def _decompose_(self, qubits: Sequence['cirq.Qid']) -> 'cirq.OP_TREE':
if len(self.dense_pauli_string) <= 0:
return
any_qubit = qubits[0]
to_z_ops = op_tree.freeze_op_tree(self._to_z_basis_ops(qubits))
xor_decomp = tuple(xor_nonlocal_decompose(qubits, any_qubit))
yield to_z_ops
yield xor_decomp
if self.exponent_neg:
yield pauli_gates.Z(any_qubit)**self.exponent_neg
if self.exponent_pos:
yield pauli_gates.X(any_qubit)
yield pauli_gates.Z(any_qubit)**self.exponent_pos
yield pauli_gates.X(any_qubit)
yield protocols.inverse(xor_decomp)
yield protocols.inverse(to_z_ops)
def _decompose_(self) -> op_tree.OP_TREE:
if len(self.pauli_string) <= 0:
return
qubits = self.qubits
any_qubit = qubits[0]
to_z_ops = op_tree.freeze_op_tree(self.pauli_string.to_z_basis_ops())
xor_decomp = tuple(xor_nonlocal_decompose(qubits, any_qubit))
yield to_z_ops
yield xor_decomp
if self.exponent_neg:
yield pauli_gates.Z(any_qubit)**self.exponent_neg
if self.exponent_pos:
yield pauli_gates.X(any_qubit)
yield pauli_gates.Z(any_qubit)**self.exponent_pos
yield pauli_gates.X(any_qubit)
yield protocols.inverse(xor_decomp)
yield protocols.inverse(to_z_ops)
def __pow__(self, exponent: int) -> 'LinearCombinationOfOperations':
if not isinstance(exponent, int):
return NotImplemented
if exponent < 0:
return NotImplemented
if len(self.qubits) != 1:
return NotImplemented
qubit = self.qubits[0]
i = identity.I(qubit)
x = pauli_gates.X(qubit)
y = pauli_gates.Y(qubit)
z = pauli_gates.Z(qubit)
pauli_basis = {i, x, y, z}
if not set(self.keys()).issubset(pauli_basis):
return NotImplemented
ai, ax, ay, az = self[i], self[x], self[y], self[z]
bi, bx, by, bz = operator_spaces.pow_pauli_combination(ai, ax, ay, az, exponent)
return LinearCombinationOfOperations({i: bi, x: bx, y: by, z: bz})
