Re: [R] problem with integrate() - correction

From: Frede Aakmann Tøgersen <FredeA.Togersen_at_agrsci.dk>
Date: Thu 22 Jun 2006 - 22:59:47 EST


Well why not do it symbolically, e.g.

int(a*x^b,x) = \frac{a}{b+1}x^{b+1}

and integrating this again gives

\frac{a}{(b+1)(b+2)}x^{b+2},

of course for resonable values of a and b such that things are well defined.

But if you follow the link

https://stat.ethz.ch/pipermail/r-help/2005-January/064026.html

you may come to this solution:

ip <- function(x) 1240 * x^(-0.88)

iip <- function(x){
  res <- rep(NA,length(x))
  for (i in seq(along=x))
    res[i] <- integrate(ip, x[i] - 0.045, x[i] + 0.045)$value   return(res)
}

f <- integrate(iip, 10, 100)

which may not be an effective way to do it.

Med venlig hilsen
Frede Aakmann Tøgersen    

> -----Oprindelig meddelelse-----
> Fra: r-help-bounces@stat.math.ethz.ch
> [mailto:r-help-bounces@stat.math.ethz.ch] På vegne af Rainer M Krug
> Sendt: 22. juni 2006 14:03
> Til: rkrug@sun.ac.za
> Cc: R help list
> Emne: [R] problem with integrate() - correction
>
> Sorry
>
> should read:
>
> ip <- function(x) 1240 * x^(-0.88)
>
>
> Rainer M Krug wrote:
> > Hi
> >
> > System:
> > Linux, SuSE 10
> > R 2.3.0
> >
> > I try to do the following
> >
> >> ip <- function(x) 1240*dip(x, 0.88)
> >> iip <- function(x) integrate(ip, x - 0.045, x + 0.045)$value f <-
> >> integrate(iip, 10, 100)
> > Error in integrate(iip, 10, 100) : evaluation of function gave a
> > result of wrong length
> >
> > How can I solve this?
> >
> > Thanks
> >
> > Rainer
> >
> >
> >
>
>
> --
> Rainer M. Krug, Dipl. Phys. (Germany), MSc Conservation Biology (UCT)
>
> Department of Conservation Ecology and Entomology University
> of Stellenbosch Matieland 7602 South Africa
>
> Tel: +27 - (0)72 808 2975 (w)
> Fax: +27 - (0)21 808 3304
> Cell: +27 - (0)83 9479 042
>
> email: RKrug@sun.ac.za
> Rainer@krugs.de
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Jun 22 23:08:33 2006

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