[PATCH] Sunbug 7131192: Optimize BigInteger.doubleValue(), floatValue()

[Louis Wasserman]

Any update on when this could get reviewed?


On Thu, Dec 13, 2012 at 3:36 PM, Louis Wasserman <lowasser at google.com>wrote:

> Hi,
>
> I'm working at Google now, but I'd like to revive this patch as a
> contribution from Google.  At the moment, what's mainly needed is review
> for http://bugs.sun.com/view_bug.do?bug_id=7192954, the fix to
> Float.parseFloat's rounding behavior, before we can go anywhere with the
> patch to optimize BigInteger.floatValue() and doubleValue().
>
>> Would anyone be able to review that patch so these can start moving
> forward?
>
> Thanks,
>
>> Louis Wasserman
> Java Core Libraries Team @ Google
> guava-libraries.googlecode.com
>
> ---------- Forwarded message ----------
>> From: Louis Wasserman <wasserman.louis at gmail.com>
>> Date: Sat, Jul 14, 2012 at 5:32 AM
>> Subject: Re: [PATCH] Sunbug 7131192: Optimize BigInteger.doubleValue(),
>> floatValue()
>> To: Joseph Darcy <joe.darcy at oracle.com>
>> Cc: Andrew Haley <aph at redhat.com>, core-libs-dev at openjdk.java.net
>>
>>
>> Understood.  FYI, testing for this change revealed a bug in
>> Float.parseFloat, a patch for which has been separately sent to this
>> mailing list under the subject line "[PATCH] Sunbug 6358355: Rounding error
>> in Float.parseFloat".  (As a result, the BigInteger patch may fail some of
>> the provided tests at the moment, but that is truly because the reference
>> implementation it's being tested against is faulty.)
>>
>> Louis Wasserman
>> wasserman.louis at gmail.com
>> http://profiles.google.com/wasserman.louis
>>
>>
>> On Sat, Jul 14, 2012 at 2:20 AM, Joseph Darcy <joe.darcy at oracle.com>wrote:
>>
>>> Hello,
>>>
>>> Thanks for the patch Louis.
>>>
>>>
>>> On 7/12/2012 3:21 AM, Andrew Haley wrote:
>>>
>>>> On 07/12/2012 10:32 AM, Louis Wasserman wrote:
>>>>
>>>>> It was attached to the previous message?  I don't know if this list
>>>>> works
>>>>> with attachments.  Alternately, the patch was attached here:
>>>>> https://bugs.openjdk.java.net/**show_bug.cgi?id=100222<https://bugs.openjdk.java.net/show_bug.cgi?id=100222>
>>>>>
>>>>> I'm not sure what you mean by double-rounding bugs, though.  It's
>>>>> not difficult to actually implement the HALF_EVEN rounding behavior
>>>>> with bit twiddling.
>>>>>
>>>> Sure, as long as you've thought about it and done it carefully.  The
>>>> bit twiddling is easy to do, and easy to get wrong.
>>>>
>>>> > From the supplied patch it looks like you've done a good job, but
>>>> there was no way to tell without it.  I presume the listserv dropped
>>>> it on the floor.
>>>>
>>>> Andrew.
>>>>
>>>
>>> I've taken a quick look at the patch.  The concept for the change is
>>> good; the current path of converting to float/double through a string is a
>>> simple but very roundabout way to accomplish this task.
>>>
>>> Unfortunately, I'm saturated with the JDK bug migration [1] and will
>>> continue to be saturated for at least several more weeks so I won't be able
>>> to take a more detailed look at the patch for a while.  I suspect some more
>>> directly test cases will be needed to test tricky rounding situations.
>>>
>>> Thanks,
>>>
>>> -Joe
>>>
>>> [1] https://blogs.oracle.com/**darcy/entry/moving_monarchs_**dragons<https://blogs.oracle.com/darcy/entry/moving_monarchs_dragons>
>>>
>>
>>
>>
>
>
> --
> Louis Wasserman
>



-- 
Louis Wasserman