From Werner KRAUTH
Revision as of 21:29, 22 September 2015;
view current revision←Older revision |
Newer revision→def gray_flip(t, N):
k = t[0]
if k > N: return t, k
t[k - 1] = t[k]
t[k] = k + 1
if k != 1: t[0] = 1
return t, k
L = 4
N = L * L
nbr = {i : ((i // L) * L + (i + 1) % L, (i + L) % N,
(i // L) * L + (i - 1) % L, (i - L) % N)
for i in range(N)}
S = [-1] * N
E = -2 * N
print S, E
tau = range(1, N + 2)
for i in range(1, 2 ** N):
tau, k = gray_flip(tau, N)
h = sum(S[n] for n in nbr[k - 1])
E += 2 * h * S[k - 1]
S[k - 1] *= -1
print S, E
