Singular value decomposition

SVD refers to singular value decomposition in linear algebra. However, in the field of collaborative filtering, SVD often means Matrix factorization.

SVD in Math

The traditional SVD can also be used as collaborative filtering algorithm. It's also named Latent Semantic Indexing(LSI) in IR.

• Wikipedia page about SVD: http://en.wikipedia.org/wiki/Singular_value_decomposition
• Wikipedia page about LSI: http://en.wikipedia.org/wiki/Latent_semantic_indexing

Matrix Factorization

Please refer to Matrix factorization