qiskit.algorithms.NumPyMinimumEigensolver

class NumPyMinimumEigensolver(filter_criterion=None)

The Numpy Minimum Eigensolver algorithm.

Parameters

filter_criterion (Optional[Callable[[Union[List, ndarray], float, Optional[List[float]]], bool]]) – callable that allows to filter eigenvalues/eigenstates. The minimum eigensolver is only searching over feasible states and returns an eigenstate that has the smallest eigenvalue among feasible states. The callable has the signature filter(eigenstate, eigenvalue, aux_values) and must return a boolean to indicate whether to consider this value or not. If there is no feasible element, the result can even be empty.

__init__(filter_criterion=None)

Parameters

filter_criterion (Optional[Callable[[Union[List, ndarray], float, Optional[List[float]]], bool]]) – callable that allows to filter eigenvalues/eigenstates. The minimum eigensolver is only searching over feasible states and returns an eigenstate that has the smallest eigenvalue among feasible states. The callable has the signature filter(eigenstate, eigenvalue, aux_values) and must return a boolean to indicate whether to consider this value or not. If there is no feasible element, the result can even be empty.

Methods

__init__([filter_criterion])	type filter_criterion Optional[Callable[[Union[List, ndarray], float, Optional[List[float]]], bool]]
compute_minimum_eigenvalue(operator[, …])	Computes minimum eigenvalue.
supports_aux_operators()	Whether computing the expectation value of auxiliary operators is supported.

Attributes

filter_criterion

returns the filter criterion if set

compute_minimum_eigenvalue(operator, aux_operators=None)

Computes minimum eigenvalue. Operator and aux_operators can be supplied here and if not None will override any already set into algorithm so it can be reused with different operators. While an operator is required by algorithms, aux_operators are optional. To ‘remove’ a previous aux_operators array use an empty list here.

Parameters

• operator (OperatorBase) – Qubit operator of the Observable

• aux_operators (Optional[List[Optional[OperatorBase]]]) – Optional list of auxiliary operators to be evaluated with the eigenstate of the minimum eigenvalue main result and their expectation values returned. For instance in chemistry these can be dipole operators, total particle count operators so we can get values for these at the ground state.

Return type

MinimumEigensolverResult

Returns

MinimumEigensolverResult

property filter_criterion

returns the filter criterion if set

Return type

Optional[Callable[[Union[List, ndarray], float, Optional[List[float]]], bool]]

classmethod supports_aux_operators()

Whether computing the expectation value of auxiliary operators is supported.

If the minimum eigensolver computes an eigenstate of the main operator then it can compute the expectation value of the aux_operators for that state. Otherwise they will be ignored.

Return type

bool

Returns

True if aux_operator expectations can be evaluated, False otherwise