def test_pow(self):
t = tensor.Tensor([1.0, 1.0])
self.assertLen(t.shape, 1)
self.assertEqual(t.shape[0], 2)
t0 = t**0.0
self.assertEqual(t0, 1.0)
t1 = t**1
self.assertLen(t1.shape, 1)
self.assertEqual(t1.shape[0], 2)
t2 = t**2
self.assertLen(t2.shape, 1)
self.assertEqual(t2.shape[0], 4)
m = tensor.Tensor([[1.0, 1.0], [1.0, 1.0]])
self.assertLen(m.shape, 2)
self.assertEqual(m.shape[0], 2)
self.assertEqual(m.shape[1], 2)
m0 = m**0.0
self.assertEqual(m0, 1.0)
m1 = m**1
self.assertLen(m1.shape, 2)
self.assertEqual(m1.shape[0], 2)
self.assertEqual(m1.shape[1], 2)
m2 = m**2
self.assertLen(m2.shape, 2)
self.assertEqual(m2.shape[0], 4)
self.assertEqual(m2.shape[1], 4)
def TraceOutSingle(rho, index):
"""Trace out single qubit from density matrix."""
nbits = int(math.log2(rho.shape[0]))
if index > nbits:
raise AssertionError('Invalid use of Ptrace, invalid index (>nbits).')
eye = Identity()
zero = Operator(np.array([1.0, 0.0]))
one = Operator(np.array([0.0, 1.0]))
p0 = p1 = tensor.Tensor(1.0)
for idx in range(nbits):
if idx == index:
p0 = p0 * zero
p1 = p1 * one
else:
p0 = p0 * eye
p1 = p1 * eye
rho0 = p0 @ rho
rho0 = rho0 @ p0.transpose()
rho1 = p1 @ rho
rho1 = rho1 @ p1.transpose()
rho_reduced = rho0 + rho1
return rho_reduced
def test_hermitian(self):
t = tensor.Tensor([[2.0, 0.0], [0.0, 2.0]])
self.assertTrue(t.is_hermitian())
self.assertFalse(t.is_unitary())
def density(self) -> tensor.Tensor:
return tensor.Tensor(np.outer(self, self.conj()))