two term exponential model
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