If you know the period and want to fit phase and amplitude, this is equivalent to fitting a * sin + b * cos
> >>> > I don't know how to set the approximate starting values. I'm not sure what you meant by that, but I suspect it's related to phase and amplitude. > >>> > Besides, does the method work for sine curve as well? sin is the same as cos with a different phase Any combination of a and b above = c * sin (theta + d) for some value of c and d and = e * cos (theta + f) for some value of e and f. Also for any c,d and for any e,f there is an a,b. the c and e are what I'm calling amplitude, the d and f are what I'm calling phase. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
