[R] Using integrate() with vectors as boundaries rather than scalars

[Gabor Grothendieck]

Or just:

   lapply(x, integrate, f = dnorm, upper = Inf)



On 10/11/06, Tobias <tobias_elbert at hotmail.com> wrote:
>
> I think I have figured it out myself, would however like to know the opinion
> of more experienced coders. Is this a "good" way of approaching this:
>
> cumdnorm1 <- function(x) {integrate(dnorm,x,Inf)}
>
> evalvec <- function(x) {lapply(x,cumdnorm1)}
>
> It does return the desired result.
>
>
>
> Tobias wrote:
> >
> > Hi all
> >
> > my apologies if above title is misleading, but here is my problem anyways:
> >
> > I need to evaluate an integral n times. Since I can't get my head around
> > vectorization as of yet, I have coded it up in a loop, i.e.:
> >
> > for (i in 1:n)
> >
> > {
> >
> >     z[i] <- integrate(dnorm,x[i],Inf)
> >
> > }
> >
> > Since n is quite large in my operation, ~40000, I would rather stack all
> > the elements of x into a vector and then evaluate the integral for each
> > vector element in x up to infinity. So that the operation would look
> > something like this:
> >
> > z <- integrate(dnorm,x,Inf)
> >
> > I am not sure if this works, as I am new to R, however managed the
> > equivalent in MatLab. Is this possible at all? If yes, your input would be
> > highly appreciated.
> >
> > Regards
> >
> > Tobias
> >
>
> --
> View this message in context: http://www.nabble.com/Using-integrate%28%29-with-vectors-as-boundaries-rather-than-scalars-tf2421074.html#a6750170
> Sent from the R help mailing list archive at Nabble.com.
>
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