BasePsfDeterminerTask

class lsst.meas.algorithms.BasePsfDeterminerTask(config, schema=None, **kwds)

Bases: Task

Base class for PSF determiners

Register all PSF determiners with the psfDeterminerRegistry using:

psfDeterminerRegistry.register(name, class)

Parameters:
configlsst.pexConfig.Config

Input for configuring the algorithm

schemalsst.afw.table.Schema

Schema used for sources; passing a schema allows the determiner to reserve a flag field to mark stars used in PSF measurement, but some PSF determiners ignore this argument.

Attributes Summary

usesMatches

Methods Summary

determinePsf(exposure, psfCandidateList[, ...])

Determine a PSF model.

downsampleCandidates(inputCandidateList)

Down-sample candidates from the input candidate list.

emptyMetadata()

Empty (clear) the metadata for this Task and all sub-Tasks.

getFullMetadata()

Get metadata for all tasks.

getFullName()

Get the task name as a hierarchical name including parent task names.

getName()

Get the name of the task.

getTaskDict()

Get a dictionary of all tasks as a shallow copy.

makeField(doc)

Make a lsst.pex.config.ConfigurableField for this task.

makeSubtask(name, **keyArgs)

Create a subtask as a new instance as the name attribute of this task.

timer(name[, logLevel])

Context manager to log performance data for an arbitrary block of code.

Attributes Documentation

usesMatches = False

Methods Documentation

abstract determinePsf(exposure, psfCandidateList, metadata=None, flagKey=None)

Determine a PSF model.

Parameters:
exposurelsst.afw.Exposure

Exposure containing the psf candidates.

psdCandidateListlist [lsst.meas.algorithms.PsfCandidate]

A sequence of PSF candidates; typically obtained by detecting sources and then running them through a star selector.

metadatastr, optional

A place to save interesting items.

flagKey: `lsst.afw.table.Key`, optional

Schema key used to mark sources actually used in PSF determination.

Returns:
psflsst.afw.detection.Psf

The fit PSF.

cellSetlsst.afw.math.SpatialCellSet

The spatial cell set used to determine the PSF

downsampleCandidates(inputCandidateList)

Down-sample candidates from the input candidate list.

Parameters:
inputCandidateListlist [lsst.meas.algorithms.PsfCandidate]

Input candidate list.

Returns:
outputCandidateListlist [lsst.meas.algorithms.PsfCandidate]

Down-selected candidate list.

emptyMetadata() None

Empty (clear) the metadata for this Task and all sub-Tasks.

getFullMetadata() TaskMetadata

Get metadata for all tasks.

Returns:
metadataTaskMetadata

The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.

Notes

The returned metadata includes timing information (if @timer.timeMethod is used) and any metadata set by the task. The name of each item consists of the full task name with . replaced by :, followed by . and the name of the item, e.g.:

topLevelTaskName:subtaskName:subsubtaskName.itemName

using : in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.

getFullName() str

Get the task name as a hierarchical name including parent task names.

Returns:
fullNamestr

The full name consists of the name of the parent task and each subtask separated by periods. For example:

  • The full name of top-level task “top” is simply “top”.

  • The full name of subtask “sub” of top-level task “top” is “top.sub”.

  • The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.

getName() str

Get the name of the task.

Returns:
taskNamestr

Name of the task.

See also

getFullName

Get the full name of the task.

getTaskDict() dict[str, weakref.ReferenceType[lsst.pipe.base.task.Task]]

Get a dictionary of all tasks as a shallow copy.

Returns:
taskDictdict

Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.

classmethod makeField(doc: str) ConfigurableField

Make a lsst.pex.config.ConfigurableField for this task.

Parameters:
docstr

Help text for the field.

Returns:
configurableFieldlsst.pex.config.ConfigurableField

A ConfigurableField for this task.

Examples

Provides a convenient way to specify this task is a subtask of another task.

Here is an example of use:

class OtherTaskConfig(lsst.pex.config.Config):
    aSubtask = ATaskClass.makeField("brief description of task")
makeSubtask(name: str, **keyArgs: Any) None

Create a subtask as a new instance as the name attribute of this task.

Parameters:
namestr

Brief name of the subtask.

**keyArgs

Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:

  • config.

  • parentTask.

Notes

The subtask must be defined by Task.config.name, an instance of ConfigurableField or RegistryField.

timer(name: str, logLevel: int = 10) Iterator[None]

Context manager to log performance data for an arbitrary block of code.

Parameters:
namestr

Name of code being timed; data will be logged using item name: Start and End.

logLevelint

A logging level constant.

See also

lsst.utils.timer.logInfo

Implementation function.

Examples

Creating a timer context:

with self.timer("someCodeToTime"):
    pass  # code to time