Hello, your integrand needs to be a function which accepts a numeric vector as first argument and returns a vector of the same length (see ?integrate). Your function does not fulfill this requirement. Hence, you have to rewrite your function or use sapply, apply or friends; something like
newintegrand <- function(x) sapply(x, integrand) By the way you use a very old R version and I would recommend to update to R 2.4.0. hth Matthias Le Wang schrieb: >Hi there. Thanks for your time in advance. > >I am using R 2.2.0 and OS: Windows XP. > >My final goal is to calculate 1/2*integral of >(f1(x)^1/2-f2(x)^(1/2))^2dx (Latex codes: >$\frac{1}{2}\int^{{\infty}}_{\infty} >(\sqrt{f_1(x)}-\sqrt{f_2(x)})^2dx $.) where f1(x) and f2(x) are two >marginal densities. > >My problem: > >I have the following R codes using "adapt" package. Although "adapt" >function is mainly designed for more than 2 dimensions, the manual >says it will also call up "integrate" if the number of dimension >equals one. I feed in the data x1 and x2 and bandwidths h1 and h2. >These codes worked well when my final goal was to take double >integrals. > > integrand <- function(x) { > # x input is evaluation point for x1 and x2, a 2x1 vector > x1.eval <- x[1] > x2.eval <- x[2] > # n is the number of observations > n <- length(x1) > # x1 and x2 are the vectors read from data.dat > # Compute the marginal densities > f.x1 <- sum(dnorm((x1.eval-x1)/h1))/(n*h1) > f.x2 <- sum(dnorm((x2.eval-x2)/h2))/(n*h2) > # Return the integrand # > return((sqrt(f.x1)-sqrt(f.x2))**2) > > } > > estimate<-0.5*adapt(1, lo=lo.default, up=up.default, > minpts=minpts.default, maxpts=maxpts.default, > functn=integrand, eps=eps.default, x1, x2,h1,h2)$value > > >But when I used it for one-dimension, it failed. Some of my >colleagues suggested getting rid of "x2.eval" in the "integrand" >because it is only one integral. But after I changed it, it still >didn't work. R gave the error msg: "evaluation of function gave a >result of wrong length" > >I am not a frequent R user..although I looked up the mailing list >for a while and there were few postings asking similar questions, I >can't still figure out why my codes won't work. Any help will be >appreciated. > >Le >- >~~~~~~~~~~~~~~~~~~~~~~ >Le Wang, Ph.D >Population Center >University of Minnesota > >______________________________________________ >R-help@stat.math.ethz.ch 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. > > -- Dr. rer. nat. Matthias Kohl E-Mail: [EMAIL PROTECTED] Home: www.stamats.de ______________________________________________ R-help@stat.math.ethz.ch 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.