FixedValueComparator

class FixedValueComparator(num_state_qubits, value, geq=True, i_state=None, i_target=None)

DEPRECATED. Fixed Value Comparator

Deprecated since version 0.7.0

Use Terra’s qiskit.circuit.library.IntegerComparator instead.

Operator compares basis states |i>_n against a classically given fixed value L and flips a target qubit if i >= L (or < depending on parameters):

$|i>_n|0> -> |i>_n|1> if i >= L else |i>|0>$

Operator is based on two’s complement implementation of binary subtraction but only uses carry bits and no actual result bits. If the most significant carry bit (= results bit) is 1, the “>=” condition is True otherwise it is False.

Parameters

num_state_qubits (int) – number of state qubits, the target qubit comes on top of this
value (int) – fixed value to compare with
geq (Optional(bool)) – evaluate “>=” condition of “<” condition
i_state (Optional(Union(list, numpy.ndarray))) – indices of state qubits in given list of qubits / register, if None, i_state = list(range(num_state_qubits)) is used
i_target (Optional(int)) – index of target qubit in given list of qubits / register, if None, i_target = num_state_qubits is used

Attributes

returns num state qubits

Returns the number of target qubits

returns value

FixedValueComparator.build(qc, q, q_ancillas=None, params=None)

Adds corresponding sub-circuit to given circuit

Parameters

FixedValueComparator.build_controlled(qc, q, q_control, q_ancillas=None, use_basis_gates=True)

Adds corresponding controlled sub-circuit to given circuit

Parameters

qc (QuantumCircuit) – quantum circuit
q (list) – list of qubits (has to be same length as self._num_qubits)
q_control (Qubit) – control qubit
q_ancillas (list) – list of ancilla qubits (or None if none needed)
use_basis_gates (bool) – use basis gates for expansion of controlled circuit

FixedValueComparator.build_controlled_inverse(qc, q, q_control, q_ancillas=None, use_basis_gates=True)

Adds controlled inverse of corresponding sub-circuit to given circuit

Parameters

qc (QuantumCircuit) – quantum circuit
q (list) – list of qubits (has to be same length as self._num_qubits)
q_control (Qubit) – control qubit
q_ancillas (list) – list of ancilla qubits (or None if none needed)
use_basis_gates (bool) – use basis gates for expansion of controlled circuit

FixedValueComparator.build_controlled_inverse_power(qc, q, q_control, power, q_ancillas=None, use_basis_gates=True)

Adds controlled, inverse, power of corresponding circuit. May be overridden if a more efficient implementation is possible

FixedValueComparator.build_controlled_power(qc, q, q_control, power, q_ancillas=None, use_basis_gates=True)

Adds controlled power of corresponding circuit. May be overridden if a more efficient implementation is possible

FixedValueComparator.build_inverse(qc, q, q_ancillas=None)

Adds inverse of corresponding sub-circuit to given circuit

Parameters

FixedValueComparator.build_inverse_power(qc, q, power, q_ancillas=None)

Adds inverse power of corresponding circuit. May be overridden if a more efficient implementation is possible

FixedValueComparator.build_power(qc, q, power, q_ancillas=None)

Adds power of corresponding circuit. May be overridden if a more efficient implementation is possible

FixedValueComparator.get_num_qubits()

returns number of qubits

FixedValueComparator.get_num_qubits_controlled()

returns number of qubits controlled

FixedValueComparator.required_ancillas()

returns required ancillas

FixedValueComparator.required_ancillas_controlled()

returns required ancillas controlled

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