The first column shows results for the single machine implementation of <cite>[23]</cite> , the second for a 'low parallelism' configuration of our system using 50 Spark executors, minibatch size of 1, and 1 thread per executor, and the third column for a 'high parallelism' configuration again with 50 executors, but with minibatch size increased to 50 and 8 threads per executor.