math-float64-exponent

    1.0.0 • Public • Published

    Exponent

    NPM version Build Status Coverage Status Dependencies

    Returns an integer corresponding to the unbiased exponent of a double-precision floating-point number.

    Installation

    $ npm install math-float64-exponent

    Usage

    var exponent = require( 'math-float64-exponent' );

    exponent( x )

    Returns an integer corresponding to the unbiased exponent of a double-precision floating-point number.

    var exp = exponent( 3.14e307 );
    // returns 1021 => 2**1021 ~ 1e307
     
    var exp = exponent( 3.14e-307 );
    // returns -1019 => 2**-1019 ~ 1e-307
     
    exp = exponent( -3.14 );
    // returns 1
     
    exp = exponent( 0 );
    // returns 0
     
    exp = exponent( NaN );
    // returns 1024 => 2**1024 ~ infinity

    Examples

    var round = require( 'math-round' );
    var pow = require( 'math-power' );
    var exponent = require( 'math-float64-exponent' );
     
    var frac;
    var exp;
    var x;
    var e;
    var i;
     
    // Generate random numbers and extract their exponents...
    for ( i = 0; i < 100; i++ ) {
        frac = Math.random() * 10;
        exp = round( Math.random()*646 ) - 323;
        x = frac * pow( 10, exp );
        e = exponent( x );
        console.log( 'x: %d. unbiased exponent: %d.', x, e );
    }

    To run the example code from the top-level application directory,

    $ node ./examples/index.js

    Tests

    Unit

    This repository uses tape for unit tests. To run the tests, execute the following command in the top-level application directory:

    $ make test

    All new feature development should have corresponding unit tests to validate correct functionality.

    Test Coverage

    This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

    $ make test-cov

    Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

    $ make view-cov

    Browser Support

    This repository uses Testling for browser testing. To run the tests in a (headless) local web browser, execute the following command in the top-level application directory:

    $ make test-browsers

    To view the tests in a local web browser,

    $ make view-browser-tests

    License

    MIT license.

    Copyright

    Copyright © 2016. The Compute.io Authors.

    Install

    npm i math-float64-exponent

    DownloadsWeekly Downloads

    2,174

    Version

    1.0.0

    License

    MIT

    Last publish

    Collaborators

    • kgryte