Metric¶

class lsst.verify.Metric(name, description, unit, tags=None, reference_doc=None, reference_url=None, reference_page=None)¶

Container for the definition of a metric.

Metrics can either be instantiated programatically, or from a metric YAML file through lsst.verify.MetricSet.

Parameters:

name : str: Name of the metric (e.g., 'PA1').
description : str: Short description about the metric.
unit : str or astropy.units.Unit: Units of the metric. Measurements of this metric must be in an equivalent (that is, convertable) unit. Argument can either be an astropy.unit.Unit instance, or a Unit-compatible string representation. Use an empty string, '', or astropy.units.dimensionless_unscaled for a unitless quantity.
tags : list of str: Tags associated with this metric. Tags are user-submitted string tokens that are used to group metrics.
reference_doc : str, optional: The document handle that originally defined the metric (e.g., 'LPM-17').
reference_url : str, optional: The document’s URL.
reference_page : str, optional: Page where metric in defined in the reference document.

Attributes Summary

`description`	Short description of the metric (`str`).
`json`	`dict` that can be serialized as semantic JSON, compatible with the SQUASH metric service.
`name`	Metric’s name (`Name`).
`reference`	Documentation reference as human-readable text (`str`, read-only).
`reference_doc`	Name of the document that specifies this metric (`str`).
`reference_page`	Page number in the document that specifies this metric (`int`).
`reference_url`	URL of the document that specifies this metric (`str`).
`tags`	Tag labels (`set` of `str`).
`unit`	The metric’s unit (`astropy.units.Unit`).
`unit_str`	The string representation of the metric’s unit (`Unit`-compatible `str`).

Methods Summary

`check_unit`(quantity)	Check that a `Quantity` has equivalent units to this metric.
`deserialize`([name, description, unit, tags, …])	Create a Metric instance from a parsed YAML/JSON document.
`jsonify_dict`(d)	Recursively build JSON-renderable objects on all values in a dict.
`write_json`(filepath)	Write JSON to a file.

Attributes Documentation

json¶: dict that can be serialized as semantic JSON, compatible with the SQUASH metric service.

reference¶

Documentation reference as human-readable text (str, read-only).

reference_doc = None¶: Name of the document that specifies this metric (str).

reference_page = None¶: Page number in the document that specifies this metric (int).

reference_url = None¶: URL of the document that specifies this metric (str).

unit_str¶: The string representation of the metric’s unit (Unit-compatible str).

Methods Documentation

check_unit(quantity)¶

Check that a Quantity has equivalent units to this metric.

Parameters:	quantity : `astropy.units.Quantity` Quantity to be tested.
Returns:	is_equivalent : `bool` `True` if the units are equivalent, meaning that the quantity can be presented in the units of this metric. `False` if not.

classmethod deserialize(name=None, description=None, unit=None, tags=None, reference=None)¶

Create a Metric instance from a parsed YAML/JSON document.

Parameters:	kwargs : `dict` Keyword arguments that match fields from the `Metric.json` serialization.
Returns:	metric : `Metric` A Metric instance.

static jsonify_dict(d)¶

Recursively build JSON-renderable objects on all values in a dict.

Parameters:	d : `dict` Dictionary to convert into a JSON-serializable object. Values are recursively JSON-ified.
Returns:	json_dict : `dict` Dictionary that can be serialized to JSON.

Examples

Subclasses can use this method to prepare output in their json-method implementation. For example:

def json(self):
    return JsonSerializationMixin.jsonify_dict({
        'value': self.value,
    })

write_json(filepath)¶

Write JSON to a file.

Parameters:	filepath : `str` Destination file name for JSON output.