This is a small change addressing a potentially significant bug in how PySpark + MLlib handles non-float64 numpy arrays. The automatic conversion to `DenseVector` that occurs when passing RDDs to MLlib algorithms in PySpark should automatically upcast to float64s, but currently this wasn't actually happening. As a result, non-float64 would be silently parsed inappropriately during SerDe, yielding erroneous results when running, for example, KMeans.
The PR includes the fix, as well as a new test for the correct conversion behavior.
davies
Author: freeman <the.freeman.lab@gmail.com>
Closes#3902 from freeman-lab/fix-vector-convert and squashes the following commits:
764db47 [freeman] Add a test for proper conversion behavior
704f97e [freeman] Return array after changing type
6c6f325740