[R] Isolation forest using "solitude" package: help to predict

Johan Lassen joh@n|@@@en @end|ng |rom gm@||@com
Wed Aug 14 11:23:26 CEST 2019

Dear community,

I would like to know if someone can help clarifying how to predict anomaly
scores on new data sets using the "solitude" package. A simple model can be
trained using:

# Training the model:
iris_train <- iris[1:100, ]
model <- isolation_forest(iris_train[, 1:4], seed =

# The anomaly scores of a new test data set can be calculated by
iris_test <- iris[100:150, ]
predicted_anomalies <- predict(mo, iris_test[, 1:4],type="anomaly_score")

#The challenge is how to predict the anomaly scores for a data set with
less observations than the #number of observations in the training data
# Example: using a subset of just 11 observations as compared to the 51
observations results in anomaly scores that are smaller:

iris_test <- iris[100:110, ]
predicted_anomalies <- predict(mo, iris_test[, 1:4],type="anomaly_score")

Anyone knows how to predict "normalised (with respect to sample size)"
anomaly scores using the solitude package for R?

Thanks in advance!

Johan Lassen

"In the cities people live in time -
in the mountains people live in space" (Budistisk munk).

	[[alternative HTML version deleted]]

More information about the R-help mailing list