Returns an integer corresponding to the unbiased exponent of a double-precision floating-point number.
npm install math-float64-exponentExponent
===
[![NPM version][npm-image]][npm-url] [![Build Status][build-image]][build-url] [![Coverage Status][coverage-image]][coverage-url] [![Dependencies][dependencies-image]][dependencies-url]
> Returns an integer corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].
`` bash`
$ npm install math-float64-exponent
` javascript`
var exponent = require( 'math-float64-exponent' );
#### exponent( x )
Returns an integer corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].
` javascript
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
`
` javascript
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,
` bash`
$ node ./examples/index.js
---
This repository uses [tape][tape] for unit tests. To run the tests, execute the following command in the top-level application directory:
` bash`
$ make test
All new feature development should have corresponding unit tests to validate correct functionality.
This repository uses [Istanbul][istanbul] as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:
` bash`
$ make test-cov
Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,
` bash`
$ make view-cov
This repository uses [Testling][testling] for browser testing. To run the tests in a (headless) local web browser, execute the following command in the top-level application directory:
` bash`
$ make test-browsers
To view the tests in a local web browser,
` bash``
$ make view-browser-tests
---
Copyright © 2016. The [Compute.io][compute-io] Authors.
[npm-image]: http://img.shields.io/npm/v/math-float64-exponent.svg
[npm-url]: https://npmjs.org/package/math-float64-exponent
[build-image]: http://img.shields.io/travis/math-io/float64-exponent/master.svg
[build-url]: https://travis-ci.org/math-io/float64-exponent
[coverage-image]: https://img.shields.io/codecov/c/github/math-io/float64-exponent/master.svg
[coverage-url]: https://codecov.io/github/math-io/float64-exponent?branch=master
[dependencies-image]: http://img.shields.io/david/math-io/float64-exponent.svg
[dependencies-url]: https://david-dm.org/math-io/float64-exponent
[dev-dependencies-image]: http://img.shields.io/david/dev/math-io/float64-exponent.svg
[dev-dependencies-url]: https://david-dm.org/dev/math-io/float64-exponent
[github-issues-image]: http://img.shields.io/github/issues/math-io/float64-exponent.svg
[github-issues-url]: https://github.com/math-io/float64-exponent/issues
[tape]: https://github.com/substack/tape
[istanbul]: https://github.com/gotwarlost/istanbul
[testling]: https://ci.testling.com
[compute-io]: https://github.com/compute-io/
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985