Let say i have a square matrix and applied the 'vech' operator to stack the lower triangular elements into a vector:
> Mat <- matrix(1:25, 5) > Mat [,1] [,2] [,3] [,4] [,5] [1,] 1 6 11 16 21 [2,] 2 7 12 17 22 [3,] 3 8 13 18 23 [4,] 4 9 14 19 24 [5,] 5 10 15 20 25 > Mat[lower.tri(Mat)] [1] 2 3 4 5 8 9 10 14 15 20 Now, I want to reverse-work with the resulting matrix. Means, given a "correct" vector, I want to place the elements of this vector into the lower-triangular portion of some "correct" square matrix. Would somebody help me to implement that? Thanks, ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
