def __init__(
self,
num_variable_qubits: int,
flags: Optional[List[int]] = None,
mcx_mode: str = "noancilla",
) -> None:
"""Create a new logical AND circuit.
Args:
num_variable_qubits: The qubits of which the OR is computed. The result will be written
into an additional result qubit.
flags: A list of +1/0/-1 marking negations or omissions of qubits.
mcx_mode: The mode to be used to implement the multi-controlled X gate.
"""
self.num_variable_qubits = num_variable_qubits
self.flags = flags
# add registers
qr_variable = QuantumRegister(num_variable_qubits, name="variable")
qr_result = QuantumRegister(1, name="result")
circuit = QuantumCircuit(qr_variable, qr_result, name="and")
# determine the control qubits: all that have a nonzero flag
flags = flags or [1] * num_variable_qubits
control_qubits = [
q for q, flag in zip(qr_variable, flags) if flag != 0
]
# determine the qubits that need to be flipped (if a flag is < 0)
flip_qubits = [q for q, flag in zip(qr_variable, flags) if flag < 0]
# determine the number of ancillas
num_ancillas = MCXGate.get_num_ancilla_qubits(len(control_qubits),
mode=mcx_mode)
if num_ancillas > 0:
qr_ancilla = AncillaRegister(num_ancillas, "ancilla")
circuit.add_register(qr_ancilla)
else:
qr_ancilla = []
if len(flip_qubits) > 0:
circuit.x(flip_qubits)
circuit.mcx(control_qubits, qr_result[:], qr_ancilla[:], mode=mcx_mode)
if len(flip_qubits) > 0:
circuit.x(flip_qubits)
super().__init__(*circuit.qregs, name="and")
self.compose(circuit.to_gate(), qubits=self.qubits, inplace=True)
def __init__(self,
num_variable_qubits: int,
flags: Optional[List[int]] = None,
mcx_mode: str = 'noancilla') -> None:
"""Create a new logical OR circuit.
Args:
num_variable_qubits: The qubits of which the OR is computed. The result will be written
into an additional result qubit.
flags: A list of +1/0/-1 marking negations or omisiions of qubits.
mcx_mode: The mode to be used to implement the multi-controlled X gate.
"""
# store num_variables_qubits and flags
self.num_variable_qubits = num_variable_qubits
self.flags = flags
# add registers
qr_variable = QuantumRegister(num_variable_qubits, name='variable')
qr_result = QuantumRegister(1, name='result')
super().__init__(qr_variable, qr_result, name='or')
# determine the control qubits: all that have a nonzero flag
flags = flags or [1] * num_variable_qubits
control_qubits = [
q for q, flag in zip(qr_variable, flags) if flag != 0
]
# determine the qubits that need to be flipped (if a flag is > 0)
flip_qubits = [q for q, flag in zip(qr_variable, flags) if flag > 0]
# determine the number of ancillas
self.num_ancilla_qubits = MCXGate.get_num_ancilla_qubits(
len(control_qubits), mode=mcx_mode)
if self.num_ancilla_qubits > 0:
qr_ancilla = QuantumRegister(self.num_ancilla_qubits, 'ancilla')
self.add_register(qr_ancilla)
else:
qr_ancilla = []
self.x(qr_result)
if len(flip_qubits) > 0:
self.x(flip_qubits)
self.mcx(control_qubits, qr_result[:], qr_ancilla[:], mode=mcx_mode)
if len(flip_qubits) > 0:
self.x(flip_qubits)
def _define(self):
definition = []
qr = QuantumRegister(self.num_ctrl_qubits + 1)
ctrl_qr = qr[:self.num_ctrl_qubits]
target_qubit = qr[self.num_ctrl_qubits]
if self.qubit_values:
for qubit_index, qubit_value in enumerate(self.qubit_values):
if not qubit_value:
definition.append((XGate(), [ctrl_qr[qubit_index]], []))
definition.append((MCXGate(self.num_ctrl_qubits),
list(ctrl_qr) + [target_qubit], []))
if self.qubit_values:
for qubit_index, qubit_value in enumerate(self.qubit_values):
if not qubit_value:
definition.append((XGate(), [ctrl_qr[qubit_index]], []))
self.definition = definition