fastmatrix (version 0.3-8)

vech: Vectorization the lower triangular part of a square matrix

Description

This function returns a vector obtained by stacking the lower triangular part of a square matrix.

Usage

vech(x)

Arguments

x

a square matrix.

Value

Let x be a \(n\) by \(n\) matrix, then vech(x) is a \(n(n+1)/2\)-dimensional vector.

Examples

# NOT RUN {
x <- matrix(rep(1:10, each = 10), ncol = 10)
x
y <- vech(x)
y
# }