Given a matrix,
M, find a matrix
N giving a basis for the
null space. That is
t(N) %*% M
is the zero and
N has the maximum number of linearly
independent columns.
USAGE:
Null(M)
REQUIRED ARGUMENTS:
M
Input matrix. A vector is coerced to a 1-column matrix.
VALUE:
The matrix
N with the basis for the null space, or an empty
vector if the matrix
M is square and of maximal rank.
SEE ALSO:
,
EXAMPLES:
# The function is currently defined as
function(M)
{
tmp <- qr(M)
set <- if(tmp$rank == 0) 1:ncol(M) else - (1:tmp$rank)
qr.Q(tmp, complete = T)[, set, drop = F]
}