Xiangrui Meng e4e8d8f395 [SPARK-1237, 1238] Improve the computation of YtY for implicit ALS ... Computing YtY can be implemented using BLAS's DSPR operations instead of generating y_i y_i^T and then combining them. The latter generates many k-by-k matrices. On the movielens data, this change improves the performance by 10-20%. The algorithm remains the same, verified by computing RMSE on the movielens data. To compare the results, I also added an option to set a random seed in ALS. JIRA: 1. https://spark-project.atlassian.net/browse/SPARK-1237 2. https://spark-project.atlassian.net/browse/SPARK-1238 Author: Xiangrui Meng <meng@databricks.com> Closes #131 from mengxr/als and squashes the following commits: ed00432 [Xiangrui Meng] minor changes d984623 [Xiangrui Meng] minor changes 2fc1641 [Xiangrui Meng] remove commented code 4c7cde2 [Xiangrui Meng] allow specifying a random seed in ALS 200bef0 [Xiangrui Meng] optimize computeYtY and updateBlock		2014-03-13 00:43:19 -07:00
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data	Added Java unit test, data, and main method for Naive Bayes	2014-01-11 22:30:48 -08:00
src	[SPARK-1237, 1238] Improve the computation of YtY for implicit ALS	2014-03-13 00:43:19 -07:00
pom.xml	SPARK-1193. Fix indentation in pom.xmls	2014-03-07 23:10:35 -08:00