R: Lower/Upper Triangle Elements of a Matrix

Tri2M {MCMCglmm} | R Documentation

## Lower/Upper Triangle Elements of a Matrix

### Description

Lower/Upper triangle elements of a matrix or forms a matrix from a vector of lower/upper triangle elements

### Usage

    Tri2M(x, lower.tri = TRUE, reverse = TRUE, diag = TRUE)

### Arguments

`x` | Matrix or vector
`lower.tri` | If `x` is a matrix then the lower triangle (`TRUE`) or upper triangle `FALSE` elements (including diagonal elements) are returned. If `x` is a vector a matrix is formed under the assumption that `x` are the lower triangle (`TRUE`) or upper triangle (`FALSE`) elements.
`reverse` | logical: if`TRUE` a symmetric matrix is formed, if `FALSE` the remaining triangle is left as zeros.
`diag` | logical: if`TRUE` diagonal elements are included.

### Value

`` | numeric or matrix

### Author(s)

Jarrod Hadfield j.hadfield@ed.ac.uk

### Examples

    M<-rIW(diag(3), 10)
    x<-Tri2M(M)
    x
    Tri2M(x, reverse=TRUE)
    Tri2M(x, reverse=FALSE)

[Package MCMCglmm version 2.32 Index]