@stdlib/math-base-special-signumf NPM

Signum

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Signum function.

The signum function is defined as

for any real number x.

Installation

npm install @stdlib/math-base-special-signumf

Usage

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

signumf( x )

Evaluates the signum function for a single-precision floating-point number.

var sign = signumf( -5.0 );
// returns -1

sign = signumf( 5.0 );
// returns 1

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

sign = signumf( 0.0 );
// returns 0

sign = signumf( NaN );
// returns NaN

Notes

Table of results:

Value	Sign
`x > 0`	`+1`
`x < 0`	`-1`
`0`	`0`
`-0`	`-0`
`NaN`	`NaN`

Examples

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

var sign;
var x;
var i;

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

C APIs

Usage

#include "stdlib/math/base/special/signumf.h"

stdlib_base_signumf( x )

Evaluates the signum function for a single-precision floating-point number.

float y = stdlib_base_signumf( -9.0f );
// returns -1.0f

The function accepts the following arguments:

x: [in] float input value.

float stdlib_base_signumf( const float x );

Examples

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

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

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

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.