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Re: [Mingw-users] msvcrt printf bug




On 2/5/2017 1:02 PM, Emanuel Falkenauer wrote:
>>> [...]
> Alexandru, myself and (it appears) at least a few others, would like to
> have a decimal print that could (at least) reliably distinguish between
> ANY two binary floats, and represent two identical binary floats THE
> SAME way (that's the (2) above), even though we ALL KNOW that each of
> the binary floats is the result of an "approximate" computation(s)
> (that's the (1) above).

No problem with the above.

There is definitely a difference in perspective, maybe quite 
subtle. Let me try and illustrate an example -- just an example, 
not implying anything positive or negative about anyone or anything.

 From Rick Regan's site:

http://www.exploringbinary.com/17-digits-gets-you-there-once-youve-found-your-way/

Everything is correct. But it's like a mathematician's 
perspective. 23*log(2) => ~7 and 53*log(2) => ~16 -- so in 'normal 
use', for inserting decimal values into single and double binary 
formats I would not use more than 7/16 digits. But Rick found 
conversion bugs. As an 'end user' if I really wanted to calculate 
values that are 9/17 digits, I would use the next better binary 
format e.g. 128 bits for the latter. From my 'user's view', it is 
a non-issue, I use what's appropriate, yet for the conditions set 
by Rick, it is a bug.

Interesting, no?

-- 
Cheers,
Kein-Hong Man (esq.)
Selangor, Malaysia


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