use angular distance instead of cossim replacement

1 files changed, 12 insertions, 10 deletions

diff --git a/src/embedders/vecmetric.rs b/src/embedders/vecmetric.rs
index 1bda3a8..9f2f143 100644
--- a/src/embedders/vecmetric.rs
+++ b/src/embedders/vecmetric.rs
@@ -4,29 +4,31 @@ use serde::{Deserialize, Serialize};
 pub trait VecMetric: MetricElem + From<Vec<f32>> {}
 
 #[derive(Deserialize, Serialize)]
-pub struct CosineSimilarity(pub Vec<f32>);
+pub struct AngularDistance(pub Vec<f32>);
 #[derive(Deserialize, Serialize)]
 pub struct EuclidianDistance(pub Vec<f32>);
 #[derive(Deserialize, Serialize)]
 pub struct ManhattenDistance(pub Vec<f32>);
 
-impl VecMetric for CosineSimilarity {}
+impl VecMetric for AngularDistance {}
 impl VecMetric for EuclidianDistance {}
 impl VecMetric for ManhattenDistance {}
-#[rustfmt::skip] impl From<Vec<f32>> for CosineSimilarity { fn from(value: Vec<f32>) -> Self { Self(value) } }
+#[rustfmt::skip] impl From<Vec<f32>> for AngularDistance { fn from(value: Vec<f32>) -> Self { Self(value) } }
 #[rustfmt::skip] impl From<Vec<f32>> for EuclidianDistance { fn from(value: Vec<f32>) -> Self { Self(value) } }
 #[rustfmt::skip] impl From<Vec<f32>> for ManhattenDistance { fn from(value: Vec<f32>) -> Self { Self(value) } }
 
-impl MetricElem for CosineSimilarity {
+impl MetricElem for AngularDistance {
     fn dist(&self, other: &Self) -> f64 {
-        let len_a = self.0.iter().map(|x| x.powi(2)).sum::<f32>().sqrt();
-        let len_b = other.0.iter().map(|x| x.powi(2)).sum::<f32>().sqrt();
-        self.0
+        let x = self
+            .0
             .iter()
             .zip(other.0.iter())
-            .map(|(a, b)| (*a / len_a - *b / len_b).powi(2))
-            .sum::<f32>()
-            .sqrt() as f64
+            .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>();
+        let cossim = x / (mag_a * mag_b).sqrt();
+        cossim.acos() as f64
     }
 }
 impl MetricElem for EuclidianDistance {