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 boost::shared_ptr < BuildSpatialKernelVisitor < PixelT > >	Ptr

Public Member Functions
	BuildSpatialKernelVisitor (lsst::afw::math::KernelList const &basisList, lsst::afw::geom::Box2I const &regionBBox, lsst::pex::policy::Policy policy)
int	getNCandidates ()
void	processCandidate (lsst::afw::math::SpatialCellCandidate *candidate)
void	solveLinearEquation ()
boost::shared_ptr < SpatialKernelSolution >	getKernelSolution ()
std::pair < lsst::afw::math::LinearCombinationKernel::Ptr, lsst::afw::math::Kernel::SpatialFunctionPtr >	getSolutionPair ()
Public Member Functions inherited from lsst::afw::math::CandidateVisitor
	CandidateVisitor ()
virtual	~CandidateVisitor ()
virtual void	reset ()

Private Attributes
boost::shared_ptr < SpatialKernelSolution >	_kernelSolution
int	_nCandidates
	Number of candidates visited. More...

Detailed Description

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

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

   Policy::Ptr policy(new Policy);
   policy->set("spatialKernelOrder", spatialKernelOrder);
   policy->set("spatialBgOrder", spatialBgOrder);
   policy->set("kernelBasisSet", "delta-function");
   policy->set("usePcaForSpatialKernel", true);

   detail::BuildSpatialKernelVisitor<PixelT> spatialKernelFitter(*basisListToUse, 
                                                                 *policy);
   kernelCells.visitCandidates(&spatialKernelFitter, nStarPerCell);
   spatialKernelFitter.solveLinearEquation();
   std::pair<afwMath::LinearCombinationKernel::Ptr, 
       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 policy. 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 27 of file BuildSpatialKernelVisitor.h.

Member Typedef Documentation

template<typename PixelT >

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

Definition at line 29 of file BuildSpatialKernelVisitor.h.

Constructor & Destructor Documentation

template<typename PixelT >

lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::BuildSpatialKernelVisitor	(	lsst::afw::math::KernelList const &	basisList,
		lsst::afw::geom::Box2I const &	regionBBox,
		lsst::pex::policy::Policy	policy
	)

Parameters

basisList	Basis functions
regionBBox	Spatial region over which the function is fit
policy	Policy file directing behavior

Definition at line 74 of file BuildSpatialKernelVisitor.cc.

          :
        afwMath::CandidateVisitor(),
        _kernelSolution(),
        _nCandidates(0) 
    {
        int spatialKernelOrder = policy.getInt("spatialKernelOrder");
        afwMath::Kernel::SpatialFunctionPtr spatialKernelFunction;

        int fitForBackground = policy.getBool("fitForBackground");
        int spatialBgOrder   = fitForBackground ? policy.getInt("spatialBgOrder") : 0;
        afwMath::Kernel::SpatialFunctionPtr background;

        std::string spatialModelType = policy.getString("spatialModelType");
        if (spatialModelType == "chebyshev1") {
            spatialKernelFunction = afwMath::Kernel::SpatialFunctionPtr(
                new afwMath::Chebyshev1Function2<double>(spatialKernelOrder, afwGeom::Box2D(regionBBox))
                );
            background = afwMath::Kernel::SpatialFunctionPtr(
                new afwMath::Chebyshev1Function2<double>(spatialBgOrder, afwGeom::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 = boost::shared_ptr<SpatialKernelSolution>(
            new SpatialKernelSolution(basisList, spatialKernelFunction, background, policy));
    };

Member Function Documentation

template<typename PixelT >

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

inline

Definition at line 43 of file BuildSpatialKernelVisitor.h.

{return _kernelSolution;}

template<typename PixelT >

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

inline

Definition at line 37 of file BuildSpatialKernelVisitor.h.

{return _nCandidates;}

template<typename PixelT >

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

(

)

Definition at line 164 of file BuildSpatialKernelVisitor.cc.

                                                       {
        return _kernelSolution->getSolutionPair();
    }

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 122 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);
            pexLogging::TTrace<3>("lsst.ip.diffim.BuildSpatialKernelVisitor.processCandidate", 
                                  "Cannot process candidate %d, continuing", kCandidate->getId());
            return;
        }
        
        pexLogging::TTrace<6>("lsst.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());
        
    }

template<typename PixelT >

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

(

)

Definition at line 158 of file BuildSpatialKernelVisitor.cc.

                                                                {
        _kernelSolution->solve();
    }

Member Data Documentation

template<typename PixelT >

boost::shared_ptr<SpatialKernelSolution> lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::_kernelSolution

private

Definition at line 49 of file BuildSpatialKernelVisitor.h.

template<typename PixelT >

int lsst::ip::diffim::detail::BuildSpatialKernelVisitor< PixelT >::_nCandidates

private

Number of candidates visited.

Definition at line 50 of file BuildSpatialKernelVisitor.h.

---

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

• /home/lsstsw/stack/Linux64/ip_diffim/11.0+1/include/lsst/ip/diffim/BuildSpatialKernelVisitor.h
• /home/lsstsw/stack/Linux64/ip_diffim/11.0+1/src/BuildSpatialKernelVisitor.cc