https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value
Test if two double-precision floating-point numbers are approximately equal within a specified number of ULPs (units in the last place).
https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value
assert assertion check equal is isalmostequal isequal issame javascript node node-js nodejs same stdlib strict type util utilities utility utils
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Test if two double-precision floating-point numbers are approximately equal within a specified number of ULPs (units in the last place).
- Host: GitHub
- URL: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value
- Owner: stdlib-js
- License: apache-2.0
- Created: 2025-06-26T03:33:12.000Z (7 months ago)
- Default Branch: main
- Last Pushed: 2025-06-30T02:37:43.000Z (7 months ago)
- Last Synced: 2025-06-30T02:38:58.225Z (7 months ago)
- Topics: assert, assertion, check, equal, is, isalmostequal, isequal, issame, javascript, node, node-js, nodejs, same, stdlib, strict, type, util, utilities, utility, utils
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 219 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
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# isAlmostEqualValue
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Test if two double-precision floating-point numbers are approximately equal within a specified number of ULPs (units in the last place).
## Installation
```bash
npm install @stdlib/number-float64-base-assert-is-almost-equal-value
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var isAlmostEqualValue = require( '@stdlib/number-float64-base-assert-is-almost-equal-value' );
```
#### isAlmostEqualValue( a, b, maxULP )
Tests if two double-precision floating-point numbers are approximately equal within a specified number of ULPs (units in the last place).
```javascript
var EPS = require( '@stdlib/constants-float64-eps' );
var bool = isAlmostEqualValue( 1.0, 1.0+EPS, 1 );
// returns true
bool = isAlmostEqualValue( 1.0, 1.0+EPS, 0 );
// returns false
```
The function returns `false` if either input value is `NaN`.
```javascript
var bool = isAlmostEqualValue( NaN, 1.0, 1 );
// returns false
bool = isAlmostEqualValue( 1.0, NaN, 1 );
// returns false
bool = isAlmostEqualValue( NaN, NaN, 1 );
// returns false
```
The function does not distinguish between `-0` and `+0`, treating them as equal.
```javascript
var bool = isAlmostEqualValue( 0.0, -0.0, 0 );
// returns true
```
## Examples
```javascript
var EPS = require( '@stdlib/constants-float64-eps' );
var isAlmostEqualValue = require( '@stdlib/number-float64-base-assert-is-almost-equal-value' );
var bool = isAlmostEqualValue( 1.0, 1.0+EPS, 1 );
console.log( bool );
// => true
bool = isAlmostEqualValue( 1.0+EPS, 1.0, 1 );
console.log( bool );
// => true
bool = isAlmostEqualValue( 1.0, 1.0+EPS+EPS, 1 );
console.log( bool );
// => false
bool = isAlmostEqualValue( 1.0, 1.0+EPS, 0 );
console.log( bool );
// => false
bool = isAlmostEqualValue( -0.0, 0.0, 0 );
console.log( bool );
// => true
bool = isAlmostEqualValue( 1.0, NaN, 1 );
console.log( bool );
// => false
bool = isAlmostEqualValue( NaN, NaN, 1 );
console.log( bool );
// => false
```
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/number-float64-base-assert-is-almost-equal-value.svg
[npm-url]: https://npmjs.org/package/@stdlib/number-float64-base-assert-is-almost-equal-value
[test-image]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/number-float64-base-assert-is-almost-equal-value/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/number-float64-base-assert-is-almost-equal-value?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/tree/deno
[deno-readme]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/tree/umd
[umd-readme]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/tree/esm
[esm-readme]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/number-float64-base-assert-is-almost-equal-value/main/LICENSE