API Reference

QML Regressors

kernel.ml.QSVR	Quantum Support Vector Regression
kernel.ml.QKRR	Quantum Kernel Ridge Regression.
kernel.ml.QGPR	Quantum Gaussian Process Regression (QGPR).
qnn.QNNRegressor	Quantum Neural Network for Regression.

QML Classifiers

kernel.ml.QSVC	Quantum Support Vector Classification
kernel.ml.QGPC	Quantum Gaussian process classification (QGPC), that extends the scikit-learn sklearn.gaussian_process.GaussianProcessClassifier.
qnn.QNNClassifier	Quantum Neural Network for Classification.

Circuit Design

Encoding Circuits

encoding_circuit.YZ_CX_EncodingCircuit	Creates the YZ-CX Encoding Circuit from reference [1].
encoding_circuit.HighDimEncodingCircuit	The high-dimensional encoding circuit from reference [1].
encoding_circuit.HubregtsenEncodingCircuit	Creates the data reuploading encoding circuit as presented in reference [1].
encoding_circuit.ChebyshevTower	A feature-map that is based on the Chebyshev Tower encoding.
encoding_circuit.ChebyshevPQC	Chebyshev Encoding Circuit from reference [1].
encoding_circuit.MultiControlEncodingCircuit	Encoding circuit with HZ encoding followed by controlled Rx, Ry Rz rotations.
encoding_circuit.ChebyshevRx	Simple Chebyshev encoding circuit build from Rx gates
encoding_circuit.ParamZFeatureMap	Parameterized Z feature map with optional CNOT gates between the default layers.
encoding_circuit.QiskitEncodingCircuit	Wrapper to create sQUlearn encoding circuits from the Qiskit circuit library.
encoding_circuit.QCNNEncodingCircuit	Encoding circuit for quantum convolutional neural networks (QCNN).

Encoding Circuit Tools

encoding_circuit.encoding_circuit_base.EncodingCircuitBase	Encoding circuit base class
encoding_circuit.PrunedEncodingCircuit	Class for pruning redundant parameter of encoding circuits.
encoding_circuit.LayeredEncodingCircuit	A class for a simple creation of layered encoding circuits.
encoding_circuit.EncodingCircuitDerivatives	Class for automatic differentiation of encoding circuits.
encoding_circuit.TranspiledEncodingCircuit	Class for generated a Encoding Circuit with a transpiled circuit.

encoding_circuit.automated_pruning	Function for automated pruning of the parameters in the inputted parameterized quantum circuit.
encoding_circuit.pruning_from_QFI	Algorithm for determining the redundant parameters from the Quantum Fischer Information.

Operators

observables.SinglePauli	Observable constructed from a single Pauli operator of a single Qubit.
observables.SummedPaulis	Observable for summation of single Pauli operators.
observables.SingleProbability	Observable for measuring the probability of being in state 0 or 1 of a specified qubit.
observables.SummedProbabilities	Observable for summing single Qubit probabilities of binary states.
observables.IsingHamiltonian	Implementation of Ising type Hamiltonians.
observables.CustomObservable	Class for defining a custom observable.

Operator Tools

observables.observable_base.ObservableBase	Base class for observables.
observables.observable_derivatives.ObservableDerivatives	Class for calculating derivatives of observables.

Execution Tools

Executor

A class for executing quantum jobs on IBM Quantum systems or simulators.

Core

Quantum Kernel Core

kernel.matrix.FidelityKernel	Fidelity Quantum Kernel.
kernel.matrix.ProjectedQuantumKernel	Projected Quantum Kernel for Quantum Kernel Algorithms

kernel.optimization.kernel_optimizer.KernelOptimizer	Quantum kernel optimizer.
kernel.optimization.negative_log_likelihood.NLL	Negative log likelihood loss function.
kernel.optimization.target_alignment.TargetAlignment	Target alignment loss function.

QNN Core

QNN module for classification and regression.

qnn.lowlevel_qnn.LowLevelQNN	Low-level QNN factory, which creates the specific low-level QNN based on the quantum framework.
qnn.lowlevel_qnn_qiskit.LowLevelQNNQiskit	Low level implementation of QNNs and its derivatives based on Qiskit.
qnn.lowlevel_qnn_qiskit.Expec	Data structure that holds the set-up of derivative of the expectation value.
qnn.lowlevel_qnn_pennylane.LowLevelQNNPennyLane	Low level implementation of QNNs and its derivatives based on PennyLane.
qnn.lowlevel_qnn_base.LowLevelQNNBase	Base class for low-level QNNs.
qnn.loss.SquaredLoss	Squared loss for regression.
qnn.loss.VarianceLoss	Variance loss for regression.
qnn.loss.ParameterRegularizationLoss	Loss for parameter regularization.

Tools for training QNNs

qnn.get_variance_fac	Function for adjusting the variance regularization along the iterations.
qnn.get_lr_decay	Function for running an Adam optimization with a decay in the learning rate.
qnn.ShotsFromRSTD	Shot control for setting the shots of the gradient evaluation after the RSTD of the loss.
qnn.training.train	Function for training a given QNN.
qnn.training.train_mini_batch	Minimize a loss function using mini-batch gradient descent.

Implemented optimizers

Module for optimizer implementations and wrappers.

optimizers.Adam	sQUlearn's implementation of the ADAM optimizer
optimizers.LBFGSB	Wrapper class for scipy's L-BFGS-B implementation.
optimizers.SLSQP	Wrapper class for scipy's SLSQP implementation.
optimizers.SPSA	Wrapper class for Qiskit's SPSA implementation.
optimizers.SGLBO	sQUlearn's implementation of the SGLBO optimizer

OpTree Data Structure

util.OpTree	Static class containing functions for working with OpTrees objects.
util.optree.OpTreeList	A OpTree node that represents its children as a list/array/vector.
util.optree.OpTreeSum	A OpTree node that sums over its children.
util.optree.OpTreeCircuit	A leaf of the OpTree that represents a circuit.
util.optree.OpTreeOperator	A leaf of the OpTree that represents an operator.
util.optree.OpTreeExpectationValue	Leaf of the OpTree that represents an expectation value of a circuit and an operator.
util.optree.OpTreeMeasuredOperator	Leaf of the OpTree that represents an measurement.
util.optree.OpTreeContainer	A container for arbitrary objects that can be used as leafs in the OpTree.
util.optree.OpTreeValue	A leaf that contains an evaluated value.

PennyLane interface

util.pennylane.PennyLaneCircuit

Class for converting a Qiskit circuit to a PennyLane circuit.

Base Classes

observables.observable_base.ObservableBase	Base class for observables.
encoding_circuit.encoding_circuit_base.EncodingCircuitBase	Encoding circuit base class
kernel.matrix.kernel_matrix_base.KernelMatrixBase	Base class for defining quantum kernels.
kernel.optimization.kernel_loss_base.KernelLossBase	Empty parent class for a kernel loss function.
kernel.optimization.kernel_optimization_base.KernelOptimizerBase	Empty parent class for defining a kernel optimizer object.
optimizers.optimizer_base.OptimizerBase	Base class for QNN optimizers.
qnn.base_qnn.BaseQNN	Base Class for Quantum Neural Networks.
qnn.loss.LossBase	Base class implementation for loss functions.