[R] do.call("+", ...)

Hi How do I make do.call() take "+" as a function for a list of more than two elements? Toy problem follows: f <- function(i){matrix((1:6)^i,2,3)} # Thus f() returns a matrix of size 2x3; I want to add a whole bunch of such matrices, # as in f(1) + f(2) + f(3) + f(4) # But: > do.cal

[R] Erosion, mathematical morphology

Hello! I need a function to compute the erosion of a binary image by a structuring element. I need the structuring element to be a ball of a given radius. As far as I know the libraries adehabitat and spatstat include functions of mathematical morphology but I couldn't find a function which

[R] Problem with "vegan" package from Koeln mirror

Hi all, I had serious problems when downloading the 'vegan' package from the Koeln mirror site. The package refused to start up. I re-installed the latest version of R for Windows (2.4.0), but this did not help. The problem was solved by simply downloading the package from another mirror (Frankfur

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