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

[Robin Hankin]

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.call("+",sapply(1:4,f,simplify=FALSE))
Error in do.call("+", sapply(1:4, f, simplify = FALSE)) :
	operator needs one or two arguments




Also,


 > do.call(sum,sapply(1:4,f,simplify=FALSE))
[1] 2828


doesn't do what I want (I would like a 2x3 matrix whose elements are the
sum of corresponding elements in my list)

How to do this nicely?





--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743