CalcE1

class lsst.analysis.tools.actions.vector.CalcE1(*args, **kw)

Bases: VectorAction

Calculate \(e_1\) (distortion-type) or \(g_1\) (shear-type).

The definitions are as follows:

\[\begin{split}e_1&=(I_{xx}-I_{yy})/(I_{xx}+I_{yy}) \\ g_1&=(I_{xx}-I_{yy})/(I_{xx}+I_{yy}+2\sqrt{I_{xx}I_{yy}-I_{xy}^{2}}).\end{split}\]

See Also

CalcE CalcE2

Notes

This is a shape measurement used for doing QA on the ellipticity of the sources.

Attributes Summary

colXx	The column name to get the xx shape component from.
colXy	The column name to get the xy shape component from.
colYy	The column name to get the yy shape component from.
ellipticityType	The type of ellipticity to calculate (str, default 'distortion')

Methods Summary

__call__(data, **kwargs)	Call self as a function.
getInputSchema()	Return the schema an AnalysisAction expects to be present in the arguments supplied to the __call__ method.
validate()	Validate the Config, raising an exception if invalid.

Attributes Documentation

colXx

The column name to get the xx shape component from. (str, default '{band}_ixx')

colXy

The column name to get the xy shape component from. (str, default '{band}_ixy')

colYy

The column name to get the yy shape component from. (str, default '{band}_iyy')

ellipticityType

The type of ellipticity to calculate (str, default 'distortion')

Allowed values:

'distortion'

Distortion, measured as \((I_{xx}-I_{yy})/(I_{xx}+I_{yy})\)

'shear'

Shear, measured as \((I_{xx}-I_{yy})/(I_{xx}+I_{yy}+2\sqrt{I_{xx}I_{yy}-I_{xy}^2})\)

Methods Documentation

__call__(data: MutableMapping[str, ndarray[tuple[Any, ...], dtype[_ScalarT]] | Scalar | HealSparseMap | Tensor | Mapping], **kwargs) → ndarray[tuple[Any, ...], dtype[_ScalarT]]

Call self as a function.

getInputSchema() → Iterable[tuple[str, type[ndarray[tuple[Any, ...], dtype[_ScalarT]]] | type[Scalar] | type[HealSparseMap] | type[Tensor] | type[Mapping]]]

Return the schema an AnalysisAction expects to be present in the arguments supplied to the __call__ method.

Returns

resultKeyedDataSchema

The schema this action requires to be present when calling this action, keys are unformatted.

validate()

Validate the Config, raising an exception if invalid.

Raises

lsst.pex.config.FieldValidationError

Raised if verification fails.

Notes

The base class implementation performs type checks on all fields by calling their validate methods.

Complex single-field validation can be defined by deriving new Field types. For convenience, some derived lsst.pex.config.Field-types (ConfigField and ConfigChoiceField) are defined in lsst.pex.config that handle recursing into subconfigs.

Inter-field relationships should only be checked in derived Config classes after calling this method, and base validation is complete.