Cyril de Vogelaere created SPARK-20265: ------------------------------------------
Summary: 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 Priority: Minor 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 : http://i67.tinypic.com/29ljswy.jpg 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