BaseSourceSelectorTask¶

class lsst.meas.algorithms.BaseSourceSelectorTask(**kwargs)¶

Bases: Task

Base class for source selectors

Source selectors are classes that perform a selection on a catalog object given a set of criteria or cuts. They return the selected catalog and can optionally set a specified Flag field in the input catalog to identify if the source was selected.

Register all source selectors with the sourceSelectorRegistry using:: sourceSelectorRegistry.register(name, class)

Attributes:

usesMatchesbool: A boolean variable specify if the inherited source selector uses matches to an external catalog, and thus requires the matches argument to run().

Attributes Summary

usesMatches

Methods Summary

`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.
`run`(sourceCat[, sourceSelectedField, ...])	Select sources and return them.
`selectSources`(sourceCat[, matches, exposure])	Return a selection of sources selected by some criteria.
`timer`(name[, logLevel])	Context manager to log performance data for an arbitrary block of code.

Attributes Documentation

usesMatches = False¶

Methods Documentation

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

getTaskDict() → Dict[str, ReferenceType[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.

run(sourceCat, sourceSelectedField=None, matches=None, exposure=None)¶

Select sources and return them.

The input catalog must be contiguous in memory.

Parameters:

sourceCatVarious table formats: Catalog of sources to select from. Can be lsst.afw.table.SourceCatalog or pandas.DataFrame or astropy.table.Table,
sourceSelectedFieldstr or None: Name of flag field in sourceCat to set for selected sources. If set, will modify sourceCat in-place.
matcheslist of lsst.afw.table.ReferenceMatch or None: List of matches to use for source selection. If usesMatches is set in source selector this field is required. If not, it is ignored.
exposurelsst.afw.image.Exposure or None: The exposure the catalog was built from; used for debug display.

Returns:

structlsst.pipe.base.Struct

The struct contains the following data:

sourceCat: The catalog of sources that were selected. (may not be memory-contiguous) (lsst.afw.table.SourceCatalog or pandas.DataFrame or astropy.table.Table)
selected: Boolean array of sources that were selected, same length as sourceCat. (numpy.ndarray of bool)

Raises:

RuntimeError: Raised if sourceCat is not contiguous.

abstract selectSources(sourceCat, matches=None, exposure=None)¶

Return a selection of sources selected by some criteria.

Parameters:

sourceCatVarious table formats: Catalog of sources to select from. Supports lsst.afw.table.SourceCatalog or pandas.DataFrame or astropy.table.Table This catalog must be contiguous in memory.
matcheslist of lsst.afw.table.ReferenceMatch or None: A list of lsst.afw.table.ReferenceMatch objects
exposurelsst.afw.image.Exposure or None: The exposure the catalog was built from; used for debug display.

Returns:

structlsst.pipe.base.Struct

The struct contains the following data:

selected: Boolean array of sources that were selected, same length as sourceCat. (numpy.ndarray of bool)

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.
logLevel: A logging level constant.

Navigation

BaseSourceSelectorTask¶