freegroup (version 1.1-8)

sum: Repeated summation by concatenation

Description

Concatenates its arguments to give a single free object

Usage

# S3 method for free
sum(..., na.rm = FALSE)

Arguments

...

Objects of class free, to be summed

na.rm

Boolean, indicating whether to ignore NA entries (currently ignored)

Author

Robin K. S. Hankin

Details

Concatenates its arguments and gives a single element of the free group. It works nicely with rev(), see the examples.

Examples

(x <- rfree(10,3))
sum(x)
abelianize(sum(x))

(y <- rfree(10,6))

sum(x,y)
sum(x,y) == sum(sum(x),sum(y))
x+y  # not the same!

sum(x,-x)
sum(x,rev(-x))

z <- alpha(26)
stopifnot(sum(x^z) == sum(x)^z)