@stdlib/math-base-special-signum
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    0.0.7 • Public • Published

    Signum

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    Signum function.

    The signum function is defined as

    Signum function

    for any real number x.

    Installation

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

    Usage

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

    signum( x )

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

    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

    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

    Installation

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

    Usage

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

    stdlib_base_signum( x )

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

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

    The function accepts the following arguments:

    • x: [in] double input value.
    double stdlib_base_signum( const double x );

    Examples

    #include "stdlib/math/base/special/signum.h"
    #include <stdio.h>
    
    int main() {
        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, 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.

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2021. The Stdlib Authors.

    Install

    npm i @stdlib/math-base-special-signum

    Homepage

    stdlib.io

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    Version

    0.0.7

    License

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