symm.info: Compact information to construct the symmetrizer matrix

In fastmatrix: Fast Computation of some Matrices Useful in Statistics

Compact information to construct the symmetrizer matrix

Description

This function provides the information required to create the symmetrizer matrix.

Usage

symm.info(n = 1)

Arguments

n	order of the symmetrizer matrix.

Details

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

Value

A list containing the following elements:

row	vector of indexes, each entry represents the row index of the symmetrizer matrix.
col	vector of indexes, each entry represents the column index of the symmetrizer matrix.
val	vector of values, each entry represents the value of the symmetrizer matrix at element given by row and col indexes.
order	order of the symmetrizer matrix.

See Also

symmetrizer, symm.prod

Examples

z <- symm.info(n = 3)
z # elements in symmetrizer matrix of order 3

N3 <- symmetrizer(n = 3, matrix = TRUE)
N3 # only recommended if n is very small

fastmatrix documentation built on Nov. 5, 2025, 6:21 p.m.