kernel::getDimensions ( ) const

inlineinherited

Return the Kernel's dimensions (width, height)

Definition at line 212 of file Kernel.h.

{ return lsst::geom::Extent2I(_width, _height); }

getHeight()

int lsst::afw::math::Kernel::getHeight ( ) const

inlineinherited

Return the Kernel's height.

Definition at line 229 of file Kernel.h.

{ return _height; }

getKernelList()

KernelList const & lsst::afw::math::LinearCombinationKernel::getKernelList ( ) const

virtual

Get the fixed basis kernels.

Definition at line 156 of file LinearCombinationKernel.cc.

{ return _kernelList; }

getKernelParameter()

virtual double lsst::afw::math::Kernel::getKernelParameter ( unsigned int i ) const

inlinevirtualinherited

Return a particular Kernel Parameter (no bounds checking).

This version is slow, but specialisations may be faster

Reimplemented in lsst::afw::math::SeparableKernel.

Definition at line 277 of file Kernel.h.

{ return getKernelParameters()[i]; }

getKernelParameters()

std::vector< double > lsst::afw::math::LinearCombinationKernel::getKernelParameters ( ) const

overridevirtual

Return the current kernel parameters.

If the kernel is spatially varying then the parameters are those last computed. See also computeKernelParametersFromSpatialModel. If there are no kernel parameters then returns an empty vector.

Reimplemented from lsst::afw::math::Kernel.

Definition at line 160 of file LinearCombinationKernel.cc.

{ return _kernelParams; }

getKernelSumList()

std::vector< double > lsst::afw::math::LinearCombinationKernel::getKernelSumList

(

)

const

Get the sum of the pixels of each fixed basis kernel.

Definition at line 158 of file LinearCombinationKernel.cc.

{ return _kernelSumList; }

getNBasisKernels()

int lsst::afw::math::LinearCombinationKernel::getNBasisKernels ( ) const

inline

Get the number of basis kernels.

Definition at line 768 of file Kernel.h.

{ return static_cast<int>(_kernelList.size()); };

getNKernelParameters()

unsigned int lsst::afw::math::Kernel::getNKernelParameters ( ) const

inlineinherited

Return the number of kernel parameters (0 if none)

Definition at line 246 of file Kernel.h.

{ return _nKernelParams; }

getNSpatialParameters()

int lsst::afw::math::Kernel::getNSpatialParameters ( ) const

inlineinherited

Return the number of spatial parameters (0 if not spatially varying)

Definition at line 251 of file Kernel.h.

                                             {
        return this->isSpatiallyVarying() ? _spatialFunctionList[0]->getNParameters() : 0;
    }

getPersistenceName()

std::string lsst::afw::math::LinearCombinationKernel::getPersistenceName ( ) const

overrideprotectedvirtual

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.

Definition at line 365 of file LinearCombinationKernel.cc.

                                                            {
    return getLinearCombinationKernelPersistenceName();
}

getPythonModule()

std::string lsst::afw::math::Kernel::getPythonModule ( ) const

overrideprotectedvirtualinherited

Return the fully-qualified Python module that should be imported to guarantee that its factory is registered.

Must be less than ArchiveIndexSchema::MAX_MODULE_LENGTH characters.

Will be ignored if empty.

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

Reimplemented in lsst::afw::math::LanczosWarpingKernel, and lsst::afw::math::NearestWarpingKernel.

Definition at line 224 of file Kernel.cc.

{ return "lsst.afw.math"; }

getSpatialFunction()

Kernel::SpatialFunctionPtr lsst::afw::math::Kernel::getSpatialFunction ( unsigned int index ) const

inherited

Return a clone of the specified spatial function (one component of the spatial model)

Parameters

index

index of desired spatial function; must be in range [0, number spatial parameters - 1]

Returns

a shared pointer to a spatial function. The function is a deep copy, so setting its parameters has no effect on the kernel.

Exceptions

lsst::pex::exceptions::InvalidParameterError	if kernel not spatially varying
lsst::pex::exceptions::InvalidParameterError	if index out of range

Definition at line 144 of file Kernel.cc.

                                                                            {
    if (index >= _spatialFunctionList.size()) {
        if (!this->isSpatiallyVarying()) {
            throw LSST_EXCEPT(pexExcept::InvalidParameterError, "kernel is not spatially varying");
        } else {
            std::ostringstream errStream;
            errStream << "index = " << index << "; must be < , " << _spatialFunctionList.size();
            throw LSST_EXCEPT(pexExcept::InvalidParameterError, errStream.str());
        }
    }
    return _spatialFunctionList[index]->clone();
}

getSpatialFunctionList()

std::vector< Kernel::SpatialFunctionPtr > lsst::afw::math::Kernel::getSpatialFunctionList ( ) const

inherited

Return a list of clones of the spatial functions.

Returns

a list of shared pointers to spatial functions. The functions are deep copies, so setting their parameters has no effect on the kernel.

Definition at line 157 of file Kernel.cc.

                                                                         {
    std::vector<SpatialFunctionPtr> spFuncCopyList;
    for (auto const &spFuncIter : _spatialFunctionList) {
        spFuncCopyList.push_back((*spFuncIter).clone());
    }
    return spFuncCopyList;
}

getSpatialParameters()

std::vector< std::vector< double > > lsst::afw::math::Kernel::getSpatialParameters ( ) const

inlineinherited

Return the spatial parameters parameters (an empty vector if not spatially varying)

Definition at line 321 of file Kernel.h.

                                                                     {
        std::vector<std::vector<double>> spatialParams;
        std::vector<SpatialFunctionPtr>::const_iterator spFuncIter = _spatialFunctionList.begin();
        for (; spFuncIter != _spatialFunctionList.end(); ++spFuncIter) {
            spatialParams.push_back((*spFuncIter)->getParameters());
        }
        return spatialParams;
    }

getWidth()

int lsst::afw::math::Kernel::getWidth ( ) const

inlineinherited

Return the Kernel's width.

Definition at line 224 of file Kernel.h.

{ return _width; }

growBBox()

lsst::geom::Box2I lsst::afw::math::Kernel::growBBox ( lsst::geom::Box2I const & bbox ) const

inherited

Given a bounding box for pixels one wishes to compute by convolving an image with this kernel, return the bounding box of pixels that must be accessed on the image to be convolved.

Thus the box shifted by -kernel.getCtr() and its size is expanded by kernel.getDimensions()-1.

Returns

the bbox expanded by the kernel.

Definition at line 167 of file Kernel.cc.

                                                              {
    return lsst::geom::Box2I(
            lsst::geom::Point2I(bbox.getMin() - lsst::geom::Extent2I(getCtr())),
            lsst::geom::Extent2I(bbox.getDimensions() + getDimensions() - lsst::geom::Extent2I(1, 1)));
}

isDeltaFunctionBasis()

bool lsst::afw::math::LinearCombinationKernel::isDeltaFunctionBasis ( ) const

inline

Return true if all basis kernels are instances of DeltaFunctionKernel.

Definition at line 780 of file Kernel.h.

{ return _isDeltaFunctionBasis; };

isPersistable()

bool lsst::afw::math::LinearCombinationKernel::isPersistable ( ) const

inlineoverridevirtualnoexcept

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

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

Definition at line 820 of file Kernel.h.

{ return true; }

isSpatiallyVarying()

bool lsst::afw::math::Kernel::isSpatiallyVarying ( ) const

inlineinherited

Return true iff the kernel is spatially varying (has a spatial function)

Definition at line 333 of file Kernel.h.

{ return _spatialFunctionList.size() != 0; }

operator=() [1/2]

LinearCombinationKernel & lsst::afw::math::LinearCombinationKernel::operator= ( const LinearCombinationKernel & )

delete

operator=() [2/2]

LinearCombinationKernel & lsst::afw::math::LinearCombinationKernel::operator= ( LinearCombinationKernel && )

delete

readFits() [1/6]

static std::shared_ptr< Kernel > lsst::afw::table::io::PersistableFacade< Kernel >::readFits ( fits::Fits & fitsfile )

inlinestaticinherited

Read an object from an already open FITS object.

Parameters

[in]

fitsfile

FITS object to read from, already positioned at the desired HDU.

Definition at line 183 of file Persistable.h.

readFits() [2/6]

static std::shared_ptr< LinearCombinationKernel > lsst::afw::table::io::PersistableFacade< LinearCombinationKernel >::readFits ( fits::Fits & fitsfile )

inlinestaticinherited

Read an object from an already open FITS object.

Parameters

[in]

fitsfile

FITS object to read from, already positioned at the desired HDU.

Definition at line 183 of file Persistable.h.

readFits() [3/6]

static std::shared_ptr< LinearCombinationKernel > lsst::afw::table::io::PersistableFacade< LinearCombinationKernel >::readFits ( fits::MemFileManager & manager, int hdu = fits::DEFAULT_HDU )

inlinestaticinherited

Read an object from a FITS file in memory.

Parameters

[in]	manager	Manager for the memory to read from.
[in]	hdu	HDU to read, where 0 is the primary. The special value of afw::fits::DEFAULT_HDU skips the primary HDU if it is empty.

Definition at line 205 of file Persistable.h.

readFits() [4/6]

static std::shared_ptr< Kernel > lsst::afw::table::io::PersistableFacade< Kernel >::readFits ( fits::MemFileManager & manager, int hdu = fits::DEFAULT_HDU )

inlinestaticinherited

Read an object from a FITS file in memory.

Parameters

[in]	manager	Manager for the memory to read from.
[in]	hdu	HDU to read, where 0 is the primary. The special value of afw::fits::DEFAULT_HDU skips the primary HDU if it is empty.

Definition at line 205 of file Persistable.h.

readFits() [5/6]

static std::shared_ptr< LinearCombinationKernel > lsst::afw::table::io::PersistableFacade< LinearCombinationKernel >::readFits ( std::string const & fileName, int hdu = fits::DEFAULT_HDU )

inlinestaticinherited

Read an object from a regular FITS file.

Parameters

[in]	fileName	Name of the file to read.
[in]	hdu	HDU to read, where 0 is the primary. The special value of afw::fits::DEFAULT_HDU skips the primary HDU if it is empty.

Definition at line 194 of file Persistable.h.

readFits() [6/6]

static std::shared_ptr< Kernel > lsst::afw::table::io::PersistableFacade< Kernel >::readFits ( std::string const & fileName, int hdu = fits::DEFAULT_HDU )

inlinestaticinherited

Read an object from a regular FITS file.

Parameters

[in]	fileName	Name of the file to read.
[in]	hdu	HDU to read, where 0 is the primary. The special value of afw::fits::DEFAULT_HDU skips the primary HDU if it is empty.

Definition at line 194 of file Persistable.h.

refactor()

std::shared_ptr< Kernel > lsst::afw::math::LinearCombinationKernel::refactor

(

)

const

Refactor the kernel as a linear combination of N bases where N is the number of parameters for the spatial model.

Refactoring is only possible if all of the following are true:

• Kernel is spatially varying
• The spatial functions are a linear combination of coefficients (return isLinearCombination() true).
• The spatial functions all are the same class (and so have the same functional form) Refactoring produces a kernel that is faster to compute only if the number of basis kernels is greater than the number of parameters in the spatial model.

Details: A spatially varying LinearCombinationKernel consisting of M basis kernels and using a spatial model that is a linear combination of N coefficients can be expressed as: K(x,y) = K0 (C00 F0(x,y) + C10 F1(x,y) + C20 F2(x,y) + ... + CN0 FN(x,y))

• K1 (C01 F0(x,y) + C11 F1(x,y) + C21 F2(x,y) + ... + CN1 FN(x,y))
• K2 (C02 F0(x,y) + C12 F1(x,y) + C22 F2(x,y) + ... + CN2 FN(x,y))
• ...
• KM (C0M F0(x,y) + C1M F1(x,y) + C2M F2(x,y) + ... + CNM FN(x,y))

This is equivalent to the following linear combination of N basis kernels:

    =      K0' F0(x,y) + K1' F1(x,y) + K2' F2(x,y) + ... + KN' FN(x,y)

      where Ki' = sum over j of Kj Cij

This is what refactor returns provided the required conditions are met. However, the spatial functions for the refactored kernel are the same as those for the original kernel (for generality and simplicity) with all coefficients equal to 0 except one that is set to 1; hence they are not computed optimally.

Thanks to Kresimir Cosic for inventing or reinventing this useful technique.

Returns

a shared pointer to new kernel, or empty pointer if refactoring not possible

Definition at line 162 of file LinearCombinationKernel.cc.

                                                              {
    if (!this->isSpatiallyVarying()) {
        return std::shared_ptr<Kernel>();
    }
    Kernel::SpatialFunctionPtr const firstSpFuncPtr = this->_spatialFunctionList[0];
    if (!firstSpFuncPtr->isLinearCombination()) {
        return std::shared_ptr<Kernel>();
    }
 
    using KernelImage = image::Image<Kernel::Pixel>;
    using KernelImagePtr = std::shared_ptr<KernelImage>;
    using KernelImageList = std::vector<KernelImagePtr>;
 
    // create kernel images for new refactored basis kernels
    int const nSpatialParameters = this->getNSpatialParameters();
    KernelImageList newKernelImagePtrList;
    newKernelImagePtrList.reserve(nSpatialParameters);
    for (int i = 0; i < nSpatialParameters; ++i) {
        KernelImagePtr kernelImagePtr(new KernelImage(this->getDimensions()));
        newKernelImagePtrList.push_back(kernelImagePtr);
    }
    KernelImage kernelImage(this->getDimensions());
    std::vector<Kernel::SpatialFunctionPtr>::const_iterator spFuncPtrIter =
            this->_spatialFunctionList.begin();
    KernelList::const_iterator kIter = _kernelList.begin();
    KernelList::const_iterator const kEnd = _kernelList.end();
    auto &firstSpFunc = *firstSpFuncPtr;
    auto &firstType = typeid(firstSpFunc);  // noncopyable object of static storage duration
    for (; kIter != kEnd; ++kIter, ++spFuncPtrIter) {
        auto &spFunc = **spFuncPtrIter;
        if (typeid(spFunc) != firstType) {
            return std::shared_ptr<Kernel>();
        }
 
        (**kIter).computeImage(kernelImage, false);
        for (int i = 0; i < nSpatialParameters; ++i) {
            double spParam = (*spFuncPtrIter)->getParameter(i);
            newKernelImagePtrList[i]->scaledPlus(spParam, kernelImage);
        }
    }
 
    // create new kernel; the basis kernels are fixed kernels computed above
    // and the corresponding spatial model is the same function as the original kernel,
    // but with all coefficients zero except coeff_i = 1.0
    KernelList newKernelList;
    newKernelList.reserve(nSpatialParameters);
    KernelImageList::iterator newKImPtrIter = newKernelImagePtrList.begin();
    KernelImageList::iterator const newKImPtrEnd = newKernelImagePtrList.end();
    for (; newKImPtrIter != newKImPtrEnd; ++newKImPtrIter) {
        newKernelList.push_back(std::shared_ptr<Kernel>(new FixedKernel(**newKImPtrIter)));
    }
    std::vector<SpatialFunctionPtr> newSpFunctionPtrList;
    for (int i = 0; i < nSpatialParameters; ++i) {
        std::vector<double> newSpParameters(nSpatialParameters, 0.0);
        newSpParameters[i] = 1.0;
        SpatialFunctionPtr newSpFunctionPtr = firstSpFuncPtr->clone();
        newSpFunctionPtr->setParameters(newSpParameters);
        newSpFunctionPtrList.push_back(newSpFunctionPtr);
    }
    std::shared_ptr<LinearCombinationKernel> refactoredKernel(
            new LinearCombinationKernel(newKernelList, newSpFunctionPtrList));
    refactoredKernel->setCtr(this->getCtr());
    return refactoredKernel;
}

resized()

std::shared_ptr< Kernel > lsst::afw::math::LinearCombinationKernel::resized ( int width, int height ) const

overridevirtual

Return a pointer to a clone with specified kernel dimensions.

Parameters

width	Number of columns in pixels
height	Number of rows in pixels

Returns

a pointer to a clone with new dimensions.

Must be implemented by derived classes.

Implements lsst::afw::math::Kernel.

Definition at line 115 of file LinearCombinationKernel.cc.

                                                                                  {
    KernelList kernelList;
    kernelList.reserve(getKernelList().size());
    for (const std::shared_ptr<Kernel> &kIter : getKernelList()) {
        kernelList.push_back(kIter->resized(width, height));
    }
 
    std::shared_ptr<Kernel> retPtr;
    if (isSpatiallyVarying()) {
        retPtr = std::make_shared<LinearCombinationKernel>(kernelList, _spatialFunctionList);
    } else {
        retPtr = std::make_shared<LinearCombinationKernel>(kernelList, _kernelParams);
    }
 
    return retPtr;
}

setCtr()

void lsst::afw::math::Kernel::setCtr ( lsst::geom::Point2I ctr )

inlineinherited

Set index of kernel's center.

Definition at line 312 of file Kernel.h.

                                            {
        _ctrX = ctr.getX();
        _ctrY = ctr.getY();
        _setKernelXY();
    }

setDimensions()

void lsst::afw::math::Kernel::setDimensions ( lsst::geom::Extent2I dims )

inlineinherited

Definition at line 214 of file Kernel.h.

                                              {
        _width = dims.getX();
        _height = dims.getY();
    }

setHeight()

void lsst::afw::math::Kernel::setHeight ( int height )

inlineinherited

Definition at line 219 of file Kernel.h.

{ _height = height; }

setKernelParameter()

void lsst::afw::math::LinearCombinationKernel::setKernelParameter ( unsigned int ind, double value ) const

overrideprotectedvirtual

Set one kernel parameter.

Classes that have kernel parameters must subclass this function.

This function is marked "const", despite modifying unimportant internals, so that computeImage can be const.

Exceptions

lsst::pex::exceptions::InvalidParameterError

always (unless subclassed)

Reimplemented from lsst::afw::math::Kernel.

Definition at line 270 of file LinearCombinationKernel.cc.

                                                                                     {
    this->_kernelParams[ind] = value;
}

setKernelParameters() [1/2]

void lsst::afw::math::Kernel::setKernelParameters ( std::pair< double, double > const & params )

inlineinherited

Set the kernel parameters of a 2-component spatially invariant kernel.

Warning

This is a low-level method intended for maximum efficiency when using warping kernels. No error checking is performed. Use the std::vector<double> form if you want safety.

Definition at line 363 of file Kernel.h.

                                                                           {
        this->setKernelParameter(0, params.first);
        this->setKernelParameter(1, params.second);
    }

setKernelParameters() [2/2]

void lsst::afw::math::Kernel::setKernelParameters ( std::vector< double > const & params )

inlineinherited

Set the kernel parameters of a spatially invariant kernel.

Exceptions

lsst::pex::exceptions::RuntimeError	if the kernel has a spatial function
lsst::pex::exceptions::InvalidParameterError	if the params vector is the wrong length

Definition at line 341 of file Kernel.h.

                                                                     {
        if (this->isSpatiallyVarying()) {
            throw LSST_EXCEPT(lsst::pex::exceptions::RuntimeError, "Kernel is spatially varying");
        }
        const unsigned int nParams = this->getNKernelParameters();
        if (nParams != params.size()) {
            throw LSST_EXCEPT(lsst::pex::exceptions::InvalidParameterError,
                              (boost::format("Number of parameters is wrong, saw %d expected %d") % nParams %
                               params.size())
                                      .str());
        }
        for (unsigned int ii = 0; ii < nParams; ++ii) {
            this->setKernelParameter(ii, params[ii]);
        }
    }

setKernelParametersFromSpatialModel()

void lsst::afw::math::Kernel::setKernelParametersFromSpatialModel ( double x, double y ) const

protectedinherited

Set the kernel parameters from the spatial model (if any).

This function has no effect if there is no spatial model.

This function is marked "const", despite modifying unimportant internals, so that computeImage can be const.

Definition at line 217 of file Kernel.cc.

                                                                         {
    std::vector<SpatialFunctionPtr>::const_iterator funcIter = _spatialFunctionList.begin();
    for (int ii = 0; funcIter != _spatialFunctionList.end(); ++funcIter, ++ii) {
        this->setKernelParameter(ii, (*(*funcIter))(x, y));
    }
}

setSpatialParameters()

void lsst::afw::math::Kernel::setSpatialParameters ( const std::vector< std::vector< double > > params )

inherited

Set the parameters of all spatial functions.

Params is indexed as [kernel parameter][spatial parameter]

Exceptions

lsst::pex::exceptions::InvalidParameterError

if params is the wrong shape (if this exception is thrown then no parameters are changed)

Definition at line 110 of file Kernel.cc.

                                                                            {
    // Check params size before changing anything
    unsigned int nKernelParams = this->getNKernelParameters();
    if (params.size() != nKernelParams) {
        throw LSST_EXCEPT(
                pexExcept::InvalidParameterError,
                (boost::format("params has %d entries instead of %d") % params.size() % nKernelParams).str());
    }
    unsigned int nSpatialParams = this->getNSpatialParameters();
    for (unsigned int ii = 0; ii < nKernelParams; ++ii) {
        if (params[ii].size() != nSpatialParams) {
            throw LSST_EXCEPT(pexExcept::InvalidParameterError,
                              (boost::format("params[%d] has %d entries instead of %d") % ii %
                               params[ii].size() % nSpatialParams)
                                      .str());
        }
    }
    // Set parameters
    if (nSpatialParams > 0) {
        for (unsigned int ii = 0; ii < nKernelParams; ++ii) {
            this->_spatialFunctionList[ii]->setParameters(params[ii]);
        }
    }
}

setWidth()

void lsst::afw::math::Kernel::setWidth ( int width )

inlineinherited

Definition at line 218 of file Kernel.h.

{ _width = width; }

shrinkBBox()

lsst::geom::Box2I lsst::afw::math::Kernel::shrinkBBox ( lsst::geom::Box2I const & bbox ) const

inherited

Given a bounding box for an image one wishes to convolve with this kernel, return the bounding box for the region of pixels that can be computed.

Thus the box shifted by kernel.getCtr() and its size is reduced by kernel.getDimensions()-1.

Returns

the bbox shrunk by the kernel.

Exceptions

lsst::pex::exceptions::InvalidParameterError

if the resulting box would have dimension < 1 in either axis

Definition at line 173 of file Kernel.cc.

                                                                {
    if ((bbox.getWidth() < getWidth()) || ((bbox.getHeight() < getHeight()))) {
        std::ostringstream os;
        os << "bbox dimensions = " << bbox.getDimensions() << " < (" << getWidth() << ", " << getHeight()
           << ") in one or both dimensions";
        throw LSST_EXCEPT(pexExcept::InvalidParameterError, os.str());
    }
    return lsst::geom::Box2I(
            lsst::geom::Point2I(bbox.getMin() + lsst::geom::Extent2I(getCtr())),
            lsst::geom::Extent2I(bbox.getWidth() + 1 - getWidth(), bbox.getHeight() + 1 - getHeight()));
}

toString()

std::string lsst::afw::math::LinearCombinationKernel::toString ( std::string const & prefix = "" ) const

overridevirtual

Return a string representation of the kernel.

Reimplemented from lsst::afw::math::Kernel.

Definition at line 227 of file LinearCombinationKernel.cc.

                                                                         {
    std::ostringstream os;
    os << prefix << "LinearCombinationKernel:" << std::endl;
    os << prefix << "..Kernels:" << std::endl;
    for (auto const &i : _kernelList) {
        os << i->toString(prefix + "\t");
    }
    os << "..parameters: [ ";
    for (std::vector<double>::const_iterator i = _kernelParams.begin(); i != _kernelParams.end(); ++i) {
        if (i != _kernelParams.begin()) os << ", ";
        os << *i;
    }
    os << " ]" << std::endl;
    os << Kernel::toString(prefix + "\t");
    return os.str();
}

write()

void lsst::afw::math::LinearCombinationKernel::write ( OutputArchiveHandle & handle ) const

overrideprotectedvirtual

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.

Definition at line 369 of file LinearCombinationKernel.cc.

                                                                     {
    bool isVarying = isSpatiallyVarying();
    LinearCombinationKernelPersistenceHelper const keys(getNBasisKernels(), isVarying);
    std::shared_ptr<afw::table::BaseRecord> record = keys.write(handle, *this);
    if (isVarying) {
        for (std::size_t n = 0; n < keys.components.getSize(); ++n) {
            record->set(keys.components[n], handle.put(_kernelList[n]));
            record->set(keys.spatialFunctions[n], handle.put(_spatialFunctionList[n]));
        }
    } else {
        for (std::size_t n = 0; n < keys.components.getSize(); ++n) {
            record->set(keys.components[n], handle.put(_kernelList[n]));
            record->set(keys.amplitudes[n], _kernelParams[n]);
        }
    }
}

writeFits() [1/3]

void lsst::afw::table::io::Persistable::writeFits ( fits::Fits & fitsfile ) const

inherited

Write the object to an already-open FITS object.

Parameters

[in]

fitsfile

Open FITS object to write to.

Definition at line 18 of file Persistable.cc.

                                                    {
    OutputArchive archive;
    archive.put(this);
    archive.writeFits(fitsfile);
}

writeFits() [2/3]

void lsst::afw::table::io::Persistable::writeFits ( fits::MemFileManager & manager, std::string const & mode = "w" ) const

inherited

Write the object to a FITS image in memory.

Parameters

[in]	manager	Name of the file to write to.
[in]	mode	If "w", any existing file with the given name will be overwritten. If "a", new HDUs will be appended to an existing file.

Definition at line 29 of file Persistable.cc.

                                                                                    {
    fits::Fits fitsfile(manager, mode, fits::Fits::AUTO_CLOSE | fits::Fits::AUTO_CHECK);
    writeFits(fitsfile);
}

writeFits() [3/3]

void lsst::afw::table::io::Persistable::writeFits ( std::string const & fileName, std::string const & mode = "w" ) const

inherited

Write the object to a regular FITS file.

Parameters

[in]	fileName	Name of the file to write to.
[in]	mode	If "w", any existing file with the given name will be overwritten. If "a", new HDUs will be appended to an existing file.

Definition at line 24 of file Persistable.cc.

                                                                                  {
    fits::Fits fitsfile(fileName, mode, fits::Fits::AUTO_CLOSE | fits::Fits::AUTO_CHECK);
    writeFits(fitsfile);
}

Member Data Documentation

_spatialFunctionList

std::vector<SpatialFunctionPtr> lsst::afw::math::Kernel::_spatialFunctionList

protectedinherited

Definition at line 449 of file Kernel.h.

---

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/afw/g9726552aa6+10f999ec6a/include/lsst/afw/math/Kernel.h
• /j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/afw/g9726552aa6+10f999ec6a/src/math/LinearCombinationKernel.cc