quri_parts.core.estimator.gradient module

quri_parts.core.estimator.gradient.numerical_gradient_estimates(op: Operator | PauliLabel, state: _ParametricStateT, params: Sequence[float], estimator: Callable[[Operator | PauliLabel, _ParametricStateT, Sequence[Sequence[float]]], Iterable[Estimate[complex]]], delta: float) → Estimates[complex]

Estimate a gradient of an expectation value of a given operator for a parametric state with respect to the state parameter by a numerical differentiation.

The gradient estimates are configured with arguments as follows.

Parameters:

• op – An operator of which expectation value is estimated.

• state – A parametric quantum state on which the operator expectation is evaluated.

• params – Parameter values for which the gradient is estimated.

• estimator – An estimator that estimates expectation values of the operator for the parametric states.

• delta – Step size for numerical differentiation.

Returns:

The estimated values (can be accessed with values) with errors of estimation (can be accessed with error_matrix).

quri_parts.core.estimator.gradient.create_numerical_gradient_estimator(parametric_estimator: Callable[[Operator | PauliLabel, _ParametricStateT, Sequence[Sequence[float]]], Iterable[Estimate[complex]]], delta: float) → Callable[[Operator | PauliLabel, _ParametricStateT, Sequence[float]], Estimates[complex]]

Create a GradientEstimator that estimates gradient values.

The gradient estimates are configured with arguments as follows.

Parameters:

• parametric_estimator – An estimator that estimates expectation values of the operator for the parametric states.

• delta – Step size for numerical differentiation.

quri_parts.core.estimator.gradient.parameter_shift_gradient_estimates(op: Operator | PauliLabel, state: _ParametricStateT, params: Sequence[float], estimator: Callable[[Operator | PauliLabel, _ParametricStateT, Sequence[Sequence[float]]], Iterable[Estimate[complex]]]) → Estimates[complex]

Estimate a gradient of an expectation value of a given operator for a parametric state with respect to the state parameter by the parameter shift rule.

The gradient estimates are configured with arguments as follows.

Parameters:

• op – An operator of which expectation value is estimated.

• state – A parametric quantum state on which the operator expectation is evaluated.

• params – Parameter values for which the gradient is estimated.

• estimator – An estimator that estimates expectation values of the operator for the parametric states.

Returns:

The estimated values (can be accessed with values) with errors of estimation (can be accessed with error_matrix).

quri_parts.core.estimator.gradient.create_parameter_shift_gradient_estimator(parametric_estimator: Callable[[Operator | PauliLabel, _ParametricStateT, Sequence[Sequence[float]]], Iterable[Estimate[complex]]]) → Callable[[Operator | PauliLabel, _ParametricStateT, Sequence[float]], Estimates[complex]]