We're closing these two issues (issue639 and issue641) because it does not look like we're going to integrate the implementations. The original patches were a bit too intrusive for us to integrate.

However, cleaning up the g-evaluator is on the radar and should help with the depth-based evaluator in issue641.

Regarding additional tie-breaking options for open lists, we feel that at the moment the use case is served well enough by implementing custom open lists. (This is also a question of prioritizing our efforts, so this may be more a question of priorities than whether this is a desirable feature. Priorities can of course be rediscussed in the future.)

now in https://github.com/guicho271828/FastDownward/compare/depth-evaluator
this branch is built on issue639.

This implementation is different from AAAI16 impl, but is fundamentally the same
and simpler.
It is already implemented, but I do not know how to push it / have it reviewed.

It requires the information of the parent node, so I added SearchSpace* slot to
EvaluationContext. If there is a better way around, please tell me.