squlearn.encoding_circuit.ParamZFeatureMap

class squlearn.encoding_circuit.ParamZFeatureMap(num_qubits: int, num_features: int, num_layers: int = 2, entangling: bool = False)

Parameterized Z feature map with optional CNOT gates between the default layers.

This encoding circuit is based on Qiskit’s qiskit.circuit.library.ZFeatureMap.

Example for 4 qubits, a 2 dimensional feature vector and 2 layers with entangling:

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

../../_images/squlearn-encoding_circuit-ParamZFeatureMap-1.png
Parameters:

  • num_qubits (int) – Number of qubits

  • num_features (int) – Dimension of the feature vector

  • num_layers (int) – Number of layers of the encoding circuit

  • entangling (bool) – If true, entangling gates are added between the layers

compose(x, concatenate_features=True, concatenate_parameters=False)

Composition of encoding circuits with options for handling features and parameters

Number of qubits and features have to be equal in both encoding circuits! The special function and properties of the both encoding circuits are lost by this composition.

Parameters:
Returns:

Returns the composed encoding circuit as special class ComposedEncodingCircuit

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 parameterized Z feature map.

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:

The circuit of the parameterized Z feature map in the form of a QuantumCircuit

get_params(deep: bool = True) → dict

Returns hyper-parameters and their values of the parameterized Z feature map.

Parameters:

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

Returns:

Dictionary with hyper-parameters and values.

inverse()

Returns the inverse of the encoding circuit.

Returns:

The inverse of the encoding circuit

set_params(**params) → EncodingCircuitBase

Sets value of the encoding circuit hyper-parameters.

Parameters:

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