Harvest

Harvest is a collaborative filtering tool for node. The envisioned use case is building recommendation engines with very little sweat. Currently harvest only supports binary choice user input e.g.: the 'like' or 'favorite' button. It persists to redis and leverages node-redis-scripting and redis-extend. NOTE: extremely early-stage and only eager developer friendly!

Usage

First adjust config.js to taste.

	harvest.subject : //could be anything depending on your app. e.g: 'likes' 'favorites' 'stars' 'liked_ppl' etc...
	harvest.threshold: //the threshold of similarity for two users to be the basis for recommendations to each other must be greater than 0 and smaller or equal to 1

Adding a 'like'

	var subject = 'likes'; //note: this could be anything based on your application
	var threshold = 0.6; //similarity threshold that two users have to cross to be be used as recommendations to each other
	var harvest = require('/path/to/harvest.js').create(subject, threshold);
	harvest.addUserElement(user_id, elements_to_add, callback);

Adding a user

	harvest.addUser(user_id, callback);

Running the filter

	node run.js
	
	//This should result in output looking like this:
	===========STARTING NEW HARVEST===========
	may take a while for large datasets........
	==========================================
	===================================
	HARVEST COMPLETED
	===================================
	USER BASE: 10
	HARVESTS: 9
	COMPARISONS: 45
	EXECUTION TIME: 14 ms
	EXECUTION RATE: 3.21 comps/ms
	====================================

Getting the user subject set

	harvest.getUserSubject(user_id, callback);
	//e.g: this may return all the 'likes' of a user

Getting the user harvest set

	harvest.getUserHarvest(user_id, callback);
	//this would return all the 'recommendations' harvested

Running tests

	//just populate a test db (uses db 10)
	node tests/populate.js [num of users] [num of els per user]
	//run full test (populate + filter)
	node tests/harvest.test.js [num of users] [num of els per user]