Dear R Users, Beginners and Experts, I want to fit to my data an exponential function with following functional form: y=exp(a*x) I used the function "nls" but this gives me exponential fits with following functional form: y=l*exp(a*x) With "l" being an scaling factor. What do I need to change in my R code? t.dataFitModel=nls(t.dataForFitY ~exp(a*t.dataForFitX), data=t.dataForFit, start=list(a = 0.01242922), trace=TRUE, algorithm = "plinear") Thanks in advance and a nice weekend, Henri
Exponential fit of form y=exp(a*x) and not of form y=l*exp(a*x)
2 messages · Henri Mone, Ben Bolker
Henri Mone <henriMone <at> gmail.com> writes:
I want to fit to my data an exponential function with following functional form: y=exp(a*x) I used the function "nls" but this gives me exponential fits with following functional form: y=l*exp(a*x) With "l" being an scaling factor. What do I need to change in my R code? t.dataFitModel=nls(t.dataForFitY ~exp(a*t.dataForFitX), data=t.dataForFit, start=list(a = 0.01242922), trace=TRUE, algorithm = "plinear")
Use an algorithm other than "plinear", I think (admittedly this is not at all clear from ?nls -- you would really have to go to the references to find out).