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Debasish Das commented on SPARK-2426: ------------------------------------- [~acopich] From your comment before "Anyway, l2 regularized stochastic matrix decomposition problem is defined as follows Minimize w.r.t. W and H : ||R - W*H|| + \lambda(||W|| + ||H||) under non-negativeness and normalization constraints. ||.|| stands for Frobenius norm (or l1).", could you please point me to a good reference with application to collaborative filtering/topic modeling ? Stochastic matrix decomposition is what we can do in this PR now https://github.com/apache/spark/pull/3221.... For MAP loss, I will open up a PR in a week through JIRA https://issues.apache.org/jira/browse/SPARK-6323...I am very curious how much slower we get compared to stochastic matrix decomposition using ALS > Quadratic Minimization for MLlib ALS > ------------------------------------ > > Key: SPARK-2426 > URL: https://issues.apache.org/jira/browse/SPARK-2426 > Project: Spark > Issue Type: New Feature > Components: MLlib > Affects Versions: 1.3.0 > Reporter: Debasish Das > Assignee: Debasish Das > Original Estimate: 504h > Remaining Estimate: 504h > > Current ALS supports least squares and nonnegative least squares. > I presented ADMM and IPM based Quadratic Minimization solvers to be used for > the following ALS problems: > 1. ALS with bounds > 2. ALS with L1 regularization > 3. ALS with Equality constraint and bounds > Initial runtime comparisons are presented at Spark Summit. > http://spark-summit.org/2014/talk/quadratic-programing-solver-for-non-negative-matrix-factorization-with-spark > Based on Xiangrui's feedback I am currently comparing the ADMM based > Quadratic Minimization solvers with IPM based QpSolvers and the default > ALS/NNLS. I will keep updating the runtime comparison results. > For integration the detailed plan is as follows: > 1. Add QuadraticMinimizer and Proximal algorithms in mllib.optimization > 2. Integrate QuadraticMinimizer in mllib ALS -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org