isAlmostSameValue

Test if two single-precision floating-point numbers are approximately the same value within a specified number of ULPs (units in the last place).

Installation

npm install @stdlib/number-float32-base-assert-is-almost-same-value

Usage

var isAlmostSameValue = require( '@stdlib/number-float32-base-assert-is-almost-same-value' );

isAlmostSameValue( a, b, maxULP )

Tests if two single-precision floating-point numbers are approximately the same value within a specified number of ULPs (units in the last place).

var EPS = require( '@stdlib/constants-float32-eps' );

var bool = isAlmostSameValue( 1.0, 1.0+EPS, 1 );
// returns true

bool = isAlmostSameValue( 1.0, 1.0+EPS, 0 );
// returns false

In contrast to the strict equality operator ===, the function distinguishes between +0 and -0 and treats NaNs as the same value.

var bool = isAlmostSameValue( NaN, 1.0, 1 );
// returns false

bool = isAlmostSameValue( 1.0, NaN, 1 );
// returns false

bool = isAlmostSameValue( NaN, NaN, 1 );
// returns true

bool = isAlmostSameValue( 0.0, -0.0, 0 );
// returns false

Notes

• The function implements the SameValue Algorithm as specified in ECMAScript 5.

Examples

var EPS = require( '@stdlib/constants-float32-eps' );
var isAlmostSameValue = require( '@stdlib/number-float32-base-assert-is-almost-same-value' );

var bool = isAlmostSameValue( 1.0, 1.0+EPS, 1 );
console.log( bool );
// => true

bool = isAlmostSameValue( 1.0+EPS, 1.0, 1 );
console.log( bool );
// => true

bool = isAlmostSameValue( 1.0, 1.0+EPS+EPS, 1 );
console.log( bool );
// => false

bool = isAlmostSameValue( 1.0, 1.0+EPS, 0 );
console.log( bool );
// => false

bool = isAlmostSameValue( -0.0, 0.0, 0 );
console.log( bool );
// => false

bool = isAlmostSameValue( 1.0, NaN, 1 );
console.log( bool );
// => false

bool = isAlmostSameValue( NaN, NaN, 1 );
console.log( bool );
// => true

Notice

This package is part of 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, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.