Color

class lsst.pipe.tasks.functors.Color(col, filt2, filt1, **kwargs)

Bases: Functor

Compute the color between two filters.

Computes color by initializing two different Mag functors based on the col and filters provided, and then returning the difference.

This is enabled by the _func method expecting a DataFrame with a multilevel column index, with both 'band' and 'column', instead of just 'column', which is the Functor default. This is controlled by the _dfLevels attribute.

Also of note, the default dataset for Color is forced_src', whereas for Mag it is 'meas'.

Parameters

colstr

Name of the flux column from which to compute; same as would be passed to Mag.

filt2, filt1str

Filters from which to compute magnitude difference. Color computed is Mag(filt2) - Mag(filt1).

Attributes Summary

columns	Columns required to perform calculation.
filt
name	Full name of functor (suitable for figure labels).
shortname	Short name of functor (suitable for column name/dict key).

Methods Summary

multilevelColumns(parq, **kwargs)

Returns columns needed by functor from multilevel dataset.

Attributes Documentation

columns

filt

name

shortname

Methods Documentation

multilevelColumns(parq, **kwargs)

Returns columns needed by functor from multilevel dataset.

To access tables with multilevel column structure, the DeferredDatasetHandle or InMemoryDatasetHandle needs to be passed either a list of tuples or a dictionary.

Parameters

datavarious

The data as either DeferredDatasetHandle, or InMemoryDatasetHandle.

columnIndex (optional): pandas Index object

Either passed or read in from DeferredDatasetHandle.

returnTuplebool

If true, then return a list of tuples rather than the column dictionary specification. This is set to True by CompositeFunctor in order to be able to combine columns from the various component functors.