def test_hf_bitstring_mapped(self):
"""Mapped bitstring test for water"""
# Original driver config when creating operator that resulted in symmetries coded
# below. The sector [1, -1] is the correct ground sector.
# PySCFDriver(
# atom="O 0.0000 0.0000 0.1173; H 0.0000 0.07572 -0.4692;H 0.0000 -0.07572 -0.4692",
# unit=UnitsType.ANGSTROM,
# charge=0,
# spin=0,
# basis='sto-3g',
# hf_method=HFMethodType.RHF)
num_spin_orbitals = 14
num_particles = (5, 5)
converter = QubitConverter(ParityMapper(), two_qubit_reduction=True)
z2symmetries = Z2Symmetries(
symmetries=[Pauli("IZZIIIIZZIII"),
Pauli("ZZIZIIZZIZII")],
sq_paulis=[Pauli("IIIIIIIIXIII"),
Pauli("IIIIIIIIIXII")],
sq_list=[3, 2],
tapering_values=[1, -1],
)
with self.subTest("Matched bitsring creation"):
converter.force_match(num_particles=num_particles,
z2symmetries=z2symmetries)
bitstr = hartree_fock_bitstring_mapped(
num_spin_orbitals=num_spin_orbitals,
num_particles=num_particles,
qubit_converter=converter,
)
ref_matched = [
True, False, True, True, False, True, False, True, False, False
]
self.assertListEqual(bitstr, ref_matched)
with self.subTest("Bitsring creation with no tapering"):
bitstr = hartree_fock_bitstring_mapped(
num_spin_orbitals=num_spin_orbitals,
num_particles=num_particles,
qubit_converter=converter,
match_convert=False,
)
ref_notaper = [
True,
False,
True,
False,
True,
True,
False,
True,
False,
True,
False,
False,
]
self.assertListEqual(bitstr, ref_notaper)
def test_qubits_6_py_lih(self):
"""qubits 6 py lih test"""
num_particles = (1, 1)
converter = QubitConverter(ParityMapper(), two_qubit_reduction=True)
z2symmetries = Z2Symmetries(
symmetries=[Pauli("ZIZIZIZI"),
Pauli("ZZIIZZII")],
sq_paulis=[Pauli("IIIIIIXI"), Pauli("IIIIIXII")],
sq_list=[2, 3],
tapering_values=[1, 1],
)
converter.force_match(num_particles=num_particles,
z2symmetries=z2symmetries)
state = HartreeFock(10, num_particles, converter)
ref = QuantumCircuit(6)
ref.x([0, 1])
self.assertEqual(state, ref)
def convert(self, operator: OperatorBase) -> OperatorBase:
"""
Converts the Operator to tapered one by Z2 symmetries.
Args:
operator: the operator
Returns:
A new operator whose qubit number is reduced by 2.
"""
if not isinstance(operator, PauliSumOp):
return operator
operator = cast(PauliSumOp, operator)
if operator.is_zero():
logger.info("Operator is empty, can not do two qubit reduction. "
"Return the empty operator back.")
return PauliSumOp.from_list([("I" * (operator.num_qubits - 2), 0)])
num_qubits = operator.num_qubits
last_idx = num_qubits - 1
mid_idx = num_qubits // 2 - 1
sq_list = [mid_idx, last_idx]
# build symmetries, sq_paulis:
symmetries, sq_paulis = [], []
for idx in sq_list:
pauli_str = ["I"] * num_qubits
pauli_str[idx] = "Z"
z_sym = Pauli("".join(pauli_str)[::-1])
symmetries.append(z_sym)
pauli_str[idx] = "X"
sq_pauli = Pauli("".join(pauli_str)[::-1])
sq_paulis.append(sq_pauli)
z2_symmetries = Z2Symmetries(symmetries, sq_paulis, sq_list,
self._tapering_values)
return z2_symmetries.taper(operator)