Reduces a square matrix to upper Hessenberg form.

Currently implemented on CPU only.


a (Union[Array, ndarray, bool_, number, bool, int, float, complex]) – A floating point or complex square matrix or batch of matrices.

Return type

Tuple[Array, Array]

Returns: A (a, taus) pair, where the upper triangle and first subdiagonal of a contain the upper Hessenberg matrix, and the elements below the first subdiagonal contain the Householder reflectors. For each Householder reflector taus contains the scalar factors of the elementary Householder reflectors.