def test_reset_2qubit(self):
"""Test reset method for 2-qubit state"""
state = DensityMatrix(np.diag([0.5, 0, 0, 0.5]))
with self.subTest(msg="reset"):
rho = state.copy()
value = rho.reset()
target = DensityMatrix(np.diag([1, 0, 0, 0]))
self.assertEqual(value, target)
with self.subTest(msg="reset"):
rho = state.copy()
value = rho.reset([0, 1])
target = DensityMatrix(np.diag([1, 0, 0, 0]))
self.assertEqual(value, target)
with self.subTest(msg="reset [0]"):
rho = state.copy()
value = rho.reset([0])
target = DensityMatrix(np.diag([0.5, 0, 0.5, 0]))
self.assertEqual(value, target)
with self.subTest(msg="reset [0]"):
rho = state.copy()
value = rho.reset([1])
target = DensityMatrix(np.diag([0.5, 0.5, 0, 0]))
self.assertEqual(value, target)
def test_copy(self):
"""Test DensityMatrix copy method"""
for _ in range(5):
rho = self.rand_rho(4)
orig = DensityMatrix(rho)
cpy = orig.copy()
cpy._data[0] += 1.0
self.assertFalse(cpy == orig)
def test_measure_qutrit(self):
"""Test measure method for qutrit"""
state = DensityMatrix(np.diag([1, 1, 1]) / 3)
seed = 200
shots = 100
for i in range(shots):
rho = state.copy()
rho.seed(seed + i)
outcome, value = rho.measure()
self.assertIn(outcome, ["0", "1", "2"])
if outcome == "0":
target = DensityMatrix(np.diag([1, 0, 0]))
self.assertEqual(value, target)
elif outcome == "1":
target = DensityMatrix(np.diag([0, 1, 0]))
self.assertEqual(value, target)
else:
target = DensityMatrix(np.diag([0, 0, 1]))
self.assertEqual(value, target)
