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NNTP-Posting-Date: Sat, 14 May 2011 15:25:49 -0500
Date: Sat, 14 May 2011 13:25:48 -0700
From: Patricia Shanahan <pats@acm.org>
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Subject: Re: Java puzzler
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On 5/14/2011 12:08 PM, Joshua Cranmer wrote:
> On 05/14/2011 11:09 AM, Patricia Shanahan wrote:
>> double d = Double.MAX_VALUE;
>> double e = (d + d) - d;
>>
>> The correct result is Double.POSITIVE_INFINITY, not Double.MAX_VALUE.
>
> I haven't double-checked, but isn't this only necessarily the case if
> the method is strictfp? Or does non-strictfp merely only permit extended
> precision in the mantissa and not the exponent?
>

Good point. If the expression is not strictfp, the addition result can
be expressed in the double-extended-exponent value set, which allows for
a finite answer.

Patricia