mirror of
https://github.com/meilisearch/MeiliSearch
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26 lines
968 B
Rust
26 lines
968 B
Rust
use serde::{Deserialize, Serialize};
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use space::Metric;
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#[derive(Debug, Default, Clone, Copy, Serialize, Deserialize)]
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pub struct DotProduct;
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impl Metric<Vec<f32>> for DotProduct {
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type Unit = u32;
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// Following <https://docs.rs/space/0.17.0/space/trait.Metric.html>.
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//
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// Here is a playground that validate the ordering of the bit representation of floats in range 0.0..=1.0:
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// <https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=6c59e31a3cc5036b32edf51e8937b56e>
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fn distance(&self, a: &Vec<f32>, b: &Vec<f32>) -> Self::Unit {
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let dist = 1.0 - dot_product_similarity(a, b);
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debug_assert!(!dist.is_nan());
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dist.to_bits()
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}
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}
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/// Returns the dot product similarity score that will between 0.0 and 1.0
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/// if both vectors are normalized. The higher the more similar the vectors are.
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pub fn dot_product_similarity(a: &[f32], b: &[f32]) -> f32 {
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a.iter().zip(b).map(|(a, b)| a * b).sum()
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}
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