lsst.meas.base.classification.CatalogCalculationClassificationPlugin Class Reference

Inheritance diagram for lsst.meas.base.classification.CatalogCalculationClassificationPlugin:

Public Member Functions
	getExecutionOrder (cls)
	__init__ (self, config, name, schema, metadata)
	calculate (self, measRecord)
	fail (self, measRecord, error=None)

Public Attributes
	keyProbability
	keyFlag

Static Public Attributes
	ConfigClass = CatalogCalculationClassificationConfig

Detailed Description

Plugin which calculates a binary measure of source extendedness.

Extendedness is based on a simple cut of the ratio of the PSF flux to the
model flux.

Notes
-----
Because the fluxes on which this algorithm is based on are slot
measurements, they can be provided by different algorithms, and the
`~CatalogCalculationClassificationConfig.fluxRatio` threshold used by this
algorithm should generally be set differently for different algorithms.
To do this, plot the difference between the PSF magnitude and the model
magnitude vs. the PSF magnitude, and look for where the cloud of galaxies
begins.

Definition at line 49 of file classification.py.

Constructor & Destructor Documentation

__init__()

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.__init__	(		self,
			config,
			name,
			schema,
			metadata )

Reimplemented from lsst.meas.base.catalogCalculation.CatalogCalculationPlugin.

Definition at line 72 of file classification.py.

    def __init__(self, config, name, schema, metadata):
        CatalogCalculationPlugin.__init__(self, config, name, schema, metadata)
        self.keyProbability = schema.addField(name + "_value", type="D",
                                              doc="Set to 1 for extended sources, 0 for point sources.")
        self.keyFlag = schema.addField(name + "_flag", type="Flag", doc="Set to 1 for any fatal failure.")
 

Member Function Documentation

calculate()

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.calculate	(		self,
			cat )

Perform the calculation specified by this plugin.

This method can either be used to operate on a single catalog record
or a whole catalog, populating it with the output defined by this
plugin.

Note that results may be added to catalog records as new columns, or
may result in changes to existing values.

Parameters
----------
cat : `lsst.afw.table.SourceCatalog` or `lsst.afw.table.SourceRecord`
    May either be a `~lsst.afw.table.SourceCatalog` or a single
    `~lsst.afw.table.SourceRecord`, depending on the plugin type. Will
    be updated in place to contain the results of plugin execution.
**kwargs
    Any additional keyword arguments that may be passed to the plugin.

Reimplemented from lsst.meas.base.catalogCalculation.CatalogCalculationPlugin.

Definition at line 78 of file classification.py.

    def calculate(self, measRecord):
        modelFlux = measRecord.getModelInstFlux()
        psfFlux = measRecord.getPsfInstFlux()
        modelFluxFlag = (measRecord.getModelFluxFlag()
                         if measRecord.table.getModelFluxSlot().isValid()
                         else False)
        psfFluxFlag = (measRecord.getPsfFluxFlag()
                       if measRecord.table.getPsfFluxSlot().isValid()
                       else False)
        flux1 = self.config.fluxRatio*modelFlux
        if self.config.modelErrFactor != 0:
            flux1 += self.config.modelErrFactor*measRecord.getModelInstFluxErr()
        flux2 = psfFlux
        if not self.config.psfErrFactor == 0:
            flux2 += self.config.psfErrFactor*measRecord.getPsfInstFluxErr()
 
        # A generic failure occurs when either FluxFlag is set to True
        # A generic failure also occurs if either calculated flux value is NaN:
        #     this can occur if the Flux field itself is NaN,
        #     or the ErrFactor != 0 and the FluxErr is NaN
        if np.isnan(flux1) or np.isnan(flux2) or modelFluxFlag or psfFluxFlag:
            self.fail(measRecord)
        else:
            measRecord.set(self.keyProbability, 0.0 if flux1 < flux2 else 1.0)
 

fail()

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.fail	(		self,
			measRecord,
			error = None )

Record a failure of the `measure` or `measureN` method.

Parameters
----------
measRecord : `lsst.afw.table.SourceRecord`
    Table record describing the source being measured.
error : `MeasurementError`, optional
    Only provided if the measurement failed due to a
    `MeasurementError` being raised; otherwise, will be `None`.

Notes
-----
When the plugin raises an exception, framework will call
`BasePlugin.fail` to allow the plugin to set its failure flag
field(s).  When `BasePlugin.measureN` raises an exception,
`BasePlugin.fail` will be called repeatedly with all the records that
were being measured.

If the exception is an `MeasurementError`, it will be passed as the
error argument; in all other cases the error argument will be `None`,
and the failure will be logged by the measurement framework as a
warning.

Reimplemented from lsst.meas.base.pluginsBase.BasePlugin.

Definition at line 103 of file classification.py.

    def fail(self, measRecord, error=None):
        measRecord.set(self.keyFlag, True)

getExecutionOrder()

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.getExecutionOrder

(

cls

)

Used to set the relative order of plugin execution.

    The values returned by `getExecutionOrder` are compared across all
    plugins, and smaller numbers run first.

    Notes
    -----
    `CatalogCalculationPlugin`\s must run with
    `BasePlugin.DEFAULT_CATALOGCALCULATION` or higher.

    All plugins must implement this method with an appropriate run level

Reimplemented from lsst.meas.base.catalogCalculation.CatalogCalculationPlugin.

Definition at line 69 of file classification.py.

    def getExecutionOrder(cls):
        return cls.DEFAULT_CATALOGCALCULATION
 

Member Data Documentation

ConfigClass

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.ConfigClass = CatalogCalculationClassificationConfig

static

Definition at line 66 of file classification.py.

keyFlag

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.keyFlag

Definition at line 76 of file classification.py.

keyProbability

lsst.meas.base.classification.CatalogCalculationClassificationPlugin.keyProbability

Definition at line 74 of file classification.py.

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/meas_base/gf18bd8381d+7268b93478/python/lsst/meas/base/classification.py