Your original code was not directly vectorizible (and I should have
noted that): this should work:
fnc <- function(x, y) {
z <- outer(y, x, FUN = "^")
exp(-x) * colSums(z)
}
y <- c(2,3,5)
integrate(fnc, 0, 3, y)
This should work and sorry for the initial confusion.
Michael
On Tue, Oct 18, 2011 at 11:05 AM, Freddy Hernandez Barajas
<fhernanb at gmail.com> wrote:
Thanks for the response. But there is a problem, the value of the integral is approximately 14.02 and the proposed procedure gives 346.85 Freddy Hern?ndez Barajas 2011/10/18 R. Michael Weylandt <michael.weylandt at gmail.com>
How about adding an additional argument to fun? R> fun <- function(x, y) exp(-x)*sum(y^x) R> y <- c(2,3,5) R> integrate(fun, 0, 3, y) [1] 346.853 with absolute error < 3.9e-12 Michael On Tue, Oct 18, 2011 at 10:01 AM, Freddy Hernandez Barajas <fhernanb at gmail.com> wrote:
Hello all R users I want to calculate this univariate integral: exp(-x)*sum(y^x) ?respect to x ?from 0 to 3 ?where y is a vector y=(2,3,5). In fact, the original y vector has a large number of elements but I propose with 3 elements. I know that I can resolve this problem doing fun <- function(x) exp(-x)*(2^x+3^x+5^x) integrate(fun,0,3) When the y vector has a large number of elements the last solution is not possible, if I use this another way I can not obtain the true answer ? y <- c(2,3,5) fun1 <- function(x) exp(-x)*sum(y^x) integrate(fun1,0,3) Someone could give me a help with the problem? Thanks. Freddy Hern?ndez Barajas ? ? ? ?[[alternative HTML version deleted]]
______________________________________________ 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.