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Subject: Re: sigmoid curve fitting in trend lines
Dear Mr. Weir: In my request below, on the line beginning "Gompertz sigmoid" please change the word "logistic" to "Gompertz". Thank you. Best regards, James Salsman On Thu, Feb 23, 2012 at 7:05 PM, James Salsman <jsalsman@gmail.com> wrote: > Rob Weir > Chair > OASIS Open Document Format for Office Applications (OpenDocument) > Technical Committee > > Dear Mr. Weir: > > True exponential curves do not actually exist in economics, biology, > or any other finite field. They are all sigmoid curves such as the > logistic or Gompertz curve. Offering users the ability to fit a trend > line to an exponential curve but not a logistic and Gompertz sigmoid > does them a disservice, and makes it much more likely that they will > make extrapolation errors. > > Therefore, I request that you modify OASIS Standard > OpenDocument-v1.2-part1, Section 20.43, "chart:regression-type" [ > http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part1.html#__RefHeading__1419514_253892949 > ] as follows: > > At the end of the bulleted list under "The defined values for the > chart:regression-type attribute are:", please add: > > "* logistic sigmoid – Regression with a logistic sigmoid function – > approximate the values of the series using the model: y = > A+B/(1+e^(-(x-C)/D)) > > "* Gompertz sigmoid – Regression with a logistic sigmoid function – > approximate the values of the series using the model: y = > A+B·e^(C·e^(D·x))" > > Please let me know by email to jps-oasis-regression@talknicer.com if > you have any questions about this request. Thank you. > > Best regards, > James Salsman > > Ref.: https://bugs.freedesktop.org/show_bug.cgi?id=46539
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