# comboGroupsCount: Number of Partitions of a Vector into Groups In RcppAlgos: High Performance Tools for Combinatorics and Computational Mathematics

 comboGroupsCount R Documentation

## Number of Partitions of a Vector into Groups

### Description

Calculate the number of partitions of a vector into groups. See the related integer sequences A025035-A025042 at OEIS (E.g. A025036 for Number of partitions of 1, 2, ..., 4n into sets of size 4.)

### Usage

``````comboGroupsCount(v, numGroups = NULL, grpSizes = NULL)
``````

### 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`. All atomic types are supported (See `is.atomic`). `numGroups` An Integer. The number of groups that the vector will be partitioned into. The default is `NULL`. If provided and `grpSize` is `NULL`, it must divide the length of v (if v is a vector) or v (if v is a scalar). `grpSizes` A vector of whole numbers representing the size of each group. The default is `NULL`. If provided, the sum of the elements must total the length of v (if v is a vector) or v (if v is a scalar).

### Value

A numerical value representing the total number of partitions of groups.

### Note

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

Joseph Wood

### Examples

``````comboGroupsCount(16, 4)
comboGroupsCount(16, grpSizes = c(1:4, 6))
comboGroupsCount(28, grpSizes = rep(2:5, each = 2))
``````

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