Dirk Mueller
f15e2a2119
- Update to 1.4.1 * Constructing a Query for a non-reference counted PostingSource object will now try to clone the PostingSource object (as happened in 1.3.4 and earlier). This clone code was removed as part of the changes in 1.3.5 to support optional reference counting of PostingSource objects, but that breaks the case when the PostingSource object is on the stack and goes out of scope before the Query object is used. Issue reported by Till Schäfer and analysed by Daniel Vrátil in a bug report against Akonadi: https://bugs.kde.org/show_bug.cgi?id=363741 * Add BM25PlusWeight class implementing the BM25+ weighting scheme, implemented by Vivek Pal (https://github.com/xapian/xapian/pull/104). * Add PL2PlusWeight class implementing the PL2+ weighting scheme, implemented by Vivek Pal (https://github.com/xapian/xapian/pull/108). * LMWeight: Implement Dir+ weighting scheme as DIRICHLET_PLUS_SMOOTHING. Patch from Vivek Pal. * Add CoordWeight class implementing coordinate matching. This can be useful for specialised uses - e.g. to implement sorting by the number of matching filters. * DLHWeight,DPHWeight,PL2Weight: With these weighting schemes, the formulae can give a negative weight contribution for a term in extreme cases. We used to try to handle this by calculating a per-term lower bound on the contribution and subtracting this from the contribution, but this idea is fundamentally flawed as the total offset it adds to a document depends on what combination of terms that document matches, meaning in general the offset isn't the same for every matching document. So instead we now clamp each term's weight contribution to be >= 0. * TfIdfWeight: Always scale term weight by wqf - this seems the logical approach as it matches the weighting we'd get if we weighted every non-unique term in the query, as well as being explicit in the Piv+ formula. OBS-URL: https://build.opensuse.org/request/show/439920 OBS-URL: https://build.opensuse.org/package/show/server:search/xapian-core?expand=0&rev=72