Class PhotometryMapping

Inheritance Relationships

Base Type

Class Documentation

class PhotometryMapping : public lsst::jointcal::PhotometryMappingBase

A mapping containing a single photometryTransform.

Public Functions

PhotometryMapping(std::shared_ptr<PhotometryTransform> transform)

Value transform takes ownership of transform, error transform aliases it.

Call freezeErrorTransform() to unalias the error transform.

std::size_t getNpar() const

Number of total parameters in this mapping.

double transform(MeasuredStar const &measuredStar, double value) const

Return the on-sky transformed flux for measuredStar on ccdImage.

Return

The on-sky value () transformed from value at measuredStar’s position.

Parameters

  • [in] measuredStar: The measured star position to transform.

  • [in] value: The instrument flux or magnitude to transform.

double transformError(MeasuredStar const &measuredStar, double value, double valueErr) const

Return the on-sky transformed flux uncertainty for measuredStar on ccdImage. Matches the underlying PhotometryTransform’s transformError() until freezeErrorTransform() is called.

Return

The on-sky value transformed from value at measuredStar’s position.

Parameters

  • [in] measuredStar: The measured star position to transform.

  • [in] value: The flux or magnitude to transform.

  • [in] valueErr: The flux or magnitude uncertainty to transform.

void freezeErrorTransform()

Once this routine has been called, the error transform is not modified by offsetParams().

The routine can be called when the mappings are roughly in place. After the call, the transformations used to propagate errors are no longer affected when updating the mappings. This allows an exactly linear fit, which can be necessary for some model+data combinations.

void computeParameterDerivatives(MeasuredStar const &measuredStar, double value, Eigen::Ref<Eigen::VectorXd> derivatives) const

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

Parameters

  • [in] measuredStar: The measured star position to 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.

void offsetParams(Eigen::VectorXd const &delta)

Offset the transform parameters by delta.

Parameters

Eigen::VectorXd getParameters()
void getMappingIndices(IndexVector &indices) const

Gets how this set of parameters (of length getNpar()) map into the “grand” fit. Expects that indices has enough space reserved.

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

Dump the contents of the transforms, for debugging.

std::shared_ptr<PhotometryTransform> getTransform() const
std::shared_ptr<PhotometryTransform> getTransformErrors() const