ChebyshevBoundedField.h

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// -*- LSST-C++ -*-
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#ifndef LSST_AFW_MATH_ChebyshevBoundedField_h_INCLUDED
#define LSST_AFW_MATH_ChebyshevBoundedField_h_INCLUDED
 
#include "ndarray.h"
 
#include "lsst/pex/config.h"
#include "lsst/geom/AffineTransform.h"
#include "lsst/afw/math/BoundedField.h"
 
namespace lsst {
namespace afw {
namespace math {

class ChebyshevBoundedFieldControl {
public:
    ChebyshevBoundedFieldControl() : orderX(2), orderY(2), triangular(true) {}
 
    LSST_CONTROL_FIELD(orderX, int, "maximum Chebyshev function order in x");
 
    LSST_CONTROL_FIELD(orderY, int, "maximum Chebyshev function order in y");
 
    LSST_CONTROL_FIELD(triangular, bool,
                       "if true, only include terms where the sum of the x and y order "
                       "is less than or equal to max(orderX, orderY)");

    int computeSize() const;
};

class ChebyshevBoundedField : public table::io::PersistableFacade<ChebyshevBoundedField>,
                              public BoundedField {
public:
    using Control = ChebyshevBoundedFieldControl;

    ChebyshevBoundedField(lsst::geom::Box2I const& bbox,
                          ndarray::Array<double const, 2, 2> const& coefficients);
 
    ChebyshevBoundedField(ChebyshevBoundedField const&);
    ChebyshevBoundedField(ChebyshevBoundedField&&);
    ChebyshevBoundedField& operator=(ChebyshevBoundedField const&) = delete;
    ChebyshevBoundedField& operator=(ChebyshevBoundedField&&) = delete;
    ~ChebyshevBoundedField() override;

    static std::shared_ptr<ChebyshevBoundedField> fit(lsst::geom::Box2I const& bbox,
                                                      ndarray::Array<double const, 1> const& x,
                                                      ndarray::Array<double const, 1> const& y,
                                                      ndarray::Array<double const, 1> const& z,
                                                      Control const& ctrl);

    static std::shared_ptr<ChebyshevBoundedField> fit(lsst::geom::Box2I const& bbox,
                                                      ndarray::Array<double const, 1> const& x,
                                                      ndarray::Array<double const, 1> const& y,
                                                      ndarray::Array<double const, 1> const& z,
                                                      ndarray::Array<double const, 1> const& w,
                                                      Control const& ctrl);

    static ndarray::Array<double, 2, 2> makeFitMatrix(
        lsst::geom::Box2I const& bbox,
        ndarray::Array<double const, 1> const& x,
        ndarray::Array<double const, 1> const& y,
        Control const& ctrl
    );

    template <typename T>
    static std::shared_ptr<ChebyshevBoundedField> fit(image::Image<T> const& image, Control const& ctrl);

    ndarray::Array<double const, 2, 2> getCoefficients() const { return _coefficients; }

    std::shared_ptr<ChebyshevBoundedField> truncate(Control const& ctrl) const;

    std::shared_ptr<ChebyshevBoundedField> relocate(lsst::geom::Box2I const& bbox) const;

    double evaluate(lsst::geom::Point2D const& position) const override;
 
    using BoundedField::evaluate;

    double integrate() const override;

    double mean() const override;

    bool isPersistable() const noexcept override { return true; }

    std::shared_ptr<BoundedField> operator*(double const scale) const override;

    bool operator==(BoundedField const& rhs) const override;
 
protected:
    std::string getPersistenceName() const override;
 
    std::string getPythonModule() const override;
 
    void write(OutputArchiveHandle& handle) const override;
 
private:
    // Internal constructor for fit() routines: just initializes the transform,
    // leaves coefficients empty.
    explicit ChebyshevBoundedField(lsst::geom::Box2I const& bbox);
 
    lsst::geom::AffineTransform _toChebyshevRange;     // maps points from the bbox to [-1,1]x[-1,1]
    ndarray::Array<double const, 2, 2> _coefficients;  // shape=(orderY+1, orderX+1)
 
    std::string toString() const override;
};
}  // namespace math
}  // namespace afw
}  // namespace lsst
 
#endif  // !LSST_AFW_MATH_ChebyshevBoundedField_h_INCLUDED