qiskit.chemistry.algorithms.NumPyEigensolverFactory

class NumPyEigensolverFactory(filter_criterion=None, k=100, use_default_filter_criterion=False)

A factory to construct a NumPyEigensolver.

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.

• use_default_filter_criterion (bool) – Whether to use default filter criteria or not

• k (int) – How many eigenvalues are to be computed, has a min. value of 1.

• use_default_filter_criterion – whether to use the transformation’s default filter criterion if filter_criterion is None.

__init__(filter_criterion=None, k=100, use_default_filter_criterion=False)

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.

• use_default_filter_criterion (bool) – Whether to use default filter criteria or not

• k (int) – How many eigenvalues are to be computed, has a min. value of 1.

• use_default_filter_criterion – whether to use the transformation’s default filter criterion if filter_criterion is None.

Methods

__init__([filter_criterion, k, …])	type filter_criterion Optional[Callable[[Union[List, ndarray], float, Optional[List[float]]], bool]]
get_solver(transformation)	Returns a NumPyEigensolver with the desired filter

Attributes

filter_criterion	returns filter criterion
k	returns k (number of eigenvalues requested)
use_default_filter_criterion	returns whether to use the default filter criterion

property filter_criterion

returns filter criterion

Return type

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

get_solver(transformation)

Returns a NumPyEigensolver with the desired filter

Parameters

transformation (Transformation) – a fermionic/bosonic qubit operator transformation.

Return type

Eigensolver

Returns

A NumPyEigensolver suitable to compute the ground state of the molecule transformed by transformation.

property k

returns k (number of eigenvalues requested)

Return type

int

property use_default_filter_criterion

returns whether to use the default filter criterion

Return type

bool