ArgMinMax

Efficient argmin & argmax (in 1 function) with SIMD (avx2) for f32, f64, i16, i32, i64 on ndarray::ArrayView1

🚀 The function is generic over the type of the array, so it can be used on an ndarray::ArrayView1<T> where T can be f32, f64, i16, i32, i64.

👀 Note that this implementation contains no if checks, ensuring that the runtime of the function is independent of the input data its order (best-case = worst-case = average-case).

Installing

Add the following to your Cargo.toml:

[dependencies]
argminmax = "0.1.1"

Example usage

use argminmax::ArgMinMax;  // extension trait for ndarray::ArrayView1
use ndarray::Array1;

let arr: Vec<i32> = (0..200_000).collect();
let arr: Array1<i32> = Array1::from(arr);

let (min, max) = arr.view().argminmax().unwrap();  // apply extension

println!("min: {}, max: {}", min, max);
println!("arr[min]: {}, arr[max]: {}", arr[min], arr[max]);

Benchmarks

Benchmarks on my laptop (AMD Ryzen 7 4800U, 1.8 GHz, 16GB RAM) using criterion show that the function is 3-20x faster than the scalar implementation (depending of data type).

See /benches/results.

Run the benchmarks yourself with the following command:

cargo bench --quiet --message-format=short | grep "time:"

Acknowledgements

Some parts of this library are inspired by the great work of minimalrust's argmm project.