@stdlib/math-base-special-flipsign
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    0.0.5 • Public • Published

    Flipsign

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    Return a double-precision floating-point number with the magnitude of x and the sign of x*y.

    Installation

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

    Usage

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

    flipsign( x, y )

    Returns a double-precision floating-point number with the magnitude of x and the sign of x*y; i.e., only return -x when y is a negative number.

    var z = flipsign( -3.14, 10.0 );
    // returns -3.14
    
    z = flipsign( -3.14, -1.0 );
    // returns 3.14
    
    z = flipsign( 1.0, -0.0 );
    // returns -1.0
    
    z = flipsign( -3.14, -0.0 );
    // returns 3.14
    
    z = flipsign( -0.0, 1.0 );
    // returns -0.0
    
    z = flipsign( 0.0, -1.0 );
    // returns -0.0

    Notes

    • According to the IEEE 754 standard, a NaN has a biased exponent equal to 2047, a significand greater than 0, and a sign bit equal to either 1 or 0. In which case, NaN may not correspond to just one but many binary representations. Accordingly, care should be taken to ensure that y is not NaN, else behavior may be indeterminate.

    Examples

    var randu = require( '@stdlib/random-base-randu' );
    var flipsign = require( '@stdlib/math-base-special-flipsign' );
    
    var x;
    var y;
    var z;
    var i;
    
    // Generate random double-precision floating-point numbers `x` and `y` and flip the sign of `x` only if `y` is negative...
    for ( i = 0; i < 100; i++ ) {
        x = (randu()*100.0) - 50.0;
        y = (randu()*10.0) - 5.0;
        z = flipsign( x, y );
        console.log( 'x: %d, y: %d => %d', x, y, z );
    }

    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-flipsign

    Homepage

    stdlib.io

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    Version

    0.0.5

    License

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    38.8 kB

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    9

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    Collaborators

    • stdlib-bot
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    • planeshifter
    • rreusser