Пример #1
0
    def __init__(self,
                 nn=3,
                 relax='J',
                 eps=1e-24,
                 classical_material=None,
                 cell=None,
                 qm_spacing=0.30,
                 cl_spacing=1.20,
                 remove_moments=(1, 1),
                 potential_coupler='Refiner',
                 communicator=serial_comm):

        self.rank = mpi.rank

        self.messages = []

        assert (potential_coupler in ['Multipoles', 'Refiner'])
        self.potential_coupling_scheme = potential_coupler

        if classical_material is None:
            self.classical_material = PolarizableMaterial()
        else:
            self.classical_material = classical_material

        self.set_calculation_mode('solve')

        self.has_subsystems = False
        self.remove_moment_cl = remove_moments[0]
        self.remove_moment_qm = remove_moments[1]
        self.time = 0.0
        self.time_step = 0.0
        self.kick = np.array([0.0, 0.0, 0.0], dtype=float)
        self.maxiter = 2000
        self.eps = eps
        self.relax = relax
        self.nn = nn

        # Only handle the quantities via self.qm or self.cl
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = cl_spacing * np.ones(3) / Bohr
        self.cl.extrapolated_qm_phi = None
        self.cl.dcomm = communicator
        self.cl.dparsize = None
        self.qm = PoissonOrganizer(FDPoissonSolver)  # Default solver
        self.qm.spacing_def = qm_spacing * np.ones(3) / Bohr
        self.qm.cell = np.array(cell) / Bohr

        # Classical spacing and simulation cell
        _cell = np.array(cell) / Bohr
        self.cl.spacing = self.cl.spacing_def
        if np.size(_cell) == 3:
            self.cl.cell = np.diag(_cell)
        else:
            self.cl.cell = _cell

        # Generate classical grid descriptor
        self.initialize_clgd()
Пример #2
0
    def read(self, reader):
        r = reader.hamiltonian.poisson

        # FDTDPoissonSolver related data
        self.description = r.description
        self.time = r.time
        self.time_step = r.time_step

        # Try to read time-dependent information
        self.kick = r.kick
        self.maxiter = r.maxiter

        # PoissonOrganizer: classical
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = r.cl_spacing_def
        self.cl.spacing = r.cl_spacing
        self.cl.cell = np.diag(r.cl_cell)
        self.cl.dparsize = None

        # TODO: it should be possible to use different
        #       communicator after restart
        if r.cl_world_comm:
            self.cl.dcomm = world
        else:
            self.cl.dcomm = mpi.serial_comm

        # Generate classical grid descriptor
        self.initialize_clgd()

        # Classical materials data
        self.classical_material = PolarizableMaterial()
        self.classical_material.read(r)
        self.classical_material.initialize(self.cl.gd)

        # PoissonOrganizer: quantum
        self.qm = PoissonOrganizer()
        self.qm.corner1 = r.qm_corner1
        self.qm.corner2 = r.qm_corner2
        self.given_corner_v1 = r.given_corner_1
        self.given_corner_v2 = r.given_corner_2
        self.given_cell = np.diag(r.given_cell)
        self.hratios = r.hratios
        self.shift_indices_1 = r.shift_indices_1.astype(int)
        self.shift_indices_2 = r.shift_indices_2.astype(int)
        self.num_indices = r.num_indices.astype(int)
        self.num_refinements = int(r.num_refinements)

        # Redefine atoms to suit the cut_cell routine
        newatoms = read_atoms(reader.atoms)
        newatoms.positions = newatoms.positions + self.qm.corner1 * Bohr
        newatoms.set_cell(np.diag(self.given_cell))
        self.create_subsystems(newatoms)

        # Read self.classical_material.charge_density
        if self.cl.gd.comm.rank == 0:
            big_charge_density = \
                np.array(r.get('classical_material_rho'), dtype=float)
        else:
            big_charge_density = None
        self.cl.gd.distribute(big_charge_density,
                              self.classical_material.charge_density)

        # Read self.classical_material.polarization_total
        if self.cl.gd.comm.rank == 0:
            big_polarization_total = \
                np.array(r.get('polarization_total'), dtype=float)
        else:
            big_polarization_total = None
        self.cl.gd.distribute(big_polarization_total,
                              self.classical_material.polarization_total)

        # Read self.classical_material.polarizations
        if self.cl.gd.comm.rank == 0:
            big_polarizations = np.array(r.get('polarizations'), dtype=float)
        else:
            big_polarizations = None
        self.cl.gd.distribute(big_polarizations,
                              self.classical_material.polarizations)

        # Read self.classical_material.currents
        if self.cl.gd.comm.rank == 0:
            big_currents = np.array(r.get('currents'), dtype=float)
        else:
            big_currents = None
        self.cl.gd.distribute(big_currents, self.classical_material.currents)
# Atoms object
atoms = Atoms('Na2', atom_center + np.array([[-1.5, 0.0, 0.0],
                                             [ 1.5, 0.0, 0.0]]))

# Permittivity of Gold (from  J. Chem. Phys. 137, 074113 (2012))
eps_gold = PermittivityPlus(data = [[0.2350, 0.1551,  95.62],
                                    [0.4411, 0.1480, -12.55],
                                    [0.7603,  1.946, -40.89],
                                    [1.161,   1.396,  17.22],
                                    [2.946,   1.183,  15.76],
                                    [4.161,   1.964,  36.63],
                                    [5.747,   1.958,  22.55],
                                    [7.912,   1.361,  81.04]])

# 1) Nanosphere only
classical_material = PolarizableMaterial()                            

classical_material.add_component(PolarizableSphere(center = sphere_center,
                                 radius                   = radius,
                                 permittivity             = eps_gold))

qsfdtd = QSFDTD(classical_material = classical_material,
                atoms              = None,
                cells              = simulation_cell,
                spacings           = [2.0, 0.5],
                remove_moments     = (1, 1))

energy = qsfdtd.ground_state('gs.gpw',
                             nbands = 1)

qsfdtd.time_propagation('gs.gpw',
Пример #4
0
class FDTDPoissonSolver:
    def __init__(self,
                 nn=3,
                 relax='J',
                 eps=1e-24,
                 classical_material=None,
                 cell=None,
                 qm_spacing=0.30,
                 cl_spacing=1.20,
                 remove_moments=(1, 1),
                 potential_coupler='Refiner',
                 communicator=serial_comm):

        self.rank = mpi.rank

        self.messages = []

        assert (potential_coupler in ['Multipoles', 'Refiner'])
        self.potential_coupling_scheme = potential_coupler

        if classical_material is None:
            self.classical_material = PolarizableMaterial()
        else:
            self.classical_material = classical_material

        self.set_calculation_mode('solve')

        self.has_subsystems = False
        self.remove_moment_cl = remove_moments[0]
        self.remove_moment_qm = remove_moments[1]
        self.time = 0.0
        self.time_step = 0.0
        self.kick = np.array([0.0, 0.0, 0.0], dtype=float)
        self.maxiter = 2000
        self.eps = eps
        self.relax = relax
        self.nn = nn

        # Only handle the quantities via self.qm or self.cl
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = cl_spacing * np.ones(3) / Bohr
        self.cl.extrapolated_qm_phi = None
        self.cl.dcomm = communicator
        self.cl.dparsize = None
        self.qm = PoissonOrganizer(FDPoissonSolver)  # Default solver
        self.qm.spacing_def = qm_spacing * np.ones(3) / Bohr
        self.qm.cell = np.array(cell) / Bohr

        # Classical spacing and simulation cell
        _cell = np.array(cell) / Bohr
        self.cl.spacing = self.cl.spacing_def
        if np.size(_cell) == 3:
            self.cl.cell = np.diag(_cell)
        else:
            self.cl.cell = _cell

        # Generate classical grid descriptor
        self.initialize_clgd()

    def todict(self):
        dct = dict(
            name='fdtd',
            nn=self.nn,
            relax=self.relax,
            eps=self.eps,
            # classical_material missing
            cell=self.cl.cell * Bohr,
            qm_spacing=self.qm.spacing_def[0] * Bohr,
            cl_spacing=self.cl.spacing_def[0] * Bohr,
            remove_moments=(self.remove_moment_cl, self.remove_moment_qm),
            potential_coupler=self.potential_coupling_scheme)

        return dct

    def get_description(self):
        return 'FDTD+TDDFT'

    # Generated classical GridDescriptors, after spacing and cell are known
    def initialize_clgd(self):
        N_c = get_number_of_grid_points(self.cl.cell, self.cl.spacing)
        self.cl.spacing = np.diag(self.cl.cell) / N_c
        self.cl.gd = GridDescriptor(N_c, self.cl.cell, False, self.cl.dcomm,
                                    self.cl.dparsize)
        self.cl.gd_global = GridDescriptor(N_c, self.cl.cell, False,
                                           serial_comm, None)
        self.cl.extrapolated_qm_phi = self.cl.gd.empty()

    def estimate_memory(self, mem):
        # self.cl.poisson_solver.estimate_memory(mem)
        #print(self.qm.poisson_solver.estimate_memory.__code__.co_varnames)
        # WTF?  How can this shabby method suddenly be unbound?  It needs both self and mem.
        # Ferchrissakes!
        #self.qm.poisson_solver.estimate_memory(mem=mem)
        pass

    # Return the TDDFT stencil by default
    def get_stencil(self, mode='qm'):
        if mode == 'qm':
            return self.qm.poisson_solver.get_stencil()
        else:
            return self.cl.poisson_solver.get_stencil()

    # Initialize both PoissonSolvers
    #def initialize(self):
    #    self.qm.poisson_solver._init()
    #    self.cl.poisson_solver._init()

    def set_grid_descriptor(self, qmgd):
        if not self.has_subsystems:
            return

        self.qm.gd = qmgd

        # Create quantum Poisson solver
        self.qm.poisson_solver = PoissonSolver(
            name='fd',
            nn=self.nn,
            eps=self.eps,
            relax=self.relax,
            remove_moment=self.remove_moment_qm)
        self.qm.poisson_solver.set_grid_descriptor(self.qm.gd)
        #self.qm.poisson_solver.initialize()
        self.qm.phi = self.qm.gd.zeros()
        self.qm.rho = self.qm.gd.zeros()

        # Set quantum grid descriptor
        self.qm.poisson_solver.set_grid_descriptor(qmgd)

        # Create classical PoissonSolver
        self.cl.poisson_solver = PoissonSolver(
            name='fd',
            nn=self.nn,
            eps=self.eps,
            relax=self.relax,
            remove_moment=self.remove_moment_cl)
        self.cl.poisson_solver.set_grid_descriptor(self.cl.gd)
        #self.cl.poisson_solver.initialize()

        # Initialize classical material,
        # its Poisson solver was generated already
        self.cl.poisson_solver.set_grid_descriptor(self.cl.gd)
        self.classical_material.initialize(self.cl.gd)
        self.cl.extrapolated_qm_phi = self.cl.gd.zeros()
        self.cl.phi = self.cl.gd.zeros()
        self.cl.extrapolated_qm_phi = self.cl.gd.empty()

        msg = self.messages.append
        msg('\nFDTDPoissonSolver/grid descriptors and coupler:')
        msg(' Domain parallelization with %i processes.' %
            self.cl.gd.comm.size)
        if self.cl.gd.comm == serial_comm:
            msg(' Communicator for domain parallelization: serial_comm')
        elif self.cl.gd.comm == world:
            msg(' Communicator for domain parallelization: world')
        elif self.cl.gd.comm == self.qm.gd.comm:
            msg(' Communicator for domain parallelization: dft_domain_comm')
        else:
            msg(' Communicator for domain parallelization: %s'
                % self.cl.gd.comm)

        # Initialize potential coupler
        if self.potential_coupling_scheme == 'Multipoles':
            msg('Classical-quantum coupling by multipole expansion ' +
                'with maxL: %i' % (self.remove_moment_qm))
            self.potential_coupler = MultipolesPotentialCoupler(
                qm=self.qm,
                cl=self.cl,
                index_offset_1=self.shift_indices_1,
                index_offset_2=self.shift_indices_2,
                extended_index_offset_1=self.extended_shift_indices_1,
                extended_index_offset_2=self.extended_shift_indices_2,
                extended_delta_index=self.extended_deltaIndex,
                num_refinements=self.num_refinements,
                remove_moment_qm=self.remove_moment_qm,
                remove_moment_cl=self.remove_moment_cl,
                rank=self.rank)
        else:
            msg('Classical-quantum coupling by coarsening/refining')
            self.potential_coupler = RefinerPotentialCoupler(
                qm=self.qm,
                cl=self.cl,
                index_offset_1=self.shift_indices_1,
                index_offset_2=self.shift_indices_2,
                extended_index_offset_1=self.extended_shift_indices_1,
                extended_index_offset_2=self.extended_shift_indices_2,
                extended_delta_index=self.extended_deltaIndex,
                num_refinements=self.num_refinements,
                remove_moment_qm=self.remove_moment_qm,
                remove_moment_cl=self.remove_moment_cl,
                rank=self.rank)

        self.phi_tot_clgd = self.cl.gd.empty()
        self.phi_tot_qmgd = self.qm.gd.empty()

    def cut_cell(self,
                 atoms_in,
                 vacuum=5.0,
                 corners=None,
                 create_subsystems=True):
        qmh = self.qm.spacing_def
        if corners is not None:
            v1 = np.array(corners[0]).ravel() / Bohr
            v2 = np.array(corners[1]).ravel() / Bohr
        else:  # Use vacuum
            pos_old = atoms_in.get_positions()[0]
            dmy_atoms = atoms_in.copy()
            dmy_atoms.center(vacuum=vacuum)
            pos_new = dmy_atoms.get_positions()[0]
            v1 = (pos_old - pos_new) / Bohr
            v2 = v1 + np.diag(dmy_atoms.get_cell()) / Bohr

        # Needed for restarting
        self.given_corner_v1 = v1 * Bohr
        self.given_corner_v2 = v2 * Bohr
        self.given_cell = atoms_in.get_cell()

        # Sanity check: quantum box must be inside the classical one
        assert (all([v1[w] <= v2[w] and v1[w] >= 0 and
                     v2[w] <= np.diag(self.cl.cell)[w] for w in range(3)]))

        # Ratios of the user-given spacings
        self.hratios = self.cl.spacing_def / qmh
        self.num_refinements = \
            1 + int(round(np.log(self.hratios[0]) / np.log(2.0)))
        assert ([int(round(np.log(self.hratios[w]) / np.log(2.0))) ==
                 self.num_refinements for w in range(3)])

        # Create quantum grid
        self.qm.cell = np.zeros((3, 3))
        for w in range(3):
            self.qm.cell[w, w] = v2[w] - v1[w]

        N_c = get_number_of_grid_points(self.qm.cell, qmh)
        self.qm.spacing = np.diag(self.qm.cell) / N_c

        # Classical corner indices must be divisible with numb
        if any(self.cl.spacing / self.qm.spacing >= 3):
            numb = 1
        elif any(self.cl.spacing / self.qm.spacing >= 2):
            numb = 2
        else:
            numb = 4

        # The index mismatch of the two simulation cells
        # Round before taking floor/ceil to avoid floating point
        # arithmetic errors
        num_indices_1 = numb * np.floor(
            np.round(np.array(v1) / self.cl.spacing / numb, 2)).astype(int)
        num_indices_2 = numb * np.ceil(
            np.round(np.array(v2) / self.cl.spacing / numb, 2)).astype(int)
        self.num_indices = num_indices_2 - num_indices_1

        # Center, left, and right points of the suggested quantum grid
        cp = 0.5 * (np.array(v1) + np.array(v2))
        lp = cp - 0.5 * self.num_indices * self.cl.spacing
        # rp = cp + 0.5 * self.num_indices * self.cl.spacing

        # Indices in the classical grid restricting the quantum grid
        self.shift_indices_1 = np.round(lp / self.cl.spacing).astype(int)
        self.shift_indices_2 = self.shift_indices_1 + self.num_indices

        # Sanity checks
        assert(all([self.shift_indices_1[w] >= 0 and
                    self.shift_indices_2[w] <= self.cl.gd.N_c[w]
                    for w in range(3)])), \
            "Could not find appropriate quantum grid. " + \
            "Move it further away from the boundary."

        # Corner coordinates
        self.qm.corner1 = self.shift_indices_1 * self.cl.spacing
        self.qm.corner2 = self.shift_indices_2 * self.cl.spacing

        # Now the information for creating the subsystems is ready
        if create_subsystems:
            return self.create_subsystems(atoms_in)

    def create_subsystems(self, atoms_in):

        # Create new Atoms object
        atoms_out = atoms_in.copy()

        # New quantum grid
        self.qm.cell = \
            np.diag([(self.shift_indices_2[w] - self.shift_indices_1[w]) *
                     self.cl.spacing[w] for w in range(3)])
        self.qm.spacing = self.cl.spacing / self.hratios
        N_c = get_number_of_grid_points(self.qm.cell, self.qm.spacing)

        atoms_out.set_cell(np.diag(self.qm.cell) * Bohr)
        atoms_out.positions = atoms_in.get_positions() - self.qm.corner1 * Bohr

        msg = self.messages.append
        msg("Quantum box readjustment:")
        msg("  Given cell:       [%10.5f %10.5f %10.5f]" %
            tuple(np.diag(atoms_in.get_cell())))
        msg("  Given atomic coordinates:")
        for s, c in zip(atoms_in.get_chemical_symbols(),
                        atoms_in.get_positions()):
            msg("              %s %10.5f %10.5f %10.5f" %
                (s, c[0], c[1], c[2]))
        msg("  Readjusted cell:  [%10.5f %10.5f %10.5f]" %
            tuple(np.diag(atoms_out.get_cell())))
        msg("  Readjusted atomic coordinates:")
        for s, c in zip(atoms_out.get_chemical_symbols(),
                        atoms_out.get_positions()):
            msg("              %s %10.5f %10.5f %10.5f" %
                (s, c[0], c[1], c[2]))

        msg("  Given corner points:       " +
            "(%10.5f %10.5f %10.5f) - (%10.5f %10.5f %10.5f)"
            % (tuple(np.concatenate((self.given_corner_v1,
                                     self.given_corner_v2)))))
        msg("  Readjusted corner points:  " +
            "(%10.5f %10.5f %10.5f) - (%10.5f %10.5f %10.5f)"
            % (tuple(np.concatenate((self.qm.corner1,
                                     self.qm.corner2)) * Bohr)))
        msg("  Indices in classical grid: " +
            "(%10i %10i %10i) - (%10i %10i %10i)"
            % (tuple(np.concatenate((self.shift_indices_1,
                                     self.shift_indices_2)))))
        msg("  Grid points in classical grid: " +
            "(%10i %10i %10i)"
            % (tuple(self.cl.gd.N_c)))
        msg("  Grid points in quantum grid:   " +
            "(%10i %10i %10i)"
            % (tuple(N_c)))
        msg("  Spacings in quantum grid:    " +
            "(%10.5f %10.5f %10.5f)"
            % (tuple(np.diag(self.qm.cell) * Bohr / N_c)))
        msg("  Spacings in classical grid:  " +
            "(%10.5f %10.5f %10.5f)"
            % (tuple(np.diag(self.cl.cell) *
                     Bohr / get_number_of_grid_points(self.cl.cell,
                                                      self.cl.spacing))))
        # msg("  Ratios of cl/qm spacings:    " +
        #    "(%10i %10i %10i)" % (tuple(self.hratios)))
        # msg("                             = (%10.2f %10.2f %10.2f)" %
        #         (tuple((np.diag(self.cl.cell) * Bohr / \
        #                 get_number_of_grid_points(self.cl.cell,
        #                                           self.cl.spacing)) / \
        #                (np.diag(self.qm.cell) * Bohr / N_c))))
        msg("  Needed number of refinements: %10i"
            % self.num_refinements)

        # First, create the quantum grid equivalent GridDescriptor
        # self.cl.subgd. Then coarsen it until its h_cv equals
        # that of self.cl.gd. Finally, map the points between
        # clgd and coarsened subgrid.
        subcell_cv = np.diag(self.qm.corner2 - self.qm.corner1)
        N_c = get_number_of_grid_points(subcell_cv, self.cl.spacing)
        N_c = self.shift_indices_2 - self.shift_indices_1
        self.cl.subgds = []
        self.cl.subgds.append(GridDescriptor(N_c, subcell_cv, False,
                                             serial_comm, self.cl.dparsize))

        # msg("  N_c/spacing of the subgrid:           " +
        #    "%3i %3i %3i / %.4f %.4f %.4f" %
        #          (self.cl.subgds[0].N_c[0],
        #           self.cl.subgds[0].N_c[1],
        #           self.cl.subgds[0].N_c[2],
        #           self.cl.subgds[0].h_cv[0][0] * Bohr,
        #           self.cl.subgds[0].h_cv[1][1] * Bohr,
        #           self.cl.subgds[0].h_cv[2][2] * Bohr))
        # msg("  shape from the subgrid:           " +
        #    "%3i %3i %3i" % (tuple(self.cl.subgds[0].empty().shape)))

        self.cl.coarseners = []
        self.cl.refiners = []
        for n in range(self.num_refinements):
            self.cl.subgds.append(self.cl.subgds[n].refine())
            self.cl.refiners.append(Transformer(self.cl.subgds[n],
                                                self.cl.subgds[n + 1]))

            # msg("  refiners[%i] can perform the transformation " +
            #    "(%3i %3i %3i) -> (%3i %3i %3i)" % (\
            #         n,
            #         self.cl.subgds[n].empty().shape[0],
            #         self.cl.subgds[n].empty().shape[1],
            #         self.cl.subgds[n].empty().shape[2],
            #         self.cl.subgds[n + 1].empty().shape[0],
            #         self.cl.subgds[n + 1].empty().shape[1],
            #         self.cl.subgds[n + 1].empty().shape[2]))
            self.cl.coarseners.append(Transformer(self.cl.subgds[n + 1],
                                                  self.cl.subgds[n]))
        self.cl.coarseners[:] = self.cl.coarseners[::-1]

        # Now extend the grid in order to handle
        # the zero boundary conditions that the refiner assumes
        # The default interpolation order
        self.extend_nn = \
            Transformer(GridDescriptor([8, 8, 8], [1, 1, 1],
                                       False, serial_comm, None),
                        GridDescriptor([8, 8, 8], [1, 1, 1],
                                       False, serial_comm, None).coarsen()).nn

        self.extended_num_indices = self.num_indices + [2, 2, 2]

        # Center, left, and right points of the suggested quantum grid
        extended_cp = 0.5 * (np.array(self.given_corner_v1 / Bohr) +
                             np.array(self.given_corner_v2 / Bohr))
        extended_lp = extended_cp - 0.5 * (self.extended_num_indices *
                                           self.cl.spacing)
        # extended_rp = extended_cp + 0.5 * (self.extended_num_indices *
        #                                    self.cl.spacing)

        # Indices in the classical grid restricting the quantum grid
        self.extended_shift_indices_1 = \
            np.round(extended_lp / self.cl.spacing).astype(int)
        self.extended_shift_indices_2 = \
            self.extended_shift_indices_1 + self.extended_num_indices

        # msg('  extended_shift_indices_1: %i %i %i'
        #     % (self.extended_shift_indices_1[0],
        #        self.extended_shift_indices_1[1],
        #        self.extended_shift_indices_1[2]))
        # msg('  extended_shift_indices_2: %i %i %i'
        #     % (self.extended_shift_indices_2[0],
        #        self.extended_shift_indices_2[1],
        #        self.extended_shift_indices_2[2]))
        # msg('  cl.gd.N_c:                %i %i %i'
        #     % (self.cl.gd.N_c[0], self.cl.gd.N_c[1], self.cl.gd.N_c[2]))

        # Sanity checks
        assert(all([self.extended_shift_indices_1[w] >= 0 and
                    self.extended_shift_indices_2[w] <= self.cl.gd.N_c[w]
                    for w in range(3)])), \
            "Could not find appropriate quantum grid. " + \
            "Move it further away from the boundary."

        # Corner coordinates
        self.qm.extended_corner1 = \
            self.extended_shift_indices_1 * self.cl.spacing
        self.qm.extended_corner2 = \
            self.extended_shift_indices_2 * self.cl.spacing
        N_c = self.extended_shift_indices_2 - self.extended_shift_indices_1

        self.cl.extended_subgds = []
        self.cl.extended_refiners = []
        extended_subcell_cv = np.diag(self.qm.extended_corner2 -
                                      self.qm.extended_corner1)

        self.cl.extended_subgds.append(GridDescriptor(
            N_c, extended_subcell_cv, False, serial_comm, None))

        for n in range(self.num_refinements):
            self.cl.extended_subgds.append(self.cl.extended_subgds[n].refine())
            self.cl.extended_refiners.append(Transformer(
                self.cl.extended_subgds[n], self.cl.extended_subgds[n + 1]))

            # msg("  extended_refiners[%i] can perform the transformation " +
            #     "(%3i %3i %3i) -> (%3i %3i %3i)"
            #     % (n,
            #        self.cl.extended_subgds[n].empty().shape[0],
            #        self.cl.extended_subgds[n].empty().shape[1],
            #        self.cl.extended_subgds[n].empty().shape[2],
            #        self.cl.extended_subgds[n + 1].empty().shape[0],
            #        self.cl.extended_subgds[n + 1].empty().shape[1],
            #        self.cl.extended_subgds[n + 1].empty().shape[2]))

            # msg("  N_c/spacing of the refined subgrid:   " +
            #     "%3i %3i %3i / %.4f %.4f %.4f"
            #     % (self.cl.subgds[-1].N_c[0],
            #        self.cl.subgds[-1].N_c[1],
            #        self.cl.subgds[-1].N_c[2],
            #        self.cl.subgds[-1].h_cv[0][0] * Bohr,
            #        self.cl.subgds[-1].h_cv[1][1] * Bohr,
            #        self.cl.subgds[-1].h_cv[2][2] * Bohr))
            # msg("  shape from the refined subgrid:       %3i %3i %3i"
            #     % (tuple(self.cl.subgds[-1].empty().shape)))

        self.extended_deltaIndex = 2**(self.num_refinements) * self.extend_nn
        # msg(" self.extended_deltaIndex = %i" % self.extended_deltaIndex)

        qgpts = self.cl.subgds[-1].coarsen().N_c

        # Assure that one returns to the original shape
        dmygd = self.cl.subgds[-1].coarsen()
        for n in range(self.num_refinements - 1):
            dmygd = dmygd.coarsen()

        # msg("  N_c/spacing of the coarsened subgrid: " +
        #     "%3i %3i %3i / %.4f %.4f %.4f"
        #     % (dmygd.N_c[0], dmygd.N_c[1], dmygd.N_c[2],
        #        dmygd.h_cv[0][0] * Bohr,
        #        dmygd.h_cv[1][1] * Bohr,
        #        dmygd.h_cv[2][2] * Bohr))

        self.has_subsystems = True
        return atoms_out, self.qm.spacing[0] * Bohr, qgpts

    def print_messages(self, printer_function):
        printer_function("\n *** QSFDTD ***\n")
        for msg in self.messages:
            printer_function(msg)

        for msg in self.classical_material.messages:
            printer_function(msg)
        printer_function("\n *********************\n")

    # Set the time step
    def set_time_step(self, time_step):
        self.time_step = time_step

    # Set the time
    def set_time(self, time):
        self.time = time

    # Setup kick
    def set_kick(self, kick):
        self.kick = np.array(kick)

    def finalize_propagation(self):
        pass

    def set_calculation_mode(self, calculation_mode):
        # Three calculation modes are available:
        #  1) solve:     just solve the Poisson equation with
        #                given quantum+classical rho
        #  2) iterate:   iterate classical density so that the Poisson
        #                equation for quantum+classical rho is satisfied
        #  3) propagate: propagate classical density in time, and solve
        #                the new Poisson equation
        assert (calculation_mode == 'solve' or calculation_mode == 'iterate' or
                calculation_mode == 'propagate')
        self.calculation_mode = calculation_mode

    # The density object must be attached, so that the electric field
    # from all-electron density can be calculated
    def set_density(self, density):
        self.density = density

    # Returns the classical density and the grid descriptor
    def get_density(self, global_array=False):
        if global_array:
            return \
                self.cl.gd.collect(self.classical_material.charge_density) * \
                self.classical_material.sign, \
                self.cl.gd
        else:
            return \
                self.classical_material.charge_density * \
                self.classical_material.sign, \
                self.cl.gd

    # Returns the quantum + classical density in the large classical box,
    # so that the classical charge is refined into it and the quantum
    # charge is coarsened there
    def get_combined_data(self, qmdata=None, cldata=None, spacing=None,
                          qmgd=None, clgd=None):

        if qmdata is None:
            qmdata = self.density.rhot_g

        if cldata is None:
            cldata = (self.classical_material.charge_density *
                      self.classical_material.sign)

        if qmgd is None:
            qmgd = self.qm.gd

        if clgd is None:
            clgd = self.cl.gd

        if spacing is None:
            spacing = clgd.h_cv[0, 0]

        spacing_au = spacing / Bohr  # from Angstroms to a.u.

        # Refine classical part
        clgd = clgd.new_descriptor()
        cl_g = cldata.copy()
        while clgd.h_cv[0, 0] > spacing_au * 1.50:  # 45:
            clgd2 = clgd.refine()
            cl_g = Transformer(clgd, clgd2).apply(cl_g)
            clgd = clgd2

        # Coarse quantum part
        qmgd = qmgd.new_descriptor()
        qm_g = qmdata.copy()
        while qmgd.h_cv[0, 0] < clgd.h_cv[0, 0] * 0.95:
            qmgd2 = qmgd.coarsen()
            qm_g = Transformer(qmgd, qmgd2).apply(qm_g)
            qmgd = qmgd2

        assert np.all(np.absolute(qmgd.h_cv - clgd.h_cv) < 1e-12), \
            " Spacings %.8f (qm) and %.8f (cl) Angstroms" \
            % (qmgd.h_cv[0][0] * Bohr, clgd.h_cv[0][0] * Bohr)

        # Do distribution on master
        big_cl_g = clgd.collect(cl_g)
        big_qm_g = qmgd.collect(qm_g, broadcast=True)

        if clgd.comm.rank == 0:
            # now find the corners
            # r_gv_cl = \
            #     clgd.get_grid_point_coordinates().transpose((1, 2, 3, 0))
            cind = (self.qm.corner1 / np.diag(clgd.h_cv) - 1).astype(int)

            n = big_qm_g.shape

            # print 'Corner points:     ', self.qm.corner1*Bohr, \
            #     ' - ', self.qm.corner2*Bohr
            # print 'Calculated points: ', r_gv_cl[tuple(cind)]*Bohr, \
            #     ' - ', r_gv_cl[tuple(cind+n+1)]*Bohr

            big_cl_g[cind[0] + 1:cind[0] + n[0] + 1,
                     cind[1] + 1:cind[1] + n[1] + 1,
                     cind[2] + 1:cind[2] + n[2] + 1] += big_qm_g

        clgd.distribute(big_cl_g, cl_g)
        return cl_g, clgd

    # Solve quantum and classical potentials, and add them up
    def solve_solve(self, **kwargs):
        self.phi_tot_qmgd, self.phi_tot_clgd, niter = \
            self.potential_coupler.getPotential(
                local_rho_qm_qmgd=self.qm.rho,
                local_rho_cl_clgd=self.classical_material.sign *
                self.classical_material.charge_density,
                **kwargs)
        self.qm.phi[:] = self.phi_tot_qmgd[:]
        self.cl.phi[:] = self.phi_tot_clgd[:]
        return niter

    # Iterate classical and quantum potentials until convergence
    def solve_iterate(self, **kwargs):
        # Initial value (unefficient?)
        self.solve_solve(**kwargs)
        old_rho_qm = self.qm.rho.copy()
        old_rho_cl = self.classical_material.charge_density.copy()

        niter_cl = 0

        while True:
            # field from the potential
            # E = -Div[Vh]
            self.classical_material.solve_electric_field(self.cl.phi)

            # Polarizations P0_j and Ptot
            # P = (eps - eps0)E
            self.classical_material.solve_polarizations()

            # Classical charge density
            # n = -Grad[P]
            self.classical_material.solve_rho()

            # Update electrostatic potential
            # nabla^2 Vh = -4*pi*n
            niter = self.solve_solve(**kwargs)

            # Mix potential
            try:
                self.mix_phi
            except:
                self.mix_phi = SimpleMixer(0.10, self.qm.phi)

            self.qm.phi = self.mix_phi.mix(self.qm.phi)

            # Check convergence
            niter_cl += 1

            dRho = self.qm.gd.integrate(abs(self.qm.rho - old_rho_qm)) + \
                self.cl.gd.integrate(
                    abs(self.classical_material.charge_density - old_rho_cl))

            if (abs(dRho) < 1e-3):
                break
            old_rho_qm = self.qm.rho.copy()
            old_rho_cl = (self.classical_material.sign *
                          self.classical_material.charge_density).copy()

        return (niter, niter_cl)

    def solve_propagate(self, **kwargs):

        # 1) P(t) from P(t-dt) and J(t-dt/2)
        self.classical_material.propagate_polarizations(self.time_step)

        # 2) n(t) from P(t)
        self.classical_material.solve_rho()

        # 3a) V(t) from n(t)
        niter = self.solve_solve(**kwargs)

        # 4a) E(r) from V(t):      E = -Div[Vh]
        self.classical_material.solve_electric_field(self.cl.phi)

        # 4b) Apply the kick by changing the electric field
        if self.time == 0:
            self.cl.rho_gs = self.classical_material.charge_density.copy()
            self.qm.rho_gs = self.qm.rho.copy()
            self.cl.phi_gs = self.cl.phi.copy()
            self.cl.extrapolated_qm_phi_gs = self.cl.gd.zeros()
            self.qm.phi_gs = self.qm.phi.copy()
            self.classical_material.kick_electric_field(self.time_step,
                                                        self.kick)

        # 5) J(t+dt/2) from J(t-dt/2) and P(t)
        self.classical_material.propagate_currents(self.time_step)

        # Update timer
        self.time = self.time + self.time_step

        # Do not propagate before the next time step
        self.set_calculation_mode('solve')

        return niter

    def solve(self,
              phi,
              rho,
              charge=None,
              eps=None,
              maxcharge=1e-6,
              zero_initial_phi=False,
              calculation_mode=None,
              timer=None):

        if self.density is None:
            raise RuntimeError('FDTDPoissonSolver requires a density object.'
                               ' Use set_density routine to initialize it.')

        # Update local variables (which may
        # have changed in SCF cycle or propagator)
        self.qm.phi = phi
        self.qm.rho = rho

        if (self.calculation_mode == 'solve'):
            # do not modify the polarizable material
            niter = self.solve_solve(charge=None,
                                     eps=eps,
                                     maxcharge=maxcharge,
                                     zero_initial_phi=False)

        elif (self.calculation_mode == 'iterate'):
            # find self-consistent density
            niter = self.solve_iterate(charge=None,
                                       eps=eps,
                                       maxcharge=maxcharge,
                                       zero_initial_phi=False)

        elif (self.calculation_mode == 'propagate'):
            # propagate one time step
            niter = self.solve_propagate(charge=None,
                                         eps=eps,
                                         maxcharge=maxcharge,
                                         zero_initial_phi=False)

        phi = self.qm.phi
        rho = self.qm.rho

        return niter

    # Classical contribution. Note the different origin.
    def get_classical_dipole_moment(self):
        r_gv = self.cl.gd.get_grid_point_coordinates().transpose((
            1, 2, 3, 0)) - self.qm.corner1
        return -1.0 * self.classical_material.sign * np.array(
            [self.cl.gd.integrate(np.multiply(
                r_gv[:, :, :, w] + self.qm.corner1[w],
                self.classical_material.charge_density)) for w in range(3)])

    # Quantum contribution
    def get_quantum_dipole_moment(self):
        return self.density.finegd.calculate_dipole_moment(self.density.rhot_g)

    # Read restart data
    def read(self, reader):
        r = reader.hamiltonian.poisson

        # FDTDPoissonSolver related data
        self.description = r.description
        self.time = r.time
        self.time_step = r.time_step

        # Try to read time-dependent information
        self.kick = r.kick
        self.maxiter = r.maxiter

        # PoissonOrganizer: classical
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = r.cl_spacing_def
        self.cl.spacing = r.cl_spacing
        self.cl.cell = np.diag(r.cl_cell)
        self.cl.dparsize = None

        # TODO: it should be possible to use different
        #       communicator after restart
        if r.cl_world_comm:
            self.cl.dcomm = world
        else:
            self.cl.dcomm = mpi.serial_comm

        # Generate classical grid descriptor
        self.initialize_clgd()

        # Classical materials data
        self.classical_material = PolarizableMaterial()
        self.classical_material.read(r)
        self.classical_material.initialize(self.cl.gd)

        # PoissonOrganizer: quantum
        self.qm = PoissonOrganizer()
        self.qm.corner1 = r.qm_corner1
        self.qm.corner2 = r.qm_corner2
        self.given_corner_v1 = r.given_corner_1
        self.given_corner_v2 = r.given_corner_2
        self.given_cell = np.diag(r.given_cell)
        self.hratios = r.hratios
        self.shift_indices_1 = r.shift_indices_1.astype(int)
        self.shift_indices_2 = r.shift_indices_2.astype(int)
        self.num_indices = r.num_indices.astype(int)
        self.num_refinements = int(r.num_refinements)

        # Redefine atoms to suit the cut_cell routine
        newatoms = read_atoms(reader.atoms)
        newatoms.positions = newatoms.positions + self.qm.corner1 * Bohr
        newatoms.set_cell(np.diag(self.given_cell))
        self.create_subsystems(newatoms)

        # Read self.classical_material.charge_density
        if self.cl.gd.comm.rank == 0:
            big_charge_density = \
                np.array(r.get('classical_material_rho'), dtype=float)
        else:
            big_charge_density = None
        self.cl.gd.distribute(big_charge_density,
                              self.classical_material.charge_density)

        # Read self.classical_material.polarization_total
        if self.cl.gd.comm.rank == 0:
            big_polarization_total = \
                np.array(r.get('polarization_total'), dtype=float)
        else:
            big_polarization_total = None
        self.cl.gd.distribute(big_polarization_total,
                              self.classical_material.polarization_total)

        # Read self.classical_material.polarizations
        if self.cl.gd.comm.rank == 0:
            big_polarizations = np.array(r.get('polarizations'), dtype=float)
        else:
            big_polarizations = None
        self.cl.gd.distribute(big_polarizations,
                              self.classical_material.polarizations)

        # Read self.classical_material.currents
        if self.cl.gd.comm.rank == 0:
            big_currents = np.array(r.get('currents'), dtype=float)
        else:
            big_currents = None
        self.cl.gd.distribute(big_currents, self.classical_material.currents)

    def write(self, writer):
        # Classical materials data
        self.classical_material.write(writer.child('classmat'))

        # FDTDPoissonSolver related data
        writer.write(
            description=self.get_description(),
            time=self.time,
            time_step=self.time_step,
            kick=self.kick,
            maxiter=self.maxiter,
            # PoissonOrganizer
            cl_cell=np.diag(self.cl.cell),
            cl_spacing_def=self.cl.spacing_def,
            cl_spacing=self.cl.spacing,
            cl_world_comm=self.cl.dcomm == world,
            qm_corner1=self.qm.corner1,
            qm_corner2=self.qm.corner2,
            given_corner_1=self.given_corner_v1,
            given_corner_2=self.given_corner_v2,
            given_cell=np.diag(self.given_cell),
            hratios=self.hratios,
            shift_indices_1=self.shift_indices_1,
            shift_indices_2=self.shift_indices_2,
            num_refinements=self.num_refinements,
            num_indices=self.num_indices)

        # Write the classical charge density
        charge_density = self.cl.gd.collect(
            self.classical_material.charge_density)
        writer.write(classical_material_rho=charge_density)

        # Write the total polarization
        polarization_total = self.cl.gd.collect(
            self.classical_material.polarization_total)
        writer.write(polarization_total=polarization_total)

        # Write the partial polarizations
        polarizations = self.cl.gd.collect(
            self.classical_material.polarizations)
        writer.write(polarizations=polarizations)

        # Write the partial currents
        currents = self.cl.gd.collect(self.classical_material.currents)
        writer.write(currents=currents)
Пример #5
0
from gpaw.fdtd.poisson_fdtd import QSFDTD
from gpaw.fdtd.polarizable_material import PermittivityPlus, PolarizableMaterial, \
    PolarizableSphere, PolarizableBox, \
    PolarizableEllipsoid, PolarizableRod, \
    PolarizableTetrahedron
from gpaw.test import equal

# Whole simulation cell (Angstroms)
cell = [40, 40, 20]

# Classical subsystem
classical_material = PolarizableMaterial()
classical_material.add_component(
    PolarizableSphere(permittivity=PermittivityPlus(data=[[1.20, 0.20, 25.0]]),
                      center=[10, 10, 10],
                      radius=4.5))
classical_material.add_component(
    PolarizableBox(permittivity=PermittivityPlus(data=[[1.40, 0.20, 25.0]]),
                   corner1=[18.1, 5.1, 5.1],
                   corner2=[22.9, 14.9, 14.9]))
classical_material.add_component(
    PolarizableEllipsoid(
        permittivity=PermittivityPlus(data=[[1.60, 0.20, 25.0]]),
        center=[30.0, 10.0, 10.0],
        radii=[3.9, 5.9, 4.9]))
classical_material.add_component(
    PolarizableRod(permittivity=PermittivityPlus(data=[[1.80, 0.20, 25.0]]),
                   corners=[[10.0, 21.5, 10.0], [10.0, 33.5, 10.0]],
                   round_corners=True,
                   radius=3.9))
classical_material.add_component(
from gpaw.mpi import world
from gpaw.tddft import photoabsorption_spectrum, units
from gpaw.test import equal
import numpy as np

# Whole simulation cell (Angstroms)
cell = [20, 20, 30];

# Quantum subsystem
atom_center = np.array([10.0, 10.0, 20.0]);
atoms = Atoms('Na2', [atom_center + [0.0, 0.0, -1.50],
                      atom_center + [0.0, 0.0, +1.50]]);

# Classical subsystem
sphere_center = np.array([10.0, 10.0, 10.0]);
classical_material = PolarizableMaterial()
classical_material.add_component(PolarizableSphere(permittivity = PermittivityPlus(data = [[1.20, 0.20, 25.0]]),
                                                   center = sphere_center,
                                                   radius = 5.0
                                                   ))

# Wrap calculators
qsfdtd = QSFDTD(classical_material = classical_material,
                atoms              = atoms,
                cells              = (cell, 2.50),
                spacings           = [1.60, 0.40],
                remove_moments     = (1, 4),
                communicator       = world)

# Run
energy = qsfdtd.ground_state('gs.gpw', eigensolver = 'cg', nbands = -1)
Пример #7
0
class FDTDPoissonSolver:
    def __init__(self,
                 nn=3,
                 relax='J',
                 eps=1e-24,
                 classical_material=None,
                 cell=None,
                 qm_spacing=0.30,
                 cl_spacing=1.20,
                 remove_moments=(1, 1),
                 potential_coupler='Refiner',
                 communicator=serial_comm,
                 restart_reader=None,
                 paw=None):

        self.rank = mpi.rank

        self.messages = []

        if restart_reader is not None:  # restart
            assert paw is not None
            self.read(paw=paw, reader=restart_reader)
            return  # we are ready

        assert (potential_coupler in ['Multipoles', 'Refiner'])
        self.potential_coupling_scheme = potential_coupler

        if classical_material is None:
            self.classical_material = PolarizableMaterial()
        else:
            self.classical_material = classical_material

        self.set_calculation_mode('solve')

        self.remove_moment_cl = remove_moments[0]
        self.remove_moment_qm = remove_moments[1]
        self.time = 0.0
        self.time_step = 0.0
        self.kick = np.array([0.0, 0.0, 0.0], dtype=float)
        self.maxiter = 2000
        self.eps = eps
        self.relax = relax
        self.nn = nn

        # Only handle the quantities via self.qm or self.cl
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = cl_spacing * np.ones(3) / Bohr
        self.cl.extrapolated_qm_phi = None
        self.cl.dcomm = communicator
        self.cl.dparsize = None
        self.qm = PoissonOrganizer(PoissonSolver)  # Default solver
        self.qm.spacing_def = qm_spacing * np.ones(3) / Bohr
        self.qm.cell = np.array(cell) / Bohr

        # Classical spacing and simulation cell
        _cell = np.array(cell) / Bohr
        self.cl.spacing = self.cl.spacing_def
        if np.size(_cell) == 3:
            self.cl.cell = np.diag(_cell)
        else:
            self.cl.cell = _cell

        # Generate classical grid descriptor
        self.initialize_clgd()

    def get_description(self):
        return 'FDTD+TDDFT'

    # Generated classical GridDescriptors, after spacing and cell are known
    def initialize_clgd(self):
        N_c = get_number_of_grid_points(self.cl.cell, self.cl.spacing)
        self.cl.spacing = np.diag(self.cl.cell) / N_c
        self.cl.gd = GridDescriptor(N_c, self.cl.cell, False, self.cl.dcomm,
                                    self.cl.dparsize)
        self.cl.gd_global = GridDescriptor(N_c, self.cl.cell, False,
                                           serial_comm, None)
        self.cl.extrapolated_qm_phi = self.cl.gd.empty()

    def estimate_memory(self, mem):
        #self.cl.poisson_solver.estimate_memory(mem)
        self.qm.poisson_solver.estimate_memory(mem)

    # Return the TDDFT stencil by default
    def get_stencil(self, mode='qm'):
        if mode == 'qm':
            return self.qm.poisson_solver.get_stencil()
        else:
            return self.cl.poisson_solver.get_stencil()

    # Initialize both PoissonSolvers
    def initialize(self, load_Gauss=False):
        self.qm.poisson_solver.initialize(load_Gauss)
        self.cl.poisson_solver.initialize(load_Gauss)

    def set_grid_descriptor(self, qmgd):

        self.qm.gd = qmgd

        # Create quantum Poisson solver
        self.qm.poisson_solver = PoissonSolver(
            nn=self.nn,
            eps=self.eps,
            relax=self.relax,
            remove_moment=self.remove_moment_qm)
        self.qm.poisson_solver.set_grid_descriptor(self.qm.gd)
        self.qm.poisson_solver.initialize()
        self.qm.phi = self.qm.gd.zeros()
        self.qm.rho = self.qm.gd.zeros()

        # Set quantum grid descriptor
        self.qm.poisson_solver.set_grid_descriptor(qmgd)

        # Create classical PoissonSolver
        self.cl.poisson_solver = PoissonSolver(
            nn=self.nn,
            eps=self.eps,
            relax=self.relax,
            remove_moment=self.remove_moment_cl)
        self.cl.poisson_solver.set_grid_descriptor(self.cl.gd)
        self.cl.poisson_solver.initialize()

        # Initialize classical material, its Poisson solver was generated already
        self.cl.poisson_solver.set_grid_descriptor(self.cl.gd)
        self.classical_material.initialize(self.cl.gd)
        self.cl.extrapolated_qm_phi = self.cl.gd.zeros()
        self.cl.phi = self.cl.gd.zeros()
        self.cl.extrapolated_qm_phi = self.cl.gd.empty()

        self.messages.append(
            '\nFDTDPoissonSolver/grid descriptors and coupler:')
        self.messages.append(' Domain parallelization with %i processes.' %
                             self.cl.gd.comm.size)
        if self.cl.gd.comm == serial_comm:
            self.messages.append(
                ' Communicator for domain parallelization: serial_comm')
        elif self.cl.gd.comm == world:
            self.messages.append(
                ' Communicator for domain parallelization: world')
        elif self.cl.gd.comm == self.qm.gd.comm:
            self.messages.append(
                ' Communicator for domain parallelization: dft_domain_comm')
        else:
            self.messages.append(
                ' Communicator for domain parallelization: %s' %
                self.cl.gd.comm)

        # Initialize potential coupler
        if self.potential_coupling_scheme == 'Multipoles':
            self.messages.append(
                'Classical-quantum coupling by multipole expansion with maxL: %i'
                % (self.remove_moment_qm))
            self.potential_coupler = MultipolesPotentialCoupler(
                qm=self.qm,
                cl=self.cl,
                index_offset_1=self.shift_indices_1,
                index_offset_2=self.shift_indices_2,
                extended_index_offset_1=self.extended_shift_indices_1,
                extended_index_offset_2=self.extended_shift_indices_2,
                extended_delta_index=self.extended_deltaIndex,
                num_refinements=self.num_refinements,
                remove_moment_qm=self.remove_moment_qm,
                remove_moment_cl=self.remove_moment_cl,
                rank=self.rank)
        else:
            self.messages.append(
                'Classical-quantum coupling by coarsening/refining')
            self.potential_coupler = RefinerPotentialCoupler(
                qm=self.qm,
                cl=self.cl,
                index_offset_1=self.shift_indices_1,
                index_offset_2=self.shift_indices_2,
                extended_index_offset_1=self.extended_shift_indices_1,
                extended_index_offset_2=self.extended_shift_indices_2,
                extended_delta_index=self.extended_deltaIndex,
                num_refinements=self.num_refinements,
                remove_moment_qm=self.remove_moment_qm,
                remove_moment_cl=self.remove_moment_cl,
                rank=self.rank)

        self.phi_tot_clgd = self.cl.gd.empty()
        self.phi_tot_qmgd = self.qm.gd.empty()

    def cut_cell(self,
                 atoms_in,
                 vacuum=5.0,
                 corners=None,
                 create_subsystems=True):
        qmh = self.qm.spacing_def
        if corners is not None:
            v1 = np.array(corners[0]).ravel() / Bohr
            v2 = np.array(corners[1]).ravel() / Bohr
        else:  # Use vacuum
            pos_old = atoms_in.get_positions()[0]
            dmy_atoms = atoms_in.copy()
            dmy_atoms.center(vacuum=vacuum)
            pos_new = dmy_atoms.get_positions()[0]
            v1 = (pos_old - pos_new) / Bohr
            v2 = v1 + np.diag(dmy_atoms.get_cell()) / Bohr

        # Needed for restarting
        self.given_corner_v1 = v1 * Bohr
        self.given_corner_v2 = v2 * Bohr
        self.given_cell = atoms_in.get_cell()

        # Sanity check: quantum box must be inside the classical one
        assert (all([
            v1[w] <= v2[w] and v1[w] >= 0 and v2[w] <= np.diag(self.cl.cell)[w]
            for w in range(3)
        ]))

        # Ratios of the user-given spacings
        self.hratios = self.cl.spacing_def / qmh
        self.num_refinements = 1 + int(
            round(np.log(self.hratios[0]) / np.log(2.0)))
        assert ([
            int(round(np.log(self.hratios[w]) /
                      np.log(2.0))) == self.num_refinements for w in range(3)
        ])

        # Create quantum grid
        self.qm.cell = np.zeros((3, 3))
        for w in range(3):
            self.qm.cell[w, w] = v2[w] - v1[w]

        N_c = get_number_of_grid_points(self.qm.cell, qmh)
        self.qm.spacing = np.diag(self.qm.cell) / N_c

        # Classical corner indices must be divisible with numb
        if any(self.cl.spacing / self.qm.spacing >= 3):
            numb = 1
        elif any(self.cl.spacing / self.qm.spacing >= 2):
            numb = 2
        else:
            numb = 4

        # The index mismatch of the two simulation cells
        self.num_indices = numb * np.ceil(
            (np.array(v2) - np.array(v1)) / self.cl.spacing / numb)

        self.num_indices_1 = numb * np.floor(
            np.array(v1) / self.cl.spacing / numb)
        self.num_indices_2 = numb * np.ceil(
            np.array(v2) / self.cl.spacing / numb)
        self.num_indices = self.num_indices_2 - self.num_indices_1

        # Center, left, and right points of the suggested quantum grid
        cp = 0.5 * (np.array(v1) + np.array(v2))
        lp = cp - 0.5 * self.num_indices * self.cl.spacing
        rp = cp + 0.5 * self.num_indices * self.cl.spacing

        # Indices in the classical grid restricting the quantum grid
        self.shift_indices_1 = np.round(lp / self.cl.spacing)
        self.shift_indices_2 = self.shift_indices_1 + self.num_indices

        # Sanity checks
        assert(all([self.shift_indices_1[w] >= 0 and
                    self.shift_indices_2[w] <= self.cl.gd.N_c[w] for w in range(3)])), \
                    "Could not find appropriate quantum grid. Move it further away from the boundary."

        # Corner coordinates
        self.qm.corner1 = self.shift_indices_1 * self.cl.spacing
        self.qm.corner2 = self.shift_indices_2 * self.cl.spacing

        # Now the information for creating the subsystems is ready
        if create_subsystems:
            return self.create_subsystems(atoms_in)

    def create_subsystems(self, atoms_in):

        # Create new Atoms object
        atoms_out = atoms_in.copy()

        # New quantum grid
        self.qm.cell = np.diag([
            (self.shift_indices_2[w] - self.shift_indices_1[w]) *
            self.cl.spacing[w] for w in range(3)
        ])
        self.qm.spacing = self.cl.spacing / self.hratios
        N_c = get_number_of_grid_points(self.qm.cell, self.qm.spacing)

        atoms_out.set_cell(np.diag(self.qm.cell) * Bohr)
        atoms_out.positions = atoms_in.get_positions() - self.qm.corner1 * Bohr

        self.messages.append("Quantum box readjustment:")
        self.messages.append("  Given cell:       [%10.5f %10.5f %10.5f]" %
                             tuple(np.diag(atoms_in.get_cell())))
        self.messages.append("  Given atomic coordinates:")
        for s, c in zip(atoms_in.get_chemical_symbols(),
                        atoms_in.get_positions()):
            self.messages.append("              %s %10.5f %10.5f %10.5f" %
                                 (s, c[0], c[1], c[2]))
        self.messages.append("  Readjusted cell:  [%10.5f %10.5f %10.5f]" %
                             tuple(np.diag(atoms_out.get_cell())))
        self.messages.append("  Readjusted atomic coordinates:")
        for s, c in zip(atoms_out.get_chemical_symbols(),
                        atoms_out.get_positions()):
            self.messages.append("              %s %10.5f %10.5f %10.5f" %
                                 (s, c[0], c[1], c[2]))

        self.messages.append(
            "  Given corner points:       (%10.5f %10.5f %10.5f) - (%10.5f %10.5f %10.5f)"
            %
            (tuple(np.concatenate(
                (self.given_corner_v1, self.given_corner_v2)))))
        self.messages.append(
            "  Readjusted corner points:  (%10.5f %10.5f %10.5f) - (%10.5f %10.5f %10.5f)"
            %
            (tuple(np.concatenate((self.qm.corner1, self.qm.corner2)) * Bohr)))
        self.messages.append(
            "  Indices in classical grid: (%10i %10i %10i) - (%10i %10i %10i)"
            %
            (tuple(np.concatenate(
                (self.shift_indices_1, self.shift_indices_2)))))
        self.messages.append(
            "  Grid points in classical grid: (%10i %10i %10i)" %
            (tuple(self.cl.gd.N_c)))
        self.messages.append(
            "  Grid points in quantum grid:   (%10i %10i %10i)" % (tuple(N_c)))

        self.messages.append(
            "  Spacings in quantum grid:    (%10.5f %10.5f %10.5f)" %
            (tuple(np.diag(self.qm.cell) * Bohr / N_c)))
        self.messages.append("  Spacings in classical grid:  (%10.5f %10.5f %10.5f)" %
                 (tuple(np.diag(self.cl.cell) * Bohr / \
                        get_number_of_grid_points(self.cl.cell, self.cl.spacing))))
        #self.messages.append("  Ratios of cl/qm spacings:    (%10i %10i %10i)" % (tuple(self.hratios)))
        #self.messages.append("                             = (%10.2f %10.2f %10.2f)" %
        #         (tuple((np.diag(self.cl.cell) * Bohr / \
        #                 get_number_of_grid_points(self.cl.cell,
        #                                           self.cl.spacing)) / \
        #                (np.diag(self.qm.cell) * Bohr / N_c))))
        self.messages.append("  Needed number of refinements: %10i" %
                             self.num_refinements)

        #   First, create the quantum grid equivalent GridDescriptor self.cl.subgd.
        #   Then coarsen it until its h_cv equals that of self.cl.gd.
        #   Finally, map the points between clgd and coarsened subgrid.
        subcell_cv = np.diag(self.qm.corner2 - self.qm.corner1)
        N_c = get_number_of_grid_points(subcell_cv, self.cl.spacing)
        N_c = self.shift_indices_2 - self.shift_indices_1
        self.cl.subgds = []
        self.cl.subgds.append(
            GridDescriptor(N_c, subcell_cv, False, serial_comm,
                           self.cl.dparsize))

        #self.messages.append("  N_c/spacing of the subgrid:           %3i %3i %3i / %.4f %.4f %.4f" %
        #          (self.cl.subgds[0].N_c[0],
        #           self.cl.subgds[0].N_c[1],
        #           self.cl.subgds[0].N_c[2],
        #           self.cl.subgds[0].h_cv[0][0] * Bohr,
        #           self.cl.subgds[0].h_cv[1][1] * Bohr,
        #           self.cl.subgds[0].h_cv[2][2] * Bohr))
        #self.messages.append("  shape from the subgrid:           %3i %3i %3i" % (tuple(self.cl.subgds[0].empty().shape)))

        self.cl.coarseners = []
        self.cl.refiners = []
        for n in range(self.num_refinements):
            self.cl.subgds.append(self.cl.subgds[n].refine())
            self.cl.refiners.append(
                Transformer(self.cl.subgds[n], self.cl.subgds[n + 1]))

            #self.messages.append("  refiners[%i] can perform the transformation (%3i %3i %3i) -> (%3i %3i %3i)" % (\
            #         n,
            #         self.cl.subgds[n].empty().shape[0],
            #         self.cl.subgds[n].empty().shape[1],
            #         self.cl.subgds[n].empty().shape[2],
            #         self.cl.subgds[n + 1].empty().shape[0],
            #         self.cl.subgds[n + 1].empty().shape[1],
            #         self.cl.subgds[n + 1].empty().shape[2]))
            self.cl.coarseners.append(
                Transformer(self.cl.subgds[n + 1], self.cl.subgds[n]))
        self.cl.coarseners[:] = self.cl.coarseners[::-1]

        # Now extend the grid in order to handle the zero boundary conditions that the refiner assumes
        # The default interpolation order
        self.extend_nn = Transformer(
            GridDescriptor([8, 8, 8], [1, 1, 1], False, serial_comm, None),
            GridDescriptor([8, 8, 8], [1, 1, 1], False, serial_comm,
                           None).coarsen()).nn

        self.extended_num_indices = self.num_indices + [2, 2, 2]

        # Center, left, and right points of the suggested quantum grid
        extended_cp = 0.5 * (np.array(self.given_corner_v1 / Bohr) +
                             np.array(self.given_corner_v2 / Bohr))
        extended_lp = extended_cp - 0.5 * (
            self.extended_num_indices) * self.cl.spacing
        extended_rp = extended_cp + 0.5 * (
            self.extended_num_indices) * self.cl.spacing

        # Indices in the classical grid restricting the quantum grid
        self.extended_shift_indices_1 = np.round(extended_lp / self.cl.spacing)
        self.extended_shift_indices_2 = self.extended_shift_indices_1 + self.extended_num_indices

        #self.messages.append('  extended_shift_indices_1: %i %i %i' % (self.extended_shift_indices_1[0],self.extended_shift_indices_1[1], self.extended_shift_indices_1[2]))
        #self.messages.append('  extended_shift_indices_2: %i %i %i' % (self.extended_shift_indices_2[0],self.extended_shift_indices_2[1], self.extended_shift_indices_2[2]))
        #self.messages.append('  cl.gd.N_c:                %i %i %i' % (self.cl.gd.N_c[0], self.cl.gd.N_c[1], self.cl.gd.N_c[2]))

        # Sanity checks
        assert(all([self.extended_shift_indices_1[w] >= 0 and
                    self.extended_shift_indices_2[w] <= self.cl.gd.N_c[w] for w in range(3)])), \
                    "Could not find appropriate quantum grid. Move it further away from the boundary."

        # Corner coordinates
        self.qm.extended_corner1 = self.extended_shift_indices_1 * self.cl.spacing
        self.qm.extended_corner2 = self.extended_shift_indices_2 * self.cl.spacing
        N_c = self.extended_shift_indices_2 - self.extended_shift_indices_1

        self.cl.extended_subgds = []
        self.cl.extended_refiners = []
        extended_subcell_cv = np.diag(self.qm.extended_corner2 -
                                      self.qm.extended_corner1)

        self.cl.extended_subgds.append(
            GridDescriptor(N_c, extended_subcell_cv, False, serial_comm, None))

        for n in range(self.num_refinements):
            self.cl.extended_subgds.append(self.cl.extended_subgds[n].refine())
            self.cl.extended_refiners.append(
                Transformer(self.cl.extended_subgds[n],
                            self.cl.extended_subgds[n + 1]))
            #self.messages.append("  extended_refiners[%i] can perform the transformation (%3i %3i %3i) -> (%3i %3i %3i)" %
            #        (n,
            #         self.cl.extended_subgds[n].empty().shape[0],
            #         self.cl.extended_subgds[n].empty().shape[1],
            #         self.cl.extended_subgds[n].empty().shape[2],
            #         self.cl.extended_subgds[n + 1].empty().shape[0],
            #         self.cl.extended_subgds[n + 1].empty().shape[1],
            #         self.cl.extended_subgds[n + 1].empty().shape[2]))

        #self.messages.append("  N_c/spacing of the refined subgrid:   %3i %3i %3i / %.4f %.4f %.4f" %
        #          (self.cl.subgds[-1].N_c[0],
        #           self.cl.subgds[-1].N_c[1],
        #           self.cl.subgds[-1].N_c[2],
        #           self.cl.subgds[-1].h_cv[0][0] * Bohr,
        #           self.cl.subgds[-1].h_cv[1][1] * Bohr,
        #           self.cl.subgds[-1].h_cv[2][2] * Bohr))
        #self.messages.append("  shape from the refined subgrid:       %3i %3i %3i" %
        #         (tuple(self.cl.subgds[-1].empty().shape)))

        self.extended_deltaIndex = 2**(self.num_refinements) * self.extend_nn
        #self.messages.append(" self.extended_deltaIndex = %i" % self.extended_deltaIndex)

        qgpts = self.cl.subgds[-1].coarsen().N_c

        # Assure that one returns to the original shape
        dmygd = self.cl.subgds[-1].coarsen()
        for n in range(self.num_refinements - 1):
            dmygd = dmygd.coarsen()

        #self.messages.append("  N_c/spacing of the coarsened subgrid: %3i %3i %3i / %.4f %.4f %.4f" %
        #          (dmygd.N_c[0], dmygd.N_c[1], dmygd.N_c[2],
        #           dmygd.h_cv[0][0] * Bohr, dmygd.h_cv[1][1] * Bohr, dmygd.h_cv[2][2] * Bohr))

        return atoms_out, self.qm.spacing[0] * Bohr, qgpts

    def print_messages(self, printer_function):
        printer_function("\n *** QSFDTD ***\n")
        for msg in self.messages:
            printer_function(msg)

        for msg in self.classical_material.messages:
            printer_function(msg)
        printer_function("\n *********************\n")

    # Set the time step
    def set_time_step(self, time_step):
        self.time_step = time_step

    # Set the time
    def set_time(self, time):
        self.time = time

    # Setup kick
    def set_kick(self, kick):
        self.kick = np.array(kick)

    def finalize_propagation(self):
        pass

    def set_calculation_mode(self, calculation_mode):
        # Three calculation modes are available:
        #  1) solve:     just solve the Poisson equation with
        #                given quantum+classical rho
        #  2) iterate:   iterate classical density so that the Poisson
        #                equation for quantum+classical rho is satisfied
        #  3) propagate: propagate classical density in time, and solve
        #                the new Poisson equation
        assert (calculation_mode == 'solve' or calculation_mode == 'iterate'
                or calculation_mode == 'propagate')
        self.calculation_mode = calculation_mode

    # The density object must be attached, so that the electric field
    # from all-electron density can be calculated
    def set_density(self, density):
        self.density = density

    # Returns the classical density and the grid descriptor
    def get_density(self, global_array=False):
        if global_array:
            return self.cl.gd.collect(self.classical_material.charge_density) * \
                   self.classical_material.sign, \
                   self.cl.gd
        else:
            return self.classical_material.charge_density * \
                   self.classical_material.sign, \
                   self.cl.gd

    # Returns the quantum + classical density in the large classical box,
    # so that the classical charge is coarsened into it and the quantum
    # charge is refined there
    def get_combined_data(self, qmdata=None, cldata=None, spacing=None):

        if qmdata is None:
            qmdata = self.density.rhot_g

        if cldata is None:
            cldata = self.classical_material.charge_density

        if spacing is None:
            spacing = self.cl.gd.h_cv[0, 0]

        spacing_au = spacing / Bohr  # from Angstroms to a.u.

        # Collect data from different processes
        cln = self.cl.gd.collect(cldata)
        qmn = self.qm.gd.collect(qmdata)

        clgd = GridDescriptor(self.cl.gd.N_c, self.cl.cell, False, serial_comm,
                              None)

        if world.rank == 0:
            cln *= self.classical_material.sign
            # refine classical part
            while clgd.h_cv[0, 0] > spacing_au * 1.50:  # 45:
                cln = Transformer(clgd, clgd.refine()).apply(cln)
                clgd = clgd.refine()

            # refine quantum part
            qmgd = GridDescriptor(self.qm.gd.N_c, self.qm.cell, False,
                                  serial_comm, None)
            while qmgd.h_cv[0, 0] < clgd.h_cv[0, 0] * 0.95:
                qmn = Transformer(qmgd, qmgd.coarsen()).apply(qmn)
                qmgd = qmgd.coarsen()

            assert np.all(qmgd.h_cv == clgd.h_cv
                          ), " Spacings %.8f (qm) and %.8f (cl) Angstroms" % (
                              qmgd.h_cv[0][0] * Bohr, clgd.h_cv[0][0] * Bohr)

            # now find the corners
            r_gv_cl = clgd.get_grid_point_coordinates().transpose((1, 2, 3, 0))
            cind = self.qm.corner1 / np.diag(clgd.h_cv) - 1

            n = qmn.shape

            # print 'Corner points:     ', self.qm.corner1*Bohr,      ' - ', self.qm.corner2*Bohr
            # print 'Calculated points: ', r_gv_cl[tuple(cind)]*Bohr, ' - ', r_gv_cl[tuple(cind+n+1)]*Bohr

            cln[cind[0] + 1:cind[0] + n[0] + 1, cind[1] + 1:cind[1] + n[1] + 1,
                cind[2] + 1:cind[2] + n[2] + 1] += qmn

        world.barrier()
        return cln, clgd

    # Solve quantum and classical potentials, and add them up
    def solve_solve(self, **kwargs):
        self.phi_tot_qmgd, self.phi_tot_clgd, niter = self.potential_coupler.getPotential(
            local_rho_qm_qmgd=self.qm.rho,
            local_rho_cl_clgd=self.classical_material.sign *
            self.classical_material.charge_density,
            **kwargs)
        self.qm.phi[:] = self.phi_tot_qmgd[:]
        self.cl.phi[:] = self.phi_tot_clgd[:]
        return niter

    # Iterate classical and quantum potentials until convergence
    def solve_iterate(self, **kwargs):
        # Initial value (unefficient?)
        self.solve_solve(**kwargs)
        old_rho_qm = self.qm.rho.copy()
        old_rho_cl = self.classical_material.charge_density.copy()

        niter_cl = 0

        while True:
            # field from the potential
            self.classical_material.solve_electric_field(
                self.cl.phi)  # E = -Div[Vh]

            # Polarizations P0_j and Ptot
            self.classical_material.solve_polarizations()  # P = (eps - eps0)E

            # Classical charge density
            self.classical_material.solve_rho()  # n = -Grad[P]

            # Update electrostatic potential         # nabla^2 Vh = -4*pi*n
            niter = self.solve_solve(**kwargs)

            # Mix potential
            try:
                self.mix_phi
            except:
                self.mix_phi = SimpleMixer(0.10, self.qm.phi)

            self.qm.phi = self.mix_phi.mix(self.qm.phi)

            # Check convergence
            niter_cl += 1

            dRho = self.qm.gd.integrate(abs(self.qm.rho - old_rho_qm)) + \
                    self.cl.gd.integrate(abs(self.classical_material.charge_density - old_rho_cl))

            if (abs(dRho) < 1e-3):
                break
            old_rho_qm = rho.copy()
            old_rho_cl = (self.classical_material.sign *
                          self.classical_material.charge_density).copy()

        return (niter, niter_cl)

    def solve_propagate(self, **kwargs):

        # 1) P(t) from P(t-dt) and J(t-dt/2)
        self.classical_material.propagate_polarizations(self.time_step)

        # 2) n(t) from P(t)
        self.classical_material.solve_rho()

        # 3a) V(t) from n(t)
        niter = self.solve_solve(**kwargs)

        # 4a) E(r) from V(t):      E = -Div[Vh]
        self.classical_material.solve_electric_field(self.cl.phi)

        # 4b) Apply the kick by changing the electric field
        if self.time == 0:
            self.cl.rho_gs = self.classical_material.charge_density.copy()
            self.qm.rho_gs = self.qm.rho.copy()
            self.cl.phi_gs = self.cl.phi.copy()
            self.cl.extrapolated_qm_phi_gs = self.cl.gd.zeros()
            self.qm.phi_gs = self.qm.phi.copy()
            self.classical_material.kick_electric_field(
                self.time_step, self.kick)

        # 5) J(t+dt/2) from J(t-dt/2) and P(t)
        self.classical_material.propagate_currents(self.time_step)

        # Update timer
        self.time = self.time + self.time_step

        # Do not propagate before the next time step
        self.set_calculation_mode('solve')

        return niter

    def solve(self,
              phi,
              rho,
              charge=None,
              eps=None,
              maxcharge=1e-6,
              zero_initial_phi=False,
              calculation_mode=None):

        if self.density is None:
            print 'FDTDPoissonSolver requires a density object.' \
                  ' Use set_density routine to initialize it.'
            raise

        # Update local variables (which may have changed in SCF cycle or propagator)
        self.qm.phi = phi
        self.qm.rho = rho

        if (self.calculation_mode == 'solve'
            ):  # do not modify the polarizable material
            niter = self.solve_solve(charge=None,
                                     eps=eps,
                                     maxcharge=maxcharge,
                                     zero_initial_phi=False)

        elif (self.calculation_mode == 'iterate'
              ):  # find self-consistent density
            niter = self.solve_iterate(charge=None,
                                       eps=eps,
                                       maxcharge=maxcharge,
                                       zero_initial_phi=False)

        elif (self.calculation_mode == 'propagate'):  # propagate one time step
            niter = self.solve_propagate(charge=None,
                                         eps=eps,
                                         maxcharge=maxcharge,
                                         zero_initial_phi=False)

        phi = self.qm.phi
        rho = self.qm.rho

        return niter

    # Classical contribution. Note the different origin.
    def get_classical_dipole_moment(self):
        r_gv = self.cl.gd.get_grid_point_coordinates().transpose(
            (1, 2, 3, 0)) - self.qm.corner1
        return -1.0 * self.classical_material.sign * np.array([
            self.cl.gd.integrate(
                np.multiply(r_gv[:, :, :, w] + self.qm.corner1[w],
                            self.classical_material.charge_density))
            for w in range(3)
        ])

    # Quantum contribution
    def get_quantum_dipole_moment(self):
        return self.density.finegd.calculate_dipole_moment(self.density.rhot_g)

    # Read restart data
    def read(self, paw, reader):
        r = reader

        version = r['version']

        # Helper function
        def read_vector(v):
            return np.array([
                float(x) for x in v.replace('[', '').replace(']', '').split()
            ])

        # FDTDPoissonSolver related data
        self.eps = r['fdtd.eps']
        self.nn = r['fdtd.nn']
        self.relax = r['fdtd.relax']
        self.potential_coupling_scheme = r['fdtd.coupling_scheme']
        self.description = r['fdtd.description']
        self.remove_moment_qm = int(r['fdtd.remove_moment_qm'])
        self.remove_moment_cl = int(r['fdtd.remove_moment_cl'])
        self.time = float(r['fdtd.time'])
        self.time_step = float(r['fdtd.time_step'])

        # Try to read time-dependent information
        self.kick = read_vector(r['fdtd.kick'])
        self.maxiter = int(r['fdtd.maxiter'])

        # PoissonOrganizer: classical
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = read_vector(r['fdtd.cl_spacing_def'])
        self.cl.spacing = read_vector(r['fdtd.cl_spacing'])
        self.cl.cell = np.diag(read_vector(r['fdtd.cl_cell']))
        self.cl.dparsize = None

        # TODO: it should be possible to use different
        #       communicator after restart
        if r['fdtd.cl_world_comm']:
            self.cl.dcomm = world
        else:
            self.cl.dcomm = mpi.serial_comm

        # Generate classical grid descriptor
        self.initialize_clgd()

        # Classical materials data
        self.classical_material = PolarizableMaterial()
        self.classical_material.read(r)
        self.classical_material.initialize(self.cl.gd)

        # PoissonOrganizer: quantum
        self.qm = PoissonOrganizer()
        self.qm.corner1 = read_vector(r['fdtd.qm_corner1'])
        self.qm.corner2 = read_vector(r['fdtd.qm_corner2'])
        self.given_corner_v1 = read_vector(r['fdtd.given_corner_1'])
        self.given_corner_v2 = read_vector(r['fdtd.given_corner_2'])
        self.given_cell = np.diag(read_vector(r['fdtd.given_cell']))
        self.hratios = read_vector(r['fdtd.hratios'])
        self.shift_indices_1 = read_vector(r['fdtd.shift_indices_1'])
        self.shift_indices_2 = read_vector(r['fdtd.shift_indices_2'])
        self.num_indices = read_vector(r['fdtd.num_indices'])
        self.num_refinements = int(r['fdtd.num_refinements'])

        # Redefine atoms to suit the cut_cell routine
        newatoms = paw.atoms.copy()
        newatoms.positions = newatoms.positions + self.qm.corner1 * Bohr
        newatoms.set_cell(np.diag(self.given_cell))
        self.create_subsystems(newatoms)

        # Read self.classical_material.charge_density
        if self.cl.gd.comm.rank == 0:
            big_charge_density = np.array(r.get('classical_material_rho'),
                                          dtype=float)
        else:
            big_charge_density = None
        self.cl.gd.distribute(big_charge_density,
                              self.classical_material.charge_density)

        # Read self.classical_material.polarization_total
        if self.cl.gd.comm.rank == 0:
            big_polarization_total = np.array(r.get('polarization_total'),
                                              dtype=float)
        else:
            big_polarization_total = None
        self.cl.gd.distribute(big_polarization_total,
                              self.classical_material.polarization_total)

        # Read self.classical_material.polarizations
        if self.cl.gd.comm.rank == 0:
            big_polarizations = np.array(r.get('polarizations'), dtype=float)
        else:
            big_polarizations = None
        self.cl.gd.distribute(big_polarizations,
                              self.classical_material.polarizations)

        # Read self.classical_material.currents
        if self.cl.gd.comm.rank == 0:
            big_currents = np.array(r.get('currents'), dtype=float)
        else:
            big_currents = None
        self.cl.gd.distribute(big_currents, self.classical_material.currents)

    # Write restart data
    def write(self, paw, writer):  #                     filename='poisson'):
        rho = self.classical_material.charge_density
        world = paw.wfs.world
        domain_comm = self.cl.gd.comm
        kpt_comm = paw.wfs.kd.comm
        band_comm = paw.wfs.band_comm
        master = (world.rank == 0)
        parallel = (world.size > 1)
        #w = gpaw_io_open(filename, 'w', world)
        w = writer

        # Classical materials data
        w['classmat.num_components'] = len(self.classical_material.components)
        self.classical_material.write(w)

        # FDTDPoissonSolver related data
        w['fdtd.eps'] = self.eps
        w['fdtd.nn'] = self.nn
        w['fdtd.relax'] = self.relax
        w['fdtd.coupling_scheme'] = self.potential_coupling_scheme
        w['fdtd.description'] = self.get_description()
        w['fdtd.remove_moment_qm'] = self.remove_moment_qm
        w['fdtd.remove_moment_cl'] = self.remove_moment_cl
        w['fdtd.time'] = self.time
        w['fdtd.time_step'] = self.time_step
        w['fdtd.kick'] = self.kick
        w['fdtd.maxiter'] = self.maxiter

        # PoissonOrganizer
        w['fdtd.cl_cell'] = np.diag(self.cl.cell)
        w['fdtd.cl_spacing_def'] = self.cl.spacing_def
        w['fdtd.cl_spacing'] = self.cl.spacing
        w['fdtd.cl_world_comm'] = self.cl.dcomm == world

        w['fdtd.qm_corner1'] = self.qm.corner1
        w['fdtd.qm_corner2'] = self.qm.corner2
        w['fdtd.given_corner_1'] = self.given_corner_v1
        w['fdtd.given_corner_2'] = self.given_corner_v2
        w['fdtd.given_cell'] = np.diag(self.given_cell)
        w['fdtd.hratios'] = self.hratios
        w['fdtd.shift_indices_1'] = self.shift_indices_1
        w['fdtd.shift_indices_2'] = self.shift_indices_2
        w['fdtd.num_refinements'] = self.num_refinements
        w['fdtd.num_indices'] = self.num_indices

        # Create dimensions for various netCDF variables:
        ng = self.cl.gd.get_size_of_global_array()

        # Write the classical charge density
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('classical_material_rho', ('nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            charge_density = self.cl.gd.collect(
                self.classical_material.charge_density)
            if master:
                w.fill(charge_density)

        # Write the total polarization
        w.dimension('3', 3)
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('polarization_total', ('3', 'nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            polarization_total = self.cl.gd.collect(
                self.classical_material.polarization_total)
            if master:
                w.fill(polarization_total)

        # Write the partial polarizations
        w.dimension('3', 3)
        w.dimension('Nj', self.classical_material.Nj)
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('polarizations', ('3', 'Nj', 'nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            polarizations = self.cl.gd.collect(
                self.classical_material.polarizations)
            if master:
                w.fill(polarizations)

        # Write the partial currents
        w.dimension('3', 3)
        w.dimension('Nj', self.classical_material.Nj)
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('currents', ('3', 'Nj', 'nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            currents = self.cl.gd.collect(self.classical_material.currents)
            if master:
                w.fill(currents)
    def __init__(self, nn=3,
                       relax='J',
                       eps=1e-24,
                       classical_material=None,
                       cell=None,
                       qm_spacing=0.30,
                       cl_spacing=1.20,
                       remove_moments=(1, 1),
                       potential_coupler='Refiner',
                       communicator=serial_comm,
                       restart_reader=None,
                       paw=None):

        self.rank = mpi.rank

        self.messages = []

        if restart_reader is not None: # restart
            assert paw is not None
            self.read(paw = paw, reader=restart_reader)
            return # we are ready
            
        assert(potential_coupler in ['Multipoles', 'Refiner'])
        self.potential_coupling_scheme = potential_coupler
        
        if classical_material is None:
            self.classical_material = PolarizableMaterial()
        else:
            self.classical_material = classical_material
        
        self.set_calculation_mode('solve')
        
        self.remove_moment_cl = remove_moments[0]
        self.remove_moment_qm = remove_moments[1]
        self.time = 0.0
        self.time_step = 0.0
        self.kick = np.array([0.0, 0.0, 0.0], dtype=float)
        self.maxiter = 2000
        self.eps = eps
        self.relax= relax
        self.nn = nn
        
        # Only handle the quantities via self.qm or self.cl 
        self.cl = PoissonOrganizer()        
        self.cl.spacing_def = cl_spacing * np.ones(3) / Bohr
        self.cl.extrapolated_qm_phi = None
        self.cl.dcomm = communicator
        self.cl.dparsize = None
        self.qm = PoissonOrganizer(PoissonSolver)  # Default solver
        self.qm.spacing_def = qm_spacing * np.ones(3) / Bohr
        self.qm.cell = np.array(cell) / Bohr
        
        # Classical spacing and simulation cell
        _cell = np.array(cell) / Bohr
        self.cl.spacing = self.cl.spacing_def
        if np.size(_cell) == 3:
            self.cl.cell = np.diag(_cell)
        else:
            self.cl.cell = _cell

        # Generate classical grid descriptor
        self.initialize_clgd()
Пример #9
0
atoms = Atoms('Na2', atom_center + np.array([[-1.5, 0.0, 0.0],
                                             [1.5, 0.0, 0.0]]))

# Permittivity of Gold
# J. Chem. Phys. 135, 084121 (2011); http://dx.doi.org/10.1063/1.3626549
eps_gold = PermittivityPlus(data=[[0.2350, 0.1551, 95.62],
                                  [0.4411, 0.1480, -12.55],
                                  [0.7603, 1.946, -40.89],
                                  [1.161, 1.396, 17.22],
                                  [2.946, 1.183, 15.76],
                                  [4.161, 1.964, 36.63],
                                  [5.747, 1.958, 22.55],
                                  [7.912, 1.361, 81.04]])

# 1) Nanosphere only
classical_material = PolarizableMaterial()
classical_material.add_component(PolarizableSphere(center=sphere_center,
                                                   radius=radius,
                                                   permittivity=eps_gold))

qsfdtd = QSFDTD(classical_material=classical_material,
                atoms=None,
                cells=simulation_cell,
                spacings=[2.0, 0.5],
                remove_moments=(1, 1))

energy = qsfdtd.ground_state('gs.gpw',
                             nbands=1)

qsfdtd.time_propagation('gs.gpw',
                        kick_strength=[0.001, 0.000, 0.000],
Пример #10
0
# This test does the same calculation as ed.py, but using QSFDTD wrapper instead

# Accuracy
energy_eps = 0.0005

# Whole simulation cell (Angstroms)
cell = [20, 20, 30]

# Quantum subsystem
atom_center = np.array([10.0, 10.0, 20.0])
atoms = Atoms(
    'Na2', [atom_center + [0.0, 0.0, -1.50], atom_center + [0.0, 0.0, +1.50]])

# Classical subsystem
sphere_center = np.array([10.0, 10.0, 10.0])
classical_material = PolarizableMaterial()
classical_material.add_component(
    PolarizableSphere(permittivity=PermittivityPlus(data=[[1.20, 0.20, 25.0]]),
                      center=sphere_center,
                      radius=5.0))

# Wrap calculators
qsfdtd = QSFDTD(classical_material=classical_material,
                atoms=atoms,
                cells=(cell, 2.50),
                spacings=[1.60, 0.40],
                remove_moments=(1, 4),
                communicator=world)

# Run
qsfdtd.ground_state('gs.gpw',
large_cell = np.array([3.0 * radius, 3.0 * radius, 3.0 * radius])

# Permittivity of Gold (from  J. Chem. Phys. 137, 074113 (2012))
gold = [
    [0.2350, 0.1551, 95.62],
    [0.4411, 0.1480, -12.55],
    [0.7603, 1.946, -40.89],
    [1.161, 1.396, 17.22],
    [2.946, 1.183, 15.76],
    [4.161, 1.964, 36.63],
    [5.747, 1.958, 22.55],
    [7.912, 1.361, 81.04],
]

# Initialize classical material
classical_material = PolarizableMaterial()

# Classical nanosphere
classical_material.add_component(
    PolarizableSphere(center=0.5 * large_cell, radius=radius, permittivity=PermittivityPlus(data=gold))
)

# Quasistatic FDTD
qsfdtd = QSFDTD(
    classical_material=classical_material,
    atoms=None,
    cells=large_cell,
    spacings=[8.0, 1.0],
    communicator=world,
    remove_moments=(4, 1),
)
Пример #12
0
    PolarizableSphere,
    PolarizableBox,
    PolarizableEllipsoid,
    PolarizableRod,
    PolarizableTetrahedron,
)
from gpaw.mpi import world
from gpaw.tddft import photoabsorption_spectrum, units
from gpaw.test import equal
import numpy as np

# Whole simulation cell (Angstroms)
cell = [40, 40, 20]

# Classical subsystem
classical_material = PolarizableMaterial()
classical_material.add_component(
    PolarizableSphere(permittivity=PermittivityPlus(data=[[1.20, 0.20, 25.0]]), center=[10, 10, 10], radius=4.5)
)
classical_material.add_component(
    PolarizableBox(
        permittivity=PermittivityPlus(data=[[1.40, 0.20, 25.0]]), corner1=[18.1, 5.1, 5.1], corner2=[22.9, 14.9, 14.9]
    )
)
classical_material.add_component(
    PolarizableEllipsoid(
        permittivity=PermittivityPlus(data=[[1.60, 0.20, 25.0]]), center=[30.0, 10.0, 10.0], radii=[3.9, 5.9, 4.9]
    )
)
classical_material.add_component(
    PolarizableRod(
    def read(self, paw, reader):
        r = reader

        version = r['version']

        # Helper function
        def read_vector(v):
            return np.array([float(x) for x in v.replace('[','').replace(']','').split()])
        
        # FDTDPoissonSolver related data
        self.eps = r['fdtd.eps']
        self.nn = r['fdtd.nn']
        self.relax = r['fdtd.relax']
        self.potential_coupling_scheme = r['fdtd.coupling_scheme']
        self.description = r['fdtd.description']
        self.remove_moment_qm = int(r['fdtd.remove_moment_qm'])
        self.remove_moment_cl = int(r['fdtd.remove_moment_cl'])
        self.time = float(r['fdtd.time'])
        self.time_step = float(r['fdtd.time_step'])
        
        # Try to read time-dependent information
        self.kick = read_vector(r['fdtd.kick'])
        self.maxiter = int(r['fdtd.maxiter'])
        
        # PoissonOrganizer: classical
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = read_vector(r['fdtd.cl_spacing_def'])
        self.cl.spacing = read_vector(r['fdtd.cl_spacing'])
        self.cl.cell = np.diag(read_vector(r['fdtd.cl_cell']))
        self.cl.dparsize = None
        
        # TODO: it should be possible to use different
        #       communicator after restart
        if r['fdtd.cl_world_comm']:
            self.cl.dcomm = world
        else:
            self.cl.dcomm = mpi.serial_comm
        
        # Generate classical grid descriptor
        self.initialize_clgd()
        
        # Classical materials data
        self.classical_material = PolarizableMaterial()
        self.classical_material.read(r)
        self.classical_material.initialize(self.cl.gd)
        
        # PoissonOrganizer: quantum
        self.qm = PoissonOrganizer()
        self.qm.corner1 = read_vector(r['fdtd.qm_corner1'])
        self.qm.corner2 = read_vector(r['fdtd.qm_corner2'])
        self.given_corner_v1 = read_vector(r['fdtd.given_corner_1'])
        self.given_corner_v2 = read_vector(r['fdtd.given_corner_2'])
        self.given_cell = np.diag(read_vector(r['fdtd.given_cell']))
        self.hratios = read_vector(r['fdtd.hratios'])
        self.shift_indices_1 = read_vector(r['fdtd.shift_indices_1'])
        self.shift_indices_2 = read_vector(r['fdtd.shift_indices_2'])
        self.num_indices = read_vector(r['fdtd.num_indices'])
        self.num_refinements = int(r['fdtd.num_refinements'])
        
        # Redefine atoms to suit the cut_cell routine
        newatoms = paw.atoms.copy()
        newatoms.positions = newatoms.positions + self.qm.corner1*Bohr
        newatoms.set_cell(np.diag(self.given_cell))
        self.create_subsystems(newatoms)
        
        # Read self.classical_material.charge_density
        if self.cl.gd.comm.rank == 0:
            big_charge_density = np.array(r.get('classical_material_rho'), dtype=float)
        else:
            big_charge_density = None
        self.cl.gd.distribute(big_charge_density, self.classical_material.charge_density)
        
        # Read self.classical_material.polarization_total
        if self.cl.gd.comm.rank == 0:
            big_polarization_total = np.array(r.get('polarization_total'), dtype=float)
        else:
            big_polarization_total = None
        self.cl.gd.distribute(big_polarization_total, self.classical_material.polarization_total)
        
        # Read self.classical_material.polarizations
        if self.cl.gd.comm.rank == 0:
            big_polarizations = np.array(r.get('polarizations'),
                                         dtype=float)
        else:
            big_polarizations = None
        self.cl.gd.distribute(big_polarizations, self.classical_material.polarizations)
        
        # Read self.classical_material.currents
        if self.cl.gd.comm.rank == 0:
            big_currents = np.array(r.get('currents'),
                                         dtype=float)
        else:
            big_currents = None
        self.cl.gd.distribute(big_currents, self.classical_material.currents)                
Пример #14
0
large_cell = [20, 20, 30]

# Quantum subsystem
atom_center = np.array([10.0, 10.0, 20.0])
atoms = Atoms(
    'Na2', [atom_center + [0.0, 0.0, -1.50], atom_center + [0.0, 0.0, +1.50]])

# Permittivity file
if world.rank == 0:
    fo = open('ed.txt', 'w')
    fo.writelines(['1.20 0.20 25.0'])
    fo.close()
world.barrier()

# Classical subsystem
classical_material = PolarizableMaterial()
sphere_center = np.array([10.0, 10.0, 10.0])
classical_material.add_component(
    PolarizableSphere(permittivity=PermittivityPlus('ed.txt'),
                      center=sphere_center,
                      radius=5.0))

# Combined Poisson solver
poissonsolver = FDTDPoissonSolver(classical_material=classical_material,
                                  qm_spacing=0.40,
                                  cl_spacing=0.40 * 4,
                                  cell=large_cell,
                                  remove_moments=(1, 4),
                                  communicator=world,
                                  potential_coupler='Refiner')
poissonsolver.set_calculation_mode('iterate')
Пример #15
0
    def read(self, paw, reader):
        r = reader

        version = r['version']

        # Helper function
        def read_vector(v):
            return np.array([
                float(x) for x in v.replace('[', '').replace(']', '').split()
            ])

        # FDTDPoissonSolver related data
        self.eps = r['fdtd.eps']
        self.nn = r['fdtd.nn']
        self.relax = r['fdtd.relax']
        self.potential_coupling_scheme = r['fdtd.coupling_scheme']
        self.description = r['fdtd.description']
        self.remove_moment_qm = int(r['fdtd.remove_moment_qm'])
        self.remove_moment_cl = int(r['fdtd.remove_moment_cl'])
        self.time = float(r['fdtd.time'])
        self.time_step = float(r['fdtd.time_step'])

        # Try to read time-dependent information
        self.kick = read_vector(r['fdtd.kick'])
        self.maxiter = int(r['fdtd.maxiter'])

        # PoissonOrganizer: classical
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = read_vector(r['fdtd.cl_spacing_def'])
        self.cl.spacing = read_vector(r['fdtd.cl_spacing'])
        self.cl.cell = np.diag(read_vector(r['fdtd.cl_cell']))
        self.cl.dparsize = None

        # TODO: it should be possible to use different
        #       communicator after restart
        if r['fdtd.cl_world_comm']:
            self.cl.dcomm = world
        else:
            self.cl.dcomm = mpi.serial_comm

        # Generate classical grid descriptor
        self.initialize_clgd()

        # Classical materials data
        self.classical_material = PolarizableMaterial()
        self.classical_material.read(r)
        self.classical_material.initialize(self.cl.gd)

        # PoissonOrganizer: quantum
        self.qm = PoissonOrganizer()
        self.qm.corner1 = read_vector(r['fdtd.qm_corner1'])
        self.qm.corner2 = read_vector(r['fdtd.qm_corner2'])
        self.given_corner_v1 = read_vector(r['fdtd.given_corner_1'])
        self.given_corner_v2 = read_vector(r['fdtd.given_corner_2'])
        self.given_cell = np.diag(read_vector(r['fdtd.given_cell']))
        self.hratios = read_vector(r['fdtd.hratios'])
        self.shift_indices_1 = read_vector(r['fdtd.shift_indices_1'])
        self.shift_indices_2 = read_vector(r['fdtd.shift_indices_2'])
        self.num_indices = read_vector(r['fdtd.num_indices'])
        self.num_refinements = int(r['fdtd.num_refinements'])

        # Redefine atoms to suit the cut_cell routine
        newatoms = paw.atoms.copy()
        newatoms.positions = newatoms.positions + self.qm.corner1 * Bohr
        newatoms.set_cell(np.diag(self.given_cell))
        self.create_subsystems(newatoms)

        # Read self.classical_material.charge_density
        if self.cl.gd.comm.rank == 0:
            big_charge_density = np.array(r.get('classical_material_rho'),
                                          dtype=float)
        else:
            big_charge_density = None
        self.cl.gd.distribute(big_charge_density,
                              self.classical_material.charge_density)

        # Read self.classical_material.polarization_total
        if self.cl.gd.comm.rank == 0:
            big_polarization_total = np.array(r.get('polarization_total'),
                                              dtype=float)
        else:
            big_polarization_total = None
        self.cl.gd.distribute(big_polarization_total,
                              self.classical_material.polarization_total)

        # Read self.classical_material.polarizations
        if self.cl.gd.comm.rank == 0:
            big_polarizations = np.array(r.get('polarizations'), dtype=float)
        else:
            big_polarizations = None
        self.cl.gd.distribute(big_polarizations,
                              self.classical_material.polarizations)

        # Read self.classical_material.currents
        if self.cl.gd.comm.rank == 0:
            big_currents = np.array(r.get('currents'), dtype=float)
        else:
            big_currents = None
        self.cl.gd.distribute(big_currents, self.classical_material.currents)
Пример #16
0
# Whole simulation cell (Angstroms)
large_cell = np.array([3 * radius, 3 * radius, 3 * radius])

# Permittivity of Gold
# J. Chem. Phys. 135, 084121 (2011); http://dx.doi.org/10.1063/1.3626549
gold = [[0.2350, 0.1551, 95.62],
        [0.4411, 0.1480, -12.55],
        [0.7603, 1.946, -40.89],
        [1.161, 1.396, 17.22],
        [2.946, 1.183, 15.76],
        [4.161, 1.964, 36.63],
        [5.747, 1.958, 22.55],
        [7.912, 1.361, 81.04]]

# Initialize classical material
classical_material = PolarizableMaterial()

# Classical nanosphere
classical_material.add_component(
    PolarizableSphere(center=0.5 * large_cell,
                      radius=radius,
                      permittivity=PermittivityPlus(data=gold)))

# Quasistatic FDTD
qsfdtd = QSFDTD(classical_material=classical_material,
                atoms=None,
                cells=large_cell,
                spacings=[8.0, 1.0],
                communicator=world,
                remove_moments=(4, 1))
class FDTDPoissonSolver:
    def __init__(self, nn=3,
                       relax='J',
                       eps=1e-24,
                       classical_material=None,
                       cell=None,
                       qm_spacing=0.30,
                       cl_spacing=1.20,
                       remove_moments=(1, 1),
                       potential_coupler='Refiner',
                       communicator=serial_comm,
                       restart_reader=None,
                       paw=None):

        self.rank = mpi.rank

        self.messages = []

        if restart_reader is not None: # restart
            assert paw is not None
            self.read(paw = paw, reader=restart_reader)
            return # we are ready
            
        assert(potential_coupler in ['Multipoles', 'Refiner'])
        self.potential_coupling_scheme = potential_coupler
        
        if classical_material is None:
            self.classical_material = PolarizableMaterial()
        else:
            self.classical_material = classical_material
        
        self.set_calculation_mode('solve')
        
        self.remove_moment_cl = remove_moments[0]
        self.remove_moment_qm = remove_moments[1]
        self.time = 0.0
        self.time_step = 0.0
        self.kick = np.array([0.0, 0.0, 0.0], dtype=float)
        self.maxiter = 2000
        self.eps = eps
        self.relax= relax
        self.nn = nn
        
        # Only handle the quantities via self.qm or self.cl 
        self.cl = PoissonOrganizer()        
        self.cl.spacing_def = cl_spacing * np.ones(3) / Bohr
        self.cl.extrapolated_qm_phi = None
        self.cl.dcomm = communicator
        self.cl.dparsize = None
        self.qm = PoissonOrganizer(PoissonSolver)  # Default solver
        self.qm.spacing_def = qm_spacing * np.ones(3) / Bohr
        self.qm.cell = np.array(cell) / Bohr
        
        # Classical spacing and simulation cell
        _cell = np.array(cell) / Bohr
        self.cl.spacing = self.cl.spacing_def
        if np.size(_cell) == 3:
            self.cl.cell = np.diag(_cell)
        else:
            self.cl.cell = _cell

        # Generate classical grid descriptor
        self.initialize_clgd()

    def get_description(self):
        return 'FDTD+TDDFT'

    # Generated classical GridDescriptors, after spacing and cell are known
    def initialize_clgd(self):
        N_c = get_number_of_grid_points(self.cl.cell, self.cl.spacing)
        self.cl.spacing = np.diag(self.cl.cell) / N_c
        self.cl.gd = GridDescriptor(N_c,
                                    self.cl.cell,
                                    False,
                                    self.cl.dcomm,
                                    self.cl.dparsize)
        self.cl.gd_global = GridDescriptor(N_c,
                                           self.cl.cell,
                                           False,
                                           serial_comm,
                                           None)
        self.cl.extrapolated_qm_phi = self.cl.gd.empty()

    def estimate_memory(self, mem):
        #self.cl.poisson_solver.estimate_memory(mem)
        self.qm.poisson_solver.estimate_memory(mem)

    # Return the TDDFT stencil by default 
    def get_stencil(self, mode='qm'):
        if mode=='qm':
            return self.qm.poisson_solver.get_stencil()
        else:
            return self.cl.poisson_solver.get_stencil()

    # Initialize both PoissonSolvers
    def initialize(self, load_Gauss=False):
        self.qm.poisson_solver.initialize(load_Gauss)
        self.cl.poisson_solver.initialize(load_Gauss)     

    def set_grid_descriptor(self, qmgd):

        self.qm.gd = qmgd
        
        # Create quantum Poisson solver
        self.qm.poisson_solver = PoissonSolver(nn=self.nn,
                                               eps=self.eps,
                                               relax=self.relax,
                                               remove_moment=self.remove_moment_qm)
        self.qm.poisson_solver.set_grid_descriptor(self.qm.gd)
        self.qm.poisson_solver.initialize()
        self.qm.phi = self.qm.gd.zeros()
        self.qm.rho = self.qm.gd.zeros()

        # Set quantum grid descriptor
        self.qm.poisson_solver.set_grid_descriptor(qmgd)

        # Create classical PoissonSolver
        self.cl.poisson_solver = PoissonSolver(nn=self.nn,
                                               eps=self.eps,
                                               relax=self.relax,
                                               remove_moment=self.remove_moment_cl)
        self.cl.poisson_solver.set_grid_descriptor(self.cl.gd)
        self.cl.poisson_solver.initialize()
        
        # Initialize classical material, its Poisson solver was generated already
        self.cl.poisson_solver.set_grid_descriptor(self.cl.gd)
        self.classical_material.initialize(self.cl.gd)
        self.cl.extrapolated_qm_phi = self.cl.gd.zeros()
        self.cl.phi = self.cl.gd.zeros()
        self.cl.extrapolated_qm_phi = self.cl.gd.empty()
        
        self.messages.append('\nFDTDPoissonSolver/grid descriptors and coupler:')
        self.messages.append(' Domain parallelization with %i processes.' % self.cl.gd.comm.size)
        if self.cl.gd.comm==serial_comm:
            self.messages.append(' Communicator for domain parallelization: serial_comm')
        elif self.cl.gd.comm==world:
            self.messages.append(' Communicator for domain parallelization: world')
        elif self.cl.gd.comm==self.qm.gd.comm:
            self.messages.append(' Communicator for domain parallelization: dft_domain_comm')
        else:
            self.messages.append(' Communicator for domain parallelization: %s' % self.cl.gd.comm)

        # Initialize potential coupler
        if self.potential_coupling_scheme == 'Multipoles':
            self.messages.append('Classical-quantum coupling by multipole expansion with maxL: %i' % (self.remove_moment_qm))
            self.potential_coupler = MultipolesPotentialCoupler(qm = self.qm,
                                                                cl = self.cl,
                                                                index_offset_1 = self.shift_indices_1,
                                                                index_offset_2 = self.shift_indices_2,
                                                                extended_index_offset_1 = self.extended_shift_indices_1,
                                                                extended_index_offset_2 = self.extended_shift_indices_2,
                                                                extended_delta_index = self.extended_deltaIndex,
                                                                num_refinements = self.num_refinements,
                                                                remove_moment_qm = self.remove_moment_qm,
                                                                remove_moment_cl = self.remove_moment_cl,
                                                                rank = self.rank)
        else:
            self.messages.append('Classical-quantum coupling by coarsening/refining')
            self.potential_coupler = RefinerPotentialCoupler(qm = self.qm,
                                                             cl = self.cl,
                                                             index_offset_1 = self.shift_indices_1,
                                                             index_offset_2 = self.shift_indices_2,
                                                             extended_index_offset_1 = self.extended_shift_indices_1,
                                                             extended_index_offset_2 = self.extended_shift_indices_2,
                                                             extended_delta_index = self.extended_deltaIndex,
                                                             num_refinements = self.num_refinements,
                                                             remove_moment_qm = self.remove_moment_qm,
                                                             remove_moment_cl = self.remove_moment_cl,
                                                             rank = self.rank)
            
        self.phi_tot_clgd = self.cl.gd.empty()
        self.phi_tot_qmgd = self.qm.gd.empty()

    def cut_cell(self, atoms_in, vacuum=5.0, corners=None, create_subsystems=True):
        qmh = self.qm.spacing_def
        if corners is not None:
            v1 = np.array(corners[0]).ravel() / Bohr
            v2 = np.array(corners[1]).ravel() / Bohr
        else: # Use vacuum
            pos_old = atoms_in.get_positions()[0];
            dmy_atoms = atoms_in.copy()
            dmy_atoms.center(vacuum=vacuum)
            pos_new = dmy_atoms.get_positions()[0];
            v1 = (pos_old - pos_new)/Bohr
            v2 = v1 + np.diag(dmy_atoms.get_cell())/Bohr

        # Needed for restarting
        self.given_corner_v1 = v1 * Bohr
        self.given_corner_v2 = v2 * Bohr
        self.given_cell = atoms_in.get_cell()

        # Sanity check: quantum box must be inside the classical one
        assert(all([v1[w] <= v2[w] and
                    v1[w] >= 0 and
                    v2[w] <= np.diag(self.cl.cell)[w] for w in range(3)]))
        
        # Ratios of the user-given spacings
        self.hratios = self.cl.spacing_def / qmh
        self.num_refinements = 1 + int(round(np.log(self.hratios[0]) / np.log(2.0)))
        assert([int(round(np.log(self.hratios[w]) / np.log(2.0))) == self.num_refinements for w in range(3)])

        # Create quantum grid
        self.qm.cell = np.zeros((3, 3))
        for w in range(3):
            self.qm.cell[w, w] = v2[w] - v1[w]
        
        N_c = get_number_of_grid_points(self.qm.cell, qmh)
        self.qm.spacing = np.diag(self.qm.cell) / N_c        

        # Classical corner indices must be divisible with numb
        if any(self.cl.spacing / self.qm.spacing >= 3):
            numb = 1
        elif any(self.cl.spacing / self.qm.spacing >= 2):
            numb = 2
        else:
            numb = 4
        
        # The index mismatch of the two simulation cells
        self.num_indices = numb * np.ceil((np.array(v2) -
                                           np.array(v1)) /
                                          self.cl.spacing / numb)
        
        self.num_indices_1 = numb * np.floor(np.array(v1) / self.cl.spacing / numb)
        self.num_indices_2 = numb * np.ceil(np.array(v2) / self.cl.spacing / numb)
        self.num_indices = self.num_indices_2 - self.num_indices_1
        
        # Center, left, and right points of the suggested quantum grid
        cp = 0.5 * (np.array(v1) + np.array(v2))
        lp = cp - 0.5 * self.num_indices * self.cl.spacing 
        rp = cp + 0.5 * self.num_indices * self.cl.spacing
                
        # Indices in the classical grid restricting the quantum grid
        self.shift_indices_1 = np.round(lp / self.cl.spacing)
        self.shift_indices_2 = self.shift_indices_1 + self.num_indices

        # Sanity checks
        assert(all([self.shift_indices_1[w] >= 0 and
                    self.shift_indices_2[w] <= self.cl.gd.N_c[w] for w in range(3)])), \
                    "Could not find appropriate quantum grid. Move it further away from the boundary."
        
        # Corner coordinates
        self.qm.corner1 = self.shift_indices_1 * self.cl.spacing
        self.qm.corner2 = self.shift_indices_2 * self.cl.spacing
        
        # Now the information for creating the subsystems is ready
        if create_subsystems:
            return self.create_subsystems(atoms_in)
    
    def create_subsystems(self, atoms_in):
        
        # Create new Atoms object
        atoms_out = atoms_in.copy()
        
        # New quantum grid
        self.qm.cell = np.diag([(self.shift_indices_2[w] - self.shift_indices_1[w])*self.cl.spacing[w] for w in range(3)])
        self.qm.spacing = self.cl.spacing / self.hratios
        N_c = get_number_of_grid_points(self.qm.cell, self.qm.spacing)
        
        atoms_out.set_cell(np.diag(self.qm.cell) * Bohr)
        atoms_out.positions = atoms_in.get_positions() - self.qm.corner1 * Bohr
        
        self.messages.append("Quantum box readjustment:")
        self.messages.append("  Given cell:       [%10.5f %10.5f %10.5f]" % tuple(np.diag(atoms_in.get_cell())))
        self.messages.append("  Given atomic coordinates:")
        for s, c in zip(atoms_in.get_chemical_symbols(), atoms_in.get_positions()):
            self.messages.append("              %s %10.5f %10.5f %10.5f" % (s, c[0], c[1], c[2]))
        self.messages.append("  Readjusted cell:  [%10.5f %10.5f %10.5f]" % tuple(np.diag(atoms_out.get_cell())))
        self.messages.append("  Readjusted atomic coordinates:")
        for s, c in zip(atoms_out.get_chemical_symbols(), atoms_out.get_positions()):
            self.messages.append("              %s %10.5f %10.5f %10.5f" % (s, c[0], c[1], c[2]))
        
        self.messages.append("  Given corner points:       (%10.5f %10.5f %10.5f) - (%10.5f %10.5f %10.5f)" %
                 (tuple(np.concatenate((self.given_corner_v1, self.given_corner_v2)))))
        self.messages.append("  Readjusted corner points:  (%10.5f %10.5f %10.5f) - (%10.5f %10.5f %10.5f)" %
                 (tuple(np.concatenate((self.qm.corner1,
                                        self.qm.corner2)) * Bohr)))
        self.messages.append("  Indices in classical grid: (%10i %10i %10i) - (%10i %10i %10i)" %
                 (tuple(np.concatenate((self.shift_indices_1,
                                        self.shift_indices_2)))))
        self.messages.append("  Grid points in classical grid: (%10i %10i %10i)" % (tuple(self.cl.gd.N_c)))
        self.messages.append("  Grid points in quantum grid:   (%10i %10i %10i)" % (tuple(N_c)))
        
        self.messages.append("  Spacings in quantum grid:    (%10.5f %10.5f %10.5f)" %
                 (tuple(np.diag(self.qm.cell) * Bohr / N_c)))
        self.messages.append("  Spacings in classical grid:  (%10.5f %10.5f %10.5f)" %
                 (tuple(np.diag(self.cl.cell) * Bohr / \
                        get_number_of_grid_points(self.cl.cell, self.cl.spacing))))
        #self.messages.append("  Ratios of cl/qm spacings:    (%10i %10i %10i)" % (tuple(self.hratios)))
        #self.messages.append("                             = (%10.2f %10.2f %10.2f)" %
        #         (tuple((np.diag(self.cl.cell) * Bohr / \
        #                 get_number_of_grid_points(self.cl.cell,
        #                                           self.cl.spacing)) / \
        #                (np.diag(self.qm.cell) * Bohr / N_c))))
        self.messages.append("  Needed number of refinements: %10i" % self.num_refinements)
        
        #   First, create the quantum grid equivalent GridDescriptor self.cl.subgd.
        #   Then coarsen it until its h_cv equals that of self.cl.gd.
        #   Finally, map the points between clgd and coarsened subgrid.
        subcell_cv = np.diag(self.qm.corner2 - self.qm.corner1)
        N_c = get_number_of_grid_points(subcell_cv, self.cl.spacing)
        N_c = self.shift_indices_2 - self.shift_indices_1
        self.cl.subgds = []
        self.cl.subgds.append(GridDescriptor(N_c, subcell_cv, False, serial_comm, self.cl.dparsize))

        #self.messages.append("  N_c/spacing of the subgrid:           %3i %3i %3i / %.4f %.4f %.4f" % 
        #          (self.cl.subgds[0].N_c[0],
        #           self.cl.subgds[0].N_c[1],
        #           self.cl.subgds[0].N_c[2],
        #           self.cl.subgds[0].h_cv[0][0] * Bohr,
        #           self.cl.subgds[0].h_cv[1][1] * Bohr,
        #           self.cl.subgds[0].h_cv[2][2] * Bohr))
        #self.messages.append("  shape from the subgrid:           %3i %3i %3i" % (tuple(self.cl.subgds[0].empty().shape)))

        self.cl.coarseners = []
        self.cl.refiners = []
        for n in range(self.num_refinements):
            self.cl.subgds.append(self.cl.subgds[n].refine())
            self.cl.refiners.append(Transformer(self.cl.subgds[n], self.cl.subgds[n + 1]))
            
            #self.messages.append("  refiners[%i] can perform the transformation (%3i %3i %3i) -> (%3i %3i %3i)" % (\
            #         n,
            #         self.cl.subgds[n].empty().shape[0],
            #         self.cl.subgds[n].empty().shape[1],
            #         self.cl.subgds[n].empty().shape[2],
            #         self.cl.subgds[n + 1].empty().shape[0],
            #         self.cl.subgds[n + 1].empty().shape[1],
            #         self.cl.subgds[n + 1].empty().shape[2]))
            self.cl.coarseners.append(Transformer(self.cl.subgds[n + 1], self.cl.subgds[n]))
        self.cl.coarseners[:] = self.cl.coarseners[::-1]
        
        # Now extend the grid in order to handle the zero boundary conditions that the refiner assumes
        # The default interpolation order
        self.extend_nn = Transformer(GridDescriptor([8, 8, 8], [1, 1, 1], False, serial_comm, None),
                                     GridDescriptor([8, 8, 8], [1, 1, 1], False, serial_comm, None).coarsen()).nn
        
        self.extended_num_indices = self.num_indices + [2, 2, 2]
        
        # Center, left, and right points of the suggested quantum grid
        extended_cp = 0.5 * (np.array(self.given_corner_v1/Bohr) + np.array(self.given_corner_v2/Bohr))
        extended_lp = extended_cp - 0.5 * (self.extended_num_indices) * self.cl.spacing 
        extended_rp = extended_cp + 0.5 * (self.extended_num_indices) * self.cl.spacing
        
        # Indices in the classical grid restricting the quantum grid
        self.extended_shift_indices_1 = np.round(extended_lp / self.cl.spacing)
        self.extended_shift_indices_2 = self.extended_shift_indices_1 + self.extended_num_indices

        #self.messages.append('  extended_shift_indices_1: %i %i %i' % (self.extended_shift_indices_1[0],self.extended_shift_indices_1[1], self.extended_shift_indices_1[2]))
        #self.messages.append('  extended_shift_indices_2: %i %i %i' % (self.extended_shift_indices_2[0],self.extended_shift_indices_2[1], self.extended_shift_indices_2[2]))
        #self.messages.append('  cl.gd.N_c:                %i %i %i' % (self.cl.gd.N_c[0], self.cl.gd.N_c[1], self.cl.gd.N_c[2]))

        # Sanity checks
        assert(all([self.extended_shift_indices_1[w] >= 0 and
                    self.extended_shift_indices_2[w] <= self.cl.gd.N_c[w] for w in range(3)])), \
                    "Could not find appropriate quantum grid. Move it further away from the boundary."
        
        # Corner coordinates
        self.qm.extended_corner1 = self.extended_shift_indices_1 * self.cl.spacing
        self.qm.extended_corner2 = self.extended_shift_indices_2 * self.cl.spacing
        N_c = self.extended_shift_indices_2 - self.extended_shift_indices_1
               
        self.cl.extended_subgds = []
        self.cl.extended_refiners = []
        extended_subcell_cv = np.diag(self.qm.extended_corner2 - self.qm.extended_corner1)

        self.cl.extended_subgds.append(GridDescriptor(N_c,
                                                      extended_subcell_cv,
                                                      False,
                                                      serial_comm,
                                                      None))
        
        for n in range(self.num_refinements):
            self.cl.extended_subgds.append(self.cl.extended_subgds[n].refine())
            self.cl.extended_refiners.append(Transformer(self.cl.extended_subgds[n], self.cl.extended_subgds[n + 1]))
            #self.messages.append("  extended_refiners[%i] can perform the transformation (%3i %3i %3i) -> (%3i %3i %3i)" %
            #        (n,
            #         self.cl.extended_subgds[n].empty().shape[0],
            #         self.cl.extended_subgds[n].empty().shape[1],
            #         self.cl.extended_subgds[n].empty().shape[2],
            #         self.cl.extended_subgds[n + 1].empty().shape[0],
            #         self.cl.extended_subgds[n + 1].empty().shape[1],
            #         self.cl.extended_subgds[n + 1].empty().shape[2]))
        
        #self.messages.append("  N_c/spacing of the refined subgrid:   %3i %3i %3i / %.4f %.4f %.4f" % 
        #          (self.cl.subgds[-1].N_c[0],
        #           self.cl.subgds[-1].N_c[1],
        #           self.cl.subgds[-1].N_c[2],
        #           self.cl.subgds[-1].h_cv[0][0] * Bohr,
        #           self.cl.subgds[-1].h_cv[1][1] * Bohr,
        #           self.cl.subgds[-1].h_cv[2][2] * Bohr))
        #self.messages.append("  shape from the refined subgrid:       %3i %3i %3i" % 
        #         (tuple(self.cl.subgds[-1].empty().shape)))
        
        self.extended_deltaIndex = 2 ** (self.num_refinements) * self.extend_nn
        #self.messages.append(" self.extended_deltaIndex = %i" % self.extended_deltaIndex)
        
        qgpts = self.cl.subgds[-1].coarsen().N_c
        
        # Assure that one returns to the original shape
        dmygd = self.cl.subgds[-1].coarsen()
        for n in range(self.num_refinements - 1):
            dmygd = dmygd.coarsen()
        
        #self.messages.append("  N_c/spacing of the coarsened subgrid: %3i %3i %3i / %.4f %.4f %.4f" % 
        #          (dmygd.N_c[0], dmygd.N_c[1], dmygd.N_c[2],
        #           dmygd.h_cv[0][0] * Bohr, dmygd.h_cv[1][1] * Bohr, dmygd.h_cv[2][2] * Bohr))
       
        return atoms_out, self.qm.spacing[0] * Bohr, qgpts

    def print_messages(self, printer_function):
        printer_function("\n *** QSFDTD ***\n")
        for msg in self.messages:
            printer_function(msg)
        
        for msg in self.classical_material.messages:
            printer_function(msg)
        printer_function("\n *********************\n")
   
    # Set the time step
    def set_time_step(self, time_step):
        self.time_step = time_step

    # Set the time
    def set_time(self, time):
        self.time = time

    # Setup kick
    def set_kick(self, kick):
        self.kick = np.array(kick)

    def finalize_propagation(self):
        pass
    
    def set_calculation_mode(self, calculation_mode):
        # Three calculation modes are available:
        #  1) solve:     just solve the Poisson equation with
        #                given quantum+classical rho
        #  2) iterate:   iterate classical density so that the Poisson
        #                equation for quantum+classical rho is satisfied
        #  3) propagate: propagate classical density in time, and solve
        #                the new Poisson equation
        assert(calculation_mode == 'solve' or
               calculation_mode == 'iterate' or
               calculation_mode == 'propagate')
        self.calculation_mode = calculation_mode

    # The density object must be attached, so that the electric field
    # from all-electron density can be calculated    
    def set_density(self, density):
        self.density = density
        
    # Returns the classical density and the grid descriptor
    def get_density(self, global_array=False):
        if global_array:
            return self.cl.gd.collect(self.classical_material.charge_density) * \
                   self.classical_material.sign, \
                   self.cl.gd
        else:
            return self.classical_material.charge_density * \
                   self.classical_material.sign, \
                   self.cl.gd
        
    # Returns the quantum + classical density in the large classical box,
    # so that the classical charge is coarsened into it and the quantum
    # charge is refined there
    def get_combined_data(self, qmdata=None, cldata=None, spacing=None):
        
        if qmdata is None:
            qmdata = self.density.rhot_g
        
        if cldata is None:
            cldata = self.classical_material.charge_density
        
        if spacing is None:
            spacing = self.cl.gd.h_cv[0, 0]
        
        spacing_au = spacing / Bohr  # from Angstroms to a.u.
        
        # Collect data from different processes
        cln = self.cl.gd.collect(cldata)
        qmn = self.qm.gd.collect(qmdata)

        clgd = GridDescriptor(self.cl.gd.N_c,
                              self.cl.cell,
                              False,
                              serial_comm,
                              None)

        if world.rank == 0:
            cln *= self.classical_material.sign
            # refine classical part
            while clgd.h_cv[0, 0] > spacing_au * 1.50:  # 45:
                cln = Transformer(clgd, clgd.refine()).apply(cln)
                clgd = clgd.refine()
                
            # refine quantum part
            qmgd = GridDescriptor(self.qm.gd.N_c,
                                  self.qm.cell,
                                  False,
                                  serial_comm,
                                  None)                           
            while qmgd.h_cv[0, 0] < clgd.h_cv[0, 0] * 0.95:
                qmn = Transformer(qmgd, qmgd.coarsen()).apply(qmn)
                qmgd = qmgd.coarsen()
            
            assert np.all(qmgd.h_cv == clgd.h_cv), " Spacings %.8f (qm) and %.8f (cl) Angstroms" % (qmgd.h_cv[0][0] * Bohr, clgd.h_cv[0][0] * Bohr)
            
            # now find the corners
            r_gv_cl = clgd.get_grid_point_coordinates().transpose((1, 2, 3, 0))
            cind = self.qm.corner1 / np.diag(clgd.h_cv) - 1
            
            n = qmn.shape

            # print 'Corner points:     ', self.qm.corner1*Bohr,      ' - ', self.qm.corner2*Bohr
            # print 'Calculated points: ', r_gv_cl[tuple(cind)]*Bohr, ' - ', r_gv_cl[tuple(cind+n+1)]*Bohr
                        
            cln[cind[0] + 1:cind[0] + n[0] + 1,
                cind[1] + 1:cind[1] + n[1] + 1,
                cind[2] + 1:cind[2] + n[2] + 1] += qmn
        
        world.barrier()
        return cln, clgd
            
    
    # Solve quantum and classical potentials, and add them up
    def solve_solve(self, **kwargs):
        self.phi_tot_qmgd, self.phi_tot_clgd, niter = self.potential_coupler.getPotential(local_rho_qm_qmgd = self.qm.rho, local_rho_cl_clgd = self.classical_material.sign * self.classical_material.charge_density, **kwargs)
        self.qm.phi[:] = self.phi_tot_qmgd[:]
        self.cl.phi[:] = self.phi_tot_clgd[:]
        return niter

 
    # Iterate classical and quantum potentials until convergence
    def solve_iterate(self, **kwargs):
        # Initial value (unefficient?) 
        self.solve_solve(**kwargs)
        old_rho_qm = self.qm.rho.copy()
        old_rho_cl = self.classical_material.charge_density.copy()
        
        niter_cl = 0
            
        while True:
            # field from the potential
            self.classical_material.solve_electric_field(self.cl.phi)  # E = -Div[Vh]

            # Polarizations P0_j and Ptot
            self.classical_material.solve_polarizations()  # P = (eps - eps0)E

            # Classical charge density
            self.classical_material.solve_rho()  # n = -Grad[P]
                
            # Update electrostatic potential         # nabla^2 Vh = -4*pi*n
            niter = self.solve_solve(**kwargs) 

            # Mix potential
            try:
                self.mix_phi
            except:
                self.mix_phi = SimpleMixer(0.10, self.qm.phi)

            self.qm.phi = self.mix_phi.mix(self.qm.phi)
                
            # Check convergence
            niter_cl += 1
            
            dRho = self.qm.gd.integrate(abs(self.qm.rho - old_rho_qm)) + \
                    self.cl.gd.integrate(abs(self.classical_material.charge_density - old_rho_cl))
            
            if(abs(dRho) < 1e-3):
                break
            old_rho_qm = rho.copy()
            old_rho_cl = (self.classical_material.sign * self.classical_material.charge_density).copy()

        return (niter, niter_cl)
        
            
    def solve_propagate(self, **kwargs):

        # 1) P(t) from P(t-dt) and J(t-dt/2)
        self.classical_material.propagate_polarizations(self.time_step)
                
        # 2) n(t) from P(t)
        self.classical_material.solve_rho()
        
        # 3a) V(t) from n(t)
        niter = self.solve_solve(**kwargs)
        
        # 4a) E(r) from V(t):      E = -Div[Vh]
        self.classical_material.solve_electric_field(self.cl.phi)
                
        # 4b) Apply the kick by changing the electric field
        if self.time == 0:
            self.cl.rho_gs = self.classical_material.charge_density.copy()
            self.qm.rho_gs = self.qm.rho.copy()
            self.cl.phi_gs = self.cl.phi.copy()
            self.cl.extrapolated_qm_phi_gs = self.cl.gd.zeros()
            self.qm.phi_gs = self.qm.phi.copy()
            self.classical_material.kick_electric_field(self.time_step, self.kick)
                    
        # 5) J(t+dt/2) from J(t-dt/2) and P(t)
        self.classical_material.propagate_currents(self.time_step)
                
        # Update timer
        self.time = self.time + self.time_step
                
        # Do not propagate before the next time step
        self.set_calculation_mode('solve')

        return niter
                                

    def solve(self, phi,
                    rho,
                    charge=None,
                    eps=None,
                    maxcharge=1e-6,
                    zero_initial_phi=False,
                    calculation_mode=None):

        if self.density is None:
            print 'FDTDPoissonSolver requires a density object.' \
                  ' Use set_density routine to initialize it.'
            raise

        # Update local variables (which may have changed in SCF cycle or propagator) 
        self.qm.phi = phi
        self.qm.rho = rho

        if(self.calculation_mode == 'solve'):  # do not modify the polarizable material
            niter = self.solve_solve(charge=None,
                                   eps=eps,
                                   maxcharge=maxcharge,
                                   zero_initial_phi=False)

        elif(self.calculation_mode == 'iterate'):  # find self-consistent density
            niter = self.solve_iterate(charge=None,
                                      eps=eps,
                                      maxcharge=maxcharge,
                                      zero_initial_phi=False)

        elif(self.calculation_mode == 'propagate'):  # propagate one time step
            niter = self.solve_propagate(charge=None,
                                        eps=eps,
                                        maxcharge=maxcharge,
                                        zero_initial_phi=False)

        phi = self.qm.phi
        rho = self.qm.rho

        return niter

    # Classical contribution. Note the different origin.
    def get_classical_dipole_moment(self):
        r_gv = self.cl.gd.get_grid_point_coordinates().transpose((1, 2, 3, 0)) - self.qm.corner1
        return -1.0 * self.classical_material.sign * np.array([self.cl.gd.integrate(np.multiply(r_gv[:, :, :, w] + self.qm.corner1[w], self.classical_material.charge_density)) for w in range(3)])

    # Quantum contribution
    def get_quantum_dipole_moment(self):
        return self.density.finegd.calculate_dipole_moment(self.density.rhot_g)

    # Read restart data
    def read(self, paw, reader):
        r = reader

        version = r['version']

        # Helper function
        def read_vector(v):
            return np.array([float(x) for x in v.replace('[','').replace(']','').split()])
        
        # FDTDPoissonSolver related data
        self.eps = r['fdtd.eps']
        self.nn = r['fdtd.nn']
        self.relax = r['fdtd.relax']
        self.potential_coupling_scheme = r['fdtd.coupling_scheme']
        self.description = r['fdtd.description']
        self.remove_moment_qm = int(r['fdtd.remove_moment_qm'])
        self.remove_moment_cl = int(r['fdtd.remove_moment_cl'])
        self.time = float(r['fdtd.time'])
        self.time_step = float(r['fdtd.time_step'])
        
        # Try to read time-dependent information
        self.kick = read_vector(r['fdtd.kick'])
        self.maxiter = int(r['fdtd.maxiter'])
        
        # PoissonOrganizer: classical
        self.cl = PoissonOrganizer()
        self.cl.spacing_def = read_vector(r['fdtd.cl_spacing_def'])
        self.cl.spacing = read_vector(r['fdtd.cl_spacing'])
        self.cl.cell = np.diag(read_vector(r['fdtd.cl_cell']))
        self.cl.dparsize = None
        
        # TODO: it should be possible to use different
        #       communicator after restart
        if r['fdtd.cl_world_comm']:
            self.cl.dcomm = world
        else:
            self.cl.dcomm = mpi.serial_comm
        
        # Generate classical grid descriptor
        self.initialize_clgd()
        
        # Classical materials data
        self.classical_material = PolarizableMaterial()
        self.classical_material.read(r)
        self.classical_material.initialize(self.cl.gd)
        
        # PoissonOrganizer: quantum
        self.qm = PoissonOrganizer()
        self.qm.corner1 = read_vector(r['fdtd.qm_corner1'])
        self.qm.corner2 = read_vector(r['fdtd.qm_corner2'])
        self.given_corner_v1 = read_vector(r['fdtd.given_corner_1'])
        self.given_corner_v2 = read_vector(r['fdtd.given_corner_2'])
        self.given_cell = np.diag(read_vector(r['fdtd.given_cell']))
        self.hratios = read_vector(r['fdtd.hratios'])
        self.shift_indices_1 = read_vector(r['fdtd.shift_indices_1'])
        self.shift_indices_2 = read_vector(r['fdtd.shift_indices_2'])
        self.num_indices = read_vector(r['fdtd.num_indices'])
        self.num_refinements = int(r['fdtd.num_refinements'])
        
        # Redefine atoms to suit the cut_cell routine
        newatoms = paw.atoms.copy()
        newatoms.positions = newatoms.positions + self.qm.corner1*Bohr
        newatoms.set_cell(np.diag(self.given_cell))
        self.create_subsystems(newatoms)
        
        # Read self.classical_material.charge_density
        if self.cl.gd.comm.rank == 0:
            big_charge_density = np.array(r.get('classical_material_rho'), dtype=float)
        else:
            big_charge_density = None
        self.cl.gd.distribute(big_charge_density, self.classical_material.charge_density)
        
        # Read self.classical_material.polarization_total
        if self.cl.gd.comm.rank == 0:
            big_polarization_total = np.array(r.get('polarization_total'), dtype=float)
        else:
            big_polarization_total = None
        self.cl.gd.distribute(big_polarization_total, self.classical_material.polarization_total)
        
        # Read self.classical_material.polarizations
        if self.cl.gd.comm.rank == 0:
            big_polarizations = np.array(r.get('polarizations'),
                                         dtype=float)
        else:
            big_polarizations = None
        self.cl.gd.distribute(big_polarizations, self.classical_material.polarizations)
        
        # Read self.classical_material.currents
        if self.cl.gd.comm.rank == 0:
            big_currents = np.array(r.get('currents'),
                                         dtype=float)
        else:
            big_currents = None
        self.cl.gd.distribute(big_currents, self.classical_material.currents)                
        
        
    # Write restart data   
    def write(self, paw, writer):#                     filename='poisson'):
        rho = self.classical_material.charge_density
        world = paw.wfs.world
        domain_comm = self.cl.gd.comm
        kpt_comm = paw.wfs.kd.comm
        band_comm = paw.wfs.band_comm
        master = (world.rank == 0)
        parallel = (world.size > 1)
        #w = gpaw_io_open(filename, 'w', world)
        w = writer
        
        # Classical materials data
        w['classmat.num_components'] = len(self.classical_material.components)
        self.classical_material.write(w)
        
        # FDTDPoissonSolver related data
        w['fdtd.eps'] = self.eps
        w['fdtd.nn'] = self.nn
        w['fdtd.relax'] = self.relax
        w['fdtd.coupling_scheme'] = self.potential_coupling_scheme
        w['fdtd.description'] = self.get_description()
        w['fdtd.remove_moment_qm'] = self.remove_moment_qm
        w['fdtd.remove_moment_cl'] = self.remove_moment_cl
        w['fdtd.time'] = self.time
        w['fdtd.time_step'] = self.time_step
        w['fdtd.kick'] = self.kick
        w['fdtd.maxiter'] = self.maxiter
        
        # PoissonOrganizer
        w['fdtd.cl_cell'] = np.diag(self.cl.cell)
        w['fdtd.cl_spacing_def'] = self.cl.spacing_def
        w['fdtd.cl_spacing'] = self.cl.spacing
        w['fdtd.cl_world_comm'] = self.cl.dcomm == world
        
        w['fdtd.qm_corner1'] = self.qm.corner1
        w['fdtd.qm_corner2'] = self.qm.corner2
        w['fdtd.given_corner_1'] = self.given_corner_v1
        w['fdtd.given_corner_2'] = self.given_corner_v2
        w['fdtd.given_cell'] = np.diag(self.given_cell)
        w['fdtd.hratios'] = self.hratios
        w['fdtd.shift_indices_1'] = self.shift_indices_1
        w['fdtd.shift_indices_2'] = self.shift_indices_2
        w['fdtd.num_refinements'] = self.num_refinements
        w['fdtd.num_indices'] = self.num_indices
        
        # Create dimensions for various netCDF variables:
        ng = self.cl.gd.get_size_of_global_array()
        
        # Write the classical charge density
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('classical_material_rho',
              ('nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            charge_density = self.cl.gd.collect(self.classical_material.charge_density)
            if master:
                w.fill(charge_density)

        # Write the total polarization
        w.dimension('3', 3)
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('polarization_total',
              ('3', 'nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            polarization_total = self.cl.gd.collect(self.classical_material.polarization_total)
            if master:
                w.fill(polarization_total)

        # Write the partial polarizations
        w.dimension('3', 3)
        w.dimension('Nj', self.classical_material.Nj)
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('polarizations',
              ('3', 'Nj', 'nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            polarizations = self.cl.gd.collect(self.classical_material.polarizations)
            if master:
                w.fill(polarizations)


        # Write the partial currents
        w.dimension('3', 3)
        w.dimension('Nj', self.classical_material.Nj)
        w.dimension('nclgptsx', ng[0])
        w.dimension('nclgptsy', ng[1])
        w.dimension('nclgptsz', ng[2])
        w.add('currents',
              ('3', 'Nj', 'nclgptsx', 'nclgptsy', 'nclgptsz'),
              dtype=float,
              write=master)
        if kpt_comm.rank == 0:
            currents = self.cl.gd.collect(self.classical_material.currents)
            if master:
                w.fill(currents)