openfermion.linalg.Davidson

Davidson algorithm to get the n states with smallest eigenvalues.

Methods

get_lowest_n

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Returns n smallest eigenvalues and corresponding eigenvectors for linear_operator.

Args
n int

The number of states corresponding to the smallest eigenvalues and associated eigenvectors for the linear_operator.

initial_guess numpy.ndarray[complex]

Initial guess of eigenvectors associated with the n smallest eigenvalues.

max_iterations int

Max number of iterations when not converging.

Returns
success bool

Indicates whether it converged, i.e. max elementwise error is smaller than eps.

eigen_values numpy.ndarray[complex]

The smallest n eigenvalues.

eigen_vectors numpy.ndarray[complex]

The smallest n eigenvectors corresponding with those eigen values.