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Possible issue for IsolationForest Division by zero #353
Description
Hello,
I'm trying to use IsolationForest.
$dataset = new CSV('test.csv', false);
$dataset = Unlabeled::fromIterator($dataset);
$oneHotEncoder = new OneHotEncoder();
$dataset->apply($oneHotEncoder);
$estimator = new IsolationForest(2, 0.1, 0.5);
$estimator->train($dataset);
There is an exemple of the csv content. In reality I have more than 1000 lines
1,1,46,3,1
1,1,58,6,3
2,5,52,3,1
1,11,52,3,3
2,11,52,6,3
3,1,46,3,1
3,1,58,6,3
3,11,52,3,3
And I have this issue
In IsolationForest.php line 311:
Division by zero
Is there a problem with the code or with my data?
Thx
Activity
andrewdalpino commentedon Mar 17, 2025
Hey @indianalalal there's no need to one-hot encode your categorical features with IsolationForest since it's compatible with categorical features. The division by zero is because there managed to be a split of samples where all features for the randomly selected continuous column were zero. This could be related to your one-hot encoding.