def pauli_basis(num_qubits, weight=False, pauli_list=False):
"""Return the ordered PauliTable or PauliList for the n-qubit Pauli basis.
Args:
num_qubits (int): number of qubits
weight (bool): if True optionally return the basis sorted by Pauli weight
rather than lexicographic order (Default: False)
pauli_list (bool): if True, the return type becomes PauliList, otherwise PauliTable.
Returns:
PauliTable, PauliList: the Paulis for the basis
"""
if pauli_list:
pauli_1q = PauliList(["I", "X", "Y", "Z"])
else:
warnings.warn(
"The pauli_basis function with PauliTable output is deprecated as of Qiskit Terra "
"0.19.0 and will be removed no sooner than 3 months after the releasedate. "
"Use PauliList by pauli_list=True instead.",
DeprecationWarning,
stacklevel=2,
)
pauli_1q = PauliTable(
np.array(
[[False, False], [True, False], [True, True], [False, True]],
dtype=bool))
if num_qubits == 1:
return pauli_1q
pauli = pauli_1q
for _ in range(num_qubits - 1):
pauli = pauli_1q.tensor(pauli)
if weight:
return pauli.sort(weight=True)
return pauli
def pauli_basis(num_qubits, weight=False, pauli_list=False):
"""Return the ordered PauliTable or PauliList for the n-qubit Pauli basis.
Args:
num_qubits (int): number of qubits
weight (bool): if True optionally return the basis sorted by Pauli weight
rather than lexicographic order (Default: False)
pauli_list (bool): if True, the return type becomes PauliList, otherwise PauliTable.
Returns:
PauliTable, PauliList: the Paulis for the basis
"""
if pauli_list:
pauli_1q = PauliList(["I", "X", "Y", "Z"])
else:
warnings.warn(
"The return type of 'pauli_basis' will change from PauliTable to PauliList in a "
"future release of Qiskit Terra. Returning PauliTable is deprecated as of "
"Qiskit Terra 0.19, and will be removed in a future release. To immediately switch "
"to the new behaviour, pass the keyword argument 'pauli_list=True'.",
FutureWarning,
stacklevel=2,
)
pauli_1q = PauliTable(
np.array(
[[False, False], [True, False], [True, True], [False, True]],
dtype=bool))
if num_qubits == 1:
return pauli_1q
pauli = pauli_1q
for _ in range(num_qubits - 1):
pauli = pauli_1q.tensor(pauli)
if weight:
return pauli.sort(weight=True)
return pauli
