[ https://issues.apache.org/jira/browse/SPARK-20265?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Apache Spark reassigned SPARK-20265: ------------------------------------ Assignee: Apache Spark > Improve Prefix'span pre-processing efficiency > --------------------------------------------- > > Key: SPARK-20265 > URL: https://issues.apache.org/jira/browse/SPARK-20265 > Project: Spark > Issue Type: Improvement > Components: MLlib > Affects Versions: 2.1.0 > Reporter: Cyril de Vogelaere > Assignee: Apache Spark > Priority: Minor > Original Estimate: 0h > Remaining Estimate: 0h > > Given the sequence : > 0 4 0 1 0 2 0 5 0 2 0 4 0 5 > And supposing only item 4 and 5 are frequent. The current implementation will > clean the sequence as follow. > 0 4 0 0 0 5 0 0 4 0 5 > Which, while still giving the same results, inneficiently leave sequences of > zero. A quick change in the code can removes those sequence of zeros, while > not changing the returned solutions. > I ran test to mesure efficiency gain, they are available in the graph below : > https://postimg.org/image/9x6ireuvn/ > As you can see, the performance increase is signifiant. -- This message was sent by Atlassian JIRA (v6.3.15#6346) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org