Generates Recommendations and Predictions using Collaborative Filtering (CF) 
Approaches including, Item-based Memory, User-based Memory, SVD Item Based,
SVD User Based and Incremental SVD.

Copyright (c) 2012 Serdar Yildirim [[email protected]]
Blog post: http://serdaryildirim.net/ai/recommender-systems-collaborative-filtering-approach.html

licence? MIT

notes
- MovieLens data files are not included. Only change is made for 100K dataset as follows:
Value separation characters are changed from space (' ') to "|" (u.data, ua.base, ua.test files)

credits
MovieLens data: http://www.grouplens.org/node/73
Incremental SVD Algorithm: http://sifter.org/~simon/journal/20061211.html

requirements
linalg: This gem should be installed for matrix operations.
For Mac Os X installation, please check: 
http://www.quora.com/Installation-Instructions/How-do-I-install-Ruby-linalg-library-on-Mac