squlearn.encoding_circuit.MultiControlEncodingCircuit

class squlearn.encoding_circuit.MultiControlEncodingCircuit(num_qubits: int, num_features: int, num_layers: int = 1, closed: bool = True, final_encoding=False)

Encoding circuit with HZ encoding followed by controlled Rx, Ry Rz rotations.

Example for 4 qubits, a 2 dimensional feature vector and 1 layer:

(Source code, png, hires.png, pdf)

../../_images/squlearn-encoding_circuit-MultiControlEncodingCircuit-1.png

The circuit is repeated for the number of layers. The circuit is closed by default, i.e. the last qubit is entangled with the first one. The encoding can be optionally repeated at the end to make the previous rotations not redundant in a fidelity kernel setting.

Parameters:

  • num_qubits (int) – Number of qubits of the MultiControlEncodingCircuit encoding circuit

  • num_features (int) – Dimension of the feature vector

  • num_layers (int) – Number of layers (default: 1)

  • closed (bool) – If true, the last and the first qubit are entangled; not necessarily hardware efficient! (default: true)

  • final_encoding (bool) – If True, the encoding is repeated at the end (default: False)

draw(output: str = None, feature_label: str = 'x', parameter_label: str = 'p', decompose: bool = False, **kwargs) → None

Draws the encoding circuit circuit using the QuantumCircuit.draw() function.

Parameters:

  • feature_label (str) – Label for the feature vector (default:”x”).

  • parameter_label (str) – Label for the parameter vector (default:”p”).

  • decompose (bool) – If True, the circuit is decomposed before printing (default: False).

  • kwargs – Additional arguments from Qiskit’s QuantumCircuit.draw() function.

Returns:

Returns the circuit in qiskit QuantumCircuit.draw() format

generate_initial_parameters(seed: int | None = None) → ndarray

Generates random parameters for the encoding circuit

Parameters:

seed (Union[int,None]) – Seed for the random number generator (default: None)

Returns:

The randomly generated parameters

get_circuit(features: ParameterVector | ndarray, parameters: ParameterVector | ndarray) → QuantumCircuit

Returns the circuit of the MultiControlEncodingCircuit encoding circuit

Parameters:

  • features (Union[ParameterVector,np.ndarray]) – Input vector of the features from which the gate inputs are obtained.

  • param_vec (Union[ParameterVector,np.ndarray]) – Input vector of the parameters from which the gate inputs are obtained.

Returns:

Returns the circuit in Qiskit’s QuantumCircuit format

get_params(deep: bool = True) → dict

Returns hyper-parameters and their values of the MultiControlEncodingCircuit encoding circuit

Parameters:

deep (bool) – If True, also the parameters for contained objects are returned (default=True).

Returns:

Dictionary with hyper-parameters and values.

set_params(**params) → EncodingCircuitBase

Sets value of the encoding circuit hyper-parameters.

Parameters:

params – Hyper-parameters and their values, e.g. num_qubits=2.