RFR 8005311: Add Scalable Updatable Variables, DoubleAccumulator, DoubleAdder, LongAccumulator, LongAdder
joe.darcy at oracle.com
Sat Jan 12 02:37:51 UTC 2013
On 01/11/2013 09:18 AM, Chris Hegarty wrote:
> On 11/01/2013 16:57, Doug Lea wrote:
>> On 01/11/13 11:35, Peter Levart wrote:
>>> On 01/11/2013 05:18 PM, Chris Hegarty wrote:
>>>> Now with explicit disclaimer on DoubleA*
>>>> "The order of accumulation within or across threads is not
>>>> guaranteed. Thus,
>>>> this class may not be applicable if numerical stability is required
>>>> combining values of substantially different orders of magnitude."
>>> It doesn't have to be substantially different order of magnitude.
>> Thanks. Chris, please add "especially":
I would prefer to cautionary note along the lines of "if you want
numerical accuracy, take care to use a summation algorithm with defined
(Varying magnitude is not so much of a problem if you add things up in
the right order.)
> Thanks Doug, done.
>> "The order of accumulation within or across threads is not guaranteed.
>> Thus, this class may not be applicable if numerical stability is
>> required, especially when combining values of substantially different
>> orders of magnitude."
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