[R] [] for R
Vitalie S.
vitosmail at rambler.ru
Tue Aug 25 12:00:55 CEST 2009
see ?[
For '['-indexing only: 'i, j, ...' can be logical vectors,
indicating elements/slices to select. Such vectors are
recycled if necessary to match the corresponding extent. 'i,
j, ...' can also be negative integers, indicating
elements/slices to leave out of the selection.
so 1+xi*xx>0 is a logical vector.
On Mon, 24 Aug 2009 17:33:36 +0200, kfcnhl <zhengchenji18 at hotmail.com>
wrote:
>
> I am assuming the variable out is the output parameter.
> However, I don't understand what is out[1+xi*xx>0]?
> Can someone explain this to me?
>
> Thanks in advance,
> Chen
>
>
> dGEV <- function(x, xi, mu = 0, sigma = 1, logvalue=FALSE)
> {
> xx <- (x-mu)/sigma
> #use the new dGumbel which passes mu and sigma:
> #if (xi==0) out <- dGumbel(xx,logvalue=TRUE)-log(sigma)
> if (xi==0) {
> return(out <- dGumbel(x, mu, sigma, logvalue));
> }
>
> else
> { out <- rep(-Inf,length(x))
> out[1+xi*xx>0] <- (-1/xi-1)*log(1+xi*xx[1+xi*xx>0]) -
> (1+xi*xx[1+xi*xx>0])^(-1/xi) -log(sigma)
> }
> if (!(logvalue))
> out <- exp(out)
> out
> }
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