MetadataMetricTask¶

class lsst.verify.tasks.MetadataMetricTask(**kwargs)¶

Bases: AbstractMetadataMetricTask

A base class for tasks that compute metrics from single metadata objects.

Parameters:

*args
**kwargs: Constructor parameters are the same as for lsst.pipe.base.PipelineTask.

Notes

This class should be customized by overriding getInputMetadataKeys and makeMeasurement. You should not need to override run.

Attributes Summary

canMultiprocess

Methods Summary

`emptyMetadata`()	Empty (clear) the metadata for this Task and all sub-Tasks.
`extractMetadata`(metadata, metadataKeys)	Read multiple keys from a metadata object.
`getFullMetadata`()	Get metadata for all tasks.
`getFullName`()	Get the task name as a hierarchical name including parent task names.
`getInputMetadataKeys`(config)	Return the metadata keys read by this task.
`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.
`makeMeasurement`(values)	Compute the metric given the values of the metadata.
`makeSubtask`(name, **keyArgs)	Create a subtask as a new instance as the `name` attribute of this task.
`run`(metadata)	Compute a measurement from science task metadata.
`runQuantum`(butlerQC, inputRefs, outputRefs)	Do Butler I/O to provide in-memory objects for run.
`timer`(name[, logLevel])	Context manager to log performance data for an arbitrary block of code.

Attributes Documentation

canMultiprocess: ClassVar[bool] = True¶

Methods Documentation

emptyMetadata() → None¶: Empty (clear) the metadata for this Task and all sub-Tasks.

static extractMetadata(metadata, metadataKeys)¶

Read multiple keys from a metadata object.

Parameters:

metadatalsst.pipe.base.TaskMetadata: A metadata object.
metadataKeysdict [str, str]: Keys are arbitrary labels, values are metadata keys (or their substrings) in the format of lsst.pipe.base.Task.getFullMetadata().

Returns:

metadataValuesdict [str, any]: Keys are the same as for metadataKeys, values are the value of each metadata key, or None if no matching key was found.

Raises:

lsst.verify.tasks.MetricComputationError: Raised if any metadata key string has more than one match in metadata.

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”.

abstract classmethod getInputMetadataKeys(config)¶

Return the metadata keys read by this task.

Parameters:

configcls.ConfigClass: Configuration for this task.

Returns:

keysdict [str, str]: The keys are the (arbitrary) names of values to use in task code, the values are the metadata keys to be looked up (see the metadataKeys parameter to extractMetadata). Metadata keys are assumed to include task prefixes in the format of lsst.pipe.base.Task.getFullMetadata(). This method may return a substring of the desired (full) key, but the string must match a unique metadata key.

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")

abstract makeMeasurement(values)¶

Compute the metric given the values of the metadata.

Parameters:

valuesdict [str, any]: A dict representation of the metadata passed to run. It has the same keys as returned by getInputMetadataKeys, and maps them to the values extracted from the metadata. Any value may be None to represent missing data.

Returns:

measurementlsst.verify.Measurement or None: The measurement corresponding to the input data.

Raises:

lsst.verify.tasks.MetricComputationError: Raised if an algorithmic or system error prevents calculation of the metric. See run for expected behavior.
lsst.pipe.base.NoWorkFound: Raised if the metric is ill-defined or otherwise inapplicable. Typically this means that the pipeline step or option being measured was not run.

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(metadata)¶

Compute a measurement from science task metadata.

Parameters:

metadatalsst.pipe.base.TaskMetadata: A metadata object for the unit of science processing to use for this metric, or a collection of such objects if this task combines many units of processing into a single metric.

Returns:

resultlsst.pipe.base.Struct

A Struct containing the following component:

measurement: the value of the metric (lsst.verify.Measurement or None)

Raises:

lsst.verify.tasks.MetricComputationError: Raised if the strings returned by getInputMetadataKeys match more than one key in any metadata object.
lsst.pipe.base.NoWorkFound: Raised if the metric is ill-defined or otherwise inapplicable. Typically this means that the pipeline step or option being measured was not run.

Notes

This implementation calls getInputMetadataKeys, then searches for matching keys in each metadata. It then passes the values of these keys (or None if no match) to makeMeasurement, and returns its result to the caller.

runQuantum(butlerQC, inputRefs, outputRefs)¶

Do Butler I/O to provide in-memory objects for run.

This specialization of runQuantum performs error-handling specific to MetricTasks.

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

MetadataMetricTask¶