duplication {rggm} | R Documentation |
duplication(n)
n |
a positive integer |
A n*(n+1)/2
matrix with real values.
Masashi Miyamura
Jan R. Magnus and Heinz Neudecker, (1999) Matrix Differential Calculus with Applications in Statistics and Econometrics, Second Edition, John Wiley & Sons
vech
, duplication.inverse
, elimination
m <- matrix(c(1, 2, 3, 2, 5, 6, 3, 6, 9), 3, 3) duplication(3) %*% vech(m) # identical to as.vector(m)