isotree.build.indexer

Builds an index of terminal nodes for faster prediction of terminal node numbers
(calling `predict` with `type="tree_num"`).
Optionally, can also pre-calculate terminal node distances in order to speed up
distance calculations (calling `predict` with `type="dist"` or `type="avg_sep"`).

Fast and multi-threaded implementation of
isolation forest (Liu, Ting, Zhou (2008) <doi:10.1109/ICDM.2008.17>),
extended isolation forest (Hariri, Kind, Brunner (2018) <arXiv:1811.02141>),
SCiForest (Liu, Ting, Zhou (2010) <doi:10.1007/978-3-642-15883-4_18>),
fair-cut forest (Cortes (2021) <arXiv:2110:13402>),
robust random-cut forest (Guha, Mishra, Roy, Schrijvers (2016) <http://proceedings.mlr.press/v48/guha16.html>),
and customizable variations of them, for isolation-based outlier detection, clustered outlier detection,
distance or similarity approximation (Cortes (2019) <arXiv:1910.12362>),
isolation kernel calculation (Ting, Zhu, Zhou (2018) <doi:10.1145/3219819.3219990>),
and imputation of missing values (Cortes (2019) <arXiv:1911.06646>),
based on random or guided decision tree splitting, and providing different metrics for
scoring anomalies based on isolation depth or density (Cortes (2021) <arXiv:2111.11639>).
Provides simple heuristics for fitting the model to categorical columns and handling missing data,
and offers options for varying between random and guided splits, and for using different splitting criteria.

David Cortes

isotree

Isolation-Based Outlier Detection

Thibaut Goetghebuer-Planchon

David Blackman

Sebastiano Vigna

NumPy Developers

isotree.build.indexer function

<dl><dt>model</dt>
<dd>An Isolation Forest model (as returned by function isolation.forest)
for which an indexer for terminal node numbers and/or distances will be added.
The object will be modified in-place.</dd>
<dt>with_distances</dt>
<dd>Whether to also pre-calculate node distances in order to speed up
`predict` with `type="dist"` or `type="avg_sep"`.
Note that this will consume a lot more memory and make the resulting object significantly
heavier.</dd></dl>

Arguments

Build Indexer for Faster Terminal Node Predictions and/or Distance Calculations — isotree.build.indexer

<dl>

<dt>model</dt>
<dd>An Isolation Forest model (as returned by function isolation.forest)
for which an indexer for terminal node numbers and/or distances will be added.
The object will be modified in-place.</dd>


<dt>with_distances</dt>
<dd>Whether to also pre-calculate node distances in order to speed up
`predict` with `type="dist"` or `type="avg_sep"`.
Note that this will consume a lot more memory and make the resulting object significantly
heavier.</dd>

</dl>

isotree.build.indexer: Build Indexer for Faster Terminal Node Predictions and/or Distance Calculations

Description

Usage

Value

Arguments

Details

See Also