[R] lower and upper limits in integrate as vectors

[baptiste auguie]

Hi,

I think you want to Vectorize integrate(), not integrand(). Here's a  
way using mapply,

> integrand <- function(z)
> {
> return(z * z)
> }
>
> vec1<-1:3
> vec2<-2:4
>
> mapply(integrate, lower=vec1, upper=vec2, MoreArgs=list(f=integrand) )

baptiste

On 20 Sep 2008, at 13:08, Andreas Wittmann wrote:

> Dear R useRs,
>
> i try to integrate the following function for many values
>
> "integrand" <- function(z)
> {
> return(z * z)
> }
>
> i do this with a for-loop
>
> for(i in 2:4)
> {
> z <- integrate(integrand, i-1, i)$value
> cat("z", z, "\n")
> }
>
> to speed up the computation for many values i tried vectors
> in integrate to do this.
>
> vec1<-1:3
> vec2<-2:4
>
> integrate(Vectorize(integrand), vec1, vec2)$value
>
> but here it seems the integration works only for the first values of  
> vec1 and vec2.
>
> If you have any advice how i can to this computations with vectors  
> or something like that, i would be very thankful,
>
> best regards
>
> Andreas
>
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_____________________________

Baptiste Auguié

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag