[R] newton.method

[Yihui Xie]

The function newton.method() in the package 'animation' is merely for
demonstration purpose instead of serious computation -- it illustrates
how Newton's method works step by step. But I'm unable to reproduce
your bogus results:

library(animation)
par(pch = 20)
ani.options(nmax = 50, interval = 0.5)
newton.method(f, init = 2, tol = 10 * exp(-8))
# $root
# [1] 7.419378
#
# $value
# [1] 1.211038e-07
#
# $iter
# [1] 17

ani.options(nmax = 50)
newton.method(f, init = -1, rg = c(-4, 12))$root
# about -2.44

ani.options(nmax = 50)
newton.method(f, init = 4, rg = c(-4, 12))$root
# 7.42


Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Phone: 515-294-6609 Web: http://yihui.name
Department of Statistics, Iowa State University
3211 Snedecor Hall, Ames, IA



On Thu, Jul 29, 2010 at 1:15 PM, sammyny <sjain at caa.columbia.edu> wrote:
>
> newton.method is in package 'animation'.
>
> Thanks Ravi.
> BBSolve/BBOptim seems to work very well although I am not familiar with the
> optimization methods being used there. Is there a way to specify a tolerance
> in the function to get the required precision.
>
> I did something like this to use newton method.
> require(animation)
> newton.method(f, init=2, tol=10*exp(-8))
> But it gives bogus results.
>
> If someone could point me a correct working version of newton method for
> finding roots and its usage, that would be helpful.
>
> cheers,
>
> Sam
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/newton-method-tp2306111p2306895.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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.
>