Mads Jeppe Tarp-Johansen wrote: > To R-helpers, > > R offers the polyroot function for solving mentioned equations iteratively. > > However, Dr Math and Mathworld (and other places) show in detail how to > solve mentioned equations non-iteratively. > > Do implementations for R that are non-iterative and that solve mentioned > equations exists?
As far as I know, we don't even have the quadratic... They can't be hard to implement, though. However, you may need to take care that non-iterative solutions are not necessarily more precise or even faster than iterative ones. There may be cancellation issues and the closed-form expressions can be complicated and involve slow function calls. -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________ R-help@r-project.org mailing list 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.
