If remove.zero.vectors == FALSE,
a matrix of the same dimensions as x whose columns are orthogonal
and span the same vector subspace as the columns of x.
Since making the columns unit vectors in the L2 sense could require
irrational numbers, the columns are made unit vectors in the L1 sense
unless they are zero vectors (which, of course, cannot be normalized).
If remove.zero.vectors == TRUE, then the result is the same
except zero vectors are removed,
so the columns of the result form a basis of the subspace.
Arguments
x
matrix of type "numeric"
or "character". If "numeric" are converted to rational
using d2q. Columns are considered vectors in space
of dimension nrow(x).