Returns the (d*(d-1)/2) x 2 matrix of the (i,j) indexes to the upper triangle of a d x d matrix. The result can then directly be used as an index, see example.
Usage
upper(d)
Arguments
d
dimension of the square matrix which we intend to index.
Value
Index values
Author(s)
Pierrick Bruneau
Examples
inds <- upper(5)
vals <- matrix(runif(25), nrow=5)
selvals <- vals[inds] # vector containing the values of the upper triangle