Questions tagged [isolation-forest]

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Meaning Of The Terms In Isolation Forest Anomaly Scoring

In an isolation forest the anomaly score of a point is given by: $$2^{\frac{-E(h(x))}{c(m)}}$$ Now supposedly c(m) is the average length to termination in the search tree. And, E(h(x)) is the ...
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Isolation forest with categorical data?

I understand how isolation forests can work with numeric data, but I wonder how it can work with categorical data? Also, at least when working with Sci-kit-Learn, the recommendation I saw was to ...
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Discordance between various methods of multivariate outliers detection

Here is a small "toy example" dataset, with 15 individuals described by 6 variables (this is R language): ...
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Oversampling/Undersampling in respect to Train and Test - Isolation Forest

I've got a quite imbalanced data set. 144.496 : 162 -> ratio of 1000:1 I would like to use IsolationForest to detect the 162 anomalys. I've already split the data. However, the iForest doesn't ...