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Pat Ferrel commented on MAHOUT-2019: ------------------------------------ This may be a non-issue: Trevor said in email: {quote}The spark is included via maven classifier- the sbt line should be libraryDependencies += "org.apache.mahout" % "mahout-spark_2.11" % "0.13.1-SNAPSHOT" classifier "spark_2.1" {quote} > SparseRowMatrix assign ops user for loops instead of iterateNonZero and so > can be optimized > ------------------------------------------------------------------------------------------- > > Key: MAHOUT-2019 > URL: https://issues.apache.org/jira/browse/MAHOUT-2019 > Project: Mahout > Issue Type: Bug > Components: Math > Affects Versions: 0.13.0 > Reporter: Pat Ferrel > Assignee: Pat Ferrel > Fix For: 0.13.1 > > > DRMs get blockified into SparseRowMatrix instances if the density is low. But > SRM inherits the implementation of method like "assign" from AbstractMatrix, > which uses nest for loops to traverse rows. For multiplying 2 matrices that > are extremely sparse, the kind if data you see in collaborative filtering, > this is extremely wasteful of execution time. Better to use a sparse vector's > iterateNonZero Iterator for some function types. -- This message was sent by Atlassian JIRA (v6.4.14#64029)