RFR 8012647: Add Arrays.parallelPrefix (prefix sum, scan, cumulative sum)

[Paul Sandoz]

On Jun 12, 2013, at 4:50 PM, Chris Hegarty <chris.hegarty at oracle.com> wrote:

> Add implementations of parallelPrefix() in Arrays for Object, int, long, and double arrays.
> 
> Specdiff:
> http://cr.openjdk.java.net/~chegar/8012647/ver.00/specdiff/java/util/Arrays.html
> Webrev:
>  http://cr.openjdk.java.net/~chegar/8012647/ver.00/webrev/
> 
> This work was done over in the lambda forest mainly by Doug Lea, with some small spec updates by myself.
> 

The API looks fine to me.

The example text could be moved to an @apiNote.


> Note: Some work still need to be done to clean up the test, but I would like to focus mainly on the API and try to get it finalized first.
> 

OK, i will still note some comments on the test:

1) it could be better named;

2) uses random data, and if a test fails there is no way to reproduce from that data; and

3) Could use a sprinkling of @DataProvider for various sizes, taking into account the threshold, minimum partition size and ForkJoinPool.getCommonPoolParallelism().

Paul.