pele.utils.hessian.get_eig

pele.utils.hessian.get_eig(hess, **kwargs)

return the eigenvalue and eigenvectors of a Hessian (symmetric)

The following is from numpy.linalg.eigh

Return the eigenvalues and eigenvectors of a Hermitian or symmetric matrix.

Returns two objects, a 1-D array containing the eigenvalues of a, and a 2-D square array or matrix (depending on the input type) of the corresponding eigenvectors (in columns).

Parameters :

a : array_like, shape (M, M)

A complex Hermitian or real symmetric matrix.

UPLO : {‘L’, ‘U’}, optional

Specifies whether the calculation is done with the lower triangular part of a (‘L’, default) or the upper triangular part (‘U’).

Returns :

w : ndarray, shape (M,)

The eigenvalues, not necessarily ordered.

v : ndarray, or matrix object if a is, shape (M, M)

The column v[:, i] is the normalized eigenvector corresponding to the eigenvalue w[i].

Raises :

LinAlgError

If the eigenvalue computation does not converge.