# QAOAAnsatz¶

class QAOAAnsatz(cost_operator=None, reps=1, initial_state=None, mixer_operator=None, name='QAOA')[ソース]

A generalized QAOA quantum circuit with a support of custom initial states and mixers.

[1]: Farhi et al., A Quantum Approximate Optimization Algorithm.

arXiv:1411.4028

パラメータ
• cost_operator (OperatorBase, optional) – The operator representing the cost of the optimization problem, denoted as $$U(C, \gamma)$$ in the original paper. Must be set either in the constructor or via property setter.

• reps (int) – The integer parameter p, which determines the depth of the circuit, as specified in the original paper, default is 1.

• initial_state (QuantumCircuit, optional) – An optional initial state to use. If None is passed then a set of Hadamard gates is applied as an initial state to all qubits.

• mixer_operator (OperatorBase or QuantumCircuit, optional) – An optional custom mixer to use instead of the global X-rotations, denoted as $$U(B, \beta)$$ in the original paper. Can be an operator or an optionally parameterized quantum circuit.

• name (str) – A name of the circuit, default 『qaoa』

Attributes

ancillas

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

List[AncillaQubit]

calibrations

Return calibration dictionary.

The custom pulse definition of a given gate is of the form

{『gate_name』: {(qubits, params): schedule}}

dict

clbits

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

List[Clbit]

cost_operator

Returns an operator representing the cost of the optimization problem.

cost operator.

OperatorBase

data
entanglement

Get the entanglement strategy.

Union[str, List[str], List[List[str]], List[int], List[List[int]], List[List[List[int]]], List[List[List[List[int]]]], Callable[[int], str], Callable[[int], List[List[int]]]]

The entanglement strategy, see get_entangler_map() for more detail on how the format is interpreted.

entanglement_blocks

The blocks in the entanglement layers.

List[Instruction]

The blocks in the entanglement layers.

evolution

The evolution converter used to compute the evolution.

The evolution converter used to compute the evolution.

EvolutionBase

extension_lib = 'include "qelib1.inc";'
global_phase

Return the global phase of the circuit in radians.

Union[ParameterExpression, float]

initial_state

Returns an optional initial state as a circuit

Optional[QuantumCircuit]

insert_barriers

If barriers are inserted in between the layers or not.

bool

True, if barriers are inserted in between the layers, False if not.

instances = 9

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.

dict

mixer_operator

Returns an optional mixer operator expressed as an operator or a quantum circuit.

mixer operator or circuit.

OperatorBase or QuantumCircuit, optional

num_ancillas

Return the number of ancilla qubits.

int

num_clbits

Return number of classical bits.

int

num_layers

Return the number of layers in the n-local circuit.

int

The number of layers in the circuit.

num_parameters

int

num_parameters_settable

The number of total parameters that can be set to distinct values.

This does not change when the parameters are bound or exchanged for same parameters, and therefore is different from num_parameters which counts the number of unique Parameter objects currently in the circuit.

int

The number of parameters originally available in the circuit.

This quantity does not require the circuit to be built yet.

num_qubits

int

operators

The operators that are evolved in this circuit.

The operators to be evolved (and circuits)

in this ansatz.

List[Union[OperatorBase, QuantumCircuit]]

ordered_parameters

The parameters used in the underlying circuit.

This includes float values and duplicates.

サンプル

>>> # prepare circuit ...
>>> print(nlocal)
┌───────┐┌──────────┐┌──────────┐┌──────────┐
q_0: ┤ Ry(1) ├┤ Ry(θ[1]) ├┤ Ry(θ[1]) ├┤ Ry(θ[3]) ├
└───────┘└──────────┘└──────────┘└──────────┘
>>> nlocal.parameters
{Parameter(θ[1]), Parameter(θ[3])}
>>> nlocal.ordered_parameters
[1, Parameter(θ[1]), Parameter(θ[1]), Parameter(θ[3])]


List[Parameter]

The parameters objects used in the circuit.

parameter_bounds

The parameter bounds for the unbound parameters in the circuit.

Optional[List[Tuple[Optional[float], Optional[float]]]]

A list of pairs indicating the bounds, as (lower, upper). None indicates an unbounded parameter in the corresponding direction. If None is returned, problem is fully unbounded.

parameters

ParameterView

preferred_init_points

Getter of preferred initial points based on the given initial state.

prefix = 'circuit'
qregs

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.

List[Qubit]

reps

Returns the reps parameter, which determines the depth of the circuit.

int

rotation_blocks

The blocks in the rotation layers.

List[Instruction]

The blocks in the rotation layers.