From 8b65d87640e7367cd88e72c320e4370f4ba471a6 Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Wed, 20 Sep 2023 21:25:54 +0200
Subject: cosine similarity (works poorly)

---
 src/embedders/vecmetric.rs | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

(limited to 'src/embedders')

diff --git a/src/embedders/vecmetric.rs b/src/embedders/vecmetric.rs
index 474a6d0..0c63911 100644
--- a/src/embedders/vecmetric.rs
+++ b/src/embedders/vecmetric.rs
@@ -18,8 +18,16 @@ impl VecMetric for ManhattenDistance {}
 #[rustfmt::skip] impl From<Vec<f32>> for ManhattenDistance { fn from(value: Vec<f32>) -> Self { Self(value) } }
 
 impl MetricElem for CosineSimilarity {
-    fn dist(&self, _other: &Self) -> f64 {
-        todo!()
+    fn dist(&self, other: &Self) -> f64 {
+        let x = self
+            .0
+            .iter()
+            .zip(other.0.iter())
+            .map(|(a, b)| *a * *b)
+            .sum::<f32>();
+        let mag_a = self.0.iter().map(|x| x.powi(2)).sum::<f32>();
+        let mag_b = other.0.iter().map(|x| x.powi(2)).sum::<f32>();
+        (x / (mag_a * mag_b).sqrt()) as f64
     }
 }
 impl MetricElem for EuclidianDistance {
-- 
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