Matrix Factorization Matrix Factorization is one of the most popular methods for collaborative filtering Given matrix r∈R*m i0)∈Rasx R each row represents an user i Rtest l While each column an item rmse ∑(0)∈Ra(R-R)2 Rtest nn目■■ nx k kx m 冒■■ n m ∑∑(R-)2+|u+21B 33Matrix Factorization • Matrix Factorization is one of the most popular methods for collaborative filtering – Given matrix 𝑅 ∈ R𝑛∗𝑚 – each row represents an user i – While each column an item j 33