Calculate columns from ParquetTable
This object manages and organizes an arbitrary set of computations
on a catalog. The catalog is defined by a
`lsst.pipe.tasks.parquetTable.ParquetTable` object (or list thereof), such as a
`deepCoadd_obj` dataset, and the computations are defined by a collection
of `lsst.pipe.tasks.functor.Functor` objects (or, equivalently,
a `CompositeFunctor`).
After the object is initialized, accessing the `.df` attribute (which
holds the `pandas.DataFrame` containing the results of the calculations) triggers
computation of said dataframe.
One of the conveniences of using this object is the ability to define a desired common
filter for all functors. This enables the same functor collection to be passed to
several different `PostprocessAnalysis` objects without having to change the original
functor collection, since the `filt` keyword argument of this object triggers an
overwrite of the `filt` property for all functors in the collection.
This object also allows a list of refFlags to be passed, and defines a set of default
refFlags that are always included even if not requested.
If a list of `ParquetTable` object is passed, rather than a single one, then the
calculations will be mapped over all the input catalogs. In principle, it should
be straightforward to parallelize this activity, but initial tests have failed
(see TODO in code comments).
Parameters
----------
parq : `lsst.pipe.tasks.ParquetTable` (or list of such)
Source catalog(s) for computation
functors : `list`, `dict`, or `lsst.pipe.tasks.functors.CompositeFunctor`
Computations to do (functors that act on `parq`).
If a dict, the output
DataFrame will have columns keyed accordingly.
If a list, the column keys will come from the
`.shortname` attribute of each functor.
filt : `str` (optional)
Filter in which to calculate. If provided,
this will overwrite any existing `.filt` attribute
of the provided functors.
flags : `list` (optional)
List of flags (per-band) to include in output table.
refFlags : `list` (optional)
List of refFlags (only reference band) to include in output table.
Definition at line 342 of file postprocess.py.