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Subject: Re: sigmoid curve fitting in trend lines
P.S. In https://bugs.freedesktop.org/show_bug.cgi?id=46539 ("sigmoid curve fitting in trend lines") I mentioned some open source free software which implement those algorithms: Here is how to do it in R: http://thebiobucket.blogspot.com/2011/04/fit-sigmoid-curve-with-confidence.html and Matlab/Octave: http://www.mathworks.com/matlabcentral/newsreader/view_thread/169459 I hope that solves most of the problem for developers. --James Salsman On Wed, Oct 24, 2012 at 7:43 PM, James Salsman <jsalsman@gmail.com> wrote: > Patrick, > > Thank you for your question. > > First, please change "Gompertz sigmoid – Regression with a > logistic...." to "Gompertz sigmoid – Regression with a Gompertz...." > on the fifth line of my original request below. I'm sorry about that > typo, and I tried to fix it, but it apparently didn't get fixed in my > request. > > As for the methods of calculating the parameters for fitting those two > very important curves, instead of trying to describe them, could you > please reference these authoritative descriptions of the algorithms > instead? > > For logistic curve fitting: J. A. Nelder (March 1961) "The Fitting of > a Generalization of the Logistic Curve" _Biometrics_ vol. 17, no. 1, > pp. 89-110: http://www.jstor.org/stable/2527498 > > For Gompertz curve fitting: Karl W. Kaufmann (1981) "Fitting and using > growth curves" _Oecologia_ vol. 49, no. 3, pp. 293-299: > http://www.springerlink.com/content/w153v81q72400q62 > > Please let me know if I can help any further. > > Best regards, > James Salsman > > > On Wed, Oct 24, 2012 at 3:28 PM, Patrick Durusau <patrick@durusau.net> wrote: >> James, >> >> With regard to your request for the addition of: >> >>> "* 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))" >> >> >> To the ODF standard. >> >> Can you define the method for calculating the parameters of these two >> functions? >> >> Please pardon our delay in reaching your request. >> >> The TC has not made a decision about your request but having the additional >> information will make that task easier. >> >> Thanks! >> >> Hope you are having a great week! >> >> Patrick >> >> -- >> Patrick Durusau >> patrick@durusau.net >> Former 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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