def test_from_label(self):
"""Test initialization from a label"""
x_p = DensityMatrix(np.array([[0.5, 0.5], [0.5, 0.5]]))
x_m = DensityMatrix(np.array([[0.5, -0.5], [-0.5, 0.5]]))
y_p = DensityMatrix(np.array([[0.5, -0.5j], [0.5j, 0.5]]))
y_m = DensityMatrix(np.array([[0.5, 0.5j], [-0.5j, 0.5]]))
z_p = DensityMatrix(np.diag([1, 0]))
z_m = DensityMatrix(np.diag([0, 1]))
label = '0+r'
target = z_p.tensor(x_p).tensor(y_p)
self.assertEqual(target, DensityMatrix.from_label(label))
label = '-l1'
target = x_m.tensor(y_m).tensor(z_m)
self.assertEqual(target, DensityMatrix.from_label(label))
def test_probabilities_product(self):
"""Test probabilities method for product state"""
state = DensityMatrix.from_label("+0")
# 2-qubit qargs
with self.subTest(msg="P(None)"):
probs = state.probabilities()
target = np.array([0.5, 0, 0.5, 0])
self.assertTrue(np.allclose(probs, target))
with self.subTest(msg="P([0, 1])"):
probs = state.probabilities([0, 1])
target = np.array([0.5, 0, 0.5, 0])
self.assertTrue(np.allclose(probs, target))
with self.subTest(msg="P([1, 0]"):
probs = state.probabilities([1, 0])
target = np.array([0.5, 0.5, 0, 0])
self.assertTrue(np.allclose(probs, target))
# 1-qubit qargs
with self.subTest(msg="P([0])"):
probs = state.probabilities([0])
target = np.array([1, 0])
self.assertTrue(np.allclose(probs, target))
with self.subTest(msg="P([1])"):
probs = state.probabilities([1])
target = np.array([0.5, 0.5])
self.assertTrue(np.allclose(probs, target))
def test_probabilities_dict_product(self):
"""Test probabilities_dict method for product state"""
state = DensityMatrix.from_label("+0")
# 2-qubit qargs
with self.subTest(msg="P(None)"):
probs = state.probabilities_dict()
target = {"00": 0.5, "10": 0.5}
self.assertDictAlmostEqual(probs, target)
with self.subTest(msg="P([0, 1])"):
probs = state.probabilities_dict([0, 1])
target = {"00": 0.5, "10": 0.5}
self.assertDictAlmostEqual(probs, target)
with self.subTest(msg="P([1, 0]"):
probs = state.probabilities_dict([1, 0])
target = {"00": 0.5, "01": 0.5}
self.assertDictAlmostEqual(probs, target)
# 1-qubit qargs
with self.subTest(msg="P([0])"):
probs = state.probabilities_dict([0])
target = {"0": 1}
self.assertDictAlmostEqual(probs, target)
with self.subTest(msg="P([1])"):
probs = state.probabilities_dict([1])
target = {"0": 0.5, "1": 0.5}
self.assertDictAlmostEqual(probs, target)
def test_probabilities_dict_product(self):
"""Test probabilities_dict method for product state"""
state = DensityMatrix.from_label('+0')
# 2-qubit qargs
with self.subTest(msg='P(None)'):
probs = state.probabilities_dict()
target = {'00': 0.5, '10': 0.5}
self.assertDictAlmostEqual(probs, target)
with self.subTest(msg='P([0, 1])'):
probs = state.probabilities_dict([0, 1])
target = {'00': 0.5, '10': 0.5}
self.assertDictAlmostEqual(probs, target)
with self.subTest(msg='P([1, 0]'):
probs = state.probabilities_dict([1, 0])
target = {'00': 0.5, '01': 0.5}
self.assertDictAlmostEqual(probs, target)
# 1-qubit qargs
with self.subTest(msg='P([0])'):
probs = state.probabilities_dict([0])
target = {'0': 1}
self.assertDictAlmostEqual(probs, target)
with self.subTest(msg='P([1])'):
probs = state.probabilities_dict([1])
target = {'0': 0.5, '1': 0.5}
self.assertDictAlmostEqual(probs, target)
def test_from_circuit(self):
"""Test initialization from a circuit."""
# random unitaries
u0 = random_unitary(2).data
u1 = random_unitary(2).data
# add to circuit
qr = QuantumRegister(2)
circ = QuantumCircuit(qr)
circ.unitary(u0, [qr[0]])
circ.unitary(u1, [qr[1]])
# Test decomposition of controlled-H gate
circuit = QuantumCircuit(2)
circ.x(0)
circuit.ch(0, 1)
target = DensityMatrix.from_label("00").evolve(Operator(circuit))
rho = DensityMatrix.from_instruction(circuit)
self.assertEqual(rho, target)
# Test initialize instruction
init = Statevector([1, 0, 0, 1j]) / np.sqrt(2)
target = DensityMatrix(init)
circuit = QuantumCircuit(2)
circuit.initialize(init.data, [0, 1])
rho = DensityMatrix.from_instruction(circuit)
self.assertEqual(rho, target)
# Test reset instruction
target = DensityMatrix([1, 0])
circuit = QuantumCircuit(1)
circuit.h(0)
circuit.reset(0)
rho = DensityMatrix.from_instruction(circuit)
self.assertEqual(rho, target)
def test_from_circuit(self):
"""Test initialization from a circuit."""
# random unitaries
u0 = random_unitary(2).data
u1 = random_unitary(2).data
# add to circuit
qr = QuantumRegister(2)
circ = QuantumCircuit(qr)
circ.unitary(u0, [qr[0]])
circ.unitary(u1, [qr[1]])
target_vec = Statevector(np.kron(u1, u0).dot([1, 0, 0, 0]))
target = DensityMatrix(target_vec)
rho = DensityMatrix.from_instruction(circ)
self.assertEqual(rho, target)
# Test tensor product of 1-qubit gates
circuit = QuantumCircuit(3)
circuit.h(0)
circuit.x(1)
circuit.ry(np.pi / 2, 2)
target = DensityMatrix.from_label('000').evolve(Operator(circuit))
rho = DensityMatrix.from_instruction(circuit)
self.assertEqual(rho, target)
# Test decomposition of Controlled-u1 gate
lam = np.pi / 4
circuit = QuantumCircuit(2)
circuit.h(0)
circuit.h(1)
circuit.cu1(lam, 0, 1)
target = DensityMatrix.from_label('00').evolve(Operator(circuit))
rho = DensityMatrix.from_instruction(circuit)
self.assertEqual(rho, target)
# Test decomposition of controlled-H gate
circuit = QuantumCircuit(2)
circ.x(0)
circuit.ch(0, 1)
target = DensityMatrix.from_label('00').evolve(Operator(circuit))
rho = DensityMatrix.from_instruction(circuit)
self.assertEqual(rho, target)
def test_density_matrix_partial_trace(self):
"""Test partial_trace function on density matrices"""
rho = DensityMatrix.from_label("10+")
self.assertEqual(partial_trace(rho, [0, 1]),
DensityMatrix.from_label("1"))
self.assertEqual(partial_trace(rho, [0, 2]),
DensityMatrix.from_label("0"))
self.assertEqual(partial_trace(rho, [1, 2]),
DensityMatrix.from_label("+"))
self.assertEqual(partial_trace(rho, [0]),
DensityMatrix.from_label("10"))
self.assertEqual(partial_trace(rho, [1]),
DensityMatrix.from_label("1+"))
self.assertEqual(partial_trace(rho, [2]),
DensityMatrix.from_label("0+"))
def test_density_matrix_partial_trace(self):
"""Test partial_trace function on density matrices"""
rho = DensityMatrix.from_label('10+')
self.assertEqual(partial_trace(rho, [0, 1]),
DensityMatrix.from_label('1'))
self.assertEqual(partial_trace(rho, [0, 2]),
DensityMatrix.from_label('0'))
self.assertEqual(partial_trace(rho, [1, 2]),
DensityMatrix.from_label('+'))
self.assertEqual(partial_trace(rho, [0]),
DensityMatrix.from_label('10'))
self.assertEqual(partial_trace(rho, [1]),
DensityMatrix.from_label('1+'))
self.assertEqual(partial_trace(rho, [2]),
DensityMatrix.from_label('0+'))
def test_statevector_partial_trace(self):
"""Test partial_trace function on statevectors"""
psi = Statevector.from_label("10+")
self.assertEqual(partial_trace(psi, [0, 1]),
DensityMatrix.from_label("1"))
self.assertEqual(partial_trace(psi, [0, 2]),
DensityMatrix.from_label("0"))
self.assertEqual(partial_trace(psi, [1, 2]),
DensityMatrix.from_label("+"))
self.assertEqual(partial_trace(psi, [0]),
DensityMatrix.from_label("10"))
self.assertEqual(partial_trace(psi, [1]),
DensityMatrix.from_label("1+"))
self.assertEqual(partial_trace(psi, [2]),
DensityMatrix.from_label("0+"))
def test_statevector_partial_trace(self):
"""Test partial_trace function on statevectors"""
psi = Statevector.from_label('10+')
self.assertEqual(partial_trace(psi, [0, 1]),
DensityMatrix.from_label('1'))
self.assertEqual(partial_trace(psi, [0, 2]),
DensityMatrix.from_label('0'))
self.assertEqual(partial_trace(psi, [1, 2]),
DensityMatrix.from_label('+'))
self.assertEqual(partial_trace(psi, [0]),
DensityMatrix.from_label('10'))
self.assertEqual(partial_trace(psi, [1]),
DensityMatrix.from_label('1+'))
self.assertEqual(partial_trace(psi, [2]),
DensityMatrix.from_label('0+'))
def test_measure_2qubit(self):
"""Test measure method for 2-qubit state"""
state = DensityMatrix.from_label("+0")
seed = 200
shots = 100
with self.subTest(msg="measure"):
for i in range(shots):
rho = state.copy()
rho.seed(seed + i)
outcome, value = rho.measure()
self.assertIn(outcome, ["00", "10"])
if outcome == "00":
target = DensityMatrix.from_label("00")
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label("10")
self.assertEqual(value, target)
with self.subTest(msg="measure [0, 1]"):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([0, 1])
self.assertIn(outcome, ["00", "10"])
if outcome == "00":
target = DensityMatrix.from_label("00")
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label("10")
self.assertEqual(value, target)
with self.subTest(msg="measure [1, 0]"):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([1, 0])
self.assertIn(outcome, ["00", "01"])
if outcome == "00":
target = DensityMatrix.from_label("00")
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label("10")
self.assertEqual(value, target)
with self.subTest(msg="measure [0]"):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([0])
self.assertEqual(outcome, "0")
target = DensityMatrix.from_label("+0")
self.assertEqual(value, target)
with self.subTest(msg="measure [1]"):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([1])
self.assertIn(outcome, ["0", "1"])
if outcome == "0":
target = DensityMatrix.from_label("00")
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label("10")
self.assertEqual(value, target)
def test_measure_2qubit(self):
"""Test measure method for 2-qubit state"""
state = DensityMatrix.from_label('+0')
seed = 200
shots = 100
with self.subTest(msg='measure'):
for i in range(shots):
rho = state.copy()
rho.seed(seed + i)
outcome, value = rho.measure()
self.assertIn(outcome, ['00', '10'])
if outcome == '00':
target = DensityMatrix.from_label('00')
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label('10')
self.assertEqual(value, target)
with self.subTest(msg='measure [0, 1]'):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([0, 1])
self.assertIn(outcome, ['00', '10'])
if outcome == '00':
target = DensityMatrix.from_label('00')
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label('10')
self.assertEqual(value, target)
with self.subTest(msg='measure [1, 0]'):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([1, 0])
self.assertIn(outcome, ['00', '01'])
if outcome == '00':
target = DensityMatrix.from_label('00')
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label('10')
self.assertEqual(value, target)
with self.subTest(msg='measure [0]'):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([0])
self.assertEqual(outcome, '0')
target = DensityMatrix.from_label('+0')
self.assertEqual(value, target)
with self.subTest(msg='measure [1]'):
for i in range(shots):
rho = state.copy()
outcome, value = rho.measure([1])
self.assertIn(outcome, ['0', '1'])
if outcome == '0':
target = DensityMatrix.from_label('00')
self.assertEqual(value, target)
else:
target = DensityMatrix.from_label('10')
self.assertEqual(value, target)
