partitionsCount: Number of Partitions/Compositions

In RcppAlgos: High Performance Tools for Combinatorics and Computational Mathematics

Number of Partitions/Compositions

Description

Calculate the number of partitions/compositions of a vector chosen m at a time with or without replacement. Additionally, these functions can calculate the number of partitions of multisets.

Usage

partitionsCount(v, m = NULL, repetition = FALSE,
                freqs = NULL, target = NULL)

compositionsCount(v, m = NULL, repetition = FALSE,
                  freqs = NULL, target = NULL, weak = FALSE)

Arguments

v	Source vector. If v is a positive integer, it will be converted to the sequence 1:v. If v is a negative integer, it will be converted to the sequence v:-1. Only integer and numeric vectors are accepted.
m	Width of the partition. If m = NULL, the length will be determined by the partitioning case (e.g. When we are generating distinct partitions of n, the width will be equal to the smallest m such that sum(1:m) >= n).
repetition	Logical value indicating whether partitions/compositions should be with or without repetition. The default is FALSE.
freqs	A vector of frequencies used for producing all partitions of a multiset of v. Each element of freqs represents how many times each element of the source vector, v, is repeated. It is analogous to the times argument in rep. The default value is NULL.
target	Number to be partitioned. If NULL, max(v) will be used.
weak	(Compositions only) Logical flag indicating whether to allow terms of the sequence to be zero.

Value

A numerical value representing the total number of partitions/compositions.

Note

When the number of results exceeds 2^{53} - 1, a number of class bigz is returned.

See Also

partitionsGeneral, compositionsGeneral

Examples

## Same interface as partitionsGeneral
partitionsCount(25, 5)
compositionsCount(25, 5, TRUE)
partitionsCount(15, 7, TRUE)
partitionsCount(25, 5, freqs = rep(2, 25))

## Return object of class 'bigz'
partitionsCount(2500, 15, TRUE)
compositionsCount(2500, 15, TRUE)

RcppAlgos documentation built on Oct. 3, 2023, 1:07 a.m.