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Use the predicate definition of nearestUnmapped.

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This commit is contained in:
Rob Rix 2017-10-23 15:54:09 -04:00
parent 76863d9e52
commit dcb4f256c1
1 changed files with 6 additions and 20 deletions
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26
src/RWS.hs
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@ -160,9 +160,9 @@ findNearestNeighbourTo canCompare kdTreeA kdTreeB term@(UnmappedTerm j _ b) = do
(previous, unmappedA, unmappedB) <- get
fromMaybe (insertion previous unmappedA unmappedB term) $ do
-- Look up the nearest unmapped term in `unmappedA`.
foundA@(UnmappedTerm i _ a) <- nearestUnmapped (IntMap.filter (isNearAndComparableTo canCompare previous b) unmappedA) kdTreeA term
foundA@(UnmappedTerm i _ a) <- nearestUnmapped (isNearAndComparableTo canCompare previous b) kdTreeA term
-- Look up the nearest `foundA` in `unmappedB`
UnmappedTerm j' _ _ <- nearestUnmapped (IntMap.filter (isNearAndComparableTo (flip canCompare) (pred j) a) unmappedB) kdTreeB foundA
UnmappedTerm j' _ _ <- nearestUnmapped (isNearAndComparableTo (flip canCompare) (pred j) a) kdTreeB foundA
-- Return Nothing if their indices don't match
guard (j == j')
pure $! do
@ -184,9 +184,9 @@ findNearestNeighbourTo' canCompare kdTreeA kdTreeB = go
go previous unmappedA (termB@(UnmappedTerm j _ b) : restUnmappedB) =
fromMaybe (That (j, b) : go previous unmappedA restUnmappedB) $ do
-- Look up the nearest unmapped term in `unmappedA`.
foundA@(UnmappedTerm i _ a) <- nearestUnmapped' (isNearAndComparableTo canCompare previous b) kdTreeA termB
foundA@(UnmappedTerm i _ a) <- nearestUnmapped (isNearAndComparableTo canCompare previous b) kdTreeA termB
-- Look up the nearest `foundA` in `unmappedB`
UnmappedTerm j' _ _ <- nearestUnmapped' (isNearAndComparableTo (flip canCompare) (pred j) a) kdTreeB foundA
UnmappedTerm j' _ _ <- nearestUnmapped (isNearAndComparableTo (flip canCompare) (pred j) a) kdTreeB foundA
-- Return Nothing if their indices don't match
guard (j == j')
pure $!
@ -202,25 +202,11 @@ isNearAndComparableTo canCompare index term (UnmappedTerm k _ term') = inRange (
--
-- cf §4.2 of RWS-Diff
nearestUnmapped :: (Foldable syntax, Functor syntax, GAlign syntax)
=> UnmappedTerms syntax ann1 -- ^ A set of terms eligible for matching against.
=> (UnmappedTerm syntax ann1 -> Bool) -- ^ A predicate selecting terms eligible for matching against.
-> KdMap Double FeatureVector (UnmappedTerm syntax ann1) -- ^ The k-d tree to look up nearest neighbours within.
-> UnmappedTerm syntax ann2 -- ^ The term to find the nearest neighbour to.
-> Maybe (UnmappedTerm syntax ann1) -- ^ The most similar unmapped term, if any.
nearestUnmapped unmapped tree key = listToMaybe (sortOn approximateEditDistance candidates)
where candidates = toList (IntMap.intersection unmapped (toMap (fmap snd (kNearest tree defaultL (feature key)))))
approximateEditDistance = editDistanceUpTo defaultM (term key) . term
-- | Finds the most-similar unmapped term to the passed-in term, if any.
--
-- RWS can produce false positives in the case of e.g. hash collisions. Therefore, we find the _l_ nearest candidates, filter out any which have already been mapped, and select the minimum of the remaining by (a constant-time approximation of) edit distance.
--
-- cf §4.2 of RWS-Diff
nearestUnmapped' :: (Foldable syntax, Functor syntax, GAlign syntax)
=> (UnmappedTerm syntax ann1 -> Bool) -- ^ A predicate selecting terms eligible for matching against.
-> KdMap Double FeatureVector (UnmappedTerm syntax ann1) -- ^ The k-d tree to look up nearest neighbours within.
-> UnmappedTerm syntax ann2 -- ^ The term to find the nearest neighbour to.
-> Maybe (UnmappedTerm syntax ann1) -- ^ The most similar unmapped term, if any.
nearestUnmapped' isEligible tree key = listToMaybe (sortOn approximateEditDistance candidates)
nearestUnmapped isEligible tree key = listToMaybe (sortOn approximateEditDistance candidates)
where candidates = filter isEligible (snd <$> kNearest tree defaultL (feature key))
approximateEditDistance = editDistanceUpTo defaultM (term key) . term