DefineVisitsTask

class lsst.obs.base.DefineVisitsTask(config: Optional[lsst.obs.base.defineVisits.DefineVisitsConfig] = None, *, butler: lsst.daf.butler._butler.Butler, **kwargs)

Bases: lsst.pipe.base.Task

Driver Task for defining visits (and their spatial regions) in Gen3 Butler repositories.

Parameters:
config : DefineVisitsConfig

Configuration for the task.

butler : Butler

Writeable butler instance. Will be used to read raw.wcs and camera datasets and insert/sync dimension data.

**kwargs

Additional keyword arguments are forwarded to the lsst.pipe.base.Task constructor.

Notes

Each instance of DefineVisitsTask reads from / writes to the same Butler. Each invocation of DefineVisitsTask.run processes an independent group of exposures into one or more new vists, all belonging to the same visit system and instrument.

The actual work of grouping exposures and computing regions is delegated to pluggable subtasks (GroupExposuresTask and ComputeVisitRegionsTask), respectively. The defaults are to create one visit for every exposure, and to use exactly one (arbitrary) detector-level raw dataset’s WCS along with camera geometry to compute regions for all detectors. Other implementations can be created and configured for instruments for which these choices are unsuitable (e.g. because visits and exposures are not one-to-one, or because raw.wcs datasets for different detectors may not be consistent with camera geomery).

It is not necessary in general to ingest all raws for an exposure before defining a visit that includes the exposure; this depends entirely on the ComputeVisitRegionTask subclass used. For the default configuration, a single raw for each exposure is sufficient.

Defining the same visit the same way multiple times (e.g. via multiple invocations of this task on the same exposures, with the same configuration) is safe, but it may be inefficient, as most of the work must be done before new visits can be compared to existing visits.

Methods Summary

emptyMetadata() Empty (clear) the metadata for this Task and all sub-Tasks.
getAllSchemaCatalogs() Get schema catalogs for all tasks in the hierarchy, combining the results into a single dict.
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.
getSchemaCatalogs() Get the schemas generated by this 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(dataIds, Mapping[str, Any]]], *, pool, …) Add visit definitions to the registry for the given exposures.
timer(name[, logLevel]) Context manager to log performance data for an arbitrary block of code.

Methods Documentation

emptyMetadata()

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

getAllSchemaCatalogs()

Get schema catalogs for all tasks in the hierarchy, combining the results into a single dict.

Returns:
schemacatalogs : dict

Keys are butler dataset type, values are a empty catalog (an instance of the appropriate lsst.afw.table Catalog type) for all tasks in the hierarchy, from the top-level task down through all subtasks.

Notes

This method may be called on any task in the hierarchy; it will return the same answer, regardless.

The default implementation should always suffice. If your subtask uses schemas the override Task.getSchemaCatalogs, not this method.

getFullMetadata()

Get metadata for all tasks.

Returns:
metadata : lsst.daf.base.PropertySet

The PropertySet 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()

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”.
getName()

Get the name of the task.

Returns:
taskName : str

Name of the task.

See also

getFullName
getSchemaCatalogs()

Get the schemas generated by this task.

Returns:
schemaCatalogs : dict

Keys are butler dataset type, values are an empty catalog (an instance of the appropriate lsst.afw.table Catalog type) for this task.

See also

Task.getAllSchemaCatalogs

Notes

Warning

Subclasses that use schemas must override this method. The default implementation returns an empty dict.

This method may be called at any time after the Task is constructed, which means that all task schemas should be computed at construction time, not when data is actually processed. This reflects the philosophy that the schema should not depend on the data.

Returning catalogs rather than just schemas allows us to save e.g. slots for SourceCatalog as well.

getTaskDict()

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.

classmethod makeField(doc)

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

Parameters:
doc : str

Help text for the field.

Returns:
configurableField : lsst.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, **keyArgs)

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”.

Notes

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

run(dataIds: Iterable[Union[lsst.daf.butler.core.dimensions._coordinate.DataCoordinate, Mapping[str, Any]]], *, pool: Optional[multiprocessing.context.BaseContext.Pool] = None, processes: int = 1, collections: Optional[str] = None, update_records: bool = False)

Add visit definitions to the registry for the given exposures.

Parameters:
dataIds : Iterable [ dict or DataCoordinate ]

Exposure-level data IDs. These must all correspond to the same instrument, and are expected to be on-sky science exposures.

pool : multiprocessing.Pool, optional

If not None, a process pool with which to parallelize some operations.

processes : int, optional

The number of processes to use. Ignored if pool is not None.

collections : Any, optional

Collections to be searched for raws and camera geometry, overriding self.butler.collections. Can be any of the types supported by the collections argument to butler construction.

update_records : bool, optional

If True (False is default), update existing visit records that conflict with the new ones instead of rejecting them (and when this occurs, update visit_detector_region as well). THIS IS AN ADVANCED OPTION THAT SHOULD ONLY BE USED TO FIX REGIONS AND/OR METADATA THAT ARE KNOWN TO BE BAD, AND IT CANNOT BE USED TO REMOVE EXPOSURES OR DETECTORS FROM A VISIT.

Raises:
lsst.daf.butler.registry.ConflictingDefinitionError

Raised if a visit ID conflict is detected and the existing visit differs from the new one.

timer(name, logLevel=10)

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

Parameters:
name : str

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

logLevel

A logging level constant.

See also

timer.logInfo

Examples

Creating a timer context:

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