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Re: [Json] I-JSON Topic #5: Numbers

John Cowan <cowan@mercury.ccil.org> Wed, 21 May 2014 18:32 UTC

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Date: Wed, 21 May 2014 14:32:27 -0400
From: John Cowan <cowan@mercury.ccil.org>
To: Carsten Bormann <cabo@tzi.org>
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References: <CF841AAE.47D86%jhildebr@cisco.com> <CAHBU6itK5HtSTPWSsHsHUPja90emqU86LsgjrBorkqcUDivS2A@mail.gmail.com> <CF87EB9C.48BB0%jhildebr@cisco.com> <537A5BE0.3020406@cisco.com> <CF9FCEC9.4A4E7%jhildebr@cisco.com> <488AE66E-725D-40B3-9FDA-ADA1018BCF65@tzi.org> <CFA0F09E.4A609%jhildebr@cisco.com> <255B9BB34FB7D647A506DC292726F6E115461FFE59@WSMSG3153V.srv.dir.telstra.com> <20140521020731.GG9283@mercury.ccil.org> <0374DE58-FC77-4CCA-B100-186C1A0701D4@tzi.org>
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Subject: Re: [Json] I-JSON Topic #5: Numbers
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Carsten Bormann scripsit:

> > as an exact value
> 
> What is your definition of this term here?
> 
> The meaning I’m used to for “exact value” implies you shouldn’t
> expect a binary64-based implementation to treat 1.1 as an exact value.

There is a binary64 number which differs from 1.1 by less than an ulp,
and may be identified with it.  This is distinct from the fact
that 1.1 + 1.1 + ... + 1.1 (ten times) is not equal to 11.

-- 
John Cowan          http://www.ccil.org/~cowan        cowan@ccil.org
Newbies always ask:
  "Elements or attributes?
Which will serve me best?"
  Those who know roar like lions;
  Wise hackers smile like tigers.         --a tanka, or extended haiku

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