Dear Søren, I suspect that the good R souls wouldn't consider this a bug, but a logical consequence of the R language design. It is of course a valid question whether this should be explicitly mentioned in documentation.
If I recall correctly about function evaluation: First all named arguments are found by partial matching, so in your example you are really providing the value 1/3 for the argument `interval` which is a user mistake. The exact same things happens for the apply family, e.g. > myfun <- function(x, F) x-F > sapply(1:3, myfun, F = 1) Error in match.fun(FUN) : '1' is not a function, character or symbol It works fine if we provide a valid value for the argument `FUN` rather than the constant value `FUN = 1`: > sapply(1:3, FUN = myfun, F = 1) [1] 0 1 2 (I realize no sane person would use the argument name `F` in this case, but you get the point.) Best, Ege On Thu, 2020-05-07 at 13:42 +0000, Søren Højsgaard wrote: > Dear all, > > I am wondering if there is a minor bug in the optimimize function; > please see below: > > > --- > > > > ## example taken from optimize documentation > > f <- function (x, a) (x - a)^2 > > xmin <- optimize(f, c(0, 1), tol = 0.0001, a = 1/3) > > xmin > > $minimum > [1] 0.3333333 > > $objective > [1] 0 > > > ## if we change argument a to j things still work fine > > f2 <- function (x, j) (x - j)^2 > > xmin2 <- optimize(f2, c(0, 1), tol = 0.0001, j = 1/3) > > xmin2 > > $minimum > [1] 0.3333333 > > $objective > [1] 0 > > > ## if we change argument a to i things fail > > f3 <- function (x, i) (x - i)^2 > > xmin3 <- optimize(f3, c(0, 1), tol = 0.0001, i = 1/3) > > Error in optimize(f3, c(0, 1), tol = 1e-04, i = 1/3) : > 'xmin' not less than 'xmax' > > xmin3 > > $minimum > [1] 0.3333333 > > $objective > [1] 0 > > > ##Same here > > xmin3 <- optimize(f3, lower=0, upper=1, tol = 0.0001, i = 1/3) > > Error in f(arg, ...) (from #1) : argument "i" is missing, with no > default > > xmin3 > > $minimum > [1] 0.3333333 > > $objective > [1] 0 > > > ## a workaround is > > xmin3 <- optimize(f3, interval=c(0, 1), tol = 0.0001, i = 1/3) > > xmin3 > > $minimum > [1] 0.3333333 > > $objective > [1] 0 > > --- > > the problem is, I guess, due to the keyword 'interval' gets mixed > up with 'i'. > > Has anyone experienced that? > > Best regards > S�ren > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. -- Ege Rubak, Associate Professor, Department of Mathematical Sciences, Aalborg University Skjernvej 4A, 9220 Aalborg East, Denmark Phone: (+45)99408861 Mobile: (+45)30230252 Email: ru...@math.aau.dk ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
