IntegerComparator

class qiskit.circuit.library.IntegerComparator(num_state_qubits=None, value=None, geq=True, name='cmp')

Bases: BlueprintCircuit

Integer Comparator.

Operator compares basis states \(|i\rangle_n\) against a classically given integer \(L\) of fixed value and flips a target qubit if \(i \geq L\) (or \(<\) depending on the parameter geq):

\[|i\rangle_n |0\rangle \mapsto |i\rangle_n |i \geq L\rangle\]

This operation 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 (the results bit) is 1, the \(\geq\) condition is True otherwise it is False.

Create a new fixed value comparator circuit.

Parameters:

• num_state_qubits (int | None) – Number of state qubits. If this is set it will determine the number of qubits required for the circuit.

• value (int | None) – The fixed value to compare with.

• geq (bool) – If True, evaluate a >= condition, else <.

• name (str) – Name of the circuit.

Attributes

ancillas

Returns a list of ancilla bits in the order that the registers were added.

calibrations

Return calibration dictionary.

The custom pulse definition of a given gate is of the form {'gate_name': {(qubits, params): schedule}}

clbits

Returns a list of classical bits in the order that the registers were added.

data

extension_lib = 'include "qelib1.inc";'

geq

Return whether the comparator compares greater or less equal.

Returns:

True, if the comparator compares >=, False if <.

global_phase

Return the global phase of the current circuit scope in radians.

header = 'OPENQASM 2.0;'

instances = 181

layout

Return any associated layout information about the circuit

This attribute contains an optional TranspileLayout object. This is typically set on the output from transpile() or PassManager.run() to retain information about the permutations caused on the input circuit by transpilation.

There are two types of permutations caused by the transpile() function, an initial layout which permutes the qubits based on the selected physical qubits on the Target, and a final layout which is an output permutation caused by SwapGates inserted during routing.

metadata

The user provided metadata associated with the circuit.

The metadata for the circuit is a user provided dict of metadata for the circuit. It will not be used to influence the execution or operation of the circuit, but it is expected to be passed between all transforms of the circuit (ie transpilation) and that providers will associate any circuit metadata with the results it returns from execution of that circuit.

num_ancilla_qubits

Deprecated. Use num_ancillas instead.

num_ancillas

Return the number of ancilla qubits.

num_clbits

Return number of classical bits.

num_parameters

num_qubits

Return number of qubits.

num_state_qubits

The number of qubits encoding the state for the comparison.

Returns:

The number of state qubits.

op_start_times

Return a list of operation start times.

This attribute is enabled once one of scheduling analysis passes runs on the quantum circuit.

Returns:

List of integers representing instruction start times. The index corresponds to the index of instruction in QuantumCircuit.data.

Raises:

AttributeError – When circuit is not scheduled.

parameters

prefix = 'circuit'

qregs: list[QuantumRegister]

A list of the quantum registers associated with the circuit.

qubits

Returns a list of quantum bits in the order that the registers were added.

value

The value to compare the qubit register to.

Returns:

The value against which the value of the qubit register is compared.