On Wed, 22 Dec 2010, Marius Hofert wrote:
Dear expeRts,I somehow don't see why the following does not work: integrand <- function(x, vec, mat, val) 1 # dummy return value A <- matrix(runif(16), ncol = 4) u <- c(0.4, 0.1, 0.2, 0.3) integrand(0.3, u, A, 4) integrate(integrand, lower = 0, upper = 1, vec = u, mat = A, val = 4) I would like to integrate a function ("integrand") which gets an "x" value (the running variable), a vector ("vec"), a matrix ("mat"), and a value ("val"). This function returns a number (set to 1 here). Of course, pointwise evaluation works without flaws. But why does integration not work? I obtain: Error in integrate(integrand, lower = 0, upper = 1, vec = u, mat = A, : evaluation of function gave a result of wrong length
Because your function isn't vectorized, i.e., does not *return* a vector. Instead,
integrand <- function(x, vec, mat, val) rep( 1, length( x)) # dummy return value should work. Hth -- Gerrit
Cheers, Marius ______________________________________________ R-help@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.
______________________________________________ R-help@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.
