mlr-org / mlr3book

Online version of Bischl, B., Sonabend, R., Kotthoff, L., & Lang, M. (Eds.). (2024). "Applied Machine Learning Using mlr3 in R". CRC Press.
https://mlr3book.mlr-org.com/
MIT License
255 stars 59 forks source link

Learner fallback wishlist #803

Open jemus42 opened 11 months ago

jemus42 commented 11 months ago

During my current benchmark setup, I have learned a few things I wish I had read in the book before:

  1. When doing nested resampling with an AutoTuner, the "inner" learner can have a fallback, which will trigger if there are errors during the inner resampling loop. However, if there are errors during the outer resampling loop, the AutoTuner itself also needs a fallback, otherwise it can crash the entire tuning process.

  2. When constructing a GraphLearner, the fallback should be added to the "finished" GraphLearner object. If the base learner gets a fallback and is then wrapped into a GraphLearner, the GraphLearners's $fallback will be NULL and errors will be silently ignored and not show up in the error column in ResampleResults. This is the worst kind of failure: The silent one 🙃 In my mind this feels like a potential use case for a note-box or something. Big ⚠️ and 🚨 and everything.