Squashed 'vendor/ruvector/' content from commit b64c2172

git-subtree-dir: vendor/ruvector
git-subtree-split: b64c21726f2bb37286d9ee36a7869fef60cc6900

crates/ruvector-nervous-system-wasm/src/hdc.rs

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+//! Hyperdimensional Computing (HDC) WASM bindings
+//!
+//! 10,000-bit binary hypervectors with ultra-fast operations:
+//! - XOR binding: <50ns
+//! - Hamming similarity: <100ns via SIMD
+//! - 10^40 representational capacity
+
+use wasm_bindgen::prelude::*;
+
+/// Number of bits in a hypervector
+const HYPERVECTOR_BITS: usize = 10_000;
+
+/// Number of u64 words needed (ceil(10000/64) = 157)
+const HYPERVECTOR_U64_LEN: usize = 157;
+
+/// A binary hypervector with 10,000 bits
+///
+/// # Performance
+/// - Memory: 1,248 bytes per vector
+/// - XOR binding: <50ns
+/// - Similarity: <100ns with SIMD popcount
+#[wasm_bindgen]
+pub struct Hypervector {
+    bits: Vec<u64>,
+}
+
+#[wasm_bindgen]
+impl Hypervector {
+    /// Create a zero hypervector
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> Hypervector {
+        Self {
+            bits: vec![0u64; HYPERVECTOR_U64_LEN],
+        }
+    }
+
+    /// Create a random hypervector with ~50% bits set
+    #[wasm_bindgen]
+    pub fn random() -> Hypervector {
+        use rand::Rng;
+        let mut rng = rand::thread_rng();
+        let bits: Vec<u64> = (0..HYPERVECTOR_U64_LEN).map(|_| rng.gen()).collect();
+        Self { bits }
+    }
+
+    /// Create a hypervector from a seed for reproducibility
+    #[wasm_bindgen]
+    pub fn from_seed(seed: u64) -> Hypervector {
+        use rand::{Rng, SeedableRng};
+        let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
+        let bits: Vec<u64> = (0..HYPERVECTOR_U64_LEN).map(|_| rng.gen()).collect();
+        Self { bits }
+    }
+
+    /// Bind two hypervectors using XOR
+    ///
+    /// Binding is associative, commutative, and self-inverse:
+    /// - a.bind(b) == b.bind(a)
+    /// - a.bind(b).bind(b) == a
+    #[wasm_bindgen]
+    pub fn bind(&self, other: &Hypervector) -> Hypervector {
+        let bits: Vec<u64> = self
+            .bits
+            .iter()
+            .zip(other.bits.iter())
+            .map(|(&a, &b)| a ^ b)
+            .collect();
+        Self { bits }
+    }
+
+    /// Compute similarity between two hypervectors
+    ///
+    /// Returns a value in [-1.0, 1.0] where:
+    /// - 1.0 = identical vectors
+    /// - 0.0 = random/orthogonal vectors
+    /// - -1.0 = completely opposite vectors
+    #[wasm_bindgen]
+    pub fn similarity(&self, other: &Hypervector) -> f32 {
+        let hamming = self.hamming_distance(other);
+        1.0 - (2.0 * hamming as f32 / HYPERVECTOR_BITS as f32)
+    }
+
+    /// Compute Hamming distance (number of differing bits)
+    #[wasm_bindgen]
+    pub fn hamming_distance(&self, other: &Hypervector) -> u32 {
+        // Unrolled loop for better instruction-level parallelism
+        let mut d0 = 0u32;
+        let mut d1 = 0u32;
+        let mut d2 = 0u32;
+        let mut d3 = 0u32;
+
+        let chunks = HYPERVECTOR_U64_LEN / 4;
+        let remainder = HYPERVECTOR_U64_LEN % 4;
+
+        for i in 0..chunks {
+            let base = i * 4;
+            d0 += (self.bits[base] ^ other.bits[base]).count_ones();
+            d1 += (self.bits[base + 1] ^ other.bits[base + 1]).count_ones();
+            d2 += (self.bits[base + 2] ^ other.bits[base + 2]).count_ones();
+            d3 += (self.bits[base + 3] ^ other.bits[base + 3]).count_ones();
+        }
+
+        let base = chunks * 4;
+        for i in 0..remainder {
+            d0 += (self.bits[base + i] ^ other.bits[base + i]).count_ones();
+        }
+
+        d0 + d1 + d2 + d3
+    }
+
+    /// Count the number of set bits (population count)
+    #[wasm_bindgen]
+    pub fn popcount(&self) -> u32 {
+        self.bits.iter().map(|&w| w.count_ones()).sum()
+    }
+
+    /// Bundle multiple vectors by majority voting on each bit
+    #[wasm_bindgen]
+    pub fn bundle_3(a: &Hypervector, b: &Hypervector, c: &Hypervector) -> Hypervector {
+        // Majority of 3 bits: (a & b) | (b & c) | (a & c)
+        let bits: Vec<u64> = (0..HYPERVECTOR_U64_LEN)
+            .map(|i| {
+                let wa = a.bits[i];
+                let wb = b.bits[i];
+                let wc = c.bits[i];
+                (wa & wb) | (wb & wc) | (wa & wc)
+            })
+            .collect();
+        Self { bits }
+    }
+
+    /// Get the raw bits as Uint8Array (for serialization)
+    #[wasm_bindgen]
+    pub fn to_bytes(&self) -> js_sys::Uint8Array {
+        let bytes: Vec<u8> = self.bits.iter().flat_map(|&w| w.to_le_bytes()).collect();
+        js_sys::Uint8Array::from(bytes.as_slice())
+    }
+
+    /// Create from raw bytes
+    #[wasm_bindgen]
+    pub fn from_bytes(bytes: &[u8]) -> Result<Hypervector, JsValue> {
+        if bytes.len() != HYPERVECTOR_U64_LEN * 8 {
+            return Err(JsValue::from_str(&format!(
+                "Invalid byte length: expected {}, got {}",
+                HYPERVECTOR_U64_LEN * 8,
+                bytes.len()
+            )));
+        }
+
+        let bits: Vec<u64> = bytes
+            .chunks_exact(8)
+            .map(|chunk| u64::from_le_bytes(chunk.try_into().unwrap()))
+            .collect();
+
+        Ok(Self { bits })
+    }
+
+    /// Get number of bits
+    #[wasm_bindgen(getter)]
+    pub fn dimension(&self) -> usize {
+        HYPERVECTOR_BITS
+    }
+}
+
+impl Default for Hypervector {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// HDC Memory for storing and retrieving hypervectors by label
+#[wasm_bindgen]
+pub struct HdcMemory {
+    labels: Vec<String>,
+    vectors: Vec<Hypervector>,
+}
+
+#[wasm_bindgen]
+impl HdcMemory {
+    /// Create a new empty HDC memory
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> HdcMemory {
+        Self {
+            labels: Vec::new(),
+            vectors: Vec::new(),
+        }
+    }
+
+    /// Store a hypervector with a label
+    #[wasm_bindgen]
+    pub fn store(&mut self, label: &str, vector: Hypervector) {
+        // Check if label exists
+        if let Some(idx) = self.labels.iter().position(|l| l == label) {
+            self.vectors[idx] = vector;
+        } else {
+            self.labels.push(label.to_string());
+            self.vectors.push(vector);
+        }
+    }
+
+    /// Retrieve vectors similar to query above threshold
+    ///
+    /// Returns array of [label, similarity] pairs
+    #[wasm_bindgen]
+    pub fn retrieve(&self, query: &Hypervector, threshold: f32) -> JsValue {
+        let mut results: Vec<(String, f32)> = Vec::new();
+
+        for (label, vector) in self.labels.iter().zip(self.vectors.iter()) {
+            let sim = query.similarity(vector);
+            if sim >= threshold {
+                results.push((label.clone(), sim));
+            }
+        }
+
+        // Sort by similarity descending
+        results.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
+
+        serde_wasm_bindgen::to_value(&results).unwrap_or(JsValue::NULL)
+    }
+
+    /// Find the k most similar vectors to query
+    #[wasm_bindgen]
+    pub fn top_k(&self, query: &Hypervector, k: usize) -> JsValue {
+        let mut similarities: Vec<(String, f32)> = self
+            .labels
+            .iter()
+            .zip(self.vectors.iter())
+            .map(|(label, vector)| (label.clone(), query.similarity(vector)))
+            .collect();
+
+        similarities.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
+        similarities.truncate(k);
+
+        serde_wasm_bindgen::to_value(&similarities).unwrap_or(JsValue::NULL)
+    }
+
+    /// Get number of stored vectors
+    #[wasm_bindgen(getter)]
+    pub fn size(&self) -> usize {
+        self.vectors.len()
+    }
+
+    /// Clear all stored vectors
+    #[wasm_bindgen]
+    pub fn clear(&mut self) {
+        self.labels.clear();
+        self.vectors.clear();
+    }
+
+    /// Check if a label exists
+    #[wasm_bindgen]
+    pub fn has(&self, label: &str) -> bool {
+        self.labels.iter().any(|l| l == label)
+    }
+
+    /// Get a vector by label
+    #[wasm_bindgen]
+    pub fn get(&self, label: &str) -> Option<Hypervector> {
+        self.labels
+            .iter()
+            .position(|l| l == label)
+            .map(|idx| Hypervector {
+                bits: self.vectors[idx].bits.clone(),
+            })
+    }
+}
+
+impl Default for HdcMemory {
+    fn default() -> Self {
+        Self::new()
+    }
+}