* Added optimisation using block wand for single TermScorer.
A proptest was also added.
* Fix block wand algorithm by taking the last doc id of scores until the pivot scorer (included).
* In block wand, when block max score is lower than the threshold, advance the scorer with best score.
* Fix wrong condition in block_wand_single_scorer and add debug_assert to have an equality check on doc to break the loop.
go_to_first_doc was typically calling seek with a target smaller than
doc.
Since SegmentPostings typically do a linear search on the full block,
regardless of the current position, it could have our segment postings
go backward.
* Do nothing when combining score values of excluded scores.
* Add test case for two excluded.
* Test score for two excluded terms.
* Use TopDocs in test_boolean_query_two_excluded
- Change in the DocSet and Scorer API. (@fulmicoton).
A freshly created DocSet point directly to their first doc. A sentinel value called TERMINATED marks the end of a DocSet.
`.advance()` returns the new DocId. `Scorer::skip(target)` has been replaced by `Scorer::seek(target)` and returns the resulting DocId.
As a result, iterating through DocSet now looks as follows
```rust
let mut doc = docset.doc();
while doc != TERMINATED {
// ...
doc = docset.advance();
}
```
The change made it possible to greatly simplify a lot of the docset's code.
- Misc internal optimization and introduction of the `Scorer::for_each_pruning` function. (@fulmicoton)
* Alternative take on boosted queries
* Fixing unit test
* Added boosting to the query grammar.
* Made BoostQuery public.
* Added support for boosting field in QueryParser
Closes#547
* Split Collector into an overall Collector and a per-segment SegmentCollector. Precursor to cross-segment parallelism, and as a side benefit cleans up any per-segment fields from being Option<T> to just T.
* Attempt to add MultiCollector back
* working. Chained collector is broken though
* Fix chained collector
* Fix test
* Make Weight Send+Sync for parallelization purposes
* Expose parameters of RangeQuery for external usage
* Removed &mut self
* fixing tests
* Restored TestCollectors
* blop
* multicollector working
* chained collector working
* test broken
* fixing unit test
* blop
* blop
* Blop
* simplifying APi
* blop
* better syntax
* Simplifying top_collector
* refactoring
* blop
* Sync with master
* Added multithread search
* Collector refactoring
* Schema::builder
* CR and rustdoc
* CR comments
* blop
* Added an executor
* Sorted the segment readers in the searcher
* Update searcher.rs
* Fixed unit testst
* changed the place where we have the sort-segment-by-count heuristic
* using crossbeam::channel
* inlining
* Comments about panics propagating
* Added unit test for executor panicking
* Readded default
* Removed Default impl
* Added unit test for executor
