qiskit.chemistry.algorithms.pes_samplers.WindowExtrapolator

class WindowExtrapolator(extrapolator=None, window=2)

An extrapolator which wraps another extrapolator, limiting the internal extrapolator’s ground truth parameter set to a fixed window size.

Constructor.

Parameters

• extrapolator (Union[PolynomialExtrapolator, DifferentialExtrapolator, None]) – ‘internal’ extrapolator that performs extrapolation on variational parameters based on data window

• window (int) – Number of previous points to use for extrapolation. A value of zero indicates that all previous points will be used for bootstrapping.

__init__(extrapolator=None, window=2)

Constructor.

Parameters

• extrapolator (Union[PolynomialExtrapolator, DifferentialExtrapolator, None]) – ‘internal’ extrapolator that performs extrapolation on variational parameters based on data window

• window (int) – Number of previous points to use for extrapolation. A value of zero indicates that all previous points will be used for bootstrapping.

Methods

__init__([extrapolator, window])	Constructor.
extrapolate(points, param_dict)	Extrapolate at specified point of interest given a set of variational parameters.
factory(mode, **kwargs)	Factory method for constructing extrapolators.

Attributes

extrapolator	Returns the internal extrapolator.
window	Returns the size of the window.

extrapolate(points, param_dict)

Extrapolate at specified point of interest given a set of variational parameters. Based on the specified window, a subset of the data points will be used for extrapolation. A default window of 2 points is used, while a value of zero indicates that all previous points will be used for extrapolation. This method defines the data window before performing the internal extrapolation.

Parameters

• points (List[float]) – List of point(s) to be used for extrapolation. Can represent some degree of freedom, ex, interatomic distance.

• param_dict (Optional[Dict[float, List[float]]]) – Dictionary of variational parameters. Each key is the point and the value is a list of the variational parameters.

Return type

Dict[float, List[float]]

Returns

Dictionary of variational parameters for extrapolated point(s).

property extrapolator

Returns the internal extrapolator.

Return type

Extrapolator

Returns

The internal extrapolator.

static factory(mode, **kwargs)

Factory method for constructing extrapolators.

Parameters

• mode (str) – Extrapolator to instantiate. Can be one of: - ‘window’ - ‘poly’ - ‘diff_model’ - ‘pca’ - ‘l1’

• kwargs – arguments to be passed to the constructor of an extrapolator

Return type

Extrapolator

Returns

A newly created extrapolator instance.

Raises

AquaError – if specified mode is unknown.

property window

Returns the size of the window.

Return type

int

Returns

The size of the window.