Gradient
class qiskit.opflow.gradients.Gradient(grad_method='param_shift', **kwargs)
Bases: GradientBase
Deprecated: Convert an operator expression to the first-order gradient.
The class qiskit.opflow.gradients.gradient.Gradient is deprecated as of qiskit-terra 0.24.0. It will be removed no earlier than 3 months after the release date. For code migration guidelines, visit https://qisk.it/opflow_migration.
Attributes
grad_method
Returns CircuitGradient.
Returns
CircuitGradient.
Methods
convert
convert(operator, params=None)
Parameters
- operator (OperatorBase) – The operator we are taking the gradient of.
- params (ParameterVector |ParameterExpression |List[ParameterExpression] | None) – The parameters we are taking the gradient with respect to. If not explicitly passed, they are inferred from the operator and sorted by name.
Returns
An operator whose evaluation yields the Gradient.
Raises
- ValueError – If
paramscontains a parameter not present inoperator. - ValueError – If
operatoris not parameterized.
Return type
get_gradient
get_gradient(operator, params)
Get the gradient for the given operator w.r.t. the given parameters
Parameters
- operator (OperatorBase) – Operator w.r.t. which we take the gradient.
- params (ParameterExpression |ParameterVector |List[ParameterExpression]) – Parameters w.r.t. which we compute the gradient.
Returns
Operator which represents the gradient w.r.t. the given params.
Raises
- ValueError – If
paramscontains a parameter not present inoperator. - OpflowError – If the coefficient of the operator could not be reduced to 1.
- OpflowError – If the differentiation of a combo_fn requires JAX but the package is not installed.
- TypeError – If the operator does not include a StateFn given by a quantum circuit
- Exception – Unintended code is reached
- MissingOptionalLibraryError – jax not installed
Return type