lsst.pipe.tasks  21.0.0-151-g12957622+e8b61e2e81
Public Member Functions | Public Attributes | List of all members
lsst.pipe.tasks.functors.Functor Class Reference
Inheritance diagram for lsst.pipe.tasks.functors.Functor:
lsst.pipe.tasks.functors.Color lsst.pipe.tasks.functors.Column lsst.pipe.tasks.functors.CompositeFunctor lsst.pipe.tasks.functors.CustomFunctor lsst.pipe.tasks.functors.DeconvolvedMoments lsst.pipe.tasks.functors.E1 lsst.pipe.tasks.functors.E2 lsst.pipe.tasks.functors.HsmFwhm lsst.pipe.tasks.functors.HsmTraceSize lsst.pipe.tasks.functors.HtmIndex20 lsst.pipe.tasks.functors.Index lsst.pipe.tasks.functors.Labeller lsst.pipe.tasks.functors.LocalPhotometry lsst.pipe.tasks.functors.LocalWcs lsst.pipe.tasks.functors.Mag lsst.pipe.tasks.functors.MagDiff lsst.pipe.tasks.functors.Photometry lsst.pipe.tasks.functors.PsfHsmTraceSizeDiff lsst.pipe.tasks.functors.PsfSdssTraceSizeDiff lsst.pipe.tasks.functors.RadiusFromQuadrupole lsst.pipe.tasks.functors.Ratio lsst.pipe.tasks.functors.ReferenceBand lsst.pipe.tasks.functors.SdssTraceSize

Public Member Functions

def __init__ (self, filt=None, dataset=None, noDup=None)
 
def noDup (self)
 
def columns (self)
 
def multilevelColumns (self, data, columnIndex=None, returnTuple=False)
 
def __call__ (self, data, dropna=False)
 
def difference (self, data1, data2, **kwargs)
 
def fail (self, df)
 
def name (self)
 
def shortname (self)
 

Public Attributes

 filt
 
 dataset
 

Detailed Description

Define and execute a calculation on a ParquetTable

The `__call__` method accepts either a `ParquetTable` object or a
`DeferredDatasetHandle`, and returns the
result of the calculation as a single column.  Each functor defines what
columns are needed for the calculation, and only these columns are read
from the `ParquetTable`.

The action of  `__call__` consists of two steps: first, loading the
necessary columns from disk into memory as a `pandas.DataFrame` object;
and second, performing the computation on this dataframe and returning the
result.


To define a new `Functor`, a subclass must define a `_func` method,
that takes a `pandas.DataFrame` and returns result in a `pandas.Series`.
In addition, it must define the following attributes

* `_columns`: The columns necessary to perform the calculation
* `name`: A name appropriate for a figure axis label
* `shortname`: A name appropriate for use as a dictionary key

On initialization, a `Functor` should declare what band (`filt` kwarg)
and dataset (e.g. `'ref'`, `'meas'`, `'forced_src'`) it is intended to be
applied to. This enables the `_get_data` method to extract the proper
columns from the parquet file. If not specified, the dataset will fall back
on the `_defaultDataset`attribute. If band is not specified and `dataset`
is anything other than `'ref'`, then an error will be raised when trying to
perform the calculation.

Originally, `Functor` was set up to expect
datasets formatted like the `deepCoadd_obj` dataset; that is, a
dataframe with a multi-level column index, with the levels of the
column index being `band`, `dataset`, and `column`.
It has since been generalized to apply to dataframes without mutli-level
indices and multi-level indices with just `dataset` and `column` levels.
In addition, the `_get_data` method that reads
the dataframe from the `ParquetTable` will return a dataframe with column
index levels defined by the `_dfLevels` attribute; by default, this is
`column`.

The `_dfLevels` attributes should generally not need to
be changed, unless `_func` needs columns from multiple filters or datasets
to do the calculation.
An example of this is the `lsst.pipe.tasks.functors.Color` functor, for
which `_dfLevels = ('band', 'column')`, and `_func` expects the dataframe
it gets to have those levels in the column index.

Parameters
----------
filt : str
    Filter upon which to do the calculation

dataset : str
    Dataset upon which to do the calculation
    (e.g., 'ref', 'meas', 'forced_src').

Definition at line 78 of file functors.py.

Constructor & Destructor Documentation

◆ __init__()

def lsst.pipe.tasks.functors.Functor.__init__ (   self,
  filt = None,
  dataset = None,
  noDup = None 
)

Definition at line 142 of file functors.py.

Member Function Documentation

◆ __call__()

def lsst.pipe.tasks.functors.Functor.__call__ (   self,
  data,
  dropna = False 
)

Definition at line 340 of file functors.py.

◆ columns()

def lsst.pipe.tasks.functors.Functor.columns (   self)

◆ difference()

def lsst.pipe.tasks.functors.Functor.difference (   self,
  data1,
  data2,
**  kwargs 
)
Computes difference between functor called on two different ParquetTable objects

Definition at line 351 of file functors.py.

◆ fail()

def lsst.pipe.tasks.functors.Functor.fail (   self,
  df 
)

Definition at line 356 of file functors.py.

◆ multilevelColumns()

def lsst.pipe.tasks.functors.Functor.multilevelColumns (   self,
  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.

Definition at line 229 of file functors.py.

◆ name()

def lsst.pipe.tasks.functors.Functor.name (   self)

◆ noDup()

def lsst.pipe.tasks.functors.Functor.noDup (   self)

Definition at line 148 of file functors.py.

◆ shortname()

def lsst.pipe.tasks.functors.Functor.shortname (   self)
Short name of functor (suitable for column name/dict key)

Reimplemented in lsst.pipe.tasks.functors.Color, and lsst.pipe.tasks.functors.MagDiff.

Definition at line 366 of file functors.py.

Member Data Documentation

◆ dataset

lsst.pipe.tasks.functors.Functor.dataset

Definition at line 144 of file functors.py.

◆ filt

lsst.pipe.tasks.functors.Functor.filt

Definition at line 143 of file functors.py.


The documentation for this class was generated from the following file: