added SSTree

Cargo.toml

@@ -6,6 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+conv = "0.3.3"
 ordered-float = "4.1.1"
 
 [dev-dependencies]

README.md

@@ -1 +1,2 @@
-# sstree
+# rindex
+Rindex: reverse nearest neighbor search index for high-dimensional clustered datasets.

src/index.rs

@@ -4,4 +4,5 @@ pub trait Index<const D: usize> {
 
     fn core_distance_of(&self, point_index: usize) -> f64;
     fn neighbors_of(&self, point_index: usize) -> Vec<usize>;
+    fn num_points(&self) -> usize;
 }

src/lib.rs

@@ -2,6 +2,8 @@ mod distance;
 mod index;
 #[allow(clippy::module_name_repetitions)]
 mod linear;
+mod tree;
 
 pub use index::Index;
 pub use linear::LinearIndex;
+pub use tree::sstree::SSTree;

src/linear.rs

@@ -39,11 +39,6 @@ impl<const D: usize> LinearIndex<D> {
             false
         }
     }
-
-    #[must_use]
-    pub fn num_points(&self) -> usize {
-        self.data.len()
-    }
 }
 
 impl<const D: usize> Index<D> for LinearIndex<D> {
@@ -86,6 +81,10 @@ impl<const D: usize> Index<D> for LinearIndex<D> {
             .map(|(_, neighbor_index)| *neighbor_index)
             .collect()
     }
+
+    fn num_points(&self) -> usize {
+        self.data.len()
+    }
 }
 
 #[cfg(test)]

src/tree/mod.rs

@@ -0,0 +1,3 @@
+mod node;
+mod sphere;
+pub mod sstree;

src/tree/node.rs

@@ -0,0 +1,35 @@
+use super::sphere::Sphere;
+
+pub struct InsertionEntry<const D: usize> {
+    pub idx: usize,
+    pub sphere: Sphere<D>,
+    pub parent_height: usize,
+}
+
+pub struct Node<const D: usize> {
+    pub idx: usize,
+    pub height: usize,
+    pub sphere: Sphere<D>,
+    pub parent: usize,
+    pub children: Vec<usize>,
+    pub variance: [f64; D],
+    pub bound: f64,
+}
+
+impl<const D: usize> Node<D> {
+    pub fn new(idx: usize, height: usize, sphere: Sphere<D>, parent: usize) -> Node<D> {
+        Node {
+            idx,
+            height,
+            sphere,
+            parent,
+            children: Vec::new(),
+            variance: [f64::INFINITY; D],
+            bound: f64::INFINITY,
+        }
+    }
+
+    pub fn is_leaf(&self) -> bool {
+        self.height == 0
+    }
+}

src/tree/sphere.rs

@@ -0,0 +1,17 @@
+use crate::distance::euclidean;
+
+#[derive(Clone, Copy)]
+pub struct Sphere<const D: usize> {
+    pub center: [f64; D],
+    pub radius: f64,
+}
+
+impl<const D: usize> Sphere<D> {
+    pub fn new(center: [f64; D], radius: f64) -> Sphere<D> {
+        Sphere { center, radius }
+    }
+
+    pub fn min_distance(&self, other: &[f64; D]) -> f64 {
+        (euclidean(&self.center, other) - self.radius).max(0.)
+    }
+}