Hi, It seems there are multiple places where we would like to compute row similarity (accurate or approximate similarities)
Basically through RowMatrix columnSimilarities we can compute column similarities of a tall skinny matrix Similarly we should have an API in RowMatrix called rowSimilarities where we can compute similar rows in a map-reduce fashion. It will be useful for following use-cases: 1. Generate topK users for each user from matrix factorization model 2. Generate topK products for each product from matrix factorization model 3. Generate kernel matrix for use in spectral clustering 4. Generate kernel matrix for use in kernel regression/classification I am not sure if there are already good implementation for map-reduce row similarity that we can use (ideas like fastfood and kitchen sink felt more like for classification use-case but for recommendation also user similarities show up which is unsupervised)... Is there a JIRA tracking it ? If not I can open one and we can discuss further on it. Thanks. Deb
