def decode(self, W, method='euclid'):
alpha = np.array([2], np.int)
curr_deg = alpha
alpha_list_t = [alpha[0]]
for i in range(2 * self.t - 1):
curr_deg = gf.prod(curr_deg, alpha, self.pm)
alpha_list_t.append(curr_deg[0])
alpha_list_n = alpha_list_t.copy()
for i in range(self.n - 2 * self.t):
curr_deg = gf.prod(curr_deg, alpha, self.pm)
alpha_list_n.append(curr_deg[0])
alpha_list_t = np.array(alpha_list_t)
alpha_list_n = np.array(alpha_list_n)
result = np.zeros(W.shape, np.int)
if method == 'pgz':
for row in range(W.shape[0]):
deg_list = gf.polyval(W[row], alpha_list_t, self.pm)
if np.all(deg_list == 0):
result[row] = W[row]
else:
curr_dim = self.t
while (curr_dim > 0):
A = np.zeros((curr_dim, curr_dim), np.int)
for i in range(curr_dim):
A[i] = deg_list[i:curr_dim + i]
b = deg_list[curr_dim:2 * curr_dim]
value = gf.linsolve(A, b, self.pm)
if value is not np.nan:
value = np.concatenate((value, np.ones(1, np.int)))
break
curr_dim -= 1
if curr_dim == 0:
result[row] = np.nan
else:
roots = gf.polyval(value, alpha_list_n, self.pm)
roots = np.nonzero(np.logical_not(roots))
err_pos = (roots[0]) % self.n
result[row] = W[row]
result[row, err_pos] = np.logical_not(
result[row, err_pos]).astype(np.int)
if np.any(
gf.polyval(result[row], alpha_list_t, self.pm)
!= 0):
result[row, :] = np.nan
elif method == 'euclid':
alpha_list_t = alpha_list_t[::-1]
for row in range(W.shape[0]):
S = gf.polyval(W[row], alpha_list_t, self.pm)
S = np.concatenate((S, np.ones(1, np.int)))
z = np.array([1] + [0 for x in range(2 * self.t + 1)], np.int)
r, A, Lambda = gf.euclid(z, S, self.pm, self.t)
roots = gf.polyval(Lambda, alpha_list_n, self.pm)
roots = np.nonzero(np.logical_not(roots))
err_pos = (roots[0]) % self.n
result[row] = W[row]
result[row, err_pos] = np.logical_not(
result[row, err_pos]).astype(np.int)
if np.any(gf.polyval(result[row], alpha_list_t, self.pm) != 0):
result[row, :] = np.nan
return result
def test_prod():
X = np.array([[1, 5],
[14, 9],
[13, 5]])
Y = np.array([[2, 3],
[5, 4],
[3, 11]])
pm = np.array([[12, 2],
[13, 4],
[ 0, 8],
[14, 1],
[ 0, 2],
[ 0, 4],
[ 0, 8],
[15, 1],
[ 0, 2],
[ 0, 4],
[ 0, 8],
[ 0, 1],
[ 0, 2],
[ 0, 4],
[ 0, 8]])
right_prod = np.array([[4, 8],
[8, 4],
[8, 8]])
assert_equal(right_prod, gf.prod(X, Y, pm))
def __init__(self, n, t):
self.n = n
self.t = t
q = -1
n_copy = n + 1
while n_copy:
n_copy = n_copy // 2
q += 1
if 2**q - 1 != n:
raise ValueError('n is not 2^{q} - 1')
with open('primpoly.txt', 'r') as file:
primpoly_list = file.read().split(', ')
for primpoly in primpoly_list:
if int(primpoly) // 2**(q): # if degree == q
break
primpoly = int(primpoly)
self.pm = gf.gen_pow_matrix(primpoly)
alpha = np.array([2], np.int)
curr_poly = alpha
degrees_list = [alpha[0]]
for i in range(2 * t - 1):
curr_poly = gf.prod(curr_poly, alpha, self.pm)
degrees_list.append(curr_poly[0])
self.g, self.R = gf.minpoly(np.array(degrees_list), self.pm)
self.deg_g = self.g.shape[0] - 1
def test_linsolve_random(self):
while True:
pm = gf.gen_pow_matrix(92127)
pm_len = len(pm)
n = 50
A = np.array(
[[pm[random.randint(0, pm_len - 1), 1] for _ in range(n)]
for _ in range(n)])
b = np.array(
[pm[random.randint(0, pm_len - 1), 1] for _ in range(n)])
solution = gf.linsolve(A, b, pm)
if not (solution is np.nan):
subst = [
gf.sum(
gf.prod(A[i].reshape(A[i].size, 1),
solution.reshape(solution.size, 1), pm))[0][0]
for i in range(n)
]
assert_array_equal(subst, b)
break
def test_divide_all(self):
pm = gf.gen_pow_matrix(357)
for elem1 in pm[:, 1]:
for elem2 in pm[:, 1]:
a = gf.divide(np.array([[elem1]]), np.array([[elem2]]), pm)
self.assertEqual(elem1, gf.prod(a, np.array([[elem2]]), pm))
def test_divide_inverse(self):
pm = gf.gen_pow_matrix(88479)
for elem in pm[:, 1]:
inverse = gf.divide(np.array([[1]]), np.array([[elem]]), pm)
self.assertEqual(1, gf.prod(inverse, np.array([[elem]]), pm))
