HFInitialPoint

class HFInitialPoint

Bases: InitialPoint

Compute the Hartree-Fock (HF) initial point.

A class that provides an all-zero initial point for the VQE parameter values.

If used in concert with the HartreeFock initial state (which will be prepended to the UCC circuit) the all-zero initial point will correspond to the HF initial point.

Attributes

ansatz

The UCC ansatz.

The excitation_list and reps used by the UCC ansatz is obtained to ensure that the shape of the initial point is appropriate.

problem

The problem.

The problem is not required to compute the HF initial point. If it is provided we will attempt to obtain the HF reference_energy.

total_energy

The Hartree-Fock reference energy.

If the reference energy was not obtained from ElectronicEnergy this will be equal to zero.

Methods

compute(ansatz=None, problem=None)

Compute the initial point parameter for each excitation.

See class documentation for more information.

Parameters:

• problem (BaseProblem | None) – The problem.

• ansatz (UCC | None) – The ansatz.

Raises:

QiskitNatureError – If ansatz is not set.

to_numpy_array()

The initial point as an array.

Return type:

ndarray