mirror of https://gitlab.com/QEF/q-e.git
89 lines
2.7 KiB
Fortran
89 lines
2.7 KiB
Fortran
!
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! Copyright (C) 2001 PWSCF group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!---------------------------------------------------------------------
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subroutine set_irr_nosym (nat, at, bg, xq, s, invs, nsym, rtau, &
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irt, irgq, nsymq, minus_q, irotmq, t, tmq, max_irr_dim, u, &
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npert, nirr, gi, gimq, iverbosity)
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!---------------------------------------------------------------------
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!
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! This routine substitute set_irr when there are no symmetries.
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! The irreducible representations are all one dimensional and
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! we set them to the displacement of a single atom in one direction
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!
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#include "f_defs.h"
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USE kinds, only : DP
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implicit none
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!
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! first the dummy variables
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!
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integer :: nat, nsym, s (3, 3, 48), invs (48), irt (48, nat), &
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iverbosity, npert (3 * nat), irgq (48), nsymq, irotmq, nirr, max_irr_dim
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! input: the number of atoms
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! input: the number of symmetries
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! input: the symmetry matrices
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! input: the inverse of each matrix
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! input: the rotated of each atom
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! input: write control
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! output: the dimension of each represe
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! output: the small group of q
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! output: the order of the small group
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! output: the symmetry sending q -> -q+
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! output: the number of irr. representa
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real(DP) :: xq (3), rtau (3, 48, nat), at (3, 3), bg (3, 3), &
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gi (3, 48), gimq (3)
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! input: the q point
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! input: the R associated to each tau
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! input: the direct lattice vectors
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! input: the reciprocal lattice vectors
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! output: [S(irotq)*q - q]
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! output: [S(irotmq)*q + q]
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complex(DP) :: u(3*nat, 3*nat), t(max_irr_dim, max_irr_dim, 48, 3*nat),&
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tmq (max_irr_dim, max_irr_dim, 3 * nat)
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! output: the pattern vectors
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! output: the symmetry matrices
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! output: the matrice sending q -> -q+G
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logical :: minus_q
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! output: if true one symmetry send q -> -q+G
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integer :: imode
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! counter on modes
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!
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! set the information on the symmetry group
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!
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call smallgq (xq,at,bg,s,nsym,irgq,nsymq,irotmq,minus_q,gi,gimq)
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!
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! set the modes
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!
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u (:,:) = (0.d0, 0.d0)
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do imode = 1, 3 * nat
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u (imode, imode) = (1.d0, 0.d0)
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enddo
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nirr = 3 * nat
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do imode = 1, 3 * nat
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npert (imode) = 1
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enddo
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!
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! And we compute the matrices which represent the symmetry transformat
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! in the basis of the displacements
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!
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t(:, :, :, :) = (0.d0, 0.d0)
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do imode = 1, 3 * nat
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t (1, 1, 1, imode) = (1.d0, 0.d0)
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enddo
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tmq (:, :, :) = (0.d0, 0.d0)
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if (minus_q) then
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tmq (1, 1, :) = (1.d0, 0.d0)
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end if
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return
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end subroutine set_irr_nosym
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