Xiangrui Meng ca7910d6dd [SPARK-3424][MLLIB] cache point distances during k-means|| init ... This PR ports the following feature implemented in #2634 by derrickburns: * During k-means|| initialization, we should cache costs (squared distances) previously computed. It also contains the following optimization: * aggregate sumCosts directly * ran multiple (#runs) k-means++ in parallel I compared the performance locally on mnist-digit. Before this patch:  with this patch:  It is clear that each k-means|| iteration takes about the same amount of time with this patch. Authors: Derrick Burns <derrickburns@gmail.com> Xiangrui Meng <meng@databricks.com> Closes #4144 from mengxr/SPARK-3424-kmeans-parallel and squashes the following commits: 0a875ec [Xiangrui Meng] address comments 4341bb8 [Xiangrui Meng] do not re-compute point distances during k-means||		2015-01-21 21:21:07 -08:00
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src	[SPARK-3424][MLLIB] cache point distances during k-means|| init	2015-01-21 21:21:07 -08:00
pom.xml	[SPARK-4048] Enhance and extend hadoop-provided profile.	2015-01-08 17:15:13 -08:00