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