apache_beam.ml.anomaly.detectors.iqr module

class apache_beam.ml.anomaly.detectors.iqr.IQR(*args, **kwargs)[source]

Bases: AnomalyDetector

Interquartile Range (IQR) anomaly detector.

This class implements an anomaly detection algorithm based on the Interquartile Range (IQR) [1] . It calculates the IQR using quantile trackers for Q1 (25th percentile) and Q3 (75th percentile) and scores data points based on their deviation from these quartiles.

The score is calculated as follows:

  • If a data point is above Q3, the score is (value - Q3) / IQR.

  • If a data point is below Q1, the score is (Q1 - value) / IQR.

  • If a data point is within the IQR (Q1 <= value <= Q3), the score is 0. Initializes the IQR anomaly detector.

Parameters:

  • q1_tracker – Optional QuantileTracker for Q1 (25th percentile). If None, a BufferedSlidingQuantileTracker with a default window size is used.

  • q3_tracker – Optional QuantileTracker for Q3 (75th percentile). If None, a SecondaryBufferedQuantileTracker based on q1_tracker is used.

  • threshold_criterion – Optional ThresholdFn to apply on the score. Defaults to FixedThreshold(1.5) since outliers are commonly defined as data points that fall below Q1 - 1.5 IQR or above Q3 + 1.5 IQR.

  • **kwargs – Additional keyword arguments.

learn_one(x: Row) → None[source]

Updates the quantile trackers with a new data point.

Parameters:

x – A beam.Row containing a single numerical value.

score_one(x: Row) → float | None[source]

Scores a data point based on its deviation from the IQR.

Parameters:

x – A beam.Row containing a single numerical value.

Returns:

The anomaly score.

Return type:

float | None

IQR__spec_type = 'IQR'
classmethod from_spec(spec: Spec, _run_init: bool = True) → Self | type[Self]

Generate a Specifiable subclass object based on a spec.

Parameters:

  • spec – the specification of a Specifiable subclass object

  • _run_init – whether to call __init__ or not for the initial instantiation

Returns:

the Specifiable subclass object

Return type:

Self

run_original_init() → None

Execute the original __init__ method with its saved arguments.

For instances of the Specifiable class, initialization is deferred (lazy initialization). This function forces the execution of the original __init__ method using the arguments captured during the object’s initial instantiation.

classmethod spec_type()
to_spec() → Spec

Generate a spec from a Specifiable subclass object.

Returns:

The specification of the instance.

Return type:

Spec

classmethod unspecifiable()