# 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