Ratio

class lsst.pipe.tasks.functors.Ratio(numerator, denominator, **kwargs)

Bases: lsst.pipe.tasks.functors.Functor

Base class for returning the ratio of 2 columns.

Can be used to compute a Signal to Noise ratio for any input flux.

Parameters:

numerator : str

Name of the column to use at the numerator in the ratio

denominator : str

Name of the column to use as the denominator in the ratio.

Attributes Summary

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

Methods Summary

__call__(data[, dropna])	Call self as a function.
difference(data1, data2, **kwargs)	Computes difference between functor called on two different ParquetTable objects
fail(df)
multilevelColumns(data[, columnIndex, …])	Returns columns needed by functor from multilevel dataset

Attributes Documentation

columns

Columns required to perform calculation

name

Full name of functor (suitable for figure labels)

noDup

shortname

Short name of functor (suitable for column name/dict key)

Methods Documentation

__call__(data, dropna=False)

Call self as a function.

difference(data1, data2, **kwargs)

Computes difference between functor called on two different ParquetTable objects

fail(df)

multilevelColumns(data, columnIndex=None, returnTuple=False)

Returns columns needed by functor from multilevel dataset

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

Parameters:

data : MultilevelParquetTable or DeferredDatasetHandle

columnIndex (optional): pandas `Index` object

either passed or read in from DeferredDatasetHandle.

`returnTuple` : bool

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.