isAlmostEqual

Test whether two double-precision complex floating-point numbers are approximately equal within a specified number of ULPs (units in the last place).

Installation

npm install @stdlib/complex-float64-base-assert-is-almost-equal

Usage

var isAlmostEqual = require( '@stdlib/complex-float64-base-assert-is-almost-equal' );

isAlmostEqual( z1, z2, maxULP )

Tests whether two double-precision complex floating-point numbers are approximately equal within a specified number of ULPs (units in the last place).

var EPS = require( '@stdlib/constants-float64-eps' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );

var z1 = new Complex128( 1.0, 3.0 );
var z2 = new Complex128( 1.0+EPS, 3.0 );

var out = isAlmostEqual( z1, z2, 0 );
// returns false

out = isAlmostEqual( z1, z2, 1 );
// returns true

The function returns false if either input value has a NaN real or imaginary component.

var Complex128 = require( '@stdlib/complex-float64-ctor' );

var z1 = new Complex128( NaN, 3.0 );
var z2 = new Complex128( 1.0, 3.0 );

var out = isAlmostEqual( z1, z2, 1 );
// returns false

out = isAlmostEqual( z2, z1, 1 );
// returns false

z1 = new Complex128( NaN, NaN );
z2 = new Complex128( NaN, NaN );

out = isAlmostEqual( z1, z2, 1 );
// returns false

The function does not distinguish between -0 and +0, treating them as equal.

var Complex128 = require( '@stdlib/complex-float64-ctor' );

var z1 = new Complex128( 0.0, 0.0 );
var z2 = new Complex128( -0.0, -0.0 );

var out = isAlmostEqual( z1, z2, 0 );
// returns true

Examples

var EPS = require( '@stdlib/constants-float64-eps' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var isAlmostEqual = require( '@stdlib/complex-float64-base-assert-is-almost-equal' );

var z1 = new Complex128( 1.0, 3.0+EPS );
var z2 = new Complex128( 1.0+EPS, 3.0 );
console.log( isAlmostEqual( z1, z2, 1 ) );
// => true

z1 = new Complex128( 1.0, 3.0+EPS );
z2 = new Complex128( 1.0+EPS+EPS, 3.0 );
console.log( isAlmostEqual( z1, z2, 1 ) );
// => false

z1 = new Complex128( 0.0, 0.0 );
z2 = new Complex128( -0.0, 0.0 );
console.log( isAlmostEqual( z1, z2, 0 ) );
// => true

z1 = new Complex128( NaN, 0.0 );
z2 = new Complex128( 1.0, 0.0 );
console.log( isAlmostEqual( z1, z2, 1 ) );
// => false

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.