R: Compact information to construct the symmetrizer matrix

symm.info {fastmatrix} | R Documentation

## 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

[Package fastmatrix version 0.3-819 Index]