Lolo is a random forest-centered machine learning library in Scala.
The core of Lolo is bagging simple base learners, like decision trees, to produce models that can generate robust uncertainty estimates.
Lolo supports:
Lolo is on the central repository, and can be used by simply adding the following dependency block in your pom file:
<dependency>
<groupId>io.citrine</groupId>
<artifactId>lolo</artifactId>
<version>6.0.0</version>
</dependency>
Lolo provides higher level wrappers for common learner combinations. For example, you can use Random Forest with:
import io.citrine.lolo.learners.RandomForestRegressor
val trainingData: Seq[TrainingRow[Double]] = TrainingRow.build(features.zip(labels))
val model = RandomForestRegressor().train(trainingData).model
val predictions: Seq[Double] = model.transform(testInputs).expected
Lolo prioritizes functionality over performance, but it is still quite fast. In its random forest use case, the complexity scales as:
Time complexity | Training rows | Features | Trees |
---|---|---|---|
train |
O(n log n) | O(n) | O(n) |
loss |
O(n log n) | O(n) | O(n) |
expected |
O(log n) | O(1) | O(n) |
uncertainty |
O(n) | O(1) | O(n) |
On an Ivy Bridge test platform, the (1024 row, 1024 tree, 8 feature) performance test took 1.4 sec to train and 2.3 ms per prediction with uncertainty.
We welcome bug reports, feature requests, and pull requests.
Pull requests should be made following the feature branch workflow: branching off of and opening PRs into main
.
Production releases are triggered by tags.
The sbt-ci-release plugin will use the tag as the lolo
version.
On the other hand, lolopy
versions are still read from setup.py
, so version bumps are needed for successful releases.
Failing to bump the lolopy
version number will result in a skipped lolopy
release rather than a build failure.
sbt scalafmtCheckAll
.
This will check whether any files need to be reformatted.
Pull requests are gated on this running successfully.
You can automatically check whether code is formatted properly before pushing to an upstream repository using a git hook.
To set this up, install the pre-commit framework by following the instructions here.
Then enable the hooks in .pre-commit-config.yaml
by running pre-commit install --hook-type pre-push
from the root directory.
This will run scalafmtCheckAll
before pushing to a remote repo.sbt scalafmtAll
from the command line or configure your IDE to format files on save.See Contributors