Gradient

class qiskit.opflow.gradients.Gradient(grad_method='param_shift', **kwargs)

Bases: GradientBase

Deprecated: Convert an operator expression to the first-order gradient.

Deprecated since version 0.24.0

The class qiskit.opflow.gradients.gradient.Gradient is deprecated as of qiskit-terra 0.24.0. It will be removed in the Qiskit 1.0 release. For code migration guidelines, visit https://qisk.it/opflow_migration(opens in a new tab).

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(opens in a new tab)[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(opens in a new tab) – If params contains a parameter not present in operator.
ValueError(opens in a new tab) – If operator is not parameterized.

Return type

OperatorBase

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(opens in a new tab)[ParameterExpression]) – Parameters w.r.t. which we compute the gradient.

Returns

Operator which represents the gradient w.r.t. the given params.

Raises

ValueError(opens in a new tab) – If params contains a parameter not present in operator.
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(opens in a new tab) – If the operator does not include a StateFn given by a quantum circuit
Exception(opens in a new tab) – Unintended code is reached
MissingOptionalLibraryError – jax not installed

Return type

OperatorBase

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