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*Subject*: **RE: [office-comment] OpenFormula: Excel FLOOR Function**

*From*:**"Dennis E. Hamilton" <dennis.hamilton@acm.org>***To*: "ODF Comments List" <office-comment@lists.oasis-open.org>*Date*: Fri, 13 Jun 2008 12:06:21 -0700

David, After I had ruminated a few hours on my remark, it occured to me that, as useful as that identity is (and how thinking about it had me want a DELTA(x) function too so I could easily tell when a number is too large to precisely represent exact integers, among other things), it is definitely not useful in an interchange situation, as you wisely point out. In fact, a translation from OpenFormula that substituted -CEILING(-x) for FLOOR(x) in going to OOXML (assuming there's really no FLOOR there) would commit the venial sin of not preserving a formula as written as closely as possible. And of course, if that formula came back into OpenFormula, it is not OK to translate -CEILING(-x) to FLOOR(x), for the same reason. This did leave me wondering about the general problem of round-tripping in these cases, and how having formulas crammed into attribute values makes it hard to provide mark-up that has a round-trip-supporting preservation function (sort of like alternate renditions), along with a related problem, disambiguating user-defined functions. So, I agree with you, although it seemed to trigger some fruitful puzzling on my part! - Dennis PS: The nice thing about FLOOR(x) = -CEILING(-x) is that it is surely an impeccable substitution, whereas computation of TAN(x) as SIN(x)/COS(x) has a number of liabilities, though not so bad as power(x, n) = EXP(n*LOG(x)). And I take your point. -----Original Message----- http://lists.oasis-open.org/archives/office-comment/200806/msg00041.html From: David A. Wheeler [mailto:dwheeler@dwheeler.com] Sent: Friday, June 13, 2008 09:07 To: office-comment@lists.oasis-open.org Cc: dennis.hamilton@acm.org Subject: Re: [office-comment] OpenFormula: Excel FLOOR Function Dennis E. Hamilton: > FLOOR(x) = -CEILING(-x) True. What I _meant_ was that there was no built-in operation to do the mathematical FLOOR operation. After all, TAN(x) = SIN(x)/COS(x) But people would rightly object if we only had SIN and COS. We should try to make it _easy_ for users to express common cases, using the functions they prefer to use. --- David A. Wheeler [ ... ]

**Follow-Ups**:**Re: [office-comment] OpenFormula: Excel FLOOR Function***From:*"David A. Wheeler" <dwheeler@dwheeler.com>

**References**:**OpenFormula: Excel FLOOR Function***From:*"Dennis E. Hamilton" <dennis.hamilton@acm.org>

**Re: [office-comment] OpenFormula: Excel FLOOR Function***From:*"David A. Wheeler" <dwheeler@dwheeler.com>

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