def test_pauli_expectation_param_qobj(self):
"""Test PauliExpectation with param_qobj"""
q_instance = QuantumInstance(
self.backend, seed_simulator=self.seed, seed_transpiler=self.seed, shots=10000
)
qubit_op = (0.1 * I ^ I) + (0.2 * I ^ Z) + (0.3 * Z ^ I) + (0.4 * Z ^ Z) + (0.5 * X ^ X)
ansatz = RealAmplitudes(qubit_op.num_qubits)
ansatz_circuit_op = CircuitStateFn(ansatz)
observable = PauliExpectation().convert(~StateFn(qubit_op))
expect_op = observable.compose(ansatz_circuit_op).reduce()
params1 = {}
params2 = {}
for param in ansatz.parameters:
params1[param] = [0]
params2[param] = [0, 0]
sampler1 = CircuitSampler(backend=q_instance, param_qobj=False)
samples1 = sampler1.convert(expect_op, params=params1)
val1 = np.real(samples1.eval())[0]
samples2 = sampler1.convert(expect_op, params=params2)
val2 = np.real(samples2.eval())
sampler2 = CircuitSampler(backend=q_instance, param_qobj=True)
samples3 = sampler2.convert(expect_op, params=params1)
val3 = np.real(samples3.eval())
samples4 = sampler2.convert(expect_op, params=params2)
val4 = np.real(samples4.eval())
np.testing.assert_array_almost_equal([val1] * 2, val2, decimal=2)
np.testing.assert_array_almost_equal(val1, val3, decimal=2)
np.testing.assert_array_almost_equal([val1] * 2, val4, decimal=2)
def setUp(self) -> None:
super().setUp()
self.seed = 97
backend = BasicAer.get_backend('qasm_simulator')
q_instance = QuantumInstance(backend, seed_simulator=self.seed, seed_transpiler=self.seed)
self.sampler = CircuitSampler(q_instance, attach_results=True)
self.expect = PauliExpectation()
def test_grouped_pauli_expectation(self):
"""grouped pauli expectation test"""
two_qubit_H2 = ((-1.052373245772859 * I ^ I) +
(0.39793742484318045 * I ^ Z) +
(-0.39793742484318045 * Z ^ I) +
(-0.01128010425623538 * Z ^ Z) +
(0.18093119978423156 * X ^ X))
wf = CX @ (H ^ I) @ Zero
expect_op = PauliExpectation(group_paulis=False).convert(
~StateFn(two_qubit_H2) @ wf)
self.sampler._extract_circuitstatefns(expect_op)
num_circuits_ungrouped = len(self.sampler._circuit_ops_cache)
self.assertEqual(num_circuits_ungrouped, 5)
expect_op_grouped = PauliExpectation(group_paulis=True).convert(
~StateFn(two_qubit_H2) @ wf)
q_instance = QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
sampler = CircuitSampler(q_instance)
sampler._extract_circuitstatefns(expect_op_grouped)
num_circuits_grouped = len(sampler._circuit_ops_cache)
self.assertEqual(num_circuits_grouped, 2)
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
vqe = VQE(self.h2_op,
wavefunction,
optimizer,
expectation=PauliExpectation())
quantum_instance = QuantumInstance(
backend,
seed_simulator=aqua_globals.random_seed,
seed_transpiler=aqua_globals.random_seed)
result = vqe.run(quantum_instance)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
def test_uccsd_hf_aer_qasm(self):
"""uccsd hf test with Aer qasm simulator."""
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
backend = Aer.get_backend("aer_simulator")
except ImportError as ex: # pylint: disable=broad-except
self.skipTest(f"Aer doesn't appear to be installed. Error: '{str(ex)}'")
return
ansatz = self._prepare_uccsd_hf(self.qubit_converter)
optimizer = SPSA(maxiter=200, last_avg=5)
solver = VQE(
ansatz=ansatz,
optimizer=optimizer,
expectation=PauliExpectation(group_paulis=False),
quantum_instance=QuantumInstance(
backend=backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
gsc = GroundStateEigensolver(self.qubit_converter, solver)
result = gsc.solve(self.electronic_structure_problem)
self.assertAlmostEqual(result.total_energies[0], -1.131, places=2)
def setUp(self):
super().setUp()
# specify "run configuration"
backend = Aer.get_backend('statevector_simulator')
quantum_instance = QuantumInstance(backend)
# specify how to evaluate expected values and gradients
expval = PauliExpectation()
gradient = Gradient()
# construct parametrized circuit
params = [Parameter('input1'), Parameter('weight1')]
qc = QuantumCircuit(1)
qc.h(0)
qc.ry(params[0], 0)
qc.rx(params[1], 0)
qc_sfn = StateFn(qc)
# construct cost operator
cost_operator = StateFn(PauliSumOp.from_list([('Z', 1.0), ('X', 1.0)]))
# combine operator and circuit to objective function
op = ~cost_operator @ qc_sfn
# define QNN
self.qnn = OpflowQNN(op, [params[0]], [params[1]],
expval,
gradient,
quantum_instance=quantum_instance)
def test_aux_operator_std_dev_pauli(self):
"""Test non-zero standard deviations of aux operators with PauliExpectation."""
wavefunction = self.ry_wavefunction
vqd = VQD(
ansatz=wavefunction,
expectation=PauliExpectation(),
initial_point=[
1.70256666,
-5.34843975,
-0.39542903,
5.99477786,
-2.74374986,
-4.85284669,
0.2442925,
-1.51638917,
],
optimizer=COBYLA(maxiter=0),
quantum_instance=self.qasm_simulator,
)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2.0,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0.0019531249999999445,
places=1)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1],
0.015183867579396111,
places=1)
# Go again with additional None and zero operators
aux_ops = [*aux_ops, None, 0]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues[0]), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2.0,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0.0019531249999999445,
places=1)
self.assertEqual(result.aux_operator_eigenvalues[0][2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[0][3][0], 0.0)
# # standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1],
0.01548658094658011,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][3][1], 0.0)
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
try:
from qiskit.providers.aer import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
def test_with_aer_qasm(self):
"""Test VQD with Aer's qasm_simulator."""
backend = Aer.get_backend("aer_simulator")
optimizer = COBYLA(maxiter=1000)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqd = VQD(
k=2,
ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqd.compute_eigenvalues(operator=self.h2_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=1)
def test_opflow_qnn_2_1(self, config):
"""Test Opflow QNN with input/output dimension 2/1."""
q_i, input_grad_required = config
# construct QNN
if q_i == STATEVECTOR:
quantum_instance = self.sv_quantum_instance
elif q_i == QASM:
quantum_instance = self.qasm_quantum_instance
else:
quantum_instance = None
# specify how to evaluate expected values and gradients
expval = PauliExpectation()
gradient = Gradient()
# construct parametrized circuit
params = [
Parameter("input1"),
Parameter("input2"),
Parameter("weight1"),
Parameter("weight2"),
]
qc = QuantumCircuit(2)
qc.h(0)
qc.ry(params[0], 0)
qc.ry(params[1], 1)
qc.rx(params[2], 0)
qc.rx(params[3], 1)
qc_sfn = StateFn(qc)
# construct cost operator
cost_operator = StateFn(PauliSumOp.from_list([("ZZ", 1.0), ("XX", 1.0)]))
# combine operator and circuit to objective function
op = ~cost_operator @ qc_sfn
# define QNN
qnn = OpflowQNN(
op,
params[:2],
params[2:],
expval,
gradient,
quantum_instance=quantum_instance,
)
qnn.input_gradients = input_grad_required
test_data = [np.array([1, 2]), np.array([[1, 2]]), np.array([[1, 2], [3, 4]])]
# test model
self.validate_output_shape(qnn, test_data)
# test the qnn after we set a quantum instance
if quantum_instance is None:
qnn.quantum_instance = self.qasm_quantum_instance
self.validate_output_shape(qnn, test_data)
def test_aux_operator_std_dev_pauli(self):
"""Test non-zero standard deviations of aux operators with PauliExpectation."""
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
expectation=PauliExpectation(),
optimizer=COBYLA(maxiter=0),
quantum_instance=self.qasm_simulator,
)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0.6796875,
places=6)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1],
0.02534712219145965,
places=6)
# Go again with additional None and zero operators
aux_ops = [*aux_ops, None, 0]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0.57421875,
places=6)
self.assertEqual(result.aux_operator_eigenvalues[2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[3][0], 0.0)
# # standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1],
0.026562146577166837,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[3][1], 0.0)
def test_compute_variance(self):
"""Test if the compute_variance method works"""
alphas = [0, .3, 0.5, 0.7, 1]
correct_vars = [0, 0, 0, 0.8163, 1]
for i, alpha in enumerate(alphas):
base_expecation = PauliExpectation()
cvar_expecation = CVaRExpectation(alpha=alpha,
expectation=base_expecation)
op = ~StateFn(Z ^ Z) @ (Plus ^ Plus)
cvar_var = cvar_expecation.compute_variance(op)
np.testing.assert_almost_equal(cvar_var,
correct_vars[i],
decimal=3)
def test_opflow_qnn_2_1(self, q_i):
""" Test Opflow QNN with input/output dimension 2/1."""
# construct QNN
if q_i == 'sv':
quantum_instance = self.sv_quantum_instance
else:
quantum_instance = self.qasm_quantum_instance
# specify how to evaluate expected values and gradients
expval = PauliExpectation()
gradient = Gradient()
# construct parametrized circuit
params = [
Parameter('input1'),
Parameter('input2'),
Parameter('weight1'),
Parameter('weight2')
]
qc = QuantumCircuit(2)
qc.h(0)
qc.ry(params[0], 0)
qc.ry(params[1], 1)
qc.rx(params[2], 0)
qc.rx(params[3], 1)
qc_sfn = StateFn(qc)
# construct cost operator
cost_operator = StateFn(
PauliSumOp.from_list([('ZZ', 1.0), ('XX', 1.0)]))
# combine operator and circuit to objective function
op = ~cost_operator @ qc_sfn
# define QNN
qnn = OpflowQNN(op,
params[:2],
params[2:],
expval,
gradient,
quantum_instance=quantum_instance)
test_data = [
np.array([1, 2]),
np.array([[1, 2]]),
np.array([[1, 2], [3, 4]])
]
# test model
self.validate_output_shape(qnn, test_data)
def test_uccsd_hf_qasm(self):
""" uccsd hf test with qasm_simulator. """
backend = BasicAer.get_backend('qasm_simulator')
optimizer = SPSA(maxiter=200, last_avg=5)
solver = VQE(var_form=self.var_form, optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=QuantumInstance(
backend=backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed))
gsc = GroundStateEigensolver(self.fermionic_transformation, solver)
result = gsc.solve(self.driver)
self.assertAlmostEqual(result.total_energies[0], -1.138, places=2)
def test_uccsd_hf_qasm(self):
""" uccsd hf test with qasm_simulator. """
qubit_converter = QubitConverter(ParityMapper())
ansatz = self._prepare_uccsd_hf(qubit_converter)
backend = BasicAer.get_backend('qasm_simulator')
optimizer = SPSA(maxiter=200, last_avg=5)
solver = VQE(ansatz=ansatz, optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=QuantumInstance(
backend=backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed))
gsc = GroundStateEigensolver(qubit_converter, solver)
result = gsc.solve(self.electronic_structure_problem)
self.assertAlmostEqual(result.total_energies[0], -1.138, places=2)
def test_uccsd_hf_aer_qasm(self):
""" uccsd hf test with Aer qasm_simulator. """
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
backend = Aer.get_backend('qasm_simulator')
except ImportError as ex: # pylint: disable=broad-except
self.skipTest("Aer doesn't appear to be installed. Error: '{}'".format(str(ex)))
return
optimizer = SPSA(maxiter=200, last_avg=5)
solver = VQE(var_form=self.var_form, optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=QuantumInstance(
backend=backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed))
gsc = GroundStateEigensolver(self.fermionic_transformation, solver)
result = gsc.solve(self.driver)
self.assertAlmostEqual(result.total_energies[0], -1.138, places=2)
def test_eval_op_qasm(self):
"""Regression tests against https://github.com/Qiskit/qiskit-nature/issues/53."""
solver = VQEUCCFactory(
optimizer=SLSQP(maxiter=100),
expectation=PauliExpectation(),
quantum_instance=QuantumInstance(
backend=BasicAer.get_backend('qasm_simulator'),
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed))
calc = GroundStateEigensolver(self.qubit_converter, solver)
res_qasm = calc.solve(self.electronic_structure_problem)
hamiltonian = self.electronic_structure_problem.second_q_ops()[0]
qubit_op = self.qubit_converter.map(hamiltonian)
ansatz = solver.get_solver(self.electronic_structure_problem,
self.qubit_converter).ansatz
circuit = ansatz.assign_parameters(res_qasm.raw_result.optimal_point)
mean = calc.evaluate_operators(circuit, qubit_op)
self.assertAlmostEqual(res_qasm.eigenenergies[0], mean[0].real)
def test_construction(self):
"""Test the correct operator expression is constructed."""
alpha = 0.5
base_expecation = PauliExpectation()
cvar_expecation = CVaRExpectation(alpha=alpha,
expectation=base_expecation)
with self.subTest('single operator'):
op = ~StateFn(Z) @ Plus
expected = CVaRMeasurement(Z, alpha) @ Plus
cvar = cvar_expecation.convert(op)
self.assertEqual(cvar, expected)
with self.subTest('list operator'):
op = ~StateFn(ListOp([Z ^ Z, I ^ Z])) @ (Plus ^ Plus)
expected = ListOp([
CVaRMeasurement((Z ^ Z), alpha) @ (Plus ^ Plus),
CVaRMeasurement((I ^ Z), alpha) @ (Plus ^ Plus)
])
cvar = cvar_expecation.convert(op)
self.assertEqual(cvar, expected)
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
backend = Aer.get_backend("aer_simulator")
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
def test_uccsd_hf_aer_qasm(self):
"""uccsd hf test with Aer qasm simulator."""
backend = qiskit.providers.aer.Aer.get_backend("aer_simulator")
ansatz = self._prepare_uccsd_hf(self.qubit_converter)
optimizer = SPSA(maxiter=200, last_avg=5)
solver = VQE(
ansatz=ansatz,
optimizer=optimizer,
expectation=PauliExpectation(group_paulis=False),
quantum_instance=QuantumInstance(
backend=backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
gsc = GroundStateEigensolver(self.qubit_converter, solver)
result = gsc.solve(self.electronic_structure_problem)
self.assertAlmostEqual(result.total_energies[0], -1.131, places=2)
def test_h2_bopes_sampler(self):
"""Test BOPES Sampler on H2"""
seed = 50
algorithm_globals.random_seed = seed
# Molecule
dof = partial(Molecule.absolute_distance, atom_pair=(1, 0))
m = Molecule(geometry=[['H', [0., 0., 1.]],
['H', [0., 0.45, 1.]]],
degrees_of_freedom=[dof])
f_t = FermionicTransformation()
driver = PySCFDriver(molecule=m)
qubitop, _ = f_t.transform(driver)
# Quantum Instance:
shots = 1
backend = 'statevector_simulator'
quantum_instance = QuantumInstance(BasicAer.get_backend(backend), shots=shots)
quantum_instance.run_config.seed_simulator = seed
quantum_instance.compile_config['seed_transpiler'] = seed
# Variational form
i_state = HartreeFock(num_orbitals=f_t._molecule_info['num_orbitals'],
qubit_mapping=f_t._qubit_mapping,
two_qubit_reduction=f_t._two_qubit_reduction,
num_particles=f_t._molecule_info['num_particles'],
sq_list=f_t._molecule_info['z2_symmetries'].sq_list
)
var_form = RealAmplitudes(qubitop.num_qubits, reps=1, entanglement='full',
skip_unentangled_qubits=False)
var_form.compose(i_state, front=True)
# Classical optimizer:
# Analytic Quantum Gradient Descent (AQGD) (with Epochs)
aqgd_max_iter = [10] + [1] * 100
aqgd_eta = [1e0] + [1.0 / k for k in range(1, 101)]
aqgd_momentum = [0.5] + [0.5] * 100
optimizer = AQGD(maxiter=aqgd_max_iter,
eta=aqgd_eta,
momentum=aqgd_momentum,
tol=1e-6,
averaging=4)
# Min Eigensolver: VQE
solver = VQE(var_form=var_form,
optimizer=optimizer,
quantum_instance=quantum_instance,
expectation=PauliExpectation())
me_gss = GroundStateEigensolver(f_t, solver)
# BOPES sampler
sampler = BOPESSampler(gss=me_gss)
# absolute internuclear distance in Angstrom
points = [0.7, 1.0, 1.3]
results = sampler.sample(driver, points)
points_run = results.points
energies = results.energies
np.testing.assert_array_almost_equal(points_run, [0.7, 1.0, 1.3])
np.testing.assert_array_almost_equal(energies,
[-1.13618945, -1.10115033, -1.03518627], decimal=2)
class TestVQD(QiskitAlgorithmsTestCase):
"""Test VQD"""
def setUp(self):
super().setUp()
self.seed = 50
algorithm_globals.random_seed = self.seed
self.h2_op = (-1.052373245772859 * (I ^ I) + 0.39793742484318045 *
(I ^ Z) - 0.39793742484318045 * (Z ^ I) -
0.01128010425623538 * (Z ^ Z) + 0.18093119978423156 *
(X ^ X))
self.h2_energy = -1.85727503
self.h2_energy_excited = [-1.85727503, -1.24458455]
self.test_op = MatrixOp(np.diagflat([3, 5, -1, 0.8, 0.2, 2, 1,
-3])).to_pauli_op()
self.test_results = [-3, -1]
self.ryrz_wavefunction = TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz",
reps=1)
self.ry_wavefunction = TwoLocal(rotation_blocks="ry",
entanglement_blocks="cz")
self.qasm_simulator = QuantumInstance(
BasicAer.get_backend("qasm_simulator"),
shots=2048,
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
self.statevector_simulator = QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
shots=1,
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
def test_basic_aer_statevector(self):
"""Test the VQD on BasicAer's statevector simulator."""
wavefunction = self.ryrz_wavefunction
vqd = VQD(
k=2,
ansatz=wavefunction,
optimizer=COBYLA(),
quantum_instance=QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
basis_gates=["u1", "u2", "u3", "cx", "id"],
coupling_map=[[0, 1]],
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
result = vqd.compute_eigenvalues(operator=self.h2_op)
with self.subTest(msg="test eigenvalue"):
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=1)
with self.subTest(msg="test dimension of optimal point"):
self.assertEqual(len(result.optimal_point[-1]), 8)
with self.subTest(msg="assert cost_function_evals is set"):
self.assertIsNotNone(result.cost_function_evals)
with self.subTest(msg="assert optimizer_time is set"):
self.assertIsNotNone(result.optimizer_time)
def test_mismatching_num_qubits(self):
"""Ensuring circuit and operator mismatch is caught"""
wavefunction = QuantumCircuit(1)
optimizer = SLSQP(maxiter=50)
vqd = VQD(
k=1,
ansatz=wavefunction,
optimizer=optimizer,
quantum_instance=self.statevector_simulator,
)
with self.assertRaises(AlgorithmError):
_ = vqd.compute_eigenvalues(operator=self.h2_op)
@data(
(MatrixExpectation(), 1),
(AerPauliExpectation(), 1),
(PauliExpectation(), 2),
)
@unpack
def test_construct_circuit(self, expectation, num_circuits):
"""Test construct circuits returns QuantumCircuits and the right number of them."""
try:
wavefunction = EfficientSU2(2, reps=1)
vqd = VQD(k=2, ansatz=wavefunction, expectation=expectation)
params = [0] * wavefunction.num_parameters
circuits = vqd.construct_circuit(parameter=params,
operator=self.h2_op)
self.assertEqual(len(circuits), num_circuits)
for circuit in circuits:
self.assertIsInstance(circuit, QuantumCircuit)
except MissingOptionalLibraryError as ex:
self.skipTest(str(ex))
return
def test_missing_varform_params(self):
"""Test specifying a variational form with no parameters raises an error."""
circuit = QuantumCircuit(self.h2_op.num_qubits)
vqd = VQD(
k=1,
ansatz=circuit,
quantum_instance=BasicAer.get_backend("statevector_simulator"))
with self.assertRaises(RuntimeError):
vqd.compute_eigenvalues(operator=self.h2_op)
def test_basic_aer_qasm(self):
"""Test the VQD on BasicAer's QASM simulator."""
optimizer = COBYLA(maxiter=1000)
wavefunction = self.ry_wavefunction
vqd = VQD(
ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=self.qasm_simulator,
)
# TODO benchmark this later.
result = vqd.compute_eigenvalues(operator=self.h2_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=1)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_statevector(self):
"""Test VQD with Aer's statevector_simulator."""
backend = Aer.get_backend("aer_simulator_statevector")
wavefunction = self.ry_wavefunction
optimizer = L_BFGS_B()
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqd = VQD(
k=2,
ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=quantum_instance,
)
result = vqd.compute_eigenvalues(operator=self.h2_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=2)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_qasm(self):
"""Test VQD with Aer's qasm_simulator."""
backend = Aer.get_backend("aer_simulator")
optimizer = COBYLA(maxiter=1000)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqd = VQD(
k=2,
ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqd.compute_eigenvalues(operator=self.h2_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=1)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_qasm_snapshot_mode(self):
"""Test the VQD using Aer's qasm_simulator snapshot mode."""
backend = Aer.get_backend("aer_simulator")
optimizer = COBYLA(maxiter=400)
wavefunction = self.ryrz_wavefunction
quantum_instance = QuantumInstance(
backend,
shots=100,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqd = VQD(
k=2,
ansatz=wavefunction,
optimizer=optimizer,
expectation=AerPauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqd.compute_eigenvalues(operator=self.test_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.test_results,
decimal=1)
def test_callback(self):
"""Test the callback on VQD."""
history = {"eval_count": [], "parameters": [], "mean": [], "std": []}
def store_intermediate_result(eval_count, parameters, mean, std):
history["eval_count"].append(eval_count)
history["parameters"].append(parameters)
history["mean"].append(mean)
history["std"].append(std)
optimizer = COBYLA(maxiter=3)
wavefunction = self.ry_wavefunction
vqd = VQD(
ansatz=wavefunction,
optimizer=optimizer,
callback=store_intermediate_result,
quantum_instance=self.qasm_simulator,
)
vqd.compute_eigenvalues(operator=self.h2_op)
self.assertTrue(
all(isinstance(count, int) for count in history["eval_count"]))
self.assertTrue(
all(isinstance(mean, float) for mean in history["mean"]))
self.assertTrue(all(isinstance(std, float) for std in history["std"]))
for params in history["parameters"]:
self.assertTrue(all(isinstance(param, float) for param in params))
def test_reuse(self):
"""Test re-using a VQD algorithm instance."""
vqd = VQD(k=1)
with self.subTest(msg="assert running empty raises AlgorithmError"):
with self.assertRaises(AlgorithmError):
_ = vqd.compute_eigenvalues(operator=self.h2_op)
ansatz = TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
vqd.ansatz = ansatz
with self.subTest(msg="assert missing operator raises AlgorithmError"):
with self.assertRaises(AlgorithmError):
_ = vqd.compute_eigenvalues(operator=self.h2_op)
vqd.expectation = MatrixExpectation()
vqd.quantum_instance = self.statevector_simulator
with self.subTest(msg="assert VQE works once all info is available"):
result = vqd.compute_eigenvalues(operator=self.h2_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy,
decimal=2)
operator = PrimitiveOp(
np.array([[1, 0, 0, 0], [0, -1, 0, 0], [0, 0, 2, 0], [0, 0, 0,
3]]))
with self.subTest(msg="assert minimum eigensolver interface works"):
result = vqd.compute_eigenvalues(operator=operator)
self.assertAlmostEqual(result.eigenvalues.real[0], -1.0, places=5)
def test_vqd_optimizer(self):
"""Test running same VQD twice to re-use optimizer, then switch optimizer"""
vqd = VQD(
k=2,
optimizer=SLSQP(),
quantum_instance=QuantumInstance(
BasicAer.get_backend("statevector_simulator")),
)
def run_check():
result = vqd.compute_eigenvalues(operator=self.h2_op)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=3)
run_check()
with self.subTest("Optimizer re-use"):
run_check()
with self.subTest("Optimizer replace"):
vqd.optimizer = L_BFGS_B()
run_check()
@data(MatrixExpectation(), None)
def test_backend_change(self, user_expectation):
"""Test that VQE works when backend changes."""
vqd = VQD(
k=1,
ansatz=TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz"),
optimizer=SLSQP(maxiter=2),
expectation=user_expectation,
quantum_instance=BasicAer.get_backend("statevector_simulator"),
)
result0 = vqd.compute_eigenvalues(operator=self.h2_op)
if user_expectation is not None:
with self.subTest("User expectation kept."):
self.assertEqual(vqd.expectation, user_expectation)
vqd.quantum_instance = BasicAer.get_backend("qasm_simulator")
# works also if no expectation is set, since it will be determined automatically
result1 = vqd.compute_eigenvalues(operator=self.h2_op)
if user_expectation is not None:
with self.subTest(
"Change backend with user expectation, it is kept."):
self.assertEqual(vqd.expectation, user_expectation)
with self.subTest("Check results."):
self.assertEqual(len(result0.optimal_point),
len(result1.optimal_point))
def test_set_ansatz_to_none(self):
"""Tests that setting the ansatz to None results in the default behavior"""
vqd = VQD(
k=1,
ansatz=self.ryrz_wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=self.statevector_simulator,
)
vqd.ansatz = None
self.assertIsInstance(vqd.ansatz, RealAmplitudes)
def test_set_optimizer_to_none(self):
"""Tests that setting the optimizer to None results in the default behavior"""
vqd = VQD(
k=1,
ansatz=self.ryrz_wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=self.statevector_simulator,
)
vqd.optimizer = None
self.assertIsInstance(vqd.optimizer, SLSQP)
def test_aux_operators_list(self):
"""Test list-based aux_operators."""
wavefunction = self.ry_wavefunction
vqd = VQD(k=2,
ansatz=wavefunction,
quantum_instance=self.statevector_simulator)
# Start with an empty list
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=[])
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=2)
self.assertIsNone(result.aux_operator_eigenvalues)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=2)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2,
places=2)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0,
places=2)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1], 0.0)
# Go again with additional None and zero operators
extra_ops = [*aux_ops, None, 0]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=extra_ops)
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=2)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2,
places=2)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0,
places=2)
self.assertEqual(result.aux_operator_eigenvalues[0][2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[0][3][0], 0.0)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[0][3][1], 0.0)
def test_aux_operators_dict(self):
"""Test dictionary compatibility of aux_operators"""
wavefunction = self.ry_wavefunction
vqd = VQD(ansatz=wavefunction,
quantum_instance=self.statevector_simulator)
# Start with an empty dictionary
result = vqd.compute_eigenvalues(self.h2_op, aux_operators={})
np.testing.assert_array_almost_equal(result.eigenvalues.real,
self.h2_energy_excited,
decimal=2)
self.assertIsNone(result.aux_operator_eigenvalues)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = {"aux_op1": aux_op1, "aux_op2": aux_op2}
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.eigenvalues), 2)
self.assertEqual(len(result.eigenstates), 2)
self.assertEqual(result.eigenvalues.dtype, np.complex128)
self.assertAlmostEqual(result.eigenvalues[0], -1.85727503)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
self.assertEqual(len(result.aux_operator_eigenvalues[0]), 2)
# expectation values
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op1"][0], 2, places=6)
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op2"][0], 0, places=1)
# standard deviations
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op1"][1], 0.0)
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op2"][1], 0.0)
# Go again with additional None and zero operators
extra_ops = {**aux_ops, "None_operator": None, "zero_operator": 0}
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=extra_ops)
self.assertEqual(len(result.eigenvalues), 2)
self.assertEqual(len(result.eigenstates), 2)
self.assertEqual(result.eigenvalues.dtype, np.complex128)
self.assertAlmostEqual(result.eigenvalues[0], -1.85727503)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
self.assertEqual(len(result.aux_operator_eigenvalues[0]), 3)
# expectation values
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op1"][0], 2, places=6)
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op2"][0], 0, places=6)
self.assertEqual(
result.aux_operator_eigenvalues[0]["zero_operator"][0], 0.0)
self.assertTrue(
"None_operator" not in result.aux_operator_eigenvalues[0].keys())
# standard deviations
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op1"][1], 0.0)
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["aux_op2"][1], 0.0)
self.assertAlmostEqual(
result.aux_operator_eigenvalues[0]["zero_operator"][1], 0.0)
def test_aux_operator_std_dev_pauli(self):
"""Test non-zero standard deviations of aux operators with PauliExpectation."""
wavefunction = self.ry_wavefunction
vqd = VQD(
ansatz=wavefunction,
expectation=PauliExpectation(),
initial_point=[
1.70256666,
-5.34843975,
-0.39542903,
5.99477786,
-2.74374986,
-4.85284669,
0.2442925,
-1.51638917,
],
optimizer=COBYLA(maxiter=0),
quantum_instance=self.qasm_simulator,
)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2.0,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0.0019531249999999445,
places=1)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1],
0.015183867579396111,
places=1)
# Go again with additional None and zero operators
aux_ops = [*aux_ops, None, 0]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues[0]), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2.0,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0.0019531249999999445,
places=1)
self.assertEqual(result.aux_operator_eigenvalues[0][2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[0][3][0], 0.0)
# # standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1],
0.01548658094658011,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][3][1], 0.0)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_aux_operator_std_dev_aer_pauli(self):
"""Test non-zero standard deviations of aux operators with AerPauliExpectation."""
wavefunction = self.ry_wavefunction
vqd = VQD(
ansatz=wavefunction,
expectation=AerPauliExpectation(),
optimizer=COBYLA(maxiter=0),
quantum_instance=QuantumInstance(
backend=Aer.get_backend("qasm_simulator"),
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2.0,
places=1)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0.6698863565455391,
places=1)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1],
0.0,
places=6)
# Go again with additional None and zero operators
aux_ops = [*aux_ops, None, 0]
result = vqd.compute_eigenvalues(self.h2_op, aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues[-1]), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][0],
0.6036400943063891,
places=6)
self.assertEqual(result.aux_operator_eigenvalues[0][2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[0][3][0], 0.0)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1][1],
0.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][3][1], 0.0)
class TestVQE(QiskitAlgorithmsTestCase):
"""Test VQE"""
def setUp(self):
super().setUp()
self.seed = 50
algorithm_globals.random_seed = self.seed
self.h2_op = (-1.052373245772859 * (I ^ I) + 0.39793742484318045 *
(I ^ Z) - 0.39793742484318045 * (Z ^ I) -
0.01128010425623538 * (Z ^ Z) + 0.18093119978423156 *
(X ^ X))
self.h2_energy = -1.85727503
self.ryrz_wavefunction = TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
self.ry_wavefunction = TwoLocal(rotation_blocks="ry",
entanglement_blocks="cz")
self.qasm_simulator = QuantumInstance(
BasicAer.get_backend("qasm_simulator"),
shots=1024,
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
self.statevector_simulator = QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
shots=1,
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
def test_basic_aer_statevector(self):
"""Test the VQE on BasicAer's statevector simulator."""
wavefunction = self.ryrz_wavefunction
vqe = VQE(
ansatz=wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
basis_gates=["u1", "u2", "u3", "cx", "id"],
coupling_map=[[0, 1]],
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
with self.subTest(msg="test eigenvalue"):
self.assertAlmostEqual(result.eigenvalue.real, self.h2_energy)
with self.subTest(msg="test dimension of optimal point"):
self.assertEqual(len(result.optimal_point), 16)
with self.subTest(msg="assert cost_function_evals is set"):
self.assertIsNotNone(result.cost_function_evals)
with self.subTest(msg="assert optimizer_time is set"):
self.assertIsNotNone(result.optimizer_time)
def test_circuit_input(self):
"""Test running the VQE on a plain QuantumCircuit object."""
wavefunction = QuantumCircuit(2).compose(EfficientSU2(2))
optimizer = SLSQP(maxiter=50)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
quantum_instance=self.statevector_simulator)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
@data(
(MatrixExpectation(), 1),
(AerPauliExpectation(), 1),
(PauliExpectation(), 2),
)
@unpack
def test_construct_circuit(self, expectation, num_circuits):
"""Test construct circuits returns QuantumCircuits and the right number of them."""
try:
wavefunction = EfficientSU2(2, reps=1)
vqe = VQE(ansatz=wavefunction, expectation=expectation)
params = [0] * wavefunction.num_parameters
circuits = vqe.construct_circuit(parameter=params,
operator=self.h2_op)
self.assertEqual(len(circuits), num_circuits)
for circuit in circuits:
self.assertIsInstance(circuit, QuantumCircuit)
except MissingOptionalLibraryError as ex:
self.skipTest(str(ex))
return
def test_missing_varform_params(self):
"""Test specifying a variational form with no parameters raises an error."""
circuit = QuantumCircuit(self.h2_op.num_qubits)
vqe = VQE(
ansatz=circuit,
quantum_instance=BasicAer.get_backend("statevector_simulator"))
with self.assertRaises(RuntimeError):
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
@data(
(SLSQP(maxiter=50), 5, 4),
(SPSA(maxiter=150), 2, 2), # max_evals_grouped=n or =2 if n>2
)
@unpack
def test_max_evals_grouped(self, optimizer, places, max_evals_grouped):
"""VQE Optimizers test"""
vqe = VQE(
ansatz=self.ryrz_wavefunction,
optimizer=optimizer,
max_evals_grouped=max_evals_grouped,
quantum_instance=self.statevector_simulator,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=places)
def test_basic_aer_qasm(self):
"""Test the VQE on BasicAer's QASM simulator."""
optimizer = SPSA(maxiter=300, last_avg=5)
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=self.qasm_simulator,
)
# TODO benchmark this later.
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86823, places=2)
def test_qasm_eigenvector_normalized(self):
"""Test VQE with qasm_simulator returns normalized eigenvector."""
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction, quantum_instance=self.qasm_simulator)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
amplitudes = list(result.eigenstate.values())
self.assertAlmostEqual(np.linalg.norm(amplitudes), 1.0, places=4)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_statevector(self):
"""Test VQE with Aer's statevector_simulator."""
backend = Aer.get_backend("aer_simulator_statevector")
wavefunction = self.ry_wavefunction
optimizer = L_BFGS_B()
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
backend = Aer.get_backend("aer_simulator")
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_qasm_snapshot_mode(self):
"""Test the VQE using Aer's qasm_simulator snapshot mode."""
backend = Aer.get_backend("aer_simulator")
optimizer = L_BFGS_B()
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
expectation=AerPauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
@data(
CG(maxiter=1),
L_BFGS_B(maxfun=1),
P_BFGS(maxfun=1, max_processes=0),
SLSQP(maxiter=1),
TNC(maxiter=1),
)
def test_with_gradient(self, optimizer):
"""Test VQE using Gradient()."""
quantum_instance = QuantumInstance(
backend=Aer.get_backend("qasm_simulator"),
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=self.ry_wavefunction,
optimizer=optimizer,
gradient=Gradient(),
expectation=AerPauliExpectation(),
quantum_instance=quantum_instance,
max_evals_grouped=1000,
)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
def test_with_two_qubit_reduction(self):
"""Test the VQE using TwoQubitReduction."""
qubit_op = PauliSumOp.from_list([
("IIII", -0.8105479805373266),
("IIIZ", 0.17218393261915552),
("IIZZ", -0.22575349222402472),
("IZZI", 0.1721839326191556),
("ZZII", -0.22575349222402466),
("IIZI", 0.1209126326177663),
("IZZZ", 0.16892753870087912),
("IXZX", -0.045232799946057854),
("ZXIX", 0.045232799946057854),
("IXIX", 0.045232799946057854),
("ZXZX", -0.045232799946057854),
("ZZIZ", 0.16614543256382414),
("IZIZ", 0.16614543256382414),
("ZZZZ", 0.17464343068300453),
("ZIZI", 0.1209126326177663),
])
tapered_qubit_op = TwoQubitReduction(num_particles=2).convert(qubit_op)
for simulator in [self.qasm_simulator, self.statevector_simulator]:
with self.subTest(f"Test for {simulator}."):
vqe = VQE(
self.ry_wavefunction,
SPSA(maxiter=300, last_avg=5),
quantum_instance=simulator,
)
result = vqe.compute_minimum_eigenvalue(tapered_qubit_op)
energy = -1.868 if simulator == self.qasm_simulator else self.h2_energy
self.assertAlmostEqual(result.eigenvalue.real,
energy,
places=2)
def test_callback(self):
"""Test the callback on VQE."""
history = {"eval_count": [], "parameters": [], "mean": [], "std": []}
def store_intermediate_result(eval_count, parameters, mean, std):
history["eval_count"].append(eval_count)
history["parameters"].append(parameters)
history["mean"].append(mean)
history["std"].append(std)
optimizer = COBYLA(maxiter=3)
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
callback=store_intermediate_result,
quantum_instance=self.qasm_simulator,
)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertTrue(
all(isinstance(count, int) for count in history["eval_count"]))
self.assertTrue(
all(isinstance(mean, float) for mean in history["mean"]))
self.assertTrue(all(isinstance(std, float) for std in history["std"]))
for params in history["parameters"]:
self.assertTrue(all(isinstance(param, float) for param in params))
def test_reuse(self):
"""Test re-using a VQE algorithm instance."""
vqe = VQE()
with self.subTest(msg="assert running empty raises AlgorithmError"):
with self.assertRaises(AlgorithmError):
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
ansatz = TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
vqe.ansatz = ansatz
with self.subTest(msg="assert missing operator raises AlgorithmError"):
with self.assertRaises(AlgorithmError):
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
vqe.expectation = MatrixExpectation()
vqe.quantum_instance = self.statevector_simulator
with self.subTest(msg="assert VQE works once all info is available"):
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
operator = PrimitiveOp(
np.array([[1, 0, 0, 0], [0, -1, 0, 0], [0, 0, 2, 0], [0, 0, 0,
3]]))
with self.subTest(msg="assert minimum eigensolver interface works"):
result = vqe.compute_minimum_eigenvalue(operator=operator)
self.assertAlmostEqual(result.eigenvalue.real, -1.0, places=5)
def test_vqe_optimizer(self):
"""Test running same VQE twice to re-use optimizer, then switch optimizer"""
vqe = VQE(
optimizer=SLSQP(),
quantum_instance=QuantumInstance(
BasicAer.get_backend("statevector_simulator")),
)
def run_check():
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
-1.85727503,
places=5)
run_check()
with self.subTest("Optimizer re-use"):
run_check()
with self.subTest("Optimizer replace"):
vqe.optimizer = L_BFGS_B()
run_check()
@data(MatrixExpectation(), None)
def test_backend_change(self, user_expectation):
"""Test that VQE works when backend changes."""
vqe = VQE(
ansatz=TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz"),
optimizer=SLSQP(maxiter=2),
expectation=user_expectation,
quantum_instance=BasicAer.get_backend("statevector_simulator"),
)
result0 = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
if user_expectation is not None:
with self.subTest("User expectation kept."):
self.assertEqual(vqe.expectation, user_expectation)
vqe.quantum_instance = BasicAer.get_backend("qasm_simulator")
# works also if no expectation is set, since it will be determined automatically
result1 = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
if user_expectation is not None:
with self.subTest(
"Change backend with user expectation, it is kept."):
self.assertEqual(vqe.expectation, user_expectation)
with self.subTest("Check results."):
self.assertEqual(len(result0.optimal_point),
len(result1.optimal_point))
def test_batch_evaluate_with_qnspsa(self):
"""Test batch evaluating with QNSPSA works."""
ansatz = TwoLocal(2,
rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
wrapped_backend = BasicAer.get_backend("qasm_simulator")
inner_backend = BasicAer.get_backend("statevector_simulator")
callcount = {"count": 0}
def wrapped_run(circuits, **kwargs):
kwargs["callcount"]["count"] += 1
return inner_backend.run(circuits)
wrapped_backend.run = partial(wrapped_run, callcount=callcount)
fidelity = QNSPSA.get_fidelity(ansatz, backend=wrapped_backend)
qnspsa = QNSPSA(fidelity, maxiter=5)
vqe = VQE(
ansatz=ansatz,
optimizer=qnspsa,
max_evals_grouped=100,
quantum_instance=wrapped_backend,
)
_ = vqe.compute_minimum_eigenvalue(Z ^ Z)
# 1 calibration + 1 stddev estimation + 1 initial blocking
# + 5 (1 loss + 1 fidelity + 1 blocking) + 1 return loss + 1 VQE eval
expected = 1 + 1 + 1 + 5 * 3 + 1 + 1
self.assertEqual(callcount["count"], expected)
def test_set_ansatz_to_none(self):
"""Tests that setting the ansatz to None results in the default behavior"""
vqe = VQE(
ansatz=self.ryrz_wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=self.statevector_simulator,
)
vqe.ansatz = None
self.assertIsInstance(vqe.ansatz, RealAmplitudes)
def test_set_optimizer_to_none(self):
"""Tests that setting the optimizer to None results in the default behavior"""
vqe = VQE(
ansatz=self.ryrz_wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=self.statevector_simulator,
)
vqe.optimizer = None
self.assertIsInstance(vqe.optimizer, SLSQP)
def test_optimizer_scipy_callable(self):
"""Test passing a SciPy optimizer directly as callable."""
vqe = VQE(
optimizer=partial(scipy_minimize,
method="L-BFGS-B",
options={"maxiter": 2}),
quantum_instance=self.statevector_simulator,
)
result = vqe.compute_minimum_eigenvalue(Z)
self.assertEqual(result.cost_function_evals, 20)
def test_optimizer_callable(self):
"""Test passing a optimizer directly as callable."""
ansatz = RealAmplitudes(1, reps=1)
vqe = VQE(ansatz=ansatz,
optimizer=_mock_optimizer,
quantum_instance=self.statevector_simulator)
result = vqe.compute_minimum_eigenvalue(Z)
self.assertTrue(
np.all(result.optimal_point == np.zeros(ansatz.num_parameters)))
def test_aux_operators_list(self):
"""Test list-based aux_operators."""
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction,
quantum_instance=self.statevector_simulator)
# Start with an empty list
result = vqe.compute_minimum_eigenvalue(self.h2_op, aux_operators=[])
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
self.assertIsNone(result.aux_operator_eigenvalues)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0,
places=6)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1], 0.0)
# Go again with additional None and zero operators
extra_ops = [*aux_ops, None, 0]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=extra_ops)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
self.assertEqual(len(result.aux_operator_eigenvalues), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0,
places=6)
self.assertEqual(result.aux_operator_eigenvalues[2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[3][0], 0.0)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[3][1], 0.0)
def test_aux_operators_dict(self):
"""Test dictionary compatibility of aux_operators"""
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction,
quantum_instance=self.statevector_simulator)
# Start with an empty dictionary
result = vqe.compute_minimum_eigenvalue(self.h2_op, aux_operators={})
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
self.assertIsNone(result.aux_operator_eigenvalues)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = {"aux_op1": aux_op1, "aux_op2": aux_op2}
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op1"][0],
2,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op2"][0],
0,
places=6)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op1"][1],
0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op2"][1],
0.0)
# Go again with additional None and zero operators
extra_ops = {**aux_ops, "None_operator": None, "zero_operator": 0}
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=extra_ops)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
self.assertEqual(len(result.aux_operator_eigenvalues), 3)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op1"][0],
2,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op2"][0],
0,
places=6)
self.assertEqual(result.aux_operator_eigenvalues["zero_operator"][0],
0.0)
self.assertTrue(
"None_operator" not in result.aux_operator_eigenvalues.keys())
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op1"][1],
0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues["aux_op2"][1],
0.0)
self.assertAlmostEqual(
result.aux_operator_eigenvalues["zero_operator"][1], 0.0)
def test_aux_operator_std_dev_pauli(self):
"""Test non-zero standard deviations of aux operators with PauliExpectation."""
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
expectation=PauliExpectation(),
optimizer=COBYLA(maxiter=0),
quantum_instance=self.qasm_simulator,
)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0.6796875,
places=6)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1],
0.02534712219145965,
places=6)
# Go again with additional None and zero operators
aux_ops = [*aux_ops, None, 0]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0.57421875,
places=6)
self.assertEqual(result.aux_operator_eigenvalues[2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[3][0], 0.0)
# # standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1],
0.026562146577166837,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[3][1], 0.0)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_aux_operator_std_dev_aer_pauli(self):
"""Test non-zero standard deviations of aux operators with AerPauliExpectation."""
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
expectation=AerPauliExpectation(),
optimizer=COBYLA(maxiter=0),
quantum_instance=QuantumInstance(
backend=Aer.get_backend("qasm_simulator"),
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
# Go again with two auxiliary operators
aux_op1 = PauliSumOp.from_list([("II", 2.0)])
aux_op2 = PauliSumOp.from_list([("II", 0.5), ("ZZ", 0.5), ("YY", 0.5),
("XX", -0.5)])
aux_ops = [aux_op1, aux_op2]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 2)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0.6698863565455391,
places=6)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1],
0.0,
places=6)
# Go again with additional None and zero operators
aux_ops = [*aux_ops, None, 0]
result = vqe.compute_minimum_eigenvalue(self.h2_op,
aux_operators=aux_ops)
self.assertEqual(len(result.aux_operator_eigenvalues), 4)
# expectation values
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][0],
2.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][0],
0.6036400943063891,
places=6)
self.assertEqual(result.aux_operator_eigenvalues[2][0], 0.0)
self.assertEqual(result.aux_operator_eigenvalues[3][0], 0.0)
# standard deviations
self.assertAlmostEqual(result.aux_operator_eigenvalues[0][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[1][1],
0.0,
places=6)
self.assertAlmostEqual(result.aux_operator_eigenvalues[2][1], 0.0)
self.assertAlmostEqual(result.aux_operator_eigenvalues[3][1], 0.0)
def test_2step_transpile(self):
"""Test the two-step transpiler pass."""
# count how often the pass for parameterized circuits is called
pre_counter = LogPass("pre_passmanager")
pre_pass = PassManager(pre_counter)
config = PassManagerConfig(basis_gates=["u3", "cx"])
pre_pass += level_1_pass_manager(config)
# ... and the pass for bound circuits
bound_counter = LogPass("bound_pass_manager")
bound_pass = PassManager(bound_counter)
quantum_instance = QuantumInstance(
backend=BasicAer.get_backend("statevector_simulator"),
basis_gates=["u3", "cx"],
pass_manager=pre_pass,
bound_pass_manager=bound_pass,
)
optimizer = SPSA(maxiter=5, learning_rate=0.01, perturbation=0.01)
vqe = VQE(optimizer=optimizer, quantum_instance=quantum_instance)
_ = vqe.compute_minimum_eigenvalue(Z)
with self.assertLogs(logger, level="INFO") as cm:
_ = vqe.compute_minimum_eigenvalue(Z)
expected = [
"pre_passmanager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"bound_pass_manager",
"pre_passmanager",
"bound_pass_manager",
]
self.assertEqual([record.message for record in cm.records], expected)
def test_construct_eigenstate_from_optpoint(self):
"""Test constructing the eigenstate from the optimal point, if the default ansatz is used."""
# use Hamiltonian yielding more than 11 parameters in the default ansatz
hamiltonian = Z ^ Z ^ Z
optimizer = SPSA(maxiter=1, learning_rate=0.01, perturbation=0.01)
quantum_instance = QuantumInstance(
backend=BasicAer.get_backend("statevector_simulator"),
basis_gates=["u3", "cx"])
vqe = VQE(optimizer=optimizer, quantum_instance=quantum_instance)
result = vqe.compute_minimum_eigenvalue(hamiltonian)
optimal_circuit = vqe.ansatz.bind_parameters(result.optimal_point)
self.assertTrue(Statevector(result.eigenstate).equiv(optimal_circuit))
class TestVQE(QiskitAlgorithmsTestCase):
"""Test VQE"""
def setUp(self):
super().setUp()
self.seed = 50
algorithm_globals.random_seed = self.seed
self.h2_op = (-1.052373245772859 * (I ^ I) + 0.39793742484318045 *
(I ^ Z) - 0.39793742484318045 * (Z ^ I) -
0.01128010425623538 * (Z ^ Z) + 0.18093119978423156 *
(X ^ X))
self.h2_energy = -1.85727503
self.ryrz_wavefunction = TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
self.ry_wavefunction = TwoLocal(rotation_blocks="ry",
entanglement_blocks="cz")
self.qasm_simulator = QuantumInstance(
BasicAer.get_backend("qasm_simulator"),
shots=1024,
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
self.statevector_simulator = QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
shots=1,
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
def test_basic_aer_statevector(self):
"""Test the VQE on BasicAer's statevector simulator."""
wavefunction = self.ryrz_wavefunction
vqe = VQE(
ansatz=wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
basis_gates=["u1", "u2", "u3", "cx", "id"],
coupling_map=[[0, 1]],
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
),
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
with self.subTest(msg="test eigenvalue"):
self.assertAlmostEqual(result.eigenvalue.real, self.h2_energy)
with self.subTest(msg="test dimension of optimal point"):
self.assertEqual(len(result.optimal_point), 16)
with self.subTest(msg="assert cost_function_evals is set"):
self.assertIsNotNone(result.cost_function_evals)
with self.subTest(msg="assert optimizer_time is set"):
self.assertIsNotNone(result.optimizer_time)
def test_circuit_input(self):
"""Test running the VQE on a plain QuantumCircuit object."""
wavefunction = QuantumCircuit(2).compose(EfficientSU2(2))
optimizer = SLSQP(maxiter=50)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
quantum_instance=self.statevector_simulator)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
@data(
(MatrixExpectation(), 1),
(AerPauliExpectation(), 1),
(PauliExpectation(), 2),
)
@unpack
def test_construct_circuit(self, expectation, num_circuits):
"""Test construct circuits returns QuantumCircuits and the right number of them."""
try:
wavefunction = EfficientSU2(2, reps=1)
vqe = VQE(ansatz=wavefunction, expectation=expectation)
params = [0] * wavefunction.num_parameters
circuits = vqe.construct_circuit(parameter=params,
operator=self.h2_op)
self.assertEqual(len(circuits), num_circuits)
for circuit in circuits:
self.assertIsInstance(circuit, QuantumCircuit)
except MissingOptionalLibraryError as ex:
self.skipTest(str(ex))
return
def test_missing_varform_params(self):
"""Test specifying a variational form with no parameters raises an error."""
circuit = QuantumCircuit(self.h2_op.num_qubits)
vqe = VQE(
ansatz=circuit,
quantum_instance=BasicAer.get_backend("statevector_simulator"))
with self.assertRaises(RuntimeError):
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
@data(
(SLSQP(maxiter=50), 5, 4),
(SPSA(maxiter=150), 3, 2), # max_evals_grouped=n or =2 if n>2
)
@unpack
def test_max_evals_grouped(self, optimizer, places, max_evals_grouped):
"""VQE Optimizers test"""
with self.assertWarns(DeprecationWarning):
vqe = VQE(
ansatz=self.ryrz_wavefunction,
optimizer=optimizer,
max_evals_grouped=max_evals_grouped,
quantum_instance=self.statevector_simulator,
sort_parameters_by_name=True,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=places)
def test_basic_aer_qasm(self):
"""Test the VQE on BasicAer's QASM simulator."""
optimizer = SPSA(maxiter=300, last_avg=5)
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=self.qasm_simulator,
)
# TODO benchmark this later.
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86823, places=2)
def test_qasm_aux_operators_normalized(self):
"""Test VQE with qasm_simulator returns normalized aux_operator eigenvalues."""
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction, quantum_instance=self.qasm_simulator)
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
opt_params = [
3.50437328,
3.87415376,
0.93684363,
5.92219622,
-1.53527887,
1.87941418,
-4.5708326,
0.70187027,
]
vqe._ret.optimal_point = opt_params
vqe._ret.optimal_parameters = dict(
zip(sorted(wavefunction.parameters, key=lambda p: p.name),
opt_params))
with self.assertWarns(DeprecationWarning):
optimal_vector = vqe.get_optimal_vector()
self.assertAlmostEqual(sum(v**2 for v in optimal_vector.values()),
1.0,
places=4)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_statevector(self):
"""Test VQE with Aer's statevector_simulator."""
backend = Aer.get_backend("aer_simulator_statevector")
wavefunction = self.ry_wavefunction
optimizer = L_BFGS_B()
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
backend = Aer.get_backend("aer_simulator")
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
def test_with_aer_qasm_snapshot_mode(self):
"""Test the VQE using Aer's qasm_simulator snapshot mode."""
backend = Aer.get_backend("aer_simulator")
optimizer = L_BFGS_B()
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
expectation=AerPauliExpectation(),
quantum_instance=quantum_instance,
)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
@unittest.skipUnless(has_aer(),
"qiskit-aer doesn't appear to be installed.")
@data(
CG(maxiter=1),
L_BFGS_B(maxfun=1),
P_BFGS(maxfun=1, max_processes=0),
SLSQP(maxiter=1),
TNC(maxiter=1),
)
def test_with_gradient(self, optimizer):
"""Test VQE using Gradient()."""
quantum_instance = QuantumInstance(
backend=Aer.get_backend("qasm_simulator"),
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed,
)
vqe = VQE(
ansatz=self.ry_wavefunction,
optimizer=optimizer,
gradient=Gradient(),
expectation=AerPauliExpectation(),
quantum_instance=quantum_instance,
max_evals_grouped=1000,
)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
def test_with_two_qubit_reduction(self):
"""Test the VQE using TwoQubitReduction."""
qubit_op = PauliSumOp.from_list([
("IIII", -0.8105479805373266),
("IIIZ", 0.17218393261915552),
("IIZZ", -0.22575349222402472),
("IZZI", 0.1721839326191556),
("ZZII", -0.22575349222402466),
("IIZI", 0.1209126326177663),
("IZZZ", 0.16892753870087912),
("IXZX", -0.045232799946057854),
("ZXIX", 0.045232799946057854),
("IXIX", 0.045232799946057854),
("ZXZX", -0.045232799946057854),
("ZZIZ", 0.16614543256382414),
("IZIZ", 0.16614543256382414),
("ZZZZ", 0.17464343068300453),
("ZIZI", 0.1209126326177663),
])
tapered_qubit_op = TwoQubitReduction(num_particles=2).convert(qubit_op)
for simulator in [self.qasm_simulator, self.statevector_simulator]:
with self.subTest(f"Test for {simulator}."):
vqe = VQE(
self.ry_wavefunction,
SPSA(maxiter=300, last_avg=5),
quantum_instance=simulator,
)
result = vqe.compute_minimum_eigenvalue(tapered_qubit_op)
energy = -1.868 if simulator == self.qasm_simulator else self.h2_energy
self.assertAlmostEqual(result.eigenvalue.real,
energy,
places=2)
def test_callback(self):
"""Test the callback on VQE."""
history = {"eval_count": [], "parameters": [], "mean": [], "std": []}
def store_intermediate_result(eval_count, parameters, mean, std):
history["eval_count"].append(eval_count)
history["parameters"].append(parameters)
history["mean"].append(mean)
history["std"].append(std)
optimizer = COBYLA(maxiter=3)
wavefunction = self.ry_wavefunction
vqe = VQE(
ansatz=wavefunction,
optimizer=optimizer,
callback=store_intermediate_result,
quantum_instance=self.qasm_simulator,
)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertTrue(
all(isinstance(count, int) for count in history["eval_count"]))
self.assertTrue(
all(isinstance(mean, float) for mean in history["mean"]))
self.assertTrue(all(isinstance(std, float) for std in history["std"]))
for params in history["parameters"]:
self.assertTrue(all(isinstance(param, float) for param in params))
def test_reuse(self):
"""Test re-using a VQE algorithm instance."""
vqe = VQE()
with self.subTest(msg="assert running empty raises AlgorithmError"):
with self.assertRaises(AlgorithmError):
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
ansatz = TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
vqe.ansatz = ansatz
with self.subTest(msg="assert missing operator raises AlgorithmError"):
with self.assertRaises(AlgorithmError):
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
vqe.expectation = MatrixExpectation()
vqe.quantum_instance = self.statevector_simulator
with self.subTest(msg="assert VQE works once all info is available"):
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
operator = PrimitiveOp(
np.array([[1, 0, 0, 0], [0, -1, 0, 0], [0, 0, 2, 0], [0, 0, 0,
3]]))
with self.subTest(msg="assert minimum eigensolver interface works"):
result = vqe.compute_minimum_eigenvalue(operator=operator)
self.assertAlmostEqual(result.eigenvalue.real, -1.0, places=5)
def test_vqe_optimizer(self):
"""Test running same VQE twice to re-use optimizer, then switch optimizer"""
vqe = VQE(
optimizer=SLSQP(),
quantum_instance=QuantumInstance(
BasicAer.get_backend("statevector_simulator")),
)
def run_check():
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
-1.85727503,
places=5)
run_check()
with self.subTest("Optimizer re-use"):
run_check()
with self.subTest("Optimizer replace"):
vqe.optimizer = L_BFGS_B()
run_check()
@data(MatrixExpectation(), None)
def test_backend_change(self, user_expectation):
"""Test that VQE works when backend changes."""
vqe = VQE(
ansatz=TwoLocal(rotation_blocks=["ry", "rz"],
entanglement_blocks="cz"),
optimizer=SLSQP(maxiter=2),
expectation=user_expectation,
quantum_instance=BasicAer.get_backend("statevector_simulator"),
)
result0 = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
if user_expectation is not None:
with self.subTest("User expectation kept."):
self.assertEqual(vqe.expectation, user_expectation)
vqe.quantum_instance = BasicAer.get_backend("qasm_simulator")
# works also if no expectation is set, since it will be determined automatically
result1 = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
if user_expectation is not None:
with self.subTest(
"Change backend with user expectation, it is kept."):
self.assertEqual(vqe.expectation, user_expectation)
with self.subTest("Check results."):
self.assertEqual(len(result0.optimal_point),
len(result1.optimal_point))
def test_batch_evaluate_with_qnspsa(self):
"""Test batch evaluating with QNSPSA works."""
ansatz = TwoLocal(2,
rotation_blocks=["ry", "rz"],
entanglement_blocks="cz")
wrapped_backend = BasicAer.get_backend("qasm_simulator")
inner_backend = BasicAer.get_backend("statevector_simulator")
callcount = {"count": 0}
def wrapped_run(circuits, **kwargs):
kwargs["callcount"]["count"] += 1
return inner_backend.run(circuits)
wrapped_backend.run = partial(wrapped_run, callcount=callcount)
fidelity = QNSPSA.get_fidelity(ansatz, backend=wrapped_backend)
qnspsa = QNSPSA(fidelity, maxiter=5)
vqe = VQE(
ansatz=ansatz,
optimizer=qnspsa,
max_evals_grouped=100,
quantum_instance=wrapped_backend,
)
_ = vqe.compute_minimum_eigenvalue(Z ^ Z)
# 1 calibration + 1 stddev estimation + 1 initial blocking
# + 5 (1 loss + 1 fidelity + 1 blocking) + 1 return loss + 1 VQE eval
expected = 1 + 1 + 1 + 5 * 3 + 1 + 1
self.assertEqual(callcount["count"], expected)
class TestVQE(QiskitAlgorithmsTestCase):
""" Test VQE """
def setUp(self):
super().setUp()
self.seed = 50
aqua_globals.random_seed = self.seed
self.h2_op = -1.052373245772859 * (I ^ I) \
+ 0.39793742484318045 * (I ^ Z) \
- 0.39793742484318045 * (Z ^ I) \
- 0.01128010425623538 * (Z ^ Z) \
+ 0.18093119978423156 * (X ^ X)
self.h2_energy = -1.85727503
self.ryrz_wavefunction = TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz')
self.ry_wavefunction = TwoLocal(rotation_blocks='ry',
entanglement_blocks='cz')
self.qasm_simulator = QuantumInstance(
BasicAer.get_backend('qasm_simulator'),
shots=1024,
seed_simulator=self.seed,
seed_transpiler=self.seed)
self.statevector_simulator = QuantumInstance(
BasicAer.get_backend('statevector_simulator'),
shots=1,
seed_simulator=self.seed,
seed_transpiler=self.seed)
def test_basic_aer_statevector(self):
"""Test the VQE on BasicAer's statevector simulator."""
wavefunction = self.ryrz_wavefunction
vqe = VQE(self.h2_op, wavefunction, L_BFGS_B())
result = vqe.run(
QuantumInstance(BasicAer.get_backend('statevector_simulator'),
basis_gates=['u1', 'u2', 'u3', 'cx', 'id'],
coupling_map=[[0, 1]],
seed_simulator=aqua_globals.random_seed,
seed_transpiler=aqua_globals.random_seed))
with self.subTest(msg='test eigenvalue'):
self.assertAlmostEqual(result.eigenvalue.real, self.h2_energy)
with self.subTest(msg='test dimension of optimal point'):
self.assertEqual(len(result.optimal_point), 16)
with self.subTest(msg='assert cost_function_evals is set'):
self.assertIsNotNone(result.cost_function_evals)
with self.subTest(msg='assert optimizer_time is set'):
self.assertIsNotNone(result.optimizer_time)
def test_circuit_input(self):
"""Test running the VQE on a plain QuantumCircuit object."""
wavefunction = QuantumCircuit(2).compose(EfficientSU2(2))
optimizer = SLSQP(maxiter=50)
vqe = VQE(self.h2_op, wavefunction, optimizer=optimizer)
result = vqe.run(self.statevector_simulator)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
@data(
(MatrixExpectation(), 1),
(AerPauliExpectation(), 1),
(PauliExpectation(), 2),
)
@unpack
def test_construct_circuit(self, expectation, num_circuits):
"""Test construct circuits returns QuantumCircuits and the right number of them."""
try:
wavefunction = EfficientSU2(2, reps=1)
vqe = VQE(self.h2_op, wavefunction, expectation=expectation)
params = [0] * wavefunction.num_parameters
circuits = vqe.construct_circuit(params)
self.assertEqual(len(circuits), num_circuits)
for circuit in circuits:
self.assertIsInstance(circuit, QuantumCircuit)
except MissingOptionalLibraryError as ex:
self.skipTest(str(ex))
return
def test_legacy_operator(self):
"""Test the VQE accepts and converts the legacy WeightedPauliOperator."""
pauli_dict = {
'paulis': [{
"coeff": {
"imag": 0.0,
"real": -1.052373245772859
},
"label": "II"
}, {
"coeff": {
"imag": 0.0,
"real": 0.39793742484318045
},
"label": "IZ"
}, {
"coeff": {
"imag": 0.0,
"real": -0.39793742484318045
},
"label": "ZI"
}, {
"coeff": {
"imag": 0.0,
"real": -0.01128010425623538
},
"label": "ZZ"
}, {
"coeff": {
"imag": 0.0,
"real": 0.18093119978423156
},
"label": "XX"
}]
}
h2_op = WeightedPauliOperator.from_dict(pauli_dict)
vqe = VQE(h2_op)
self.assertEqual(vqe.operator, self.h2_op)
def test_missing_varform_params(self):
"""Test specifying a variational form with no parameters raises an error."""
circuit = QuantumCircuit(self.h2_op.num_qubits)
vqe = VQE(self.h2_op, circuit)
with self.assertRaises(RuntimeError):
vqe.run(BasicAer.get_backend('statevector_simulator'))
@data(
(SLSQP(maxiter=50), 5, 4),
(SPSA(maxiter=150), 3, 2), # max_evals_grouped=n or =2 if n>2
)
@unpack
def test_max_evals_grouped(self, optimizer, places, max_evals_grouped):
""" VQE Optimizers test """
vqe = VQE(self.h2_op,
self.ryrz_wavefunction,
optimizer,
max_evals_grouped=max_evals_grouped,
quantum_instance=self.statevector_simulator)
result = vqe.run()
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=places)
def test_basic_aer_qasm(self):
"""Test the VQE on BasicAer's QASM simulator."""
optimizer = SPSA(maxiter=300, last_avg=5)
wavefunction = self.ry_wavefunction
vqe = VQE(self.h2_op, wavefunction, optimizer, max_evals_grouped=1)
# TODO benchmark this later.
result = vqe.run(self.qasm_simulator)
self.assertAlmostEqual(result.eigenvalue.real, -1.86823, places=2)
def test_qasm_aux_operators_normalized(self):
"""Test VQE with qasm_simulator returns normalized aux_operator eigenvalues."""
wavefunction = self.ry_wavefunction
vqe = VQE(self.h2_op,
wavefunction,
quantum_instance=self.qasm_simulator)
opt_params = [
3.50437328, 3.87415376, 0.93684363, 5.92219622, -1.53527887,
1.87941418, -4.5708326, 0.70187027
]
vqe._ret = {}
vqe._ret['opt_params'] = opt_params
vqe._ret['opt_params_dict'] = \
dict(zip(sorted(wavefunction.parameters, key=lambda p: p.name), opt_params))
optimal_vector = vqe.get_optimal_vector()
self.assertAlmostEqual(sum([v**2 for v in optimal_vector.values()]),
1.0,
places=4)
def test_with_aer_statevector(self):
"""Test VQE with Aer's statevector_simulator."""
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('statevector_simulator')
wavefunction = self.ry_wavefunction
optimizer = L_BFGS_B()
vqe = VQE(self.h2_op, wavefunction, optimizer, max_evals_grouped=1)
quantum_instance = QuantumInstance(
backend,
seed_simulator=aqua_globals.random_seed,
seed_transpiler=aqua_globals.random_seed)
result = vqe.run(quantum_instance)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
vqe = VQE(self.h2_op,
wavefunction,
optimizer,
expectation=PauliExpectation())
quantum_instance = QuantumInstance(
backend,
seed_simulator=aqua_globals.random_seed,
seed_transpiler=aqua_globals.random_seed)
result = vqe.run(quantum_instance)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
def test_with_aer_qasm_snapshot_mode(self):
"""Test the VQE using Aer's qasm_simulator snapshot mode."""
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
optimizer = L_BFGS_B()
wavefunction = self.ry_wavefunction
vqe = VQE(self.h2_op,
wavefunction,
optimizer,
expectation=AerPauliExpectation())
quantum_instance = QuantumInstance(
backend,
shots=1,
seed_simulator=aqua_globals.random_seed,
seed_transpiler=aqua_globals.random_seed)
result = vqe.run(quantum_instance)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
def test_callback(self):
"""Test the callback on VQE."""
history = {'eval_count': [], 'parameters': [], 'mean': [], 'std': []}
def store_intermediate_result(eval_count, parameters, mean, std):
history['eval_count'].append(eval_count)
history['parameters'].append(parameters)
history['mean'].append(mean)
history['std'].append(std)
optimizer = COBYLA(maxiter=3)
wavefunction = self.ry_wavefunction
vqe = VQE(self.h2_op,
wavefunction,
optimizer,
callback=store_intermediate_result)
vqe.run(self.qasm_simulator)
self.assertTrue(
all(isinstance(count, int) for count in history['eval_count']))
self.assertTrue(
all(isinstance(mean, float) for mean in history['mean']))
self.assertTrue(all(isinstance(std, float) for std in history['std']))
for params in history['parameters']:
self.assertTrue(all(isinstance(param, float) for param in params))
def test_reuse(self):
"""Test re-using a VQE algorithm instance."""
vqe = VQE()
with self.subTest(msg='assert running empty raises AlgorithmError'):
with self.assertRaises(AlgorithmError):
_ = vqe.run()
var_form = TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz')
vqe.var_form = var_form
with self.subTest(msg='assert missing operator raises AlgorithmError'):
with self.assertRaises(AlgorithmError):
_ = vqe.run()
vqe.operator = self.h2_op
with self.subTest(msg='assert missing backend raises AlgorithmError'):
with self.assertRaises(AlgorithmError):
_ = vqe.run()
vqe.quantum_instance = self.statevector_simulator
with self.subTest(msg='assert VQE works once all info is available'):
result = vqe.run()
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
operator = PrimitiveOp(
np.array([[1, 0, 0, 0], [0, -1, 0, 0], [0, 0, 2, 0], [0, 0, 0,
3]]))
with self.subTest(msg='assert minimum eigensolver interface works'):
result = vqe.compute_minimum_eigenvalue(operator)
self.assertAlmostEqual(result.eigenvalue.real, -1.0, places=5)
def test_vqe_optimizer(self):
""" Test running same VQE twice to re-use optimizer, then switch optimizer """
vqe = VQE(self.h2_op,
optimizer=SLSQP(),
quantum_instance=QuantumInstance(
BasicAer.get_backend('statevector_simulator')))
def run_check():
result = vqe.compute_minimum_eigenvalue()
self.assertAlmostEqual(result.eigenvalue.real,
-1.85727503,
places=5)
run_check()
with self.subTest('Optimizer re-use'):
run_check()
with self.subTest('Optimizer replace'):
vqe.optimizer = L_BFGS_B()
run_check()
def test_vqe_expectation_select(self):
"""Test expectation selection with Aer's qasm_simulator."""
try:
# pylint: disable=import-outside-toplevel
from qiskit import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
with self.subTest('Defaults'):
vqe = VQE(self.h2_op, quantum_instance=backend)
self.assertIsInstance(vqe.expectation, PauliExpectation)
with self.subTest('Include custom'):
vqe = VQE(self.h2_op,
include_custom=True,
quantum_instance=backend)
self.assertIsInstance(vqe.expectation, AerPauliExpectation)
with self.subTest('Set explicitly'):
vqe = VQE(self.h2_op,
expectation=AerPauliExpectation(),
quantum_instance=backend)
self.assertIsInstance(vqe.expectation, AerPauliExpectation)
@unittest.skip(reason="IBMQ testing not available in general.")
def test_ibmq(self):
""" IBMQ VQE Test """
from qiskit import IBMQ
provider = IBMQ.load_account()
backend = provider.get_backend('ibmq_qasm_simulator')
ansatz = TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz')
opt = SLSQP(maxiter=1)
opt.set_max_evals_grouped(100)
vqe = VQE(self.h2_op, ansatz, SLSQP(maxiter=2))
result = vqe.run(backend)
print(result)
self.assertAlmostEqual(result.eigenvalue.real, self.h2_energy)
np.testing.assert_array_almost_equal(result.eigenvalue.real,
self.h2_energy, 5)
self.assertEqual(len(result.optimal_point), 16)
self.assertIsNotNone(result.cost_function_evals)
self.assertIsNotNone(result.optimizer_time)
@data(MatrixExpectation(), None)
def test_backend_change(self, user_expectation):
"""Test that VQE works when backend changes."""
vqe = VQE(
operator=self.h2_op,
var_form=TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz'),
optimizer=SLSQP(maxiter=2),
expectation=user_expectation,
quantum_instance=BasicAer.get_backend('statevector_simulator'))
result0 = vqe.run()
if user_expectation is not None:
with self.subTest('User expectation kept.'):
self.assertEqual(vqe.expectation, user_expectation)
else:
with self.subTest('Expectation created.'):
self.assertIsInstance(vqe.expectation, ExpectationBase)
try:
vqe.set_backend(BasicAer.get_backend('qasm_simulator'))
except Exception as ex: # pylint: disable=broad-except
self.fail("Failed to change backend. Error: '{}'".format(str(ex)))
return
result1 = vqe.run()
if user_expectation is not None:
with self.subTest(
'Change backend with user expectation, it is kept.'):
self.assertEqual(vqe.expectation, user_expectation)
else:
with self.subTest(
'Change backend without user expectation, one created.'):
self.assertIsInstance(vqe.expectation, ExpectationBase)
with self.subTest('Check results.'):
self.assertEqual(len(result0.optimal_point),
len(result1.optimal_point))
class TestCVaRExpectation(QiskitOpflowTestCase):
"""Test the CVaR expectation object."""
def test_construction(self):
"""Test the correct operator expression is constructed."""
alpha = 0.5
base_expecation = PauliExpectation()
cvar_expecation = CVaRExpectation(alpha=alpha,
expectation=base_expecation)
with self.subTest('single operator'):
op = ~StateFn(Z) @ Plus
expected = CVaRMeasurement(Z, alpha) @ Plus
cvar = cvar_expecation.convert(op)
self.assertEqual(cvar, expected)
with self.subTest('list operator'):
op = ~StateFn(ListOp([Z ^ Z, I ^ Z])) @ (Plus ^ Plus)
expected = ListOp([
CVaRMeasurement((Z ^ Z), alpha) @ (Plus ^ Plus),
CVaRMeasurement((I ^ Z), alpha) @ (Plus ^ Plus)
])
cvar = cvar_expecation.convert(op)
self.assertEqual(cvar, expected)
def test_unsupported_expectation(self):
"""Assert passing an AerPauliExpectation raises an error."""
expecation = AerPauliExpectation()
with self.assertRaises(NotImplementedError):
_ = CVaRExpectation(alpha=1, expectation=expecation)
@data(PauliExpectation(), MatrixExpectation())
def test_underlying_expectation(self, base_expecation):
"""Test the underlying expectation works correctly."""
cvar_expecation = CVaRExpectation(alpha=0.3,
expectation=base_expecation)
circuit = QuantumCircuit(2)
circuit.z(0)
circuit.cp(0.5, 0, 1)
circuit.t(1)
op = ~StateFn(CircuitOp(circuit)) @ (Plus ^ 2)
cvar = cvar_expecation.convert(op)
expected = base_expecation.convert(op)
# test if the operators have been transformed in the same manner
self.assertEqual(cvar.oplist[0].primitive,
expected.oplist[0].primitive)
def test_compute_variance(self):
"""Test if the compute_variance method works"""
alphas = [0, .3, 0.5, 0.7, 1]
correct_vars = [0, 0, 0, 0.8163, 1]
for i, alpha in enumerate(alphas):
base_expecation = PauliExpectation()
cvar_expecation = CVaRExpectation(alpha=alpha,
expectation=base_expecation)
op = ~StateFn(Z ^ Z) @ (Plus ^ Plus)
cvar_var = cvar_expecation.compute_variance(op)
np.testing.assert_almost_equal(cvar_var,
correct_vars[i],
decimal=3)
class TestPauliExpectation(QiskitOpflowTestCase):
"""Pauli Change of Basis Expectation tests."""
def setUp(self) -> None:
super().setUp()
self.seed = 97
backend = BasicAer.get_backend("qasm_simulator")
q_instance = QuantumInstance(backend,
seed_simulator=self.seed,
seed_transpiler=self.seed)
self.sampler = CircuitSampler(q_instance, attach_results=True)
self.expect = PauliExpectation()
def test_pauli_expect_pair(self):
"""pauli expect pair test"""
op = Z ^ Z
# wf = (Pl^Pl) + (Ze^Ze)
wf = CX @ (H ^ I) @ Zero
converted_meas = self.expect.convert(~StateFn(op) @ wf)
self.assertAlmostEqual(converted_meas.eval(), 0, delta=0.1)
sampled = self.sampler.convert(converted_meas)
self.assertAlmostEqual(sampled.eval(), 0, delta=0.1)
def test_pauli_expect_single(self):
"""pauli expect single test"""
paulis = [Z, X, Y, I]
states = [Zero, One, Plus, Minus, S @ Plus, S @ Minus]
for pauli, state in itertools.product(paulis, states):
converted_meas = self.expect.convert(~StateFn(pauli) @ state)
matmulmean = state.adjoint().to_matrix() @ pauli.to_matrix(
) @ state.to_matrix()
self.assertAlmostEqual(converted_meas.eval(),
matmulmean,
delta=0.1)
sampled = self.sampler.convert(converted_meas)
self.assertAlmostEqual(sampled.eval(), matmulmean, delta=0.1)
def test_pauli_expect_op_vector(self):
"""pauli expect op vector test"""
paulis_op = ListOp([X, Y, Z, I])
converted_meas = self.expect.convert(~StateFn(paulis_op))
plus_mean = converted_meas @ Plus
np.testing.assert_array_almost_equal(plus_mean.eval(), [1, 0, 0, 1],
decimal=1)
sampled_plus = self.sampler.convert(plus_mean)
np.testing.assert_array_almost_equal(sampled_plus.eval(), [1, 0, 0, 1],
decimal=1)
minus_mean = converted_meas @ Minus
np.testing.assert_array_almost_equal(minus_mean.eval(), [-1, 0, 0, 1],
decimal=1)
sampled_minus = self.sampler.convert(minus_mean)
np.testing.assert_array_almost_equal(sampled_minus.eval(),
[-1, 0, 0, 1],
decimal=1)
zero_mean = converted_meas @ Zero
np.testing.assert_array_almost_equal(zero_mean.eval(), [0, 0, 1, 1],
decimal=1)
sampled_zero = self.sampler.convert(zero_mean)
np.testing.assert_array_almost_equal(sampled_zero.eval(), [0, 0, 1, 1],
decimal=1)
sum_zero = (Plus + Minus) * (0.5**0.5)
sum_zero_mean = converted_meas @ sum_zero
np.testing.assert_array_almost_equal(sum_zero_mean.eval(),
[0, 0, 1, 1],
decimal=1)
sampled_zero_mean = self.sampler.convert(sum_zero_mean)
# !!NOTE!!: Depolarizing channel (Sampling) means interference
# does not happen between circuits in sum, so expectation does
# not equal expectation for Zero!!
np.testing.assert_array_almost_equal(sampled_zero_mean.eval(),
[0, 0, 0, 1],
decimal=1)
for i, op in enumerate(paulis_op.oplist):
mat_op = op.to_matrix()
np.testing.assert_array_almost_equal(
zero_mean.eval()[i],
Zero.adjoint().to_matrix() @ mat_op @ Zero.to_matrix(),
decimal=1,
)
np.testing.assert_array_almost_equal(
plus_mean.eval()[i],
Plus.adjoint().to_matrix() @ mat_op @ Plus.to_matrix(),
decimal=1,
)
np.testing.assert_array_almost_equal(
minus_mean.eval()[i],
Minus.adjoint().to_matrix() @ mat_op @ Minus.to_matrix(),
decimal=1,
)
def test_pauli_expect_state_vector(self):
"""pauli expect state vector test"""
states_op = ListOp([One, Zero, Plus, Minus])
paulis_op = X
converted_meas = self.expect.convert(~StateFn(paulis_op) @ states_op)
np.testing.assert_array_almost_equal(converted_meas.eval(),
[0, 0, 1, -1],
decimal=1)
sampled = self.sampler.convert(converted_meas)
np.testing.assert_array_almost_equal(sampled.eval(), [0, 0, 1, -1],
decimal=1)
# Small test to see if execution results are accessible
for composed_op in sampled:
self.assertIn("counts", composed_op[1].execution_results)
def test_pauli_expect_op_vector_state_vector(self):
"""pauli expect op vector state vector test"""
paulis_op = ListOp([X, Y, Z, I])
states_op = ListOp([One, Zero, Plus, Minus])
valids = [[+0, 0, 1, -1], [+0, 0, 0, 0], [-1, 1, 0, -0], [+1, 1, 1, 1]]
converted_meas = self.expect.convert(~StateFn(paulis_op) @ states_op)
np.testing.assert_array_almost_equal(converted_meas.eval(),
valids,
decimal=1)
sampled = self.sampler.convert(converted_meas)
np.testing.assert_array_almost_equal(sampled.eval(), valids, decimal=1)
def test_to_matrix_called(self):
"""test to matrix called in different situations"""
qs = 45
states_op = ListOp([Zero ^ qs, One ^ qs, (Zero ^ qs) + (One ^ qs)])
paulis_op = ListOp([Z ^ qs, (I ^ Z ^ I) ^ int(qs / 3)])
# 45 qubit calculation - throws exception if to_matrix is called
# massive is False
with self.assertRaises(ValueError):
states_op.to_matrix()
paulis_op.to_matrix()
# now set global variable or argument
try:
algorithm_globals.massive = True
with self.assertRaises(MemoryError):
states_op.to_matrix()
paulis_op.to_matrix()
algorithm_globals.massive = False
with self.assertRaises(MemoryError):
states_op.to_matrix(massive=True)
paulis_op.to_matrix(massive=True)
finally:
algorithm_globals.massive = False
def test_not_to_matrix_called(self):
"""45 qubit calculation - literally will not work if to_matrix is
somehow called (in addition to massive=False throwing an error)"""
qs = 45
states_op = ListOp([Zero ^ qs, One ^ qs, (Zero ^ qs) + (One ^ qs)])
paulis_op = ListOp([Z ^ qs, (I ^ Z ^ I) ^ int(qs / 3)])
converted_meas = self.expect.convert(~StateFn(paulis_op) @ states_op)
np.testing.assert_array_almost_equal(converted_meas.eval(),
[[1, -1, 0], [1, -1, 0]])
def test_grouped_pauli_expectation(self):
"""grouped pauli expectation test"""
two_qubit_H2 = ((-1.052373245772859 * I ^ I) +
(0.39793742484318045 * I ^ Z) +
(-0.39793742484318045 * Z ^ I) +
(-0.01128010425623538 * Z ^ Z) +
(0.18093119978423156 * X ^ X))
wf = CX @ (H ^ I) @ Zero
expect_op = PauliExpectation(group_paulis=False).convert(
~StateFn(two_qubit_H2) @ wf)
self.sampler._extract_circuitstatefns(expect_op)
num_circuits_ungrouped = len(self.sampler._circuit_ops_cache)
self.assertEqual(num_circuits_ungrouped, 5)
expect_op_grouped = PauliExpectation(group_paulis=True).convert(
~StateFn(two_qubit_H2) @ wf)
q_instance = QuantumInstance(
BasicAer.get_backend("statevector_simulator"),
seed_simulator=self.seed,
seed_transpiler=self.seed,
)
sampler = CircuitSampler(q_instance)
sampler._extract_circuitstatefns(expect_op_grouped)
num_circuits_grouped = len(sampler._circuit_ops_cache)
self.assertEqual(num_circuits_grouped, 2)
@unittest.skip(reason="IBMQ testing not available in general.")
def test_ibmq_grouped_pauli_expectation(self):
"""pauli expect op vector state vector test"""
from qiskit import IBMQ
p = IBMQ.load_account()
backend = p.get_backend("ibmq_qasm_simulator")
q_instance = QuantumInstance(backend,
seed_simulator=self.seed,
seed_transpiler=self.seed)
paulis_op = ListOp([X, Y, Z, I])
states_op = ListOp([One, Zero, Plus, Minus])
valids = [[+0, 0, 1, -1], [+0, 0, 0, 0], [-1, 1, 0, -0], [+1, 1, 1, 1]]
converted_meas = self.expect.convert(~StateFn(paulis_op) @ states_op)
sampled = CircuitSampler(q_instance).convert(converted_meas)
np.testing.assert_array_almost_equal(sampled.eval(), valids, decimal=1)
def test_multi_representation_ops(self):
"""Test observables with mixed representations"""
mixed_ops = ListOp([X.to_matrix_op(), H, H + I, X])
converted_meas = self.expect.convert(~StateFn(mixed_ops))
plus_mean = converted_meas @ Plus
sampled_plus = self.sampler.convert(plus_mean)
np.testing.assert_array_almost_equal(sampled_plus.eval(),
[1, 0.5**0.5, (1 + 0.5**0.5), 1],
decimal=1)
def test_pauli_expectation_non_hermite_op(self):
"""Test PauliExpectation for non hermitian operator"""
exp = ~StateFn(1j * Z) @ One
self.assertEqual(self.expect.convert(exp).eval(), 1j)
def test_list_pauli_sum_op(self):
"""Test PauliExpectation for List[PauliSumOp]"""
test_op = ListOp([
~StateFn(PauliSumOp.from_list([("XX", 1), ("ZI", 3), ("ZZ", 5)]))
])
observable = self.expect.convert(test_op)
self.assertIsInstance(observable, ListOp)
self.assertIsInstance(observable[0][0][0].primitive, PauliSumOp)
self.assertIsInstance(observable[0][1][0].primitive, PauliSumOp)
class TestVQE(QiskitAlgorithmsTestCase):
""" Test VQE """
def setUp(self):
super().setUp()
self.seed = 50
algorithm_globals.random_seed = self.seed
self.h2_op = -1.052373245772859 * (I ^ I) \
+ 0.39793742484318045 * (I ^ Z) \
- 0.39793742484318045 * (Z ^ I) \
- 0.01128010425623538 * (Z ^ Z) \
+ 0.18093119978423156 * (X ^ X)
self.h2_energy = -1.85727503
self.ryrz_wavefunction = TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz')
self.ry_wavefunction = TwoLocal(rotation_blocks='ry',
entanglement_blocks='cz')
self.qasm_simulator = QuantumInstance(
BasicAer.get_backend('qasm_simulator'),
shots=1024,
seed_simulator=self.seed,
seed_transpiler=self.seed)
self.statevector_simulator = QuantumInstance(
BasicAer.get_backend('statevector_simulator'),
shots=1,
seed_simulator=self.seed,
seed_transpiler=self.seed)
def test_basic_aer_statevector(self):
"""Test the VQE on BasicAer's statevector simulator."""
wavefunction = self.ryrz_wavefunction
vqe = VQE(ansatz=wavefunction,
optimizer=L_BFGS_B(),
quantum_instance=QuantumInstance(
BasicAer.get_backend('statevector_simulator'),
basis_gates=['u1', 'u2', 'u3', 'cx', 'id'],
coupling_map=[[0, 1]],
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed))
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
with self.subTest(msg='test eigenvalue'):
self.assertAlmostEqual(result.eigenvalue.real, self.h2_energy)
with self.subTest(msg='test dimension of optimal point'):
self.assertEqual(len(result.optimal_point), 16)
with self.subTest(msg='assert cost_function_evals is set'):
self.assertIsNotNone(result.cost_function_evals)
with self.subTest(msg='assert optimizer_time is set'):
self.assertIsNotNone(result.optimizer_time)
def test_circuit_input(self):
"""Test running the VQE on a plain QuantumCircuit object."""
wavefunction = QuantumCircuit(2).compose(EfficientSU2(2))
optimizer = SLSQP(maxiter=50)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
quantum_instance=self.statevector_simulator)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
@data(
(MatrixExpectation(), 1),
(AerPauliExpectation(), 1),
(PauliExpectation(), 2),
)
@unpack
def test_construct_circuit(self, expectation, num_circuits):
"""Test construct circuits returns QuantumCircuits and the right number of them."""
try:
wavefunction = EfficientSU2(2, reps=1)
vqe = VQE(ansatz=wavefunction, expectation=expectation)
params = [0] * wavefunction.num_parameters
circuits = vqe.construct_circuit(parameter=params,
operator=self.h2_op)
self.assertEqual(len(circuits), num_circuits)
for circuit in circuits:
self.assertIsInstance(circuit, QuantumCircuit)
except MissingOptionalLibraryError as ex:
self.skipTest(str(ex))
return
def test_missing_varform_params(self):
"""Test specifying a variational form with no parameters raises an error."""
circuit = QuantumCircuit(self.h2_op.num_qubits)
vqe = VQE(
ansatz=circuit,
quantum_instance=BasicAer.get_backend('statevector_simulator'))
with self.assertRaises(RuntimeError):
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
@data(
(SLSQP(maxiter=50), 5, 4),
(SPSA(maxiter=150), 3, 2), # max_evals_grouped=n or =2 if n>2
)
@unpack
def test_max_evals_grouped(self, optimizer, places, max_evals_grouped):
""" VQE Optimizers test """
vqe = VQE(ansatz=self.ryrz_wavefunction,
optimizer=optimizer,
max_evals_grouped=max_evals_grouped,
quantum_instance=self.statevector_simulator)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=places)
def test_basic_aer_qasm(self):
"""Test the VQE on BasicAer's QASM simulator."""
optimizer = SPSA(maxiter=300, last_avg=5)
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=self.qasm_simulator)
# TODO benchmark this later.
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86823, places=2)
def test_qasm_aux_operators_normalized(self):
"""Test VQE with qasm_simulator returns normalized aux_operator eigenvalues."""
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction, quantum_instance=self.qasm_simulator)
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
opt_params = [
3.50437328, 3.87415376, 0.93684363, 5.92219622, -1.53527887,
1.87941418, -4.5708326, 0.70187027
]
vqe._ret.optimal_point = opt_params
vqe._ret.optimal_parameters = \
dict(zip(sorted(wavefunction.parameters, key=lambda p: p.name), opt_params))
optimal_vector = vqe.get_optimal_vector()
self.assertAlmostEqual(sum([v**2 for v in optimal_vector.values()]),
1.0,
places=4)
def test_with_aer_statevector(self):
"""Test VQE with Aer's statevector_simulator."""
try:
from qiskit.providers.aer import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('statevector_simulator')
wavefunction = self.ry_wavefunction
optimizer = L_BFGS_B()
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
max_evals_grouped=1,
quantum_instance=quantum_instance)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
def test_with_aer_qasm(self):
"""Test VQE with Aer's qasm_simulator."""
try:
from qiskit.providers.aer import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
optimizer = SPSA(maxiter=200, last_avg=5)
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
expectation=PauliExpectation(),
quantum_instance=quantum_instance)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real, -1.86305, places=2)
def test_with_aer_qasm_snapshot_mode(self):
"""Test the VQE using Aer's qasm_simulator snapshot mode."""
try:
from qiskit.providers.aer import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
optimizer = L_BFGS_B()
wavefunction = self.ry_wavefunction
quantum_instance = QuantumInstance(
backend,
shots=1,
seed_simulator=algorithm_globals.random_seed,
seed_transpiler=algorithm_globals.random_seed)
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
expectation=AerPauliExpectation(),
quantum_instance=quantum_instance)
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=6)
def test_with_two_qubit_reduction(self):
"""Test the VQE using TwoQubitReduction."""
qubit_op = PauliSumOp.from_list([
("IIII", -0.8105479805373266),
("IIIZ", 0.17218393261915552),
("IIZZ", -0.22575349222402472),
("IZZI", 0.1721839326191556),
("ZZII", -0.22575349222402466),
("IIZI", 0.1209126326177663),
("IZZZ", 0.16892753870087912),
("IXZX", -0.045232799946057854),
("ZXIX", 0.045232799946057854),
("IXIX", 0.045232799946057854),
("ZXZX", -0.045232799946057854),
("ZZIZ", 0.16614543256382414),
("IZIZ", 0.16614543256382414),
("ZZZZ", 0.17464343068300453),
("ZIZI", 0.1209126326177663),
])
tapered_qubit_op = TwoQubitReduction(num_particles=2).convert(qubit_op)
for simulator in [self.qasm_simulator, self.statevector_simulator]:
with self.subTest(f"Test for {simulator}."):
vqe = VQE(
self.ry_wavefunction,
SPSA(maxiter=300, last_avg=5),
quantum_instance=simulator,
)
result = vqe.compute_minimum_eigenvalue(tapered_qubit_op)
energy = -1.868 if simulator == self.qasm_simulator else self.h2_energy
self.assertAlmostEqual(result.eigenvalue.real,
energy,
places=2)
def test_callback(self):
"""Test the callback on VQE."""
history = {'eval_count': [], 'parameters': [], 'mean': [], 'std': []}
def store_intermediate_result(eval_count, parameters, mean, std):
history['eval_count'].append(eval_count)
history['parameters'].append(parameters)
history['mean'].append(mean)
history['std'].append(std)
optimizer = COBYLA(maxiter=3)
wavefunction = self.ry_wavefunction
vqe = VQE(ansatz=wavefunction,
optimizer=optimizer,
callback=store_intermediate_result,
quantum_instance=self.qasm_simulator)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertTrue(
all(isinstance(count, int) for count in history['eval_count']))
self.assertTrue(
all(isinstance(mean, float) for mean in history['mean']))
self.assertTrue(all(isinstance(std, float) for std in history['std']))
for params in history['parameters']:
self.assertTrue(all(isinstance(param, float) for param in params))
def test_reuse(self):
"""Test re-using a VQE algorithm instance."""
vqe = VQE()
with self.subTest(msg='assert running empty raises AlgorithmError'):
with self.assertRaises(AlgorithmError):
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
ansatz = TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz')
vqe.ansatz = ansatz
with self.subTest(msg='assert missing operator raises AlgorithmError'):
with self.assertRaises(AlgorithmError):
_ = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
vqe.quantum_instance = self.statevector_simulator
with self.subTest(msg='assert VQE works once all info is available'):
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
self.h2_energy,
places=5)
operator = PrimitiveOp(
np.array([[1, 0, 0, 0], [0, -1, 0, 0], [0, 0, 2, 0], [0, 0, 0,
3]]))
with self.subTest(msg='assert minimum eigensolver interface works'):
result = vqe.compute_minimum_eigenvalue(operator=operator)
self.assertAlmostEqual(result.eigenvalue.real, -1.0, places=5)
def test_vqe_optimizer(self):
""" Test running same VQE twice to re-use optimizer, then switch optimizer """
vqe = VQE(optimizer=SLSQP(),
quantum_instance=QuantumInstance(
BasicAer.get_backend('statevector_simulator')))
def run_check():
result = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertAlmostEqual(result.eigenvalue.real,
-1.85727503,
places=5)
run_check()
with self.subTest('Optimizer re-use'):
run_check()
with self.subTest('Optimizer replace'):
vqe.optimizer = L_BFGS_B()
run_check()
def test_vqe_expectation_select(self):
"""Test expectation selection with Aer's qasm_simulator."""
try:
from qiskit.providers.aer import Aer
except Exception as ex: # pylint: disable=broad-except
self.skipTest(
"Aer doesn't appear to be installed. Error: '{}'".format(
str(ex)))
return
backend = Aer.get_backend('qasm_simulator')
with self.subTest('Defaults'):
vqe = VQE(quantum_instance=backend)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertIsInstance(vqe.expectation, PauliExpectation)
with self.subTest('Include custom'):
vqe = VQE(include_custom=True, quantum_instance=backend)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertIsInstance(vqe.expectation, AerPauliExpectation)
with self.subTest('Set explicitly'):
vqe = VQE(expectation=AerPauliExpectation(),
quantum_instance=backend)
vqe.compute_minimum_eigenvalue(operator=self.h2_op)
self.assertIsInstance(vqe.expectation, AerPauliExpectation)
@data(MatrixExpectation(), None)
def test_backend_change(self, user_expectation):
"""Test that VQE works when backend changes."""
vqe = VQE(
ansatz=TwoLocal(rotation_blocks=['ry', 'rz'],
entanglement_blocks='cz'),
optimizer=SLSQP(maxiter=2),
expectation=user_expectation,
quantum_instance=BasicAer.get_backend('statevector_simulator'))
result0 = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
if user_expectation is not None:
with self.subTest('User expectation kept.'):
self.assertEqual(vqe.expectation, user_expectation)
else:
with self.subTest('Expectation created.'):
self.assertIsInstance(vqe.expectation, ExpectationBase)
try:
vqe.quantum_instance = BasicAer.get_backend('qasm_simulator')
except Exception as ex: # pylint: disable=broad-except
self.fail("Failed to change backend. Error: '{}'".format(str(ex)))
return
result1 = vqe.compute_minimum_eigenvalue(operator=self.h2_op)
if user_expectation is not None:
with self.subTest(
'Change backend with user expectation, it is kept.'):
self.assertEqual(vqe.expectation, user_expectation)
else:
with self.subTest(
'Change backend without user expectation, one created.'):
self.assertIsInstance(vqe.expectation, ExpectationBase)
with self.subTest('Check results.'):
self.assertEqual(len(result0.optimal_point),
len(result1.optimal_point))
