lsst::jointcal::FluxTransformChebyshev Class Reference

nth-order 2d Chebyshev photometry transform, times the input flux. More...

#include <PhotometryTransform.h>

Inheritance diagram for lsst::jointcal::FluxTransformChebyshev:

Public Member Functions
	FluxTransformChebyshev (size_t order, geom::Box2D const &bbox)
	FluxTransformChebyshev (ndarray::Array< double, 2, 2 > const &coefficients, geom::Box2D const &bbox)
double	transform (double x, double y, double value) const override
	Return the transform of value at (x,y). More...
void	computeParameterDerivatives (double x, double y, double value, Eigen::Ref< Eigen::VectorXd > derivatives) const override
	Compute the derivatives with respect to the parameters (i.e. More...
std::shared_ptr< PhotometryTransform >	clone () const override
	return a copy (allocated by new) of the transformation. More...
double	transformError (double x, double y, double value, double valueErr) const override
	Return the transformed valueErr at Point(x,y). More...
double	transformError (Point const &in, double value, double valueErr) const
	Return the transformed valueErr at Point(x,y). More...
void	print (std::ostream &out) const override
	Print the transform coefficients to stream. More...
std::size_t	getNpar () const override
	Return the number of parameters (used to compute chisq) More...
void	offsetParams (Eigen::VectorXd const &delta) override
	Offset the parameters by some (negative) amount during fitting. More...
ndarray::Array< double, 2, 2 >	getCoefficients () const
	Get a copy of the coefficients of the polynomials, as a 2d array (NOTE: layout is [y][x]) More...
Eigen::VectorXd	getParameters () const override
	Get a copy of the parameters of this model, in the same order as offsetParams. More...
ndarray::Size	getOrder () const
geom::Box2D	getBBox () const
double	mean (geom::Box2D const &bbox) const
	Compute the mean of this tranform on the bbox (default to our bbox). More...
double	mean () const
double	integrate (geom::Box2D const &bbox) const
double	integrate () const
double	transform (Point const &in, double value) const
	Return the transformed value at Point(x,y). More...

Protected Member Functions
double	computeChebyshev (double x, double y) const
	Return the value of this polynomial at x,y. More...
void	computeChebyshevDerivatives (double x, double y, Eigen::Ref< Eigen::VectorXd > derivatives) const
	Set the derivatives of this polynomial at x,y. More...

Detailed Description

nth-order 2d Chebyshev photometry transform, times the input flux.

Definition at line 302 of file PhotometryTransform.h.

Constructor & Destructor Documentation

FluxTransformChebyshev() [1/2]

lsst::jointcal::FluxTransformChebyshev::FluxTransformChebyshev ( size_t  order, geom::Box2D const &  bbox  )

inline

Definition at line 304 of file PhotometryTransform.h.

            : PhotometryTransformChebyshev(order, bbox, true) {}

FluxTransformChebyshev() [2/2]

lsst::jointcal::FluxTransformChebyshev::FluxTransformChebyshev ( ndarray::Array< double, 2, 2 > const &  coefficients, geom::Box2D const &  bbox  )

inline

Definition at line 307 of file PhotometryTransform.h.

            : PhotometryTransformChebyshev(coefficients, bbox) {}

Member Function Documentation

clone()

std::shared_ptr<PhotometryTransform> lsst::jointcal::FluxTransformChebyshev::clone ( ) const

inlineoverridevirtual

return a copy (allocated by new) of the transformation.

Implements lsst::jointcal::PhotometryTransform.

Definition at line 323 of file PhotometryTransform.h.

                                                              {
        return std::make_shared<FluxTransformChebyshev>(getCoefficients(), getBBox());
    }

computeChebyshev()

double lsst::jointcal::PhotometryTransformChebyshev::computeChebyshev ( double  x, double  y  ) const

protectedinherited

Return the value of this polynomial at x,y.

For use in the sublcass transform() methods.

Definition at line 224 of file PhotometryTransform.cc.

                                                                              {
    geom::Point2D p = _toChebyshevRange(geom::Point2D(x, y));
    return evaluateFunction1d(RecursionArrayImitator(_coefficients, p.getX()), p.getY(),
                              _coefficients.getSize<0>());
}

computeChebyshevDerivatives()

void lsst::jointcal::PhotometryTransformChebyshev::computeChebyshevDerivatives ( double  x, double  y, Eigen::Ref< Eigen::VectorXd >  derivatives  ) const

protectedinherited

Set the derivatives of this polynomial at x,y.

For use in the sublcass computeParameterDerivatives() methods.

Definition at line 230 of file PhotometryTransform.cc.

                                                                       {
    geom::Point2D p = _toChebyshevRange(geom::Point2D(x, y));
    // Algorithm: compute all the individual components recursively (since we'll need them anyway),
    // then combine them into the final answer vectors.
    Eigen::VectorXd Tnx(_order + 1);
    Eigen::VectorXd Tmy(_order + 1);
    Tnx[0] = 1;
    Tmy[0] = 1;
    if (_order >= 1) {
        Tnx[1] = p.getX();
        Tmy[1] = p.getY();
    }
    for (ndarray::Size i = 2; i <= _order; ++i) {
        Tnx[i] = 2 * p.getX() * Tnx[i - 1] - Tnx[i - 2];
        Tmy[i] = 2 * p.getY() * Tmy[i - 1] - Tmy[i - 2];
    }
 
    // NOTE: the indexing in this method and offsetParams must be kept consistent!
    Eigen::VectorXd::Index k = 0;
    for (ndarray::Size j = 0; j <= _order; ++j) {
        ndarray::Size const iMax = _order - j;  // to save re-computing `i+j <= order` every inner step.
        for (ndarray::Size i = 0; i <= iMax; ++i, ++k) {
            derivatives[k] = Tmy[j] * Tnx[i];
        }
    }
}

computeParameterDerivatives()

void lsst::jointcal::FluxTransformChebyshev::computeParameterDerivatives ( double  x, double  y, double  value, Eigen::Ref< Eigen::VectorXd >  derivatives  ) const

inlineoverridevirtual

Compute the derivatives with respect to the parameters (i.e.

the coefficients).

Parameters

[in]	x	The x coordinate to compute at (in the appropriate units for this transform).
[in]	y	The y coordinate to compute at (in the appropriate units for this transform).
[in]	value	The instrument flux or magnitude to compute the derivative at.
[out]	derivatives	The computed derivatives, in the same order as the deltas in offsetParams.

Implements lsst::jointcal::PhotometryTransform.

Definition at line 316 of file PhotometryTransform.h.

                                                                                         {
        computeChebyshevDerivatives(x, y, derivatives);
        derivatives *= value;
    }

getBBox()

geom::Box2D lsst::jointcal::PhotometryTransformChebyshev::getBBox ( ) const

inlineinherited

Definition at line 263 of file PhotometryTransform.h.

{ return _bbox; }

getCoefficients()

ndarray::Array<double, 2, 2> lsst::jointcal::PhotometryTransformChebyshev::getCoefficients ( ) const

inlineinherited

Get a copy of the coefficients of the polynomials, as a 2d array (NOTE: layout is [y][x])

Definition at line 256 of file PhotometryTransform.h.

{ return ndarray::copy(_coefficients); }

getNpar()

std::size_t lsst::jointcal::PhotometryTransformChebyshev::getNpar ( ) const

inlineoverridevirtualinherited

Return the number of parameters (used to compute chisq)

Implements lsst::jointcal::PhotometryTransform.

Definition at line 250 of file PhotometryTransform.h.

{ return _nParameters; }

getOrder()

ndarray::Size lsst::jointcal::PhotometryTransformChebyshev::getOrder ( ) const

inlineinherited

Definition at line 261 of file PhotometryTransform.h.

{ return _order; }

getParameters()

Eigen::VectorXd lsst::jointcal::PhotometryTransformChebyshev::getParameters ( ) const

overridevirtualinherited

Get a copy of the parameters of this model, in the same order as offsetParams.

Implements lsst::jointcal::PhotometryTransform.

Definition at line 210 of file PhotometryTransform.cc.

                                                                {
    Eigen::VectorXd parameters(_nParameters);
    // NOTE: the indexing in this method and offsetParams must be kept consistent!
    Eigen::VectorXd::Index k = 0;
    for (ndarray::Size j = 0; j <= _order; ++j) {
        ndarray::Size const iMax = _order - j;  // to save re-computing `i+j <= order` every inner step.
        for (ndarray::Size i = 0; i <= iMax; ++i, ++k) {
            parameters[k] = _coefficients[j][i];
        }
    }
 
    return parameters;
}

integrate() [1/2]

double lsst::jointcal::PhotometryTransformChebyshev::integrate ( ) const

inherited

Definition at line 193 of file PhotometryTransform.cc.

                                                     {
    double result = 0;
    double determinant = _bbox.getArea() / 4.0;
    for (ndarray::Size j = 0; j < _coefficients.getSize<0>(); j++) {
        for (ndarray::Size i = 0; i < _coefficients.getSize<1>(); i++) {
            result += _coefficients[j][i] * integrateTn(i) * integrateTn(j);
        }
    }
    return result * determinant;
}

integrate() [2/2]

double lsst::jointcal::PhotometryTransformChebyshev::integrate ( geom::Box2D const &  bbox ) const

inherited

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 181 of file PhotometryTransform.cc.

                                                                          {
    double result = 0;
 
    result += oneIntegral(bbox.getMaxX(), bbox.getMaxY());
    result += oneIntegral(bbox.getMinX(), bbox.getMinY());
    result -= oneIntegral(bbox.getMaxX(), bbox.getMinY());
    result -= oneIntegral(bbox.getMinX(), bbox.getMaxY());
 
    // scale factor due to the change of limits in the integral
    return result / _toChebyshevRange.getLinear().computeDeterminant();
}

mean() [1/2]

double lsst::jointcal::PhotometryTransformChebyshev::mean ( ) const

inherited

Definition at line 208 of file PhotometryTransform.cc.

{ return integrate() / _bbox.getArea(); }

mean() [2/2]

double lsst::jointcal::PhotometryTransformChebyshev::mean ( geom::Box2D const &  bbox ) const

inherited

Compute the mean of this tranform on the bbox (default to our bbox).

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 204 of file PhotometryTransform.cc.

                                                                     {
    return integrate(bbox) / bbox.getArea();
}

offsetParams()

void lsst::jointcal::PhotometryTransformChebyshev::offsetParams ( Eigen::VectorXd const &  delta )

overridevirtualinherited

Offset the parameters by some (negative) amount during fitting.

Equivalent to flatten(parameters) -= delta

Ordering of delta is the same as the ordering of the derivatives returned from computeParameterDerivatives.

Implements lsst::jointcal::PhotometryTransform.

Definition at line 107 of file PhotometryTransform.cc.

                                                                          {
    // NOTE: the indexing in this method and computeParameterDerivatives must be kept consistent!
    Eigen::VectorXd::Index k = 0;
    for (ndarray::Size j = 0; j <= _order; ++j) {
        ndarray::Size const iMax = _order - j;  // to save re-computing `i+j <= order` every inner step.
        for (ndarray::Size i = 0; i <= iMax; ++i, ++k) {
            _coefficients[j][i] -= delta[k];
        }
    }
}

print()

void lsst::jointcal::PhotometryTransformChebyshev::print ( std::ostream &  out ) const

inlineoverridevirtualinherited

Print the transform coefficients to stream.

Implements lsst::jointcal::PhotometryTransform.

Definition at line 247 of file PhotometryTransform.h.

{ out << "PhotometryTransformChebyshev: " << _coefficients; }

transform() [1/2]

double lsst::jointcal::FluxTransformChebyshev::transform ( double  x, double  y, double  value  ) const

inlineoverridevirtual

Return the transform of value at (x,y).

Implements lsst::jointcal::PhotometryTransform.

Definition at line 311 of file PhotometryTransform.h.

                                                                      {
        return value * computeChebyshev(x, y);
    }

transform() [2/2]

double lsst::jointcal::PhotometryTransform::transform ( Point const &  in, double  value  ) const

inlineinherited

Return the transformed value at Point(x,y).

Definition at line 58 of file PhotometryTransform.h.

{ return transform(in.x, in.y, value); }

transformError() [1/2]

double lsst::jointcal::PhotometryTransformChebyshev::transformError ( double  x, double  y, double  value, double  valueErr  ) const

inlineoverridevirtualinherited

Return the transformed valueErr at Point(x,y).

Implements lsst::jointcal::PhotometryTransform.

Definition at line 244 of file PhotometryTransform.h.

{ return 0; }

transformError() [2/2]

double lsst::jointcal::PhotometryTransform::transformError ( Point const &  in, double  value, double  valueErr  ) const

inlineinherited

Return the transformed valueErr at Point(x,y).

Definition at line 64 of file PhotometryTransform.h.

                                                                                {
        return transformError(in.x, in.y, value, valueErr);
    }

---

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

• /j/snowflake/release/lsstsw/stack/cb4e2dc/Linux64/jointcal/19.0.0-14-gb0260a2+72efe9b372/include/lsst/jointcal/PhotometryTransform.h