Class PhotometryTransform

Inheritance Relationships

Derived Types

Class Documentation

class PhotometryTransform

A photometric transform, defined in terms of the input flux or magnitude.

Unit agnostic: a higher level Model must keep track of the units going into and out of of its Transforms.

See

lsst::afw::image::PhotoCalib

Subclassed by lsst::jointcal::PhotometryTransformChebyshev, lsst::jointcal::PhotometryTransformSpatiallyInvariant

Public Functions

virtual double transform(double x, double y, double value) const = 0

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

double transform(Point const &in, double value) const

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

virtual double transformError(double x, double y, double value, double valueErr) const = 0

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

double transformError(Point const &in, double value, double valueErr) const

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

virtual void dump(std::ostream &stream = std::cout) const = 0

dumps the transform coefficients to stream.

virtual std::size_t getNpar() const = 0

Return the number of parameters (used to compute chisq)

virtual void offsetParams(Eigen::VectorXd const &delta) = 0

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.

virtual std::shared_ptr<PhotometryTransform> clone() const = 0

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

virtual void computeParameterDerivatives(double x, double y, double value, Eigen::Ref<Eigen::VectorXd> derivatives) const = 0

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.

virtual Eigen::VectorXd getParameters() const = 0

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

Friends

std::ostream &operator<<(std::ostream &s, PhotometryTransform const &transform)