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Subject: Re: [office-comment] Re: improvements for interpolation in charts
Andreas, Thanks!Are there any lists you can think of where we could appeal for help with specific items like this one? Content would have to come in over the comment list but nothing says we can't appeal for help outside the TC.
Hope you are having a great day! Patrick On 11/10/2011 07:49 PM, Andreas J. Guelzow wrote:
Hi Patrick, On Thu, 2011-11-10 at 16:54 -0700, Patrick Durusau wrote:Will you have time to review the proposal Regina references in the message with subject line: "polynomial regression curve in charts"?The proposal referenced is quite incomplete and refers to an earlier version of ODF than 1.2. It would be easy to adjust the proposal to ODF 1.2 but it is missing the specific calculation details. For example in polynomial regression it needs to be more specifically stated in which sense the "best" fit should be obtained. There are various ways this could be defined leading to different regression curves. I don't think we should include this in the standard unless we can be precise about which regression curve is intended. Since Gnumeric implements versions of this, I am obviously interested in having it included in ODF (preferably ODF 1.3), but since this is not just a question of reviewing the proposal I can't guarantee that I will have sufficient time. Sincerely AndreasThanks! Hope you are having a great week! Patrick On 11/10/2011 03:29 PM, Andreas J. Guelzow wrote:Hi Regina, On Thu, 2011-11-10 at 12:32 -0700, Regina Henschel wrote:Hi all, I have noticed, that you are discussing improvements for interpolations in charts. Currently both kind of interpolations are parametric. That gives nice curves, but for some functions the result can be better with non-parametric methods. So I want to see non-parametric interpolation methods in addition. For example my textbook "Engeln-Müllges, Gisela: Numerik-Algorithmen" suggests the "Akima Subsplines" for not smooth functions. It should be possible to use such interpolations too.In fact they should be relatively easy to implement. I'll put them on the list of interpolation methods to define (hopefully for 1.3).If the already made suggestion "fixed derivatives at both ends" includes "non-parametric" too, I would second that kind. I do not find the term "parabolic limits" besides in the description of the application "goffice". What does it mean? Is it the same as "parabolically terminated"? And what does "cubic limits" mean? [I'm no professional mathematician, but will implement those interpolations. So please excuse me, if my questions are stupid.]I really don't yet what specifically these methods are. I still have to analyse the goffice code to see what they are calculating, determine whether these are mathematically reasonable (and standard (in the sense of "accepted in the field") and then write them down in a way that non-mathematicians can implement them. I'll let you know when I have a first draft. Andreas-- Patrick Durusau patrick@durusau.net Chair, V1 - US TAG to JTC 1/SC 34 Convener, JTC 1/SC 34/WG 3 (Topic Maps) Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300 Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps) Another Word For It (blog): http://tm.durusau.net Homepage: http://www.durusau.net Twitter: patrickDurusau
-- Patrick Durusau patrick@durusau.net Chair, V1 - US TAG to JTC 1/SC 34 Convener, JTC 1/SC 34/WG 3 (Topic Maps) Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300 Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps) Another Word For It (blog): http://tm.durusau.net Homepage: http://www.durusau.net Twitter: patrickDurusau
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