Java 8 RFR 8010430: Math.round has surprising behavior for odd values of ulp 1

Brian Burkhalter brian.burkhalter at
Mon Aug 26 23:19:52 UTC 2013

On Aug 26, 2013, at 7:52 AM, Guy Steele wrote:

> On Aug 24, 2013, at 3:02 PM, Jeff Hain <jeffhain at> wrote:
>> Dmitry Nadezhin wrote:
>>> Nevertheless, I send this variant now in hope that it may be useful.
>> Great! It's much faster than what I proposed, cleaner (only integers),
>> and according to my tests it behaves the same.
> Excellent!  Nice piece of work---thanks, Dmitry.

Indeed - thanks, Dmitry! That is much better than what I proposed.

I did a quick and dirty JMH test with this code and it looks to be more than 6% faster for double and more than 24% faster for float versus the current codebase. The speed up is probably more than these values which should be considered lower bounds on speed improvement.

I have updated the webrev accordingly:

Approval by a Reviewer of this patch is still needed.



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