Duplication matrix.
Syntax: @duplic(n)
n: integer
Return: matrix
The duplication matrix transforms the half vectorization of a sym matrix to the full vectorization of the matrix.
Given the
sym matrix
, returns the
matrix
, which satisfies
Examples
sym s1 = @unvech(@mnrnd(15))
vector diff = @vec(s1) - @duplic(s1.@cols) * @vech(s1)
demonstrates the properties of the duplication matrix since DIFF equals zero.
Cross-references
