[ML] Numerical robustness improvements for Bayesian Optimisation #2249
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This improves handling of numerical issues computing EI.
In particular, we weren't checking the condition of kernel covariance matrix. We don't need a lot of accuracy, but we need to handle edge cases, like singular matrices, NaNs, etc. In this case, zeroing the EI and its gradient is fine, the solver will fallback to taking random step.
Note that this is also a potential source of
[CTools.cc@152] x = NaN, distribution = class...
log errors.