stablematch

A pure javascript implementation of a Stable Matching Algorithm, which is used to provide a solution to the stable marriage problem (http://wikipedia.org/wiki/Stable_marriage_problem) using a left-optimized algorithm.

The core implementation was shamelessly scrubbed and adapted from the "toy" implementation by Paul Butler (https://github.com/paulgb/Python-Gale-Shapley/), adapted to javascript and improved to support asymmetric data sets.

Installation

This is the easy part, provided you have npm installed:

npm install stablematch

Usage

Here is an example of how to pair up two six-element sets. Note the use of amdefine, which allows stablematch to be used in any javascript-enabled context.

`` if ( typeof(define) !== 'function' ) var define = require('amdefine')(module);

define(['stablematch'], function(sma) {

// setup two sets that will be paired var setA = ['1','2','3','4','5','6']; var setB = ['a','b','c','d','e','f'];

// callback function rankA returns the preference order // of setB given any element in setA. var rankA = function(a) { switch ( a ) { case '1': return ['a', 'd', 'b', 'f', 'e', 'c']; case '2': return ['c', 'a', 'b', 'd', 'e', 'f']; case '3': return ['a', 'b', 'd', 'c', 'e', 'f']; case '4': return ['d', 'a', 'b', 'e', 'c', 'f']; case '5': return ['a', 'b', 'c', 'f', 'd', 'e']; case '6': return ['b', 'a', 'd', 'c', 'e', 'f']; default: throw 'no such element "' + a + '" in set A'; } };

// callback function rankB returns the preference order // of setA given any element in setB. var rankB = function(b) { switch ( b ) { case 'a': return ['1', '2', '3', '4', '5', '6']; case 'b': return ['2', '1', '4', '3', '5', '6']; case 'c': return ['5', '1', '6', '3', '2', '4']; case 'd': return ['1', '3', '2', '5', '4', '6']; case 'e': return ['4', '1', '3', '6', '2', '5']; case 'f': return ['2', '1', '4', '3', '6', '5']; default: throw 'no such element "' + b + '" in set B'; } };

// call stablematch.match() to pair all of the elements. var solution = sma.match(setA, setB, rankA, rankB);

// solution ::= // [ // ['1', 'a'], ['2', 'b'], ['3', 'd'], // ['4', 'e'], ['5', 'c'], ['6', 'f'] // ]

}); `` Performance and Optimality

The implementation is not intended to be the world's best... it was, after all, a quick-n-dirty implementation done one Saturday morning just so that a basic pairing could be done inside the syncml-js package...

If you care to improve it in any way, please do so! I'll accept any pull requests that don't break it and improve performance.