def test_nd(self):
sign = lambda v: -1 if v < 0 else 1 if v > 0 else 0
for n in range(2, 6):
with self.subTest(n=n):
desired = numpy.empty((n,)*n, int)
for I in itertools.product(*[range(n)]*n):
desired[I] = util.product(sign(b-a) for a, b in itertools.combinations(I, 2))
self.assertAllEqual(numeric.levicivita(n, int), desired)
def test_2d(self):
self.assertAllEqual(numeric.levicivita(2, int),
numpy.array([[0, 1], [-1, 0]]))
def test_1d(self):
with self.assertRaisesRegex(
ValueError,
'^The Levi-Civita symbol is undefined for dimensions lower than 2.'
):
numeric.levicivita(1)