scqubits.core.diag.evals_scipy_sparse

scqubits.core.diag.evals_scipy_sparse(matrix, evals_count, **kwargs)[source]

Diagonalization based on scipy’s (sparse) eigsh function. Only evals are returned.

Note the convoluted convention when it comes to ordering and how it is related to the presence of return_eigenvectors parameter. See here for details: https://github.com/scipy/scipy/issues/9082

Parameters:

  • matrix (Union[ndarray, csc_matrix, Qobj]) – ndarray or qutip.Qobj to be diagonalized

  • evals_count (int) – how many eigenvalues should be returned

  • kwargs – optional settings that are passed onto the diagonalization routine

Return type:

ndarray

Returns:

eigenvalues of matrix