ulp (epsilon function)

Compute the unit of least precision of a given IEEE-754 64-bit number.

Install

npm install @lvlte/ulp

Usage

// ESM
import { eps } from '@lvlte/ulp';

// CJS
const { eps } = require('@lvlte/ulp');

console.log(eps());                             // 2.220446049250313e-16
console.log(eps() === eps(1));                  // true
console.log(eps() === Number.EPSILON);          // true

console.log(eps(Number.MAX_SAFE_INTEGER));      // 1
console.log(eps(Number.MAX_SAFE_INTEGER + 1));  // 2

console.log(eps(0));                            // 5e-324
console.log(eps(0) === Number.MIN_VALUE);       // true

console.log(eps(Infinity));                     // NaN

Use case

• Check whether two floating point numbers can be considered equal.
• Approximate a floating point number x as a rational number.
• Get the next/previous float on the float64 number line.