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_reverse_qargs(self):
"""Test reverse_qargs method"""
circ1 = QFT(5)
circ2 = circ1.reverse_bits()
state1 = DensityMatrix.from_instruction(circ1)
state2 = DensityMatrix.from_instruction(circ2)
self.assertEqual(state1.reverse_qargs(), state2)
def tomography_random_circuit(self, n):
q = QuantumRegister(n)
qc = QuantumCircuit(q)
psi = ((2 * np.random.rand(2**n) - 1) + 1j *
(2 * np.random.rand(2**n) - 1))
psi /= np.linalg.norm(psi)
qc.initialize(psi, q)
rho = DensityMatrix.from_instruction(qc).data
circ = pairwise_state_tomography_circuits(qc, q)
job = execute(circ, Aer.get_backend("qasm_simulator"), shots=nshots)
fitter = PairwiseStateTomographyFitter(job.result(), circ, q)
result = fitter.fit()
result_exp = fitter.fit(output='expectation')
# Compare the tomography matrices with the partial trace of
# the original state using fidelity
for (k, v) in result.items():
trace_qubits = list(range(n))
trace_qubits.remove(k[0])
trace_qubits.remove(k[1])
rhok = partial_trace(rho, trace_qubits)
try:
self.check_density_matrix(v, rhok)
except:
print("Problem with density matrix:", k)
raise
try:
self.check_pauli_expectaion(result_exp[k], rhok)
except:
print("Problem with expectation values:", k)
raise
def test_drawings(self):
"""Test draw method"""
qc1 = QFT(5)
dm = DensityMatrix.from_instruction(qc1)
with self.subTest(msg="str(density_matrix)"):
str(dm)
for drawtype in ["repr", "text", "latex", "latex_source", "qsphere", "hinton", "bloch"]:
with self.subTest(msg=f"draw('{drawtype}')"):
dm.draw(drawtype)
def test_drawings(self):
"""Test draw method"""
qc1 = QFT(5)
dm = DensityMatrix.from_instruction(qc1)
with self.subTest(msg='str(density_matrix)'):
str(dm)
for drawtype in ['repr', 'text', 'latex', 'latex_source',
'qsphere', 'hinton', 'bloch']:
with self.subTest(msg=f"draw('{drawtype}')"):
dm.draw(drawtype)
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_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)
def test_meas_qubit_specification(self):
n = 4
q = QuantumRegister(n)
qc = QuantumCircuit(q)
psi = ((2 * np.random.rand(2**n) - 1) + 1j *
(2 * np.random.rand(2**n) - 1))
psi /= np.linalg.norm(psi)
qc.initialize(psi, q)
rho = DensityMatrix.from_instruction(qc).data
measured_qubits = [q[0], q[2], q[3]]
circ = pairwise_state_tomography_circuits(qc, measured_qubits)
job = execute(circ, Aer.get_backend("qasm_simulator"), shots=nshots)
fitter = PairwiseStateTomographyFitter(job.result(), circ,
measured_qubits)
result = fitter.fit()
result_exp = fitter.fit(output='expectation')
# Compare the tomography matrices with the partial trace of
# the original state using fidelity
for (k, v) in result.items():
#TODO: This method won't work if measured_qubits is not ordered in
# wrt the DensityMatrix object.
trace_qubits = list(range(n))
trace_qubits.remove(measured_qubits[k[0]].index)
trace_qubits.remove(measured_qubits[k[1]].index)
rhok = partial_trace(rho, trace_qubits)
try:
self.check_density_matrix(v, rhok)
except:
print("Problem with density matrix:", k)
raise
try:
self.check_pauli_expectaion(result_exp[k], rhok)
except:
print("Problem with expectation values:", k)
raise
def test_multiple_registers(self):
n = 4
q = QuantumRegister(n / 2)
p = QuantumRegister(n / 2)
qc = QuantumCircuit(q, p)
qc.h(q[0])
qc.rx(np.pi / 4, q[1])
qc.cx(q[0], p[0])
qc.cx(q[1], p[1])
rho = DensityMatrix.from_instruction(qc).data
measured_qubits = q #[q[0], q[1], q[2]]
circ = pairwise_state_tomography_circuits(qc, measured_qubits)
job = execute(circ, Aer.get_backend("qasm_simulator"), shots=nshots)
fitter = PairwiseStateTomographyFitter(job.result(), circ,
measured_qubits)
result = fitter.fit()
result_exp = fitter.fit(output='expectation')
# Compare the tomography matrices with the partial trace of
# the original state using fidelity
for (k, v) in result.items():
trace_qubits = list(range(n))
trace_qubits.remove(measured_qubits[k[0]].index)
trace_qubits.remove(measured_qubits[k[1]].index)
rhok = partial_trace(rho, trace_qubits)
try:
self.check_density_matrix(v, rhok)
except:
print("Problem with density matrix:", k)
raise
try:
self.check_pauli_expectaion(result_exp[k], rhok)
except:
print("Problem with expectation values:", k)
raise
def test_from_instruction(self):
"""Test initialization from an instruction."""
target_vec = Statevector(np.dot(HGate().to_matrix(), [1, 0]))
target = DensityMatrix(target_vec)
rho = DensityMatrix.from_instruction(HGate())
self.assertEqual(rho, target)
