MeasurePsfTask¶
- class lsst.pipe.tasks.measurePsf.MeasurePsfTask(schema=None, **kwargs)¶
Bases:
Task
A task that selects stars from a catalog of sources and uses those to measure the PSF.
- Parameters:
- schema
lsst.sfw.table.Schema
An
lsst.afw.table.Schema
used to create the outputlsst.afw.table.SourceCatalog
.- **kwargs
Keyword arguments passed to lsst.pipe.base.task.Task.__init__.
- schema
Notes
If schema is not None, ‘calib_psf_candidate’ and ‘calib_psf_used’ fields will be added to identify which stars were employed in the PSF estimation.
This task can add fields to the schema, so any code calling this task must ensure that these fields are indeed present in the input table.
The star selector is a subclass of
lsst.meas.algorithms.starSelector.BaseStarSelectorTask
“lsst.meas.algorithms.BaseStarSelectorTask” and the PSF determiner is a sublcass oflsst.meas.algorithms.psfDeterminer.BasePsfDeterminerTask
“lsst.meas.algorithms.BasePsfDeterminerTask”There is no establised set of configuration parameters for these algorithms, so once you start modifying parameters (as we do in @ref pipe_tasks_measurePsf_Example) your code is no longer portable.
Debugging:
- display
If True, display debugging plots
- displayExposure
display the Exposure + spatialCells
- displayPsfCandidates
show mosaic of candidates
- showBadCandidates
Include bad candidates
- displayPsfMosaic
show mosaic of reconstructed PSF(xy)
- displayResiduals
show residuals
- normalizeResiduals
Normalise residuals by object amplitude
Additionally you can enable any debug outputs that your chosen star selector and psf determiner support.
Attributes Summary
Return True if this task makes use of the "matches" argument to the run method
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
Get metadata for all tasks.
Get the task name as a hierarchical name including parent task names.
getName
()Get the name of the task.
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
(exposure, sources[, expId, matches])Measure the PSF.
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
Attributes Documentation
- usesMatches¶
Return True if this task makes use of the “matches” argument to the run method
Methods Documentation
- getFullMetadata() TaskMetadata ¶
Get metadata for all tasks.
- Returns:
- metadata
TaskMetadata
The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.
- metadata
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:
- fullName
str
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”.
- fullName
- getName() str ¶
Get the name of the task.
- Returns:
- taskName
str
Name of the task.
- taskName
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:
- taskDict
dict
Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.
- taskDict
- classmethod makeField(doc: str) ConfigurableField ¶
Make a
lsst.pex.config.ConfigurableField
for this task.- Parameters:
- doc
str
Help text for the field.
- doc
- Returns:
- configurableField
lsst.pex.config.ConfigurableField
A
ConfigurableField
for this task.
- configurableField
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:
- name
str
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
.
- name
Notes
The subtask must be defined by
Task.config.name
, an instance ofConfigurableField
orRegistryField
.
- run(exposure, sources, expId=0, matches=None)¶
Measure the PSF.
- Parameters:
- exposure
lsst.afw.image.Exposure
Exposure to process; measured PSF will be added.
- sources
Unknown
Measured sources on exposure; flag fields will be set marking stars chosen by the star selector and the PSF determiner if a schema was passed to the task constructor.
- expId
int
, optional Exposure id used for generating random seed.
- matches
list
, optional A list of
lsst.afw.table.ReferenceMatch
objects (i.e. oflsst.afw.table.Match
with @c first being of typelsst.afw.table.SimpleRecord
and @c second type lsst.afw.table.SourceRecord — the reference object and detected object respectively) as returned by @em e.g. the AstrometryTask. Used by star selectors that choose to refer to an external catalog.
- exposure
- Returns:
- measurement
lsst.pipe.base.Struct
PSF measurement as a struct with attributes:
psf
The measured PSF (also set in the input exposure).
cellSet
An
lsst.afw.math.SpatialCellSet
containing the PSF candidates as returned by the psf determiner.
- measurement