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Signum

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[Signum][signum] function.

The [signum][signum] function is defined as

$Signum function$

for any real number x.

## Installation

bash
npm install @stdlib/math-base-special-signum

## Usage

javascript
var signum = require( '@stdlib/math-base-special-signum' );

#### signum( x ) Evaluates the [signum][signum] function for a double-precision floating-point number.

javascript
var sign = signum( -5.0 );
// returns -1

sign = signum( 5.0 );
// returns 1

sign = signum( -0.0 );
// returns -0

sign = signum( 0.0 );
// returns 0

sign = signum( NaN );
// returns NaN

## Notes Table of results: | Value | Sign | | ------- | ----- | | x > 0 | +1 | | x < 0 | -1 | | 0 | 0 | | -0 | -0 | | NaN | NaN |

## Examples

javascript
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var signum = require( '@stdlib/math-base-special-signum' );

var sign;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = round( randu()*100.0 ) - 50.0;
    sign = signum( x );
    console.log( 'signum(%d) = %d', x, sign );
}

## C APIs

### Usage

c
#include "stdlib/math/base/special/signum.h"

#### stdlib_base_signum( x ) Evaluates the [signum][signum] function for a double-precision floating-point number.

c
double y = stdlib_base_signum( -9.0 );
// returns -1.0

The function accepts the following arguments: - x: [in] double input value.

c
double stdlib_base_signum( const double x );

### Examples

c
#include "stdlib/math/base/special/signum.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { 3.14, -3.14, 0.0, 0.0/0.0 };

    double y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_signum( x[ i ] );
        printf( "signum(%lf) = %lf\n", x[ i ], y );
    }
}

* ## 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 © 2016-2024. The Stdlib [Authors][stdlib-authors].

Package detail

readme

Signum