Re: [Spglib-users] Fwd: How to get equivalent_atoms using fortran code

[Atsushi T. <atz...@gm...>]

Yes, almost. A slight change may exist in spg_get_symmetry_with_collinear_spin.

Togo

On Thu, Jun 15, 2023 at 3:31 PM VeiWANG via Spglib-users
<spg...@li...> wrote:
>
> Hi Togo sensei,
>
> Thank for your valuable advice. I have got the equivalent_atoms list by via spg_get_dataset function. By the way, I still use spglig.1.x. Is the spglig.2.x fully compatible with spglig.1.x for fortran interface?
>
> Best,
> Wang
>
>
> 下面是被转发的邮件：
>
> 发件人: Atsushi Togo <atz...@gm...>
> 主题: 回复：[Spglib-users] How to get equivalent_atoms using fortran code
> 日期: 2023年6月15日 GMT+8 09:14:30
> 收件人: spg...@li...
> 回复给: spg...@li...
>
> Hi Wang,
>
> Without spin, spg_get_dataset, and with spin, spg_get_magnetic_dataset
> is recommended to use. However for the latter, the fortran interface
> has not been written yet. A possible route is using
> spg_get_symmetry_with_site_tensors. The interface is
>
> function spg_get_symmetry_with_site_tensors(rotation, translation, &
> & equivalent_atoms, primitive_lattice, spin_flips, max_size, lattice, &
> & position, types, tensors, tensor_rank, num_atom, with_time_reversal, &
> & is_axial, symprec) bind(c)
> import c_int, c_double
> integer(c_int), intent(out) :: rotation(3, 3, *)
> real(c_double), intent(out) :: translation(3, *)
> integer(c_int), intent(out) :: equivalent_atoms(*)
> real(c_double), intent(out) :: primitive_lattice(3, 3)
> integer(c_int), intent(out) :: spin_flips(*)
> integer(c_int), intent(in), value :: max_size
> real(c_double), intent(in) :: lattice(3, 3), position(3, *)
> integer(c_int), intent(in) :: types(*)
> real(c_double), intent(in) :: tensors(*)
> integer(c_int), intent(in), value :: tensor_rank
> integer(c_int), intent(in), value :: num_atom
> integer(c_int), intent(in), value :: with_time_reversal
> integer(c_int), intent(in), value :: is_axial
> real(c_double), intent(in), value :: symprec
> integer(c_int) :: spg_get_symmetry_with_site_tensors
> end function spg_get_symmetry_with_site_tensors
>
> Unfortunately, I haven't wrote any example of it, but I hope it can be
> guessed from C-api doc.
> https://spglib.readthedocs.io/en/latest/api.html#spg-get-symmetry-with-site-tensors
> https://spglib.readthedocs.io/en/latest/development/magnetic_symmetry_flags.html#magnetic-action-flags
>
> If you want to specify collinear spin, the array length is the number
> of atoms, tensor_rank=0, is_axial=0, and with_time_reversal =1. For
> the non-collinear case, the array length is the number-of-atoms x 3,
> tensor_rank=1, is_axial=1, and with_time_reversal =1. These are the
> typical choices.
> The spin_flips array stores if the spin is flipped or not by the found
> symmety operations. Therefore the length is the number of symmetry
> operations. The number of symmetry operations is unknown before
> running this function, so you have to prepare large enough symmetry
> operations related arrays, whose length is considered to inform to
> spglib by max_size.
>
> Togo
>
> On Tue, Jun 13, 2023 at 8:29 PM VeiWANG via Spglib-users
> <spg...@li...> wrote:
>
>
> Dear all,
>
> I am currently trying to use Fortran code to obtain the equivalent_atoms using spglib, with input variables of lattice vectors and atom positions. Could anyone provide guidance on how to implement this?
>
> If I understand correctly, to obtain the equivalent_atoms, I first simply call the spg_get_symmetry function, which requires input variables of max_size, lattice, position, types, num_atom, and optional parameter symprec. And then I use the spg_get_symmetry_with_collinear_spin function, which takes an additional input variable of spins and outputs equivalent_atoms directly from the function. I was wondering if anyone has experience using spin information with spglib and if so, how to incorporate it into the function. Thank you for your assistance.
>
> Best,
> Wang
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>
>
> --
> Atsushi Togo
>
>
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-- 
Atsushi Togo