Re: Letor: returning MSet after re-ranking

>
>
> I'd prefer to avoid adding things to the public API that don't get
> used by end users. However because LTR is outside the Xapian build
> tree, we can't easily give it privileged access to Xapian internals.
>

Sorry for a delayed response.

The way I was thinking of performing reranking with updated weights was to
add a class MSetRanker (basically containing a copy of MSet to be
re-ranked) to Xapian public API, which would be a friend of MSet::Internal
class so that it could access/update the weights and sort MSetItems
accordingly, returning an updated MSet.

As you pointed out, two obvious issues with this are: 1) Unnecessary
addition to Xapian public API since this class is not useful beyond letor.
2) It gives access to MSet internals to end users

What would you suggest should be the way out to access MSet internals from
-letor, if we can't add things to -core's public API?

Regards,
Ayush