!> @file
!! Routines to nullify the structures used in the linear version
!! @author
!!    Copyright (C) 2013-2013 BigDFT group
!!    This file is distributed under the terms of the
!!    GNU General Public License, see ~/COPYING file
!!    or http://www.gnu.org/copyleft/gpl.txt .
!!    For the list of contributors, see ~/AUTHORS
