R: Compute all pairwise combinations of indices

pairwise_combination_indices {MESS} | R Documentation

## Compute all pairwise combinations of indices

### Description

Fast computation of indices of all pairwise element of a vector of length n.

### Usage

    pairwise_combination_indices(n, self = FALSE)

### Arguments

`n` | A number giving the number of elements to create all pairwise indices from
`self` | A logical that determines whether a column should also be multiplied by itself.

### Details

Note that the output order of columns corresponds to the order of the columns in x. First column 1 is multiplied with each of the other columns, then column 2 with the remaining columns etc.

### Value

A matrix with n*(n+1)/2 rows (if self=TRUE) or n*(n-1)/2 rows (if self=FALSE, the default) and two columns gicing all possible combinations of indices.

### Author(s)

Claus Ekstrom <claus@rprimer.dk>

### Examples

    pairwise_combination_indices(3)
    pairwise_combination_indices(4, self=TRUE)

[Package MESS version 0.5.9 Index]