def get_uccsd_circuit(molecule, theta_vector=None, use_basis_gates=False):
"""Produce the full UCCSD circuit.
Args:
molecule :: string - must be a key of MOLECULE_TO_INFO
theta_vector :: array - arguments for the vqe ansatz. If None, will generate random angles.
use_basis_gates :: bool - Mike and Ike gates if False, Basis gates if True.
Returns:
circuit :: qiskit.QuantumCircuit - the UCCSD circuit parameterized
by theta_vector, unoptimized
"""
molecule_info = MOLECULE_TO_INFO[molecule]
driver = PySCFDriver(atom=molecule_info.atomic_string, basis='sto3g')
qmolecule = driver.run()
hamiltonian = Hamiltonian(
qubit_mapping=QubitMappingType.PARITY,
two_qubit_reduction=True,
freeze_core=True,
orbital_reduction=molecule_info.orbital_reduction)
energy_input = hamiltonian.run(qmolecule)
qubit_op = energy_input.qubit_op
num_spin_orbitals = hamiltonian.molecule_info['num_orbitals']
num_particles = hamiltonian.molecule_info['num_particles']
map_type = hamiltonian._qubit_mapping
qubit_reduction = hamiltonian.molecule_info['two_qubit_reduction']
HF_state = HartreeFock(qubit_op.num_qubits, num_spin_orbitals,
num_particles, map_type, qubit_reduction)
var_form = UCCSD(qubit_op.num_qubits,
depth=1,
num_orbitals=num_spin_orbitals,
num_particles=num_particles,
active_occupied=molecule_info.active_occupied,
active_unoccupied=molecule_info.active_unoccupied,
initial_state=HF_state,
qubit_mapping=map_type,
two_qubit_reduction=qubit_reduction,
num_time_slices=1)
if theta_vector is None:
theta_vector = [
np.random.rand() * 2 * np.pi
for _ in range(var_form._num_parameters)
]
circuit = var_form.construct_circuit(theta_vector,
use_basis_gates=use_basis_gates)
return circuit
HF_state = HartreeFock(qubitOp.num_qubits, num_spin_orbitals, num_particles,
map_type, qubit_reduction)
# setup UCCSD variational form
var_form = UCCSD(qubitOp.num_qubits,
depth=1,
num_orbitals=num_spin_orbitals,
num_particles=num_particles,
active_occupied=[0],
active_unoccupied=[0, 1],
initial_state=HF_state,
qubit_mapping=map_type,
two_qubit_reduction=qubit_reduction,
num_time_slices=1)
circuit = var_form.construct_circuit(parameters, use_basis_gates=False)
print("Target circuit initialized.", flush=True)
#circuit.draw(output='text', line_length=350)
backend_sim = Aer.get_backend('unitary_simulator')
result = qiskit.execute(circuit, backend_sim).result()
U = result.get_unitary()
print(U.shape, flush=True)
print(U, flush=True)
U = transmon_gate(U, d)
print("Target U initialized.", flush=True)