tuples: Determine all n-tuples using the elements of a set.

In mpoly: Symbolic Computation and More with Multivariate Polynomials

Description

Determine all n-tuples using the elements of a set. This is really just a simple wrapper for expand.grid, so it is not optimized.

Usage

tuples(set, n = length(set), repeats = FALSE, list = FALSE)

Arguments

set	a set
n	length of each tuple
repeats	if set contains duplicates, should the result?
list	tuples as list?

Value

a matrix whose rows are the n-tuples

Examples

tuples(1:2, 3)
tuples(1:2, 3, list = TRUE)

apply(tuples(c("x","y","z"), 3), 1, paste, collapse = "")

# multinomial coefficients
r <- 2 # number of variables, e.g. x, y
n <- 2 # power, e.g. (x+y)^2
apply(burst(n,r), 1, function(v) factorial(n)/ prod(factorial(v))) # x, y, xy
mp("x + y")^n

r <- 2 # number of variables, e.g. x, y
n <- 3 # power, e.g. (x+y)^3
apply(burst(n,r), 1, function(v) factorial(n)/ prod(factorial(v)))
mp("x + y")^n

r <- 3 # number of variables, e.g. x, y, z
n <- 2 # power, e.g. (x+y+z)^2
apply(burst(n,r), 1, function(v) factorial(n)/ prod(factorial(v))) # x, y, z, xy, xz, yz
mp("x + y + z")^n

mpoly documentation built on March 26, 2020, 7:33 p.m.