Package reference

dacp.solver.eigvalsh(A, window, bounds=None, random_vectors=2, filter_order=12, tol=0.0001)

Eigenvalue solver. Automatically resolves degeneracies and remove incorrect eigenvalues.

Parameters:

• A (ndarray | LinearOperator | sparray) – Hermitian operator.

• window (tuple) – Eigenvalue window.

• bounds (tuple | None) – Boundaries of the spectrum. If not provided the maximum and minimum eigenvalues are calculated.

• random_vectors (int) – When return_eigenvectors=False, specifies the maximum expected degeneracy of the matrix.

• filter_order (int) – The number of times a vector is filtered is given by filter_order*E_max/a.

• tol (float) – Maximum relative error tolerance for eigenvalues.

Returns:

Eigenvalues.

Return type:

ndarray

dacp.solver.estimated_errors(eigvals, window, tol=0.0001, filter_order=12)

Computes estimated relative errors of eigenvalues.

Parameters:

• eigvals (ndarray) – Eigenvalues found by the eigensolver.

• window (tuple) – Upper and lower bounds of eigenvalues.

• tol (float) – Tolerance of the eigensolver (default 1e-4).

• filter_order (int) – Order of the Chebyshev filter (default 12).

Returns:

Relative errors.