Construct a Hadamard matrix (Hn) of size n-by-n.
The size n must be of the form 2^k * p in which p is one of
1, 12, 20 or 28. The returned matrix is normalized, meaning
Hn(:,1) == 1
and Hn(1,:) == 1
.
Some of the properties of Hadamard matrices are:
kron (Hm, Hn)
is a Hadamard matrix of size m-by-n.
Hn * Hn' = n * eye (n)
.
det (A) <= abs (det (Hn))
for all A with
abs (A(i, j)) <= 1
.
See also: compan, hankel, toeplitz.
Package: octave