lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT > Class Template Reference

Creates a spatial kernel and background from a list of candidates. More...

#include <BuildSpatialKernelVisitor.h>

Inheritance diagram for lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >:

Public Types
typedef std::shared_ptr< BuildSpatialKernelVisitor< PixelT > >	Ptr

Public Member Functions
	BuildSpatialKernelVisitor (lsst::afw::math::KernelList const &basisList, lsst::geom::Box2I const &regionBBox, lsst::daf::base::PropertySet const &ps)
int	getNCandidates ()
void	processCandidate (lsst::afw::math::SpatialCellCandidate *candidate)
void	solveLinearEquation ()
std::shared_ptr< SpatialKernelSolution >	getKernelSolution ()
std::pair< std::shared_ptr< lsst::afw::math::LinearCombinationKernel >, lsst::afw::math::Kernel::SpatialFunctionPtr >	getSolutionPair ()
virtual void	reset ()

Detailed Description

template<typename PixelT>
class lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >

Creates a spatial kernel and background from a list of candidates.

std::shared_ptr<PropertySet> ps(new PropertySet);
ps->set("spatialKernelOrder", spatialKernelOrder);
ps->set("spatialBgOrder", spatialBgOrder);
ps->set("kernelBasisSet", "delta-function");
ps->set("usePcaForSpatialKernel", true);
 
detail::BuildSpatialKernelVisitor<PixelT> spatialKernelFitter(*basisListToUse,
                                                              *ps);
kernelCells.visitCandidates(&spatialKernelFitter, nStarPerCell);
spatialKernelFitter.solveLinearEquation();
std::pair<std::shared_ptr<afwMath::LinearCombinationKernel>,
    afwMath::Kernel::SpatialFunctionPtr> kb = spatialKernelFitter.getKernelSolution();
spatialKernel     = kb.first;
spatialBackground = kb.second;

Note

After visiting all candidates, solveLinearEquation() must be called to trigger the matrix math.

The user has the option to enfore conservation of the kernel sum across the image through the property set. In this case, all terms but the first are fit for spatial variation. This requires a little extra code to make sure the matrices are the correct size, and that it is accessing the appropriate terms in the matrices when creating the spatial models.

Definition at line 28 of file BuildSpatialKernelVisitor.h.

Member Typedef Documentation

Ptr

template<typename PixelT >

typedef std::shared_ptr<BuildSpatialKernelVisitor<PixelT> > lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::Ptr

Definition at line 30 of file BuildSpatialKernelVisitor.h.

Constructor & Destructor Documentation

BuildSpatialKernelVisitor()

template<typename PixelT >

lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::BuildSpatialKernelVisitor	(	lsst::afw::math::KernelList const &	basisList,
		lsst::geom::Box2I const &	regionBBox,
		lsst::daf::base::PropertySet const &	ps )

Parameters

basisList	Basis functions
regionBBox	Spatial region over which the function is fit
ps	PropertySet directing behavior

Definition at line 72 of file BuildSpatialKernelVisitor.cc.

          :
        afwMath::CandidateVisitor(),
        _kernelSolution(),
        _nCandidates(0)
    {
        int spatialKernelOrder = ps.getAsInt("spatialKernelOrder");
        afwMath::Kernel::SpatialFunctionPtr spatialKernelFunction;
 
        int fitForBackground = ps.getAsBool("fitForBackground");
        int spatialBgOrder   = fitForBackground ? ps.getAsInt("spatialBgOrder") : 0;
        afwMath::Kernel::SpatialFunctionPtr background;
 
        std::string spatialModelType = ps.getAsString("spatialModelType");
        if (spatialModelType == "chebyshev1") {
            spatialKernelFunction = afwMath::Kernel::SpatialFunctionPtr(
                new afwMath::Chebyshev1Function2<double>(spatialKernelOrder, geom::Box2D(regionBBox))
                );
            background = afwMath::Kernel::SpatialFunctionPtr(
                new afwMath::Chebyshev1Function2<double>(spatialBgOrder, geom::Box2D(regionBBox))
                );
 
        }
        else if (spatialModelType == "polynomial") {
            spatialKernelFunction = afwMath::Kernel::SpatialFunctionPtr(
                new afwMath::PolynomialFunction2<double>(spatialKernelOrder)
                );
            background = afwMath::Kernel::SpatialFunctionPtr(
                new afwMath::PolynomialFunction2<double>(spatialBgOrder)
                );
        }
        else {
            throw LSST_EXCEPT(pexExcept::Exception,
                              str(boost::format("Invalid type (%s) for spatial models") %
                                  spatialModelType));
        }
 
        /* */
 
        _kernelSolution = std::shared_ptr<SpatialKernelSolution>(
            new SpatialKernelSolution(basisList, spatialKernelFunction, background, ps));
    };

Member Function Documentation

getKernelSolution()

template<typename PixelT >

std::shared_ptr< SpatialKernelSolution > lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::getKernelSolution ( )

inline

Definition at line 44 of file BuildSpatialKernelVisitor.h.

{return _kernelSolution;}

getNCandidates()

template<typename PixelT >

int lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::getNCandidates ( )

inline

Definition at line 38 of file BuildSpatialKernelVisitor.h.

{return _nCandidates;}

getSolutionPair()

template<typename PixelT >

std::pair< std::shared_ptr< afwMath::LinearCombinationKernel >, afwMath::Kernel::SpatialFunctionPtr > lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::getSolutionPair

(

)

Definition at line 162 of file BuildSpatialKernelVisitor.cc.

                                                       {
        return _kernelSolution->getSolutionPair();
    }

processCandidate()

template<typename PixelT >

void lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::processCandidate ( lsst::afw::math::SpatialCellCandidate * candidate )

virtual

Reimplemented from lsst::afw::math::CandidateVisitor.

Definition at line 120 of file BuildSpatialKernelVisitor.cc.

          {
        KernelCandidate<PixelT> *kCandidate = dynamic_cast<KernelCandidate<PixelT> *>(candidate);
        if (kCandidate == NULL) {
            throw LSST_EXCEPT(pexExcept::LogicError,
                              "Failed to cast SpatialCellCandidate to KernelCandidate");
        }
        if (!(kCandidate->isInitialized())) {
            kCandidate->setStatus(afwMath::SpatialCellCandidate::BAD);
            LOGL_DEBUG("TRACE2.ip.diffim.BuildSpatialKernelVisitor.processCandidate",
                       "Cannot process candidate %d, continuing", kCandidate->getId());
            return;
        }
 
        LOGL_DEBUG("TRACE5.ip.diffim.BuildSpatialKernelVisitor.processCandidate",
                   "Processing candidate %d", kCandidate->getId());
        _nCandidates += 1;
 
        /*
           Build the spatial kernel from the most recent fit, e.g. if its Pca
           you want to build a spatial model on the Pca basis, not original
           basis
        */
        _kernelSolution->addConstraint(kCandidate->getXCenter(),
                                       kCandidate->getYCenter(),
                                       kCandidate->getKernelSolution(
                                           KernelCandidate<PixelT>::RECENT
                                           )->getM(),
                                       kCandidate->getKernelSolution(
                                           KernelCandidate<PixelT>::RECENT
                                           )->getB());
 
    }

reset()

virtual void lsst::afw::math::CandidateVisitor::reset ( )

inlinevirtualinherited

Reimplemented in lsst::ip::diffim::detail::AssessSpatialKernelVisitor< PixelT >, lsst::ip::diffim::detail::BuildSingleKernelVisitor< PixelT >, and lsst::meas::algorithms::evalChi2Visitor< PixelT >.

Definition at line 63 of file SpatialCell.h.

{}

solveLinearEquation()

template<typename PixelT >

void lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::solveLinearEquation

(

)

Definition at line 156 of file BuildSpatialKernelVisitor.cc.

                                                                {
        _kernelSolution->solve();
    }

---

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/ip_diffim/g1470d8bcf6+de7501a2e0/include/lsst/ip/diffim/BuildSpatialKernelVisitor.h
• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/ip_diffim/g1470d8bcf6+de7501a2e0/src/BuildSpatialKernelVisitor.cc