On Mon, 8 Aug 2005, Deming Mi wrote:
> Does anybody know if there is an R function (package) to fit a two-terms
> exponential model like y = a*exp(bx) + c*exp(dx) where y is dependent
> variable and x is independent variable. MATLAB has a Curve Fitting Toolbox
> to implement this fitting, but I don't know if there is an R package
for
> this fitting. Thank you!
See ?nls
>From my experience with such models the coefficients are often not
well-determined and so you need a good starting point.
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595