@stdlib/number-float32-base-normalize
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    0.0.6 • Public • Published

    Normalize

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    Return a normal number y and exponent exp satisfying x = y * 2^exp.

    Installation

    npm install @stdlib/number-float32-base-normalize

    Usage

    var normalizef = require( '@stdlib/number-float32-base-normalize' );

    normalizef( [out,] x )

    Returns a normal number y and exponent exp satisfying x = y * 2^exp.

    var toFloat32 = require( '@stdlib/number-float64-base-to-float32' );
    
    var out = normalizef( toFloat32( 1.401e-45 ) );
    // returns [ 1.1754943508222875e-38, -23 ]

    By default, the function returns y and exp as a two-element array.

    var toFloat32 = require( '@stdlib/number-float64-base-to-float32' );
    var pow = require( '@stdlib/math-base-special-pow' );
    
    var out = normalizef( toFloat32( 1.401e-45 ) );
    // returns [ 1.1754943508222875e-38, -23 ]
    
    var y = out[ 0 ];
    var exp = out[ 1 ];
    
    var bool = ( y*pow(2, exp) === toFloat32(1.401e-45) );
    // returns true

    To avoid unnecessary memory allocation, the function supports providing an output (destination) object.

    var toFloat32 = require( '@stdlib/number-float64-base-to-float32' );
    var Float32Array = require( '@stdlib/array-float32' );
    
    var out = new Float32Array( 2 );
    
    var v = normalizef( out, toFloat32( 1.401e-45 ) );
    // returns <Float32Array>[ 1.1754943508222875e-38, -23 ]
    
    var bool = ( v === out );
    // returns true

    The function expects a finite, non-zero single-precision floating-point number x. If x == 0,

    var out = normalizef( 0.0 );
    // returns [ 0.0, 0 ];

    If x is either positive or negative infinity or NaN,

    var PINF = require( '@stdlib/constants-float32-pinf' );
    var NINF = require( '@stdlib/constants-float32-ninf' );
    
    var out = normalizef( PINF );
    // returns [ Infinity, 0 ]
    
    out = normalizef( NINF );
    // returns [ -Infinity, 0 ]
    
    out = normalizef( NaN );
    // returns [ NaN, 0 ]

    Notes

    • While the function accepts higher precision floating-point numbers, beware that providing such numbers can be a source of subtle bugs as the relation x = y * 2^exp may not hold.

    Examples

    var randu = require( '@stdlib/random-base-randu' );
    var round = require( '@stdlib/math-base-special-round' );
    var pow = require( '@stdlib/math-base-special-pow' );
    var toFloat32 = require( '@stdlib/number-float64-base-to-float32' );
    var normalizef = require( '@stdlib/number-float32-base-normalize' );
    
    var frac;
    var exp;
    var x;
    var v;
    var i;
    
    // Generate denormalized single-precision floating-point numbers and then normalize them...
    for ( i = 0; i < 100; i++ ) {
        frac = randu() * 10.0;
        exp = 38 + round( randu()*6.0 );
        x = frac * pow( 10.0, -exp );
        x = toFloat32( x );
        v = normalizef( x );
        console.log( '%d = %d * 2^%d = %d', x, v[0], v[1], v[0]*pow(2.0, v[1]) );
    }

    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 © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/number-float32-base-normalize

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    53

    Version

    0.0.6

    License

    Apache-2.0

    Unpacked Size

    45.3 kB

    Total Files

    10

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser