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Diffstat (limited to 'src/soft.rs')
-rw-r--r-- | src/soft.rs | 288 |
1 files changed, 0 insertions, 288 deletions
diff --git a/src/soft.rs b/src/soft.rs deleted file mode 100644 index 4ce4204..0000000 --- a/src/soft.rs +++ /dev/null @@ -1,288 +0,0 @@ -//! [Soft deletion](https://en.wiktionary.org/wiki/soft_deletion) for nearest neighbor search. - -use super::forest::{KdForest, VpForest}; - -use acap::distance::Proximity; -use acap::kd::FlatKdTree; -use acap::knn::{NearestNeighbors, Neighborhood}; -use acap::vp::FlatVpTree; - -use std::iter; -use std::mem; - -/// A trait for objects that can be soft-deleted. -pub trait SoftDelete { - /// Check whether this item is deleted. - fn is_deleted(&self) -> bool; -} - -/// Blanket [SoftDelete] implementation for references. -impl<'a, T: SoftDelete> SoftDelete for &'a T { - fn is_deleted(&self) -> bool { - (*self).is_deleted() - } -} - -/// [Neighborhood] wrapper that ignores soft-deleted items. -#[derive(Debug)] -struct SoftNeighborhood<N>(N); - -impl<K, V, N> Neighborhood<K, V> for SoftNeighborhood<N> -where - V: SoftDelete, - K: Proximity<V>, - N: Neighborhood<K, V>, -{ - fn target(&self) -> K { - self.0.target() - } - - fn contains<D>(&self, distance: D) -> bool - where - D: PartialOrd<K::Distance> - { - self.0.contains(distance) - } - - fn consider(&mut self, item: V) -> K::Distance { - if item.is_deleted() { - self.target().distance(&item) - } else { - self.0.consider(item) - } - } -} - -/// A [NearestNeighbors] implementation that supports [soft deletes](https://en.wiktionary.org/wiki/soft_deletion). -#[derive(Debug)] -pub struct SoftSearch<T>(T); - -impl<T, U> SoftSearch<U> -where - T: SoftDelete, - U: FromIterator<T> + IntoIterator<Item = T>, -{ - /// Create a new empty soft index. - pub fn new() -> Self { - Self(iter::empty().collect()) - } - - /// Push a new item into this index. - pub fn push(&mut self, item: T) - where - U: Extend<T>, - { - self.0.extend(iter::once(item)); - } - - /// Rebuild this index, discarding deleted items. - pub fn rebuild(&mut self) { - let items = mem::replace(&mut self.0, iter::empty().collect()); - self.0 = items.into_iter().filter(|e| !e.is_deleted()).collect(); - } -} - -impl<T, U> Default for SoftSearch<U> -where - T: SoftDelete, - U: FromIterator<T> + IntoIterator<Item = T>, -{ - fn default() -> Self { - Self::new() - } -} - -impl<T, U: Extend<T>> Extend<T> for SoftSearch<U> { - fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { - self.0.extend(iter); - } -} - -impl<T, U: FromIterator<T>> FromIterator<T> for SoftSearch<U> { - fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self { - Self(U::from_iter(iter)) - } -} - -impl<T: IntoIterator> IntoIterator for SoftSearch<T> { - type Item = T::Item; - type IntoIter = T::IntoIter; - - fn into_iter(self) -> Self::IntoIter { - self.0.into_iter() - } -} - -impl<K, V, T> NearestNeighbors<K, V> for SoftSearch<T> -where - K: Proximity<V>, - V: SoftDelete, - T: NearestNeighbors<K, V>, -{ - fn search<'k, 'v, N>(&'v self, neighborhood: N) -> N - where - K: 'k, - V: 'v, - N: Neighborhood<&'k K, &'v V> - { - self.0.search(SoftNeighborhood(neighborhood)).0 - } -} - -/// A k-d forest that supports soft deletes. -pub type SoftKdForest<T> = SoftSearch<KdForest<T>>; - -/// A k-d tree that supports soft deletes. -pub type SoftKdTree<T> = SoftSearch<FlatKdTree<T>>; - -/// A VP forest that supports soft deletes. -pub type SoftVpForest<T> = SoftSearch<VpForest<T>>; - -/// A VP tree that supports soft deletes. -pub type SoftVpTree<T> = SoftSearch<FlatVpTree<T>>; - -#[cfg(test)] -mod tests { - use super::*; - - use acap::coords::Coordinates; - use acap::euclid::{euclidean_distance, Euclidean, EuclideanDistance}; - use acap::knn::Neighbor; - - type Point = Euclidean<[f32; 3]>; - - #[derive(Debug, PartialEq)] - struct SoftPoint { - point: [f32; 3], - deleted: bool, - } - - impl SoftPoint { - fn new(x: f32, y: f32, z: f32) -> Self { - Self { - point: [x, y, z], - deleted: false, - } - } - - fn deleted(x: f32, y: f32, z: f32) -> Self { - Self { - point: [x, y, z], - deleted: true, - } - } - } - - impl SoftDelete for SoftPoint { - fn is_deleted(&self) -> bool { - self.deleted - } - } - - impl Proximity for SoftPoint { - type Distance = EuclideanDistance<f32>; - - fn distance(&self, other: &Self) -> Self::Distance { - euclidean_distance(&self.point, &other.point) - } - } - - impl Coordinates for SoftPoint { - type Value = <Point as Coordinates>::Value; - - fn dims(&self) -> usize { - self.point.dims() - } - - fn coord(&self, i: usize) -> Self::Value { - self.point.coord(i) - } - } - - impl Proximity<SoftPoint> for Point { - type Distance = EuclideanDistance<f32>; - - fn distance(&self, other: &SoftPoint) -> Self::Distance { - euclidean_distance(&self, &other.point) - } - } - - fn test_index<T>(index: &T) - where - T: NearestNeighbors<Point, SoftPoint>, - { - let target = Euclidean([0.0, 0.0, 0.0]); - - assert_eq!( - index.nearest(&target).expect("No nearest neighbor found"), - Neighbor::new(&SoftPoint::new(1.0, 2.0, 2.0), 3.0) - ); - - assert_eq!(index.nearest_within(&target, 2.0), None); - assert_eq!( - index.nearest_within(&target, 4.0).expect("No nearest neighbor found within 4.0"), - Neighbor::new(&SoftPoint::new(1.0, 2.0, 2.0), 3.0) - ); - - assert_eq!( - index.k_nearest(&target, 3), - vec![ - Neighbor::new(&SoftPoint::new(1.0, 2.0, 2.0), 3.0), - Neighbor::new(&SoftPoint::new(3.0, 4.0, 0.0), 5.0), - Neighbor::new(&SoftPoint::new(2.0, 3.0, 6.0), 7.0), - ] - ); - - assert_eq!( - index.k_nearest_within(&target, 3, 6.0), - vec![ - Neighbor::new(&SoftPoint::new(1.0, 2.0, 2.0), 3.0), - Neighbor::new(&SoftPoint::new(3.0, 4.0, 0.0), 5.0), - ] - ); - assert_eq!( - index.k_nearest_within(&target, 3, 8.0), - vec![ - Neighbor::new(&SoftPoint::new(1.0, 2.0, 2.0), 3.0), - Neighbor::new(&SoftPoint::new(3.0, 4.0, 0.0), 5.0), - Neighbor::new(&SoftPoint::new(2.0, 3.0, 6.0), 7.0), - ] - ); - } - - fn test_soft_index<T>(index: &mut SoftSearch<T>) - where - T: Extend<SoftPoint>, - T: FromIterator<SoftPoint>, - T: IntoIterator<Item = SoftPoint>, - T: NearestNeighbors<Point, SoftPoint>, - { - let points = vec![ - SoftPoint::deleted(0.0, 0.0, 0.0), - SoftPoint::new(3.0, 4.0, 0.0), - SoftPoint::new(5.0, 0.0, 12.0), - SoftPoint::new(0.0, 8.0, 15.0), - SoftPoint::new(1.0, 2.0, 2.0), - SoftPoint::new(2.0, 3.0, 6.0), - SoftPoint::new(4.0, 4.0, 7.0), - ]; - - for point in points { - index.push(point); - } - test_index(index); - - index.rebuild(); - test_index(index); - } - - #[test] - fn test_soft_kd_forest() { - test_soft_index(&mut SoftKdForest::new()); - } - - #[test] - fn test_soft_vp_forest() { - test_soft_index(&mut SoftVpForest::new()); - } -} |