Re: sigmoid curve fitting in trend lines

[James Salsman <jsalsman@gmail.com>]

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