What is the use of recommender system?

What is the use of recommender system?

Recommender system has the ability to predict whether a particular user would prefer an item or not based on the user’s profile. Recommender systems are beneficial to both service providers and users [3]. They reduce transaction costs of finding and selecting items in an online shopping environment [4].

Why item based collaborative filtering is better?

Results. Item-item collaborative filtering had less error than user-user collaborative filtering. In addition, its less-dynamic model was computed less often and stored in a smaller matrix, so item-item system performance was better than user-user systems.

What is alternating least squares (ALS) matrix factorisation?

Alternating Least Squares (ALS) matrix factorisation attempts to estimate the ratings matrix R as the product of two lower-rank matrices, X and Y, i.e. X * Yt = R. Typically these approximations are called ‘factor’ matrices. The general approach is iterative.

What is ALS algorithm in machine learning?

ALS (Alternating Least Squares) is an implicit recommendation algorithm to make a recommendation of products and product categories to the users. ALS is an iterative optimization process where for every iteration it tries to arrive closer and closer to a factorized representation of the original data. R (nxm) = U (nxp) xV (pxm)

What is alternating least squares algorithm?

Alternating least squares does just that. It is a two-step iterative optimization process. In every iteration it first fixes P and solves for U, and following that it fixes U and solves for P. Since OLS solution is unique and guarantees a minimal MSE, in each step the cost function can either decrease or stay unchanged, but never increase.

What is alternating least squares (OLS)?

The solution is ultimately given by the Ordinary Least Squares (OLS) formula . Alternating least squares does just that. It is a two-step iterative optimization process. In every iteration it first fixes P and solves for U, and following that it fixes U and solves for P.