Crate trig_const

trig-const

Rust implementation of const trig functions.

The majority of functions have been implemented using a modified version of libm for const Rust.

This implementation carries forward the original MIT license.

Project Goals

• Correctness while const (same result as std within a rounding error)
• no-std
• No unsafe

Requirements

This crate supports any compiler version back to rustc 1.85.0

[dependencies]
trig-const = "0"

Example

use std::f64::consts::PI;
use trig_const::cos;

const COS_PI: f64 = cos(PI);
assert_eq!(COS_PI, -1.0);

use std::f64::consts::PI;
use trig_const::{atan2, cos, sin};

/// 45° in radians
const DEG_45: f64 = 45.0 * PI / 180.0;

/// Pre-computed matrix to rotate object 30°
const ROTATIONAL_MATRIX: [[f64; 3]; 3] = [
    [cos(DEG_45), 0.0, sin(DEG_45)],
    [0.0, 1.0, 0.0],
    [-sin(DEG_45), 0.0, cos(DEG_45)],
];

/// atan2 calculation
const ATAN2_0_0: f64 = atan2(0.0, 0.0);

fn main() {
    println!("{:?}", ROTATIONAL_MATRIX);
    println!("{}", ATAN2_0_0);
}

History

This crate was originally implemented using trigonometric Taylor series approximations, inspired by the work of Dr. Austin Henley and Dr. Stephen Marz:

• GitHub Repo: https://github.com/AZHenley/cosine
• Article: https://austinhenley.com/blog/cosine.html

However, several functions have since been implemented using a modified version of lib for const Rust which improved precision.

Functions

acos

Arccosine

acosh

Inverse hyperbolic cosine (f64)

asin

Arcsine

asinh

Inverse hyperbolic sine (f64)

atan

Arctangent

atan2

Arctan2

atanh

Inverse hyperbolic tangent (f64)

cos

Cosine

cosh

Hyperbolic Cosine

cot

Cotangent

csc

Cosecant

exp

Exponential, base e (f64)

expi

x^pow

fabs

factorial

Factorial (x!)

floor

ln

Computes natural log using a port from Rust’s libm

pow

Power function

sec

Secant

sin

Sine

sinh

Hyperbolic Sine

sqrt

Const sqrt function using Newton’s method

tan

The tangent of x (f64).