同埋叫你做得collaborative filtering, 應該會有missing data (唔係要你predict d咩野),咁計個exact Pearson correlation matrix 把鬼?
我識既collaborative filtering 係搵U,V兩個lower rank matrix, 令UV 大約等如 原本個movie-user rating matrix
用gradient descent, minimize X-UV 既frobenenius norm, 忽略未知既ranking
有左optimize 左既U同V,就可以估計未知既ranking
不過我唔知你個course係學咩野