cfbd45bfc0
* Improve features * Add wasm32-wasi as a target * Update .github/workflows/ci.yml Co-authored-by: morenol <22335041+morenol@users.noreply.github.com>
83 lines
2.1 KiB
Rust
83 lines
2.1 KiB
Rust
//! # Manhattan Distance
|
||
//!
|
||
//! 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.
|
||
//!
|
||
//! \\[ d(x, y) = \sum_{i=0}^n \lvert x_i - y_i \rvert \\]
|
||
//!
|
||
//! Example:
|
||
//!
|
||
//! ```
|
||
//! use smartcore::metrics::distance::Distance;
|
||
//! use smartcore::metrics::distance::manhattan::Manhattan;
|
||
//!
|
||
//! let x = vec![1., 1.];
|
||
//! let y = vec![2., 2.];
|
||
//!
|
||
//! let l1: f64 = Manhattan::new().distance(&x, &y);
|
||
//! ```
|
||
//! <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
|
||
//! <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
|
||
#[cfg(feature = "serde")]
|
||
use serde::{Deserialize, Serialize};
|
||
use std::marker::PhantomData;
|
||
|
||
use crate::linalg::basic::arrays::ArrayView1;
|
||
use crate::numbers::basenum::Number;
|
||
|
||
use super::Distance;
|
||
|
||
/// Manhattan distance
|
||
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
|
||
#[derive(Debug, Clone)]
|
||
pub struct Manhattan<T: Number> {
|
||
_t: PhantomData<T>,
|
||
}
|
||
|
||
impl<T: Number> Manhattan<T> {
|
||
/// instatiate the initial structure
|
||
pub fn new() -> Manhattan<T> {
|
||
Manhattan { _t: PhantomData }
|
||
}
|
||
}
|
||
|
||
impl<T: Number> Default for Manhattan<T> {
|
||
fn default() -> Self {
|
||
Self::new()
|
||
}
|
||
}
|
||
|
||
impl<T: Number, A: ArrayView1<T>> Distance<A> for Manhattan<T> {
|
||
fn distance(&self, x: &A, y: &A) -> f64 {
|
||
if x.shape() != y.shape() {
|
||
panic!("Input vector sizes are different");
|
||
}
|
||
|
||
let dist: f64 = x
|
||
.iterator(0)
|
||
.zip(y.iterator(0))
|
||
.map(|(&a, &b)| (a - b).to_f64().unwrap().abs())
|
||
.sum();
|
||
|
||
dist
|
||
}
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
#[cfg_attr(
|
||
all(target_arch = "wasm32", not(target_os = "wasi")),
|
||
wasm_bindgen_test::wasm_bindgen_test
|
||
)]
|
||
#[test]
|
||
fn manhattan_distance() {
|
||
let a = vec![1., 2., 3.];
|
||
let b = vec![4., 5., 6.];
|
||
|
||
let l1: f64 = Manhattan::new().distance(&a, &b);
|
||
|
||
assert!((l1 - 9.0).abs() < 1e-8);
|
||
}
|
||
}
|