pysad.models.LocalOutlierProbability

class pysad.models.LocalOutlierProbability(initial_X, num_neighbors=10, extent=3)[source]

The implementation of streaming Local Outlier Probabilities method [BKKrogerSZ09], which uses the implementation of PyNomaly library [BCon18].

Parameters
  • initial_X (np.float array of shape (num_instances, num_features)) – Initial training data to calibrate the model.

  • num_neighbors (int) – Number of neighbors (Default=10).

  • extent (int) – an integer value that controls the statistical extent, e.g. lambda times the standard deviation from the mean (optional, default 3)

  • n_neighbors (int) – the total number of neighbors to consider w.r.t. each sample (optional, default 10)

Methods

__init__(initial_X[, num_neighbors, extent])

Initialize self.

fit(X[, y])

Fits the model to all instances in order.

fit_partial(X[, y])

Fits the model to next instance.

fit_score(X[, y])

This helper method applies fit_score_partial to all instances in order.

fit_score_partial(X[, y])

Applies fit_partial and score_partial to the next instance, respectively.

score(X)

Scores all instaces via score_partial iteratively.

score_partial(X)

Scores the anomalousness of the next instance.

fit(X, y=None)

Fits the model to all instances in order.

Parameters
  • X (np.float array of shape (num_instances, num_features)) – The instances in order to fit.

  • y (int) – The labels of the instances in order to fit (Optional for unsupervised models, default=None).

Returns

Fitted model.

Return type

object

fit_partial(X, y=None)[source]

Fits the model to next instance.

Parameters
  • X (np.float array of shape (num_features,)) – The instance to fit.

  • y (int) – Ignored since the model is unsupervised (Default=None).

Returns

self.

Return type

object

fit_score(X, y=None)

This helper method applies fit_score_partial to all instances in order.

Parameters
  • X (np.float array of shape (num_instances, num_features)) – The instances in order to fit.

  • y (np.int array of shape (num_instances, )) – The labels of the instances in order to fit (Optional for unsupervised models, default=None).

Returns

The anomalousness scores of the instances in order.

Return type

np.float array of shape (num_instances,)

fit_score_partial(X, y=None)

Applies fit_partial and score_partial to the next instance, respectively.

Parameters
  • X (np.float array of shape (num_features,)) – The instance to fit and score.

  • y (int) – The label of the instance (Optional for unsupervised models, default=None).

Returns

The anomalousness score of the input instance.

Return type

float

score(X)

Scores all instaces via score_partial iteratively.

Parameters

X (np.float array of shape (num_instances, num_features)) – The instances in order to score.

Returns

The anomalousness scores of the instances in order.

Return type

np.float array of shape (num_instances,)

score_partial(X)[source]

Scores the anomalousness of the next instance.

Parameters

X (np.float array of shape (num_features,)) – The instance to score. Higher scores represent more anomalous instances whereas lower scores correspond to more normal instances.

Returns

The anomalousness score of the input instance.

Return type

float