def test_integration_hamiltonian_to_vqe_cost(monkeypatch, mol_name, terms_ref,
expected_cost, tol):
r"""Test if `convert_hamiltonian()` in qchem integrates with `VQECost()` in pennylane"""
qOp = QubitOperator()
if terms_ref is not None:
monkeypatch.setattr(qOp, "terms", terms_ref)
vqe_hamiltonian = qchem.convert_hamiltonian(qOp)
# maybe make num_qubits a @property of the Hamiltonian class?
num_qubits = max(
1, len(set([w for op in vqe_hamiltonian.ops for w in op.wires])))
dev = qml.device("default.qubit", wires=num_qubits)
print(vqe_hamiltonian.terms)
# can replace the ansatz with more suitable ones later.
def dummy_ansatz(phis, wires):
for phi, w in zip(phis, wires):
qml.RX(phi, wires=w)
dummy_cost = qml.VQECost(dummy_ansatz, vqe_hamiltonian, dev)
params = [0.1 * i for i in range(num_qubits)]
res = dummy_cost(params)
assert np.allclose(res, expected_cost, **tol)
def test_hamiltonian_conversion(mol_name, terms_ref, monkeypatch):
r"""Test the correctness of the QubitOperator Hamiltonian conversion from
OpenFermion to Pennylane.
The parametrized inputs are `.terms` attribute of the output `QubitOperator`s based on
the same set of test molecules as `test_gen_hamiltonian_pauli_basis`.
The equality checking is implemented in the `qchem` module itself as it could be
something useful to the users as well.
"""
qOp = QubitOperator()
if terms_ref is not None:
monkeypatch.setattr(qOp, "terms", terms_ref)
vqe_hamiltonian = qchem.convert_hamiltonian(qOp)
assert qchem._qubit_operators_equivalent(qOp, vqe_hamiltonian)
def test_integration_mol_file_to_vqe_cost(hf_filename, docc_mo, act_mo,
type_of_transformation,
expected_cost, tol):
r"""Test if the output of `decompose_hamiltonian()` works with `convert_hamiltonian()`
to generate `VQECost()`"""
ref_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)),
"test_ref_files")
transformed_hamiltonian = qchem.decompose_hamiltonian(
hf_filename,
ref_dir,
mapping=type_of_transformation,
docc_mo_indices=docc_mo,
active_mo_indices=act_mo,
)
vqe_hamiltonian = qchem.convert_hamiltonian(transformed_hamiltonian)
assert len(vqe_hamiltonian.ops) > 1 # just to check if this runs
num_qubits = max(
1,
len(
set([
w for op in vqe_hamiltonian.ops for ws in op.wires for w in ws
])))
assert num_qubits == 2 * len(act_mo)
dev = qml.device("default.qubit", wires=num_qubits)
# can replace the ansatz with more suitable ones later.
def dummy_ansatz(phis, wires):
for phi, w in zip(phis, wires):
qml.RX(phi, wires=w)
phis = np.load(os.path.join(ref_dir, "dummy_ansatz_parameters.npy"))
dummy_cost = qml.VQECost(dummy_ansatz, vqe_hamiltonian, dev)
res = dummy_cost(phis)
assert np.abs(res - expected_cost) < tol["atol"]