Gradients (qiskit_algorithms.gradients)

Algorithms to calculate the gradient of a quantum circuit.

Base Classes

BaseEstimatorGradient

Base class for an EstimatorGradient to compute the gradients of the expectation value.

BaseQGT

Base class to computes the Quantum Geometric Tensor (QGT) given a pure, parameterized quantum state.

BaseSamplerGradient

Base class for a SamplerGradient to compute the gradients of the sampling probability.

EstimatorGradientResult

Result of EstimatorGradient.

SamplerGradientResult

Result of SamplerGradient.

QGTResult

Result of QGT.

Finite Differences

FiniteDiffEstimatorGradient

Compute the gradients of the expectation values by finite difference method [1].

FiniteDiffSamplerGradient

Compute the gradients of the sampling probability by finite difference method [1].

Linear Combination of Unitaries

LinCombEstimatorGradient

Compute the gradients of the expectation values.

LinCombSamplerGradient

Compute the gradients of the sampling probability.

LinCombQGT

Computes the Quantum Geometric Tensor (QGT) given a pure, parameterized quantum state.

Parameter Shift Rules

ParamShiftEstimatorGradient

Compute the gradients of the expectation values by the parameter shift rule [1].

ParamShiftSamplerGradient

Compute the gradients of the sampling probability by the parameter shift rule [1].

Quantum Fisher Information

QFIResult

Result of QFI.

QFI

Computes the Quantum Fisher Information (QFI) given a pure, parameterized quantum state.

Classical Methods

ReverseEstimatorGradient

Estimator gradients with the classically efficient reverse mode.

ReverseQGT

QGT calculation with the classically efficient reverse mode.

Simultaneous Perturbation Stochastic Approximation

SPSAEstimatorGradient

Compute the gradients of the expectation value by the Simultaneous Perturbation Stochastic Approximation (SPSA) [1].

SPSASamplerGradient

Compute the gradients of the sampling probability by the Simultaneous Perturbation Stochastic Approximation (SPSA) [1].