Precision issue

[Cameron Laird]

In article <Ooicne5U3dhZdhuiU-KYgg at comcast.com>,
Terry Reedy <tjreedy at udel.edu> wrote:
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>It is for decimally representing, as precisely as possible *with 17
>digits*, the actual value.  I presume that 17 in the minimum necessary
>to guarantee a unique, back-convertible prepresentation for every
>float.
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Stuff in this area is difficult to express precisely.  I'm
not sure what your, "I presume that ..." means.  Here's one
way to think about that magic number:  there are "floats"
which are distinct, but agree to sixteen (decimal-)digits
of accuracy.

Some (seventeen-digit) decimals canNOT be achieved through
a round trip.
-- 

Cameron Laird <claird at phaseit.net>
Business:  http://www.Phaseit.net