apache/spark — pull request #687 by etrain (2014-05-08 01:18:51+00:00)
Title: Use numpy directly for matrix multiply.

Using matrix multiply to compute XtX and XtY yields a 5-20x speedup depending on problem size.

For example - the following takes 19s locally after this change vs. 5m21s before the change. (16x speedup).
bin/pyspark examples/src/main/python/als.py local[8] 1000 1000 50 10 10