magic (version 1.5-9)

do.index: Apply a function to array element indices

Description

Given a function f() that takes a vector of indices, and an array of arbitrary dimensions, apply f() to the elements of a

Usage

do.index(a, f, ...)

Arguments

a

Array

f

Function that takes a vector argument of the same length as dim(a)

...

Further arguments supplied to f()

Value

Returns a matrix of the same dimensions as a

See Also

arow

Examples

# NOT RUN {
a <- array(0,c(2,3,4))
b <- array(rpois(60,1),c(3,4,5))

f1 <- function(x){sum(x)}
f2 <- function(x){sum((x-1)^2)}
f3 <- function(x){b[t(x)]}
f4 <- function(x){sum(x)%%2}
f5 <- function(x,u){x[u]}

do.index(a,f1)    # should match   arow(a,1)+arow(a,2)+arow(a,3)
do.index(a,f2)
do.index(a,f3)    # same as  apltake(b,dim(a))
do.index(a,f4)    # Male/female toilets at NOC
do.index(a,f5,2)  # same as  arow(a,2)
# }