Computes the greatest common divisor (gcd).
npm install compute-gcdGreatest Common Divisor
===
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> Computes the greatest common divisor (gcd).
Note: the gcd is also known as the __greatest common factor__ (gcf), __highest common factor__ (hcf), __highest common divisor__, and __greatest common measure__ (gcm).
`` bash`
$ npm install compute-gcd
For use in the browser, use browserify.
` javascript`
var gcd = require( 'compute-gcd' );
#### gcd( a, b[, c,...,n] )
Computes the greatest common divisor (gcd) of two or more integers.
` javascript
var val = gcd( 48, 18 );
// returns 6
var val = gcd( 8, 12, 16 );
// returns 4
`
#### gcd( arr[, accessor] )
Computes the greatest common divisor (gcd) of two or more integers.
` javascript
var val = gcd( [48, 18] );
// returns 6
var val = gcd( [8, 12, 16] );
// returns 4
`
For object arrays, provide an accessor function for accessing array values
` javascript
var data = [
['beep', 4],
['boop', 8],
['bap', 12],
['baz', 16]
];
function getValue( d, i ) {
return d[ 1 ];
}
var arr = gcd( arr, getValue );
// returns 4
`
- For more than 3 values, a performance gain can be achieved if the values are sorted in ascending order.
- If provided an array with a length less than 2 or a single integer argument, the function returns null.
` javascript
var gcd = require( 'compute-gcd' );
// Compute the gcd of random tuples...
var x, y, z, arr, val;
for ( var i = 0; i < 100; i++ ) {
x = Math.round( Math.random()*50 );
y = Math.round( Math.random()*50 );
z = Math.round( Math.random()*50 );
arr = [ x, y, z ];
val = gcd( arr );
console.log( arr, val );
}
`
To run the example code from the top-level application directory,
` bash`
$ node ./examples/index.js
Unit tests use the Mocha test framework with Chai assertions. 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 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
---
Copyright © 2014-2015. Athan Reines.
[npm-image]: http://img.shields.io/npm/v/compute-gcd.svg
[npm-url]: https://npmjs.org/package/compute-gcd
[travis-image]: http://img.shields.io/travis/compute-io/gcd/master.svg
[travis-url]: https://travis-ci.org/compute-io/gcd
[coveralls-image]: https://img.shields.io/coveralls/compute-io/gcd/master.svg
[coveralls-url]: https://coveralls.io/r/compute-io/gcd?branch=master
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[dependencies-url]: https://david-dm.org/compute-io/gcd
[dev-dependencies-image]: http://img.shields.io/david/dev/compute-io/gcd.svg
[dev-dependencies-url]: https://david-dm.org/dev/compute-io/gcd
[github-issues-image]: http://img.shields.io/github/issues/compute-io/gcd.svg
[github-issues-url]: https://github.com/compute-io/gcd/issues