A few quick thoughts:
1. What does the `isoreg` method in the `isotone` R library do with this data? We have seen multiple situations where differences between our implementation/behavior and the R implementation was not expected/communicated for users, so it would be good to know and potentially address here.
2. I'd like to draw our attention back to this PR's discussion:
In particular, this comment distinguishing between a monotonic optimization of a specific sample* and a model fit from a training sample:
For a long time, fit_transform() and fit() returned different results, and we have broken and unbroken this package for different use cases a few times over the last two years (e.g., `slinear` switch).