Description
ALS returns a matrix factorization model, which we can use to predict ratings for individual queries as well as small batches. In practice, users may want to compute top-k recommendations offline for all users. It is very expensive but a common problem. We can do some optimization like
1) collect one side (either user or product) and broadcast it as a matrix
2) use level-3 BLAS to compute inner products
3) use Utils.takeOrdered to find top-k
Attachments
Issue Links
- is duplicated by
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SPARK-4231 Add RankingMetrics to examples.MovieLensALS
- Resolved
- is related to
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SPARK-4823 rowSimilarities
- Resolved
- relates to
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SPARK-11968 ALS recommend all methods spend most of time in GC
- Resolved
- links to