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<!--

@license Apache-2.0

Copyright (c) 2026 The Stdlib Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

-->

# isNegativeZero

> Test if a half-precision floating-point numeric value is negative zero.

<section class="usage">

## Usage

```javascript
var isNegativeZero = require( '@stdlib/number/float16/base/assert/is-negative-zero' );
```

#### isNegativeZero( x )

Tests if a half-precision floating-point `numeric` value is negative zero.

```javascript
var bool = isNegativeZero( -0.0 );
// returns true

bool = isNegativeZero( 0.0 );
// returns false
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

```javascript
var isNegativeZero = require( '@stdlib/number/float16/base/assert/is-negative-zero' );

var bool = isNegativeZero( -0.0 );
// returns true

bool = isNegativeZero( 0.0 );
// returns false

bool = isNegativeZero( 5.0 );
// returns false

bool = isNegativeZero( -1.0 );
// returns false

bool = isNegativeZero( NaN );
// returns false
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

</section>

<!-- /.links -->
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/**
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var bench = require( '@stdlib/bench' );
var uniform = require( '@stdlib/random/array/uniform' );
var toFloat16 = require( '@stdlib/number/float64/base/to-float16' );
var map = require( '@stdlib/array/base/map' );
var naryFunction = require( '@stdlib/utils/nary-function' );
var isBoolean = require( '@stdlib/assert/is-boolean' ).isPrimitive;
var pkg = require( './../package.json' ).name;
var isNegativeZero = require( './../lib' );


// MAIN //

bench( pkg, function benchmark( b ) {
var x;
var y;
var i;

x = map( uniform( 100, -5.0e4, 5.0e4 ), naryFunction( toFloat16, 1 ) );

b.tic();
for ( i = 0; i < b.iterations; i++ ) {
y = isNegativeZero( x[ i%x.length ] );
if ( typeof y !== 'boolean' ) {
b.fail( 'should return a boolean' );
}
}
b.toc();
if ( !isBoolean( y ) ) {
b.fail( 'should return a boolean' );
}
b.pass( 'benchmark finished' );
b.end();
});
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{{alias}}( x )
Tests if a half-precision floating-point numeric value is negative zero.

Parameters
----------
x: number
Value to test.

Returns
-------
bool: boolean
Boolean indicating whether the value is negative zero.

Examples
--------
> var bool = {{alias}}( -0.0 )
true
> bool = {{alias}}( 0.0 )
false

See Also
--------

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/*
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

// TypeScript Version: 4.1

/**
* Tests if a half-precision floating-point numeric value is negative zero.
*
* @param x - value to test
* @returns boolean indicating whether the value is negative zero
*
* @example
* var bool = isNegativeZero( -0.0 );
* // returns true
*
* @example
* var bool = isNegativeZero( 0.0 );
* // returns false
*/
declare function isNegativeZero( x: number ): boolean;


// EXPORTS //

export = isNegativeZero;
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/*
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

import isNegativeZero = require( './index' );


// TESTS //

// The function returns a boolean...
{
isNegativeZero( 0 ); // $ExpectType boolean
isNegativeZero( -0 ); // $ExpectType boolean
isNegativeZero( 2 ); // $ExpectType boolean
}

// The compiler throws an error if the function is provided a value other than a number...
{
isNegativeZero( true ); // $ExpectError
isNegativeZero( false ); // $ExpectError
isNegativeZero( null ); // $ExpectError
isNegativeZero( undefined ); // $ExpectError
isNegativeZero( [] ); // $ExpectError
isNegativeZero( {} ); // $ExpectError
isNegativeZero( ( x: number ): number => x ); // $ExpectError
}

// The compiler throws an error if the function is provided an unsupported number of arguments...
{
isNegativeZero(); // $ExpectError
isNegativeZero( undefined, 123 ); // $ExpectError
}
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/**
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

var isNegativeZero = require( './../lib' );

console.log( isNegativeZero( -0.0 ) );
// => true

console.log( isNegativeZero( 0.0 ) );
// => false

console.log( isNegativeZero( 5.0 ) );
// => false

console.log( isNegativeZero( -1.0 ) );
// => false

console.log( isNegativeZero( NaN ) );
// => false
Original file line number Diff line number Diff line change
@@ -0,0 +1,43 @@
/**
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

/**
* Test if a half-precision floating-point numeric value is negative zero.
*
* @module @stdlib/number/float16/base/assert/is-negative-zero
*
* @example
* var isNegativeZero = require( '@stdlib/number/float16/base/assert/is-negative-zero' );
*
* var bool = isNegativeZero( -0.0 );
* // returns true
*
* bool = isNegativeZero( 0.0 );
* // returns false
*/

// MODULES //

var main = require( './main.js' );


// EXPORTS //

module.exports = main;
Original file line number Diff line number Diff line change
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/**
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var NINF = require( '@stdlib/constants/float16/ninf' );


// MAIN //

/**
* Tests if a half-precision floating-point numeric value is negative zero.
*
* @param {number} x - value to test
* @returns {boolean} boolean indicating whether the value is negative zero
*
* @example
* var bool = isNegativeZero( -0.0 );
* // returns true
*
* @example
* var bool = isNegativeZero( 0.0 );
* // returns false
*/
function isNegativeZero( x ) {
return (x === 0.0 && 1.0/x === NINF);
}


// EXPORTS //

module.exports = isNegativeZero;
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