arrangements: icompositions – R documentation

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icompositions

Compositions iterator

Description

This function returns a Compositions iterator for iterating compositions of an non-negative integer n into k parts or parts of any sizes. The iterator allows users to fetch the next partition(s) via the getnext() method.

Usage

Compositions

icompositions(n, k = NULL, descending = FALSE, skip = NULL)

Arguments

`n`	an non-negative integer to be partitioned
`k`	number of parts
`descending`	an logical to use reversed lexicographical order
`skip`	the number of compositions skipped

Format

An object of class R6ClassGenerator of length 25.

Details

The Compositions class can be initialized by using the convenient wrapper icompositions or

Compositions$new(n, k = NULL, descending = FALSE)

getnext(d = 1L, layout = NULL, drop = NULL)
collect(layout = "row")
reset()

d: number of fetched arrangements
layout: if "row", "column" or "list" is specified, the returned value would be a "row-major" matrix, a "column-major" matrix or a list respectively
drop: vectorize a matrix or unlist a list

Examples

ipart <- icompositions(4)
ipart$getnext()
ipart$getnext(2)
ipart$getnext(layout = "column", drop = FALSE)
# collect remaining compositions
ipart$collect()

library(foreach)
foreach(x = icompositions(6, 2), .combine=c) %do% {
  prod(x)
}

arrangements

Fast Generators and Iterators for Permutations, Combinations, Integer Partitions and Compositions

v1.1.9

MIT + file LICENSE

Authors

Randy Lai [aut, cre]

Initial release

2020-09-12