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Sean Owen commented on SPARK-5766: ---------------------------------- Given that RowMatrix is a row-by-row representation, it would have to be vector-matrix multiplication I think. In principle I think you can leverage native code here; the only question is whether it overcomes the overhead of the call for typical inputs, but it's possible. > Slow RowMatrix multiplication > ----------------------------- > > Key: SPARK-5766 > URL: https://issues.apache.org/jira/browse/SPARK-5766 > Project: Spark > Issue Type: Improvement > Components: MLlib > Reporter: Amaru Cuba Gyllensten > Priority: Minor > Labels: matrix > > Looking at the source code for RowMatrix multiplication by a local matrix, it > seems like it is going through all columnvectors of the matrix, doing > pairwise dot product on each column. > It seems like this could be sped up by using gemm, performing full > matrix-matrix multiplication on the local data, (or gemv, for vector-matrix > multiplication), as is done in BlockMatrix or Matrix. -- 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