dupl.info: Compact information to construct the duplication matrix

In fastmatrix: Fast Computation of some Matrices Useful in Statistics

Compact information to construct the duplication matrix

Description

This function provides the minimum information required to create the duplication matrix.

Usage

dupl.info(n = 1, condensed = TRUE)

Arguments

n	order of the duplication matrix.
condensed	logical. Information should be returned in compact form?

Details

This function returns a list containing two vectors that represent an element of the duplication matrix and is accesed by the indexes in vectors row and col. This information is used by function dupl.prod to do some operations involving the duplication matrix without forming it. This information also can be obtained using function duplication

Value

A list containing the following elements:

row	vector of indexes, each entry represents the row index of the duplication matrix. Only present if condensed = FALSE.
col	vector of indexes, each entry represents the column index of the duplication matrix.
order	order of the duplication matrix.

See Also

duplication, dupl.prod

Examples

z <- dupl.info(n = 3, condensed = FALSE)
z # where are the ones in duplication of order 3?

D3 <- duplication(n = 3, matrix = TRUE)
D3 # only recommended if n is very small

fastmatrix documentation built on Aug. 8, 2025, 6:19 p.m.