You are correct, in the long run it doesn't matter which matrix you begin the iterative process with. I was thinking in terms of doing a side-by-side comparison to Oryx.
I've posted a bug report as SPARK-1262. I described the problem I found and the mitigation strategy I've used. I think that this problem has many possible solutions, so I'm omitting a patch to let the community hash out the best approach. However, I will suggest we move to a pure Java implementation of a linear system solver to provide better assurances of correctness across platforms (differences in java.lang.Math notwithstanding) and to make the implementation more transparent. It is not clear exactly what native code JBlas is linked to and using for its solver. I suggested the QR decomposition-based solvers provided by Colt and Commons Math as candidate replacements. Cheers. -- View this message in context: http://apache-spark-user-list.1001560.n3.nabble.com/possible-bug-in-Spark-s-ALS-implementation-tp2567p2783.html Sent from the Apache Spark User List mailing list archive at Nabble.com.
