A Java implementation of ListRank-MF as mentioned in: Y.Shi, M.Larson, and A.Hanjalic. List-wise Learning to Rank with Matrix Factorization for Collaborative Filtering. ACM RecSys 2010.
ListRank-MF combines a list-wise learning-to-rank algorithm with matrix factorization (MF) to produce a ranking list of items.
The program takes in input in the form (user, item, rating) pairs, seprated by a single tab. A valid input example is:
U01 I23 5.0
U01 I53 5.0
U01 I14 5.0
U01 I66 5.0
U5 I14 5.0
U77 I66 5.0
Where we have user U01 have rated item I23 a 5.0
We can run the following
ListRankMF lrmf = new ListRankMF(r);
System.out.println("User: U01 \t Item:I23: "+ lrmf.finalPrediction("U01","I23"));
to get a predicted score of item I23 for user U01. To get a ranked list for a user, we run the finalPrediction method for each item in the dataset for that user. Sorting the list in descending order in terms of the score gives us the ranked list.
The code hasn't been tested thoughrly. If you find any mistakes, please do let me know. If you use this code in any projects/research, I would like to learn more about how you used it.
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