npm package: @stdlib/complex-float64-base-assert-is-almost-same-value
Description: Test whether two double-precision complex floating-point numbers are approximately the same value within a specified number of ULPs (units in the last place).
Author: The Stdlib Authors
Latest version: 0.1.1

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# isAlmostSameValue

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

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/complex-float64-base-assert-is-almost-same-value
```

</section>

<section class="usage">

## Usage

```javascript
var isAlmostSameValue = require( '@stdlib/complex-float64-base-assert-is-almost-same-value' );
```

#### isAlmostSameValue( z1, z2, maxULP )

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

```javascript
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 = isAlmostSameValue( z1, z2, 0 );
// returns false

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

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

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

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

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

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

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

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

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

out = isAlmostSameValue( z1, z2, 0 );
// returns false
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   The function implements the [SameValue Algorithm][ecma-262-same-value-algorithm] as specified in ECMAScript 5.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var EPS = require( '@stdlib/constants-float64-eps' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var isAlmostSameValue = require( '@stdlib/complex-float64-base-assert-is-almost-same-value' );

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

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

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

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

</section>

<!-- /.examples -->

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</section>

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* * *

## 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

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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