qiskit.chemistry.algorithms.AdaptVQE

class AdaptVQE(transformation, solver, threshold=1e-05, delta=1, max_iterations=None)

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A ground state calculation employing the AdaptVQE algorithm.

Parameters

transformation (FermionicTransformation) – a fermionic driver to operator transformation strategy.
solver (MinimumEigensolverFactory) – a factory for the VQE solver employing a UCCSD variational form.
threshold (float) – the energy convergence threshold. It has a minimum value of 1e-15.
delta (float) – the finite difference step size for the gradient computation. It has a minimum value of 1e-5.
max_iterations (Optional[int]) – the maximum number of iterations of the AdaptVQE algorithm.

init

__init__(transformation, solver, threshold=1e-05, delta=1, max_iterations=None)

Parameters

transformation (FermionicTransformation) – a fermionic driver to operator transformation strategy.
solver (MinimumEigensolverFactory) – a factory for the VQE solver employing a UCCSD variational form.
threshold (float) – the energy convergence threshold. It has a minimum value of 1e-15.
delta (float) – the finite difference step size for the gradient computation. It has a minimum value of 1e-5.
max_iterations (Optional[int]) – the maximum number of iterations of the AdaptVQE algorithm.

Methods


`__init__`(transformation, solver[, …])	type transformation`FermionicTransformation`
`evaluate_operators`(state, operators)	Evaluates additional operators at the given state.
`returns_groundstate`()	Whether the eigensolver returns the ground state or only ground state energy.
`solve`(driver[, aux_operators])	Computes the ground state.

Attributes


`solver`	Returns the minimum eigensolver or factory.
`transformation`	Returns the transformation used to obtain a qubit operator from the molecule.

evaluate_operators

evaluate_operators(state, operators)

Evaluates additional operators at the given state.

Parameters

state (Union[str, dict, Result, list, ndarray, Statevector, QuantumCircuit, Instruction, OperatorBase]) – any kind of input that can be used to specify a state. See also StateFn for more details.
operators (Union[WeightedPauliOperator, OperatorBase, list, dict]) – either a single, list or dictionary of WeightedPauliOperator``s or any kind of operator implementing the ``OperatorBase.

Return type

Union[float, List[float], Dict[str, List[float]]]

Returns

The expectation value of the given operator(s). The return type will be identical to the format of the provided operators.

returns_groundstate

returns_groundstate()

Whether the eigensolver returns the ground state or only ground state energy.

Return type

bool

solve

solve(driver, aux_operators=None)

Computes the ground state.

Parameters

driver (BaseDriver) – a chemistry driver.
aux_operators (Union[List[FermionicOperator], List[BosonicOperator], None]) – Additional auxiliary FermionicOperator instances to evaluate at the ground state.

Raises

AquaError – if a solver other than VQE or a variational form other than UCCSD is provided or if the algorithm finishes due to an unforeseen reason.

Return type

Union[ElectronicStructureResult, VibronicStructureResult]

Returns

An AdaptVQEResult which is an ElectronicStructureResult but also includes runtime information about the AdaptVQE algorithm like the number of iterations, finishing criterion, and the final maximum gradient.

solver

Returns the minimum eigensolver or factory.

Return type

Union[MinimumEigensolver, MinimumEigensolverFactory]

transformation

Returns the transformation used to obtain a qubit operator from the molecule.

Return type

Transformation

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