def read_data(self, as_dataarray=False):
        r""" Returns data associated with the PDOS file

        For spin-polarized calculations the returned values are up/down, orbitals, energy.
        For non-collinear calculations the returned values are sum/x/y/z, orbitals, energy.

        Parameters
        ----------
        as_dataarray: bool, optional
           If True the returned PDOS is a `xarray.DataArray` with energy, spin
           and orbital information as coordinates in the data.
           The geometry, unit and Fermi level are stored as attributes in the
           DataArray.

        Returns
        -------
        geom : Geometry instance with positions, atoms and orbitals. The
               orbitals of these atoms are `AtomicOrbital` instances.
        E : the energies at which the PDOS has been evaluated at (if the Fermi-level is present the energies
            are shifted to :math:`E - E_F = 0`, this will *only* be done from Siesta 4.0.2 and later).
        PDOS : an array of DOS, for non-polarized calculations it has dimension ``(atom.no, len(E))``,
               else it has dimension ``(nspin, atom.no, len(E))``.
        DataArray : if `as_dataarray` is True, only this data array is returned, in this case
               all data can be post-processed using the `xarray` selection routines.
        """
        # Get the element-tree
        ET = ElementTree('pdos', self.file)
        root = ET.getroot()

        # Get number of orbitals
        nspin = int(root.find('nspin').text)
        # Try and find the fermi-level
        Ef = root.find('fermi_energy')
        E = arrayd(list(map(float, root.find('energy_values').text.split())))
        if Ef is not None:
            Ef = float(Ef.text)
            E -= Ef
        ne = len(E)

        # All coordinate, atoms and species data
        xyz = []
        atoms = []
        atom_species = []

        def ensure_size(ia):
            while len(atom_species) <= ia:
                atom_species.append(None)
                xyz.append(None)

        def ensure_size_orb(ia, i):
            while len(atoms) <= ia:
                atoms.append([])
            while len(atoms[ia]) <= i:
                atoms[ia].append(None)

        if nspin == 4:

            def process(D):
                tmp = np.empty(D.shape[0], D.dtype)
                tmp[:] = D[:, 3]
                D[:, 3] = D[:, 0] - D[:, 1]
                D[:, 0] = D[:, 0] + D[:, 1]
                D[:, 1] = D[:, 2]
                D[:, 2] = tmp[:]
                return D
        else:

            def process(D):
                return D

        if as_dataarray:
            import xarray as xr
            if nspin == 1:
                spin = ['sum']
            elif nspin == 2:
                spin = ['up', 'down']
            elif nspin == 4:
                spin = ['sum', 'x', 'y' 'z']

            # Dimensions of the PDOS data-array
            dims = ['E', 'spin', 'n', 'l', 'm', 'zeta', 'polarization']

            shape = (ne, nspin, 1, 1, 1, 1, 1)

            def to(o, DOS):
                # Coordinates for this dataarray
                coords = [E, spin, [o.n], [o.l], [o.m], [o.Z], [o.P]]

                return xr.DataArray(data=process(DOS).reshape(shape),
                                    dims=dims,
                                    coords=coords,
                                    name='PDOS')

        else:

            def to(o, DOS):
                return process(DOS)

        D = []
        for orb in root.findall('orbital'):

            # Short-hand function to retrieve integers for the attributes
            def oi(name):
                return int(orb.get(name))

            # Get indices
            ia = oi('atom_index') - 1
            i = oi('index') - 1

            species = orb.get('species')

            # Create the atomic orbital
            try:
                Z = oi('Z')
            except:
                try:
                    Z = PeriodicTable().Z(species)
                except:
                    # Unknown
                    Z = -1

            try:
                P = orb.get('P') == 'true'
            except:
                P = False

            ensure_size(ia)
            xyz[ia] = list(map(float, orb.get('position').split()))
            atom_species[ia] = Z

            # Construct the atomic orbital
            O = AtomicOrbital(n=oi('n'), l=oi('l'), m=oi('m'), Z=oi('z'), P=P)

            # We know that the index is far too high. However,
            # this ensures a consecutive orbital
            ensure_size_orb(ia, i)
            atoms[ia][i] = O

            # it is formed like : spin-1, spin-2 (however already in eV)
            DOS = arrayd(list(map(float,
                                  orb.find('data').text.split()))).reshape(
                                      -1, nspin)

            if as_dataarray:
                if len(D) == 0:
                    D = to(O, DOS)
                else:
                    D = D.combine_first(to(O, DOS))
            else:
                D.append(process(DOS))

        # Now we need to parse the data
        # First reduce the atom
        atoms = [[o for o in a if o] for a in atoms]
        atoms = Atoms([Atom(Z, os) for Z, os in zip(atom_species, atoms)])
        geom = Geometry(arrayd(xyz) * Bohr2Ang, atoms)

        if as_dataarray:
            # Add attributes
            D.attrs['geometry'] = geom
            D.attrs['units'] = '1/eV'
            if Ef is None:
                D.attrs['Ef'] = 'Unknown'
            else:
                D.attrs['Ef'] = Ef

            return D

        return geom, E, np.moveaxis(np.stack(D, axis=0), 2, 0)
    def density(self, grid, spinor=None, tol=1e-7, eta=False):
        r""" Expand the density matrix to the charge density on a grid

        This routine calculates the real-space density components on a specified grid.

        This is an *in-place* operation that *adds* to the current values in the grid.

        Note: To calculate :math:`\rho(\mathbf r)` in a unit-cell different from the
        originating geometry, simply pass a grid with a unit-cell different than the originating
        supercell.

        The real-space density is calculated as:

        .. math::
            \rho(\mathbf r) = \sum_{\nu\mu}\phi_\nu(\mathbf r)\phi_\mu(\mathbf r) D_{\nu\mu}

        While for non-collinear/spin-orbit calculations the density is determined from the
        spinor component (`spinor`) by

        .. math::
           \rho_{\boldsymbol\sigma}(\mathbf r) = \sum_{\nu\mu}\phi_\nu(\mathbf r)\phi_\mu(\mathbf r) \sum_\alpha [\boldsymbol\sigma \mathbf \rho_{\nu\mu}]_{\alpha\alpha}

        Here :math:`\boldsymbol\sigma` corresponds to a spinor operator to extract relevant quantities. By passing the identity matrix the total charge is added. By using the Pauli matrix :math:`\boldsymbol\sigma_x`
        only the :math:`x` component of the density is added to the grid (see `Spin.X`).

        Parameters
        ----------
        grid : Grid
           the grid on which to add the density (the density is in ``e/Ang^3``)
        spinor : (2,) or (2, 2), optional
           the spinor matrix to obtain the diagonal components of the density. For un-polarized density matrices
           this keyword has no influence. For spin-polarized it *has* to be either 1 integer or a vector of
           length 2 (defaults to total density).
           For non-collinear/spin-orbit density matrices it has to be a 2x2 matrix (defaults to total density).
        tol : float, optional
           DM tolerance for accepted values. For all density matrix elements with absolute values below
           the tolerance, they will be treated as strictly zeros.
        eta: bool, optional
           show a progressbar on stdout
        """
        try:
            # Once unique has the axis keyword, we know we can safely
            # use it in this routine
            # Otherwise we raise an ImportError
            unique([[0, 1], [2, 3]], axis=0)
        except:
            raise NotImplementedError(
                self.__class__.__name__ +
                '.density requires numpy >= 1.13, either update '
                'numpy or do not use this function!')

        geometry = self.geometry
        # Check that the atomic coordinates, really are all within the intrinsic supercell.
        # If not, it may mean that the DM does not conform to the primary unit-cell paradigm
        # of matrix elements. It complicates things.
        fxyz = geometry.fxyz
        f_min = fxyz.min()
        f_max = fxyz.max()
        if f_min < 0 or 1. < f_max:
            warn(
                self.__class__.__name__ +
                '.density has been passed a geometry where some coordinates are '
                'outside the primary unit-cell. This may potentially lead to problems! '
                'Double check the charge density!')
        del fxyz, f_min, f_max

        # Extract sub variables used throughout the loop
        shape = _a.asarrayi(grid.shape)
        dcell = grid.dcell

        # Sparse matrix data
        csr = self._csr

        # In the following we don't care about division
        # So 1) save error state, 2) turn off divide by 0, 3) calculate, 4) turn on old error state
        old_err = np.seterr(divide='ignore', invalid='ignore')

        # Placeholder for the resulting coefficients
        DM = None
        if self.spin.kind > Spin.POLARIZED:
            if spinor is None:
                # Default to the total density
                spinor = np.identity(2, dtype=np.complex128)
            else:
                spinor = _a.arrayz(spinor)
            if spinor.size != 4 or spinor.ndim != 2:
                raise ValueError(
                    self.__class__.__name__ +
                    '.density with NC/SO spin, requires a 2x2 matrix.')

            DM = _a.emptyz([self.nnz, 2, 2])
            idx = array_arange(csr.ptr[:-1], n=csr.ncol)
            if self.spin.kind == Spin.NONCOLINEAR:
                # non-collinear
                DM[:, 0, 0] = csr._D[idx, 0]
                DM[:, 1, 1] = csr._D[idx, 1]
                DM[:, 1,
                   0] = csr._D[idx,
                               2] - 1j * csr._D[idx, 3]  #TODO check sign here!
                DM[:, 0, 1] = np.conj(DM[:, 1, 0])
            else:
                # spin-orbit
                DM[:, 0, 0] = csr._D[idx, 0] + 1j * csr._D[idx, 4]
                DM[:, 1, 1] = csr._D[idx, 1] + 1j * csr._D[idx, 5]
                DM[:, 1,
                   0] = csr._D[idx,
                               2] - 1j * csr._D[idx, 3]  #TODO check sign here!
                DM[:, 0, 1] = csr._D[idx, 6] + 1j * csr._D[idx, 7]

            # Perform dot-product with spinor, and take out the diagonal real part
            DM = dot(DM, spinor.T)[:, [0, 1], [0, 1]].sum(1).real

        elif self.spin.kind == Spin.POLARIZED:
            if spinor is None:
                spinor = _a.onesd(2)

            elif isinstance(spinor, Integral):
                # extract the provided spin-polarization
                s = _a.zerosd(2)
                s[spinor] = 1.
                spinor = s
            else:
                spinor = _a.arrayd(spinor)

            if spinor.size != 2 or spinor.ndim != 1:
                raise ValueError(
                    self.__class__.__name__ +
                    '.density with polarized spin, requires spinor '
                    'argument as an integer, or a vector of length 2')

            idx = array_arange(csr.ptr[:-1], n=csr.ncol)
            DM = csr._D[idx, 0] * spinor[0] + csr._D[idx, 1] * spinor[1]

        else:
            idx = array_arange(csr.ptr[:-1], n=csr.ncol)
            DM = csr._D[idx, 0]

        # Create the DM csr matrix.
        csrDM = csr_matrix(
            (DM, csr.col[idx], np.insert(np.cumsum(csr.ncol), 0, 0)),
            shape=(self.shape[:2]),
            dtype=DM.dtype)

        # Clean-up
        del idx, DM

        # To heavily speed up the construction of the density we can recreate
        # the sparse csrDM matrix by summing the lower and upper triangular part.
        # This means we only traverse the sparse UPPER part of the DM matrix
        # I.e.:
        #    psi_i * DM_{ij} * psi_j + psi_j * DM_{ji} * psi_i
        # is equal to:
        #    psi_i * (DM_{ij} + DM_{ji}) * psi_j
        # Secondly, to ease the loops we extract the main diagonal (on-site terms)
        # and store this for separate usage
        csr_sum = [None] * geometry.n_s
        no = geometry.no
        primary_i_s = geometry.sc_index([0, 0, 0])
        for i_s in range(geometry.n_s):
            # Extract the csr matrix
            o_start, o_end = i_s * no, (i_s + 1) * no
            csr = csrDM[:, o_start:o_end]
            if i_s == primary_i_s:
                csr_sum[i_s] = triu(csr) + tril(csr, -1).transpose()
            else:
                csr_sum[i_s] = csr

        # Recreate the column-stacked csr matrix
        csrDM = ss_hstack(csr_sum, format='csr')
        del csr, csr_sum

        # Remove all zero elements (note we use the tolerance here!)
        csrDM.data = np.where(np.fabs(csrDM.data) > tol, csrDM.data, 0.)

        # Eliminate zeros and sort indices etc.
        csrDM.eliminate_zeros()
        csrDM.sort_indices()
        csrDM.prune()

        # 1. Ensure the grid has a geometry associated with it
        sc = grid.sc.copy()
        if grid.geometry is None:
            # Create the actual geometry that encompass the grid
            ia, xyz, _ = geometry.within_inf(sc)
            if len(ia) > 0:
                grid.set_geometry(Geometry(xyz, geometry.atom[ia], sc=sc))

        # Instead of looping all atoms in the supercell we find the exact atoms
        # and their supercell indices.
        add_R = _a.zerosd(3) + geometry.maxR()
        # Calculate the required additional vectors required to increase the fictitious
        # supercell by add_R in each direction.
        # For extremely skewed lattices this will be way too much, hence we make
        # them square.
        o = sc.toCuboid(True)
        sc = SuperCell(o._v, origo=o.origo) + np.diag(2 * add_R)
        sc.origo -= add_R

        # Retrieve all atoms within the grid supercell
        # (and the neighbours that connect into the cell)
        IA, XYZ, ISC = geometry.within_inf(sc)

        # Retrieve progressbar
        eta = tqdm_eta(len(IA), self.__class__.__name__ + '.density', 'atom',
                       eta)

        cell = geometry.cell
        atom = geometry.atom
        axyz = geometry.axyz
        a2o = geometry.a2o

        def xyz2spherical(xyz, offset):
            """ Calculate the spherical coordinates from indices """
            rx = xyz[:, 0] - offset[0]
            ry = xyz[:, 1] - offset[1]
            rz = xyz[:, 2] - offset[2]

            # Calculate radius ** 2
            xyz_to_spherical_cos_phi(rx, ry, rz)
            return rx, ry, rz

        def xyz2sphericalR(xyz, offset, R):
            """ Calculate the spherical coordinates from indices """
            rx = xyz[:, 0] - offset[0]
            idx = indices_fabs_le(rx, R)
            ry = xyz[idx, 1] - offset[1]
            ix = indices_fabs_le(ry, R)
            ry = ry[ix]
            idx = idx[ix]
            rz = xyz[idx, 2] - offset[2]
            ix = indices_fabs_le(rz, R)
            ry = ry[ix]
            rz = rz[ix]
            idx = idx[ix]
            if len(idx) == 0:
                return [], [], [], []
            rx = rx[idx]

            # Calculate radius ** 2
            ix = indices_le(rx**2 + ry**2 + rz**2, R**2)
            idx = idx[ix]
            if len(idx) == 0:
                return [], [], [], []
            rx = rx[ix]
            ry = ry[ix]
            rz = rz[ix]
            xyz_to_spherical_cos_phi(rx, ry, rz)
            return idx, rx, ry, rz

        # Looping atoms in the sparse pattern is better since we can pre-calculate
        # the radial parts and then add them.
        # First create a SparseOrbital matrix, then convert to SparseAtom
        spO = SparseOrbital(geometry, dtype=np.int16)
        spO._csr = SparseCSR(csrDM)
        spA = spO.toSparseAtom(dtype=np.int16)
        del spO
        na = geometry.na
        # Remove the diagonal part of the sparse atom matrix
        off = na * primary_i_s
        for ia in range(na):
            del spA[ia, off + ia]

        # Get pointers and delete the atomic sparse pattern
        # The below complexity is because we are not finalizing spA
        csr = spA._csr
        a_ptr = np.insert(_a.cumsumi(csr.ncol), 0, 0)
        a_col = csr.col[array_arange(csr.ptr, n=csr.ncol)]
        del spA, csr

        # Get offset in supercell in orbitals
        off = geometry.no * primary_i_s
        origo = grid.origo
        # TODO sum the non-origo atoms to the csrDM matrix
        #      this would further decrease the loops required.

        # Loop over all atoms in the grid-cell
        for ia, ia_xyz, isc in zip(IA, XYZ - origo.reshape(1, 3), ISC):
            # Get current atom
            ia_atom = atom[ia]
            IO = a2o(ia)
            IO_range = range(ia_atom.no)
            cell_offset = (cell * isc.reshape(3, 1)).sum(0) - origo

            # Extract maximum R
            R = ia_atom.maxR()
            if R <= 0.:
                warn("Atom '{}' does not have a wave-function, skipping atom.".
                     format(ia_atom))
                eta.update()
                continue

            # Retrieve indices of the grid for the atomic shape
            idx = grid.index(ia_atom.toSphere(ia_xyz))

            # Now we have the indices for the largest orbital on the atom

            # Subsequently we have to loop the orbitals and the
            # connecting orbitals
            # Then we find the indices that overlap with these indices
            # First reduce indices to inside the grid-cell
            idx[idx[:, 0] < 0, 0] = 0
            idx[shape[0] <= idx[:, 0], 0] = shape[0] - 1
            idx[idx[:, 1] < 0, 1] = 0
            idx[shape[1] <= idx[:, 1], 1] = shape[1] - 1
            idx[idx[:, 2] < 0, 2] = 0
            idx[shape[2] <= idx[:, 2], 2] = shape[2] - 1

            # Remove duplicates, requires numpy >= 1.13
            idx = unique(idx, axis=0)
            if len(idx) == 0:
                eta.update()
                continue

            # Get real-space coordinates for the current atom
            # as well as the radial parts
            grid_xyz = dot(idx, dcell)

            # Perform loop on connection atoms
            # Allocate the DM_pj arrays
            # This will have a size equal to number of elements times number of
            # orbitals on this atom
            # In this way we do not have to calculate the psi_j multiple times
            DM_io = csrDM[IO:IO + ia_atom.no, :].tolil()
            DM_pj = _a.zerosd([ia_atom.no, grid_xyz.shape[0]])

            # Now we perform the loop on the connections for this atom
            # Remark that we have removed the diagonal atom (it-self)
            # As that will be calculated in the end
            for ja in a_col[a_ptr[ia]:a_ptr[ia + 1]]:
                # Retrieve atom (which contains the orbitals)
                ja_atom = atom[ja % na]
                JO = a2o(ja)
                jR = ja_atom.maxR()
                # Get actual coordinate of the atom
                ja_xyz = axyz(ja) + cell_offset

                # Reduce the ia'th grid points to those that connects to the ja'th atom
                ja_idx, ja_r, ja_theta, ja_cos_phi = xyz2sphericalR(
                    grid_xyz, ja_xyz, jR)

                if len(ja_idx) == 0:
                    # Quick step
                    continue

                # Loop on orbitals on this atom
                for jo in range(ja_atom.no):
                    o = ja_atom.orbital[jo]
                    oR = o.R

                    # Downsize to the correct indices
                    if jR - oR < 1e-6:
                        ja_idx1 = ja_idx.view()
                        ja_r1 = ja_r.view()
                        ja_theta1 = ja_theta.view()
                        ja_cos_phi1 = ja_cos_phi.view()
                    else:
                        ja_idx1 = indices_le(ja_r, oR)
                        if len(ja_idx1) == 0:
                            # Quick step
                            continue

                        # Reduce arrays
                        ja_r1 = ja_r[ja_idx1]
                        ja_theta1 = ja_theta[ja_idx1]
                        ja_cos_phi1 = ja_cos_phi[ja_idx1]
                        ja_idx1 = ja_idx[ja_idx1]

                    # Calculate the psi_j component
                    psi = o.psi_spher(ja_r1,
                                      ja_theta1,
                                      ja_cos_phi1,
                                      cos_phi=True)

                    # Now add this orbital to all components
                    for io in IO_range:
                        DM_pj[io, ja_idx1] += DM_io[io, JO + jo] * psi

                # Temporary clean up
                del ja_idx, ja_r, ja_theta, ja_cos_phi
                del ja_idx1, ja_r1, ja_theta1, ja_cos_phi1, psi

            # Now we have all components for all orbitals connection to all orbitals on atom
            # ia. We simply need to add the diagonal components

            # Loop on the orbitals on this atom
            ia_r, ia_theta, ia_cos_phi = xyz2spherical(grid_xyz, ia_xyz)
            del grid_xyz
            for io in IO_range:
                # Only loop halve the range.
                # This is because: triu + tril(-1).transpose()
                # removes the lower half of the on-site matrix.
                for jo in range(io + 1, ia_atom.no):
                    DM = DM_io[io, off + IO + jo]

                    oj = ia_atom.orbital[jo]
                    ojR = oj.R

                    # Downsize to the correct indices
                    if R - ojR < 1e-6:
                        ja_idx1 = slice(None)
                        ja_r1 = ia_r.view()
                        ja_theta1 = ia_theta.view()
                        ja_cos_phi1 = ia_cos_phi.view()
                    else:
                        ja_idx1 = indices_le(ia_r, ojR)
                        if len(ja_idx1) == 0:
                            # Quick step
                            continue

                        # Reduce arrays
                        ja_r1 = ia_r[ja_idx1]
                        ja_theta1 = ia_theta[ja_idx1]
                        ja_cos_phi1 = ia_cos_phi[ja_idx1]

                    # Calculate the psi_j component
                    DM_pj[io, ja_idx1] += DM * oj.psi_spher(
                        ja_r1, ja_theta1, ja_cos_phi1, cos_phi=True)

                # Calculate the psi_i component
                # Note that this one *also* zeroes points outside the shell
                # I.e. this step is important because it "nullifies" all but points where
                # orbital io is defined.
                psi = ia_atom.orbital[io].psi_spher(ia_r,
                                                    ia_theta,
                                                    ia_cos_phi,
                                                    cos_phi=True)
                DM_pj[io, :] += DM_io[io, off + IO + io] * psi
                DM_pj[io, :] *= psi

            # Temporary clean up
            ja_idx1 = ja_r1 = ja_theta1 = ja_cos_phi1 = None
            del ia_r, ia_theta, ia_cos_phi, psi, DM_io

            # Now add the density
            grid.grid[idx[:, 0], idx[:, 1], idx[:, 2]] += DM_pj.sum(0)

            # Clean-up
            del DM_pj, idx

            eta.update()
        eta.close()

        # Reset the error code for division
        np.seterr(**old_err)
def wavefunction(v,
                 grid,
                 geometry=None,
                 k=None,
                 spinor=0,
                 spin=None,
                 eta=False):
    r""" Add the wave-function (`Orbital.psi`) component of each orbital to the grid

    This routine calculates the real-space wave-function components in the
    specified grid.

    This is an *in-place* operation that *adds* to the current values in the grid.

    It may be instructive to check that an eigenstate is normalized:

    >>> grid = Grid(...) # doctest: +SKIP
    >>> psi(state, grid) # doctest: +SKIP
    >>> (np.abs(grid.grid) ** 2).sum() * grid.dvolume == 1. # doctest: +SKIP

    Note: To calculate :math:`\psi(\mathbf r)` in a unit-cell different from the
    originating geometry, simply pass a grid with a unit-cell smaller than the originating
    supercell.

    The wavefunctions are calculated in real-space via:

    .. math::
       \psi(\mathbf r) = \sum_i\phi_i(\mathbf r) |\psi\rangle_i \exp(-i\mathbf k \mathbf R)

    While for non-collinear/spin-orbit calculations the wavefunctions are determined from the
    spinor component (`spinor`)

    .. math::
       \psi_{\alpha/\beta}(\mathbf r) = \sum_i\phi_i(\mathbf r) |\psi_{\alpha/\beta}\rangle_i \exp(-i\mathbf k \mathbf R)

    where ``spinor in [0, 1]`` determines :math:`\alpha` or :math:`\beta`, respectively.

    Notes
    -----
    Currently this method only works for :math:`\Gamma` states

    Parameters
    ----------
    v : array_like
       coefficients for the orbital expansion on the real-space grid.
       If `v` is a complex array then the `grid` *must* be complex as well.
    grid : Grid
       grid on which the wavefunction will be plotted.
       If multiple eigenstates are in this object, they will be summed.
    geometry : Geometry, optional
       geometry where the orbitals are defined. This geometry's orbital count must match
       the number of elements in `v`.
       If this is ``None`` the geometry associated with `grid` will be used instead.
    k : array_like, optional
       k-point associated with wavefunction, by default the inherent k-point used
       to calculate the eigenstate will be used (generally shouldn't be used unless the `EigenstateElectron` object
       has not been created via `Hamiltonian.eigenstate`).
    spinor : int, optional
       the spinor for non-collinear/spin-orbit calculations. This is only used if the
       eigenstate object has been created from a parent object with a `Spin` object
       contained, *and* if the spin-configuration is non-collinear or spin-orbit coupling.
       Default to the first spinor component.
    spin : Spin, optional
       specification of the spin configuration of the orbital coefficients. This only has
       influence for non-collinear wavefunctions where `spinor` choice is important.
    eta : bool, optional
       Display a console progressbar.
    """
    if geometry is None:
        geometry = grid.geometry
        warn(
            'wavefunction was not passed a geometry associated, will use the geometry associated with the Grid.'
        )
    if geometry is None:
        raise SislError(
            'wavefunction did not find a usable Geometry through keywords or the Grid!'
        )

    # In case the user has passed several vectors we sum them to plot the summed state
    if v.ndim == 2:
        v = v.sum(0)

    if spin is None:
        if len(v) // 2 == geometry.no:
            # We can see from the input that the vector *must* be a non-collinear calculation
            v = v.reshape(-1, 2)[:, spinor]
            info(
                'wavefunction assumes the input wavefunction coefficients to originate from a non-collinear calculation!'
            )

    elif spin.kind > Spin.POLARIZED:
        # For non-collinear cases the user selects the spinor component.
        v = v.reshape(-1, 2)[:, spinor]

    if len(v) != geometry.no:
        raise ValueError(
            "wavefunction require wavefunction coefficients corresponding to number of orbitals in the geometry."
        )

    # Check for k-points
    k = _a.asarrayd(k)
    kl = (k**2).sum()**0.5
    has_k = kl > 0.000001
    if has_k:
        raise NotImplementedError(
            'wavefunction for k != Gamma does not produce correct wavefunctions!'
        )

    # Check that input/grid makes sense.
    # If the coefficients are complex valued, then the grid *has* to be
    # complex valued.
    # Likewise if a k-point has been passed.
    is_complex = np.iscomplexobj(v) or has_k
    if is_complex and not np.iscomplexobj(grid.grid):
        raise SislError(
            "wavefunction input coefficients are complex, while grid only contains real."
        )

    if is_complex:
        psi_init = _a.zerosz
    else:
        psi_init = _a.zerosd

    # Extract sub variables used throughout the loop
    shape = _a.asarrayi(grid.shape)
    dcell = grid.dcell
    ic = grid.sc.icell * shape.reshape(1, -1)
    geom_shape = dot(ic, geometry.cell.T).T

    # In the following we don't care about division
    # So 1) save error state, 2) turn off divide by 0, 3) calculate, 4) turn on old error state
    old_err = np.seterr(divide='ignore', invalid='ignore')

    addouter = add.outer

    def idx2spherical(ix, iy, iz, offset, dc, R):
        """ Calculate the spherical coordinates from indices """
        rx = addouter(addouter(ix * dc[0, 0], iy * dc[1, 0]),
                      iz * dc[2, 0] - offset[0]).ravel()
        ry = addouter(addouter(ix * dc[0, 1], iy * dc[1, 1]),
                      iz * dc[2, 1] - offset[1]).ravel()
        rz = addouter(addouter(ix * dc[0, 2], iy * dc[1, 2]),
                      iz * dc[2, 2] - offset[2]).ravel()
        # Total size of the indices
        n = rx.shape[0]
        # Reduce our arrays to where the radius is "fine"
        idx = indices_le(rx**2 + ry**2 + rz**2, R**2)
        rx = rx[idx]
        ry = ry[idx]
        rz = rz[idx]
        xyz_to_spherical_cos_phi(rx, ry, rz)
        return n, idx, rx, ry, rz

    # Figure out the max-min indices with a spacing of 1 radian
    rad1 = pi / 180
    theta, phi = ogrid[-pi:pi:rad1, 0:pi:rad1]
    cphi, sphi = cos(phi), sin(phi)
    ctheta_sphi = cos(theta) * sphi
    stheta_sphi = sin(theta) * sphi
    del sphi
    nrxyz = (theta.size, phi.size, 3)
    del theta, phi, rad1

    # First we calculate the min/max indices for all atoms
    idx_mm = _a.emptyi([geometry.na, 2, 3])
    rxyz = _a.emptyd(nrxyz)
    rxyz[..., 0] = ctheta_sphi
    rxyz[..., 1] = stheta_sphi
    rxyz[..., 2] = cphi
    # Reshape
    rxyz.shape = (-1, 3)
    idx = dot(ic, rxyz.T)
    idxm = idx.min(1).reshape(1, 3)
    idxM = idx.max(1).reshape(1, 3)
    del ctheta_sphi, stheta_sphi, cphi, idx, rxyz, nrxyz

    origo = grid.sc.origo.reshape(1, -1)
    for atom, ia in geometry.atom.iter(True):
        if len(ia) == 0:
            continue
        R = atom.maxR()

        # Now do it for all the atoms to get indices of the middle of
        # the atoms
        # The coordinates are relative to origo, so we need to shift (when writing a grid
        # it is with respect to origo)
        xyz = geometry.xyz[ia, :] - origo
        idx = dot(ic, xyz.T).T

        # Get min-max for all atoms
        idx_mm[ia, 0, :] = idxm * R + idx
        idx_mm[ia, 1, :] = idxM * R + idx

    # Now we have min-max for all atoms
    # When we run the below loop all indices can be retrieved by looking
    # up in the above table.

    # Before continuing, we can easily clean up the temporary arrays
    del origo, idx

    aranged = _a.aranged

    # In case this grid does not have a Geometry associated
    # We can *perhaps* easily attach a geometry with the given
    # atoms in the unit-cell
    sc = grid.sc.copy()
    if grid.geometry is None:
        # Create the actual geometry that encompass the grid
        ia, xyz, _ = geometry.within_inf(sc)
        if len(ia) > 0:
            grid.set_geometry(Geometry(xyz, geometry.atom[ia], sc=sc))

    # Instead of looping all atoms in the supercell we find the exact atoms
    # and their supercell indices.
    add_R = _a.zerosd(3) + geometry.maxR()
    # Calculate the required additional vectors required to increase the fictitious
    # supercell by add_R in each direction.
    # For extremely skewed lattices this will be way too much, hence we make
    # them square.
    o = sc.toCuboid(True)
    sc = SuperCell(o._v, origo=o.origo) + np.diag(2 * add_R)
    sc.origo -= add_R

    # Retrieve all atoms within the grid supercell
    # (and the neighbours that connect into the cell)
    IA, XYZ, ISC = geometry.within_inf(sc)

    r_k = dot(geometry.rcell, k)
    r_k_cell = dot(r_k, geometry.cell)
    phase = 1

    # Retrieve progressbar
    eta = tqdm_eta(len(IA), 'wavefunction', 'atom', eta)

    # Loop over all atoms in the grid-cell
    for ia, xyz, isc in zip(IA, XYZ - grid.origo.reshape(1, 3), ISC):
        # Get current atom
        atom = geometry.atom[ia]

        # Extract maximum R
        R = atom.maxR()
        if R <= 0.:
            warn("Atom '{}' does not have a wave-function, skipping atom.".
                 format(atom))
            eta.update()
            continue

        # Get indices in the supercell grid
        idx = (isc.reshape(3, 1) * geom_shape).sum(0)
        idxm = floor(idx_mm[ia, 0, :] + idx).astype(int32)
        idxM = ceil(idx_mm[ia, 1, :] + idx).astype(int32) + 1

        # Fast check whether we can skip this point
        if idxm[0] >= shape[0] or idxm[1] >= shape[1] or idxm[2] >= shape[2] or \
           idxM[0] <= 0 or idxM[1] <= 0 or idxM[2] <= 0:
            eta.update()
            continue

        # Truncate values
        if idxm[0] < 0:
            idxm[0] = 0
        if idxM[0] > shape[0]:
            idxM[0] = shape[0]
        if idxm[1] < 0:
            idxm[1] = 0
        if idxM[1] > shape[1]:
            idxM[1] = shape[1]
        if idxm[2] < 0:
            idxm[2] = 0
        if idxM[2] > shape[2]:
            idxM[2] = shape[2]

        # Now idxm/M contains min/max indices used
        # Convert to spherical coordinates
        n, idx, r, theta, phi = idx2spherical(aranged(idxm[0], idxM[0]),
                                              aranged(idxm[1], idxM[1]),
                                              aranged(idxm[2], idxM[2]), xyz,
                                              dcell, R)

        # Get initial orbital
        io = geometry.a2o(ia)

        if has_k:
            phase = np.exp(-1j * (dot(r_k_cell, isc)))
            # TODO
            # Possibly the phase should be an additional
            # array for the position in the unit-cell!
            #   + np.exp(-1j * dot(r_k, spher2cart(r, theta, np.arccos(phi)).T) )

        # Allocate a temporary array where we add the psi elements
        psi = psi_init(n)

        # Loop on orbitals on this atom, grouped by radius
        for os in atom.iter(True):

            # Get the radius of orbitals (os)
            oR = os[0].R

            if oR <= 0.:
                warn(
                    "Orbital(s) '{}' does not have a wave-function, skipping orbital!"
                    .format(os))
                # Skip these orbitals
                io += len(os)
                continue

            # Downsize to the correct indices
            if R - oR < 1e-6:
                idx1 = idx.view()
                r1 = r.view()
                theta1 = theta.view()
                phi1 = phi.view()
            else:
                idx1 = indices_le(r, oR)
                # Reduce arrays
                r1 = r[idx1]
                theta1 = theta[idx1]
                phi1 = phi[idx1]
                idx1 = idx[idx1]

            # Loop orbitals with the same radius
            for o in os:
                # Evaluate psi component of the wavefunction and add it for this atom
                psi[idx1] += o.psi_spher(r1, theta1, phi1,
                                         cos_phi=True) * (v[io] * phase)
                io += 1

        # Clean-up
        del idx1, r1, theta1, phi1, idx, r, theta, phi

        # Convert to correct shape and add the current atom contribution to the wavefunction
        psi.shape = idxM - idxm
        grid.grid[idxm[0]:idxM[0], idxm[1]:idxM[1], idxm[2]:idxM[2]] += psi

        # Clean-up
        del psi

        # Step progressbar
        eta.update()

    eta.close()

    # Reset the error code for division
    np.seterr(**old_err)