59 lines
1.4 KiB
Rust
59 lines
1.4 KiB
Rust
//! # Manhattan Distance
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//!
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//! The Manhattan distance between two points \\(x \in ℝ^n \\) and \\( y \in ℝ^n \\) in n-dimensional space is the sum of the distances in each dimension.
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//!
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//! \\[ d(x, y) = \sum_{i=0}^n \lvert x_i - y_i \rvert \\]
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//!
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//! Example:
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//!
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//! ```
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//! use smartcore::math::distance::Distance;
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//! use smartcore::math::distance::manhattan::Manhattan;
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//!
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//! let x = vec![1., 1.];
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//! let y = vec![2., 2.];
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//!
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//! let l1: f64 = Manhattan {}.distance(&x, &y);
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//! ```
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//! <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
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//! <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
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use serde::{Deserialize, Serialize};
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use crate::math::num::RealNumber;
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use super::Distance;
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/// Manhattan distance
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#[derive(Serialize, Deserialize, Debug)]
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pub struct Manhattan {}
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impl<T: RealNumber> Distance<Vec<T>, T> for Manhattan {
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fn distance(&self, x: &Vec<T>, y: &Vec<T>) -> T {
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if x.len() != y.len() {
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panic!("Input vector sizes are different");
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}
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let mut dist = T::zero();
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for i in 0..x.len() {
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dist += (x[i] - y[i]).abs();
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}
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dist
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn manhattan_distance() {
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let a = vec![1., 2., 3.];
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let b = vec![4., 5., 6.];
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let l1: f64 = Manhattan {}.distance(&a, &b);
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assert!((l1 - 9.0).abs() < 1e-8);
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}
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}
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