xpnd {MCMCpack}R Documentation

Expand a Vector into a Symmetric Matrix

Description

This function takes a vector of appropriate length (typically created using vech) and creates a symmetric matrix.

Usage

   xpnd(x, nrow)

Arguments

x A list of elements to expand into symmetric matrix.
nrow The number of rows (and columns) in the returned matrix.

Details

This function is particularly useful when dealing with variance covariance matrices. Note that R stores matrices in column major order, and that the items in x will be recycled to fill the matrix if need be.

Value

An (nrows * nrows) symmetric matrix.

See Also

vech

Examples

  xpnd(c(1,2,3,4,4,5,6,7,8,9),4)

[Package MCMCpack version 0.5-2 Index]