mirror of https://gitlab.com/QEF/q-e.git
77 lines
2.4 KiB
Fortran
77 lines
2.4 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 rotate_and_add_dyn (phi, phi2, nat, isym, s, invs, irt, &
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rtau, sxq)
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!-----------------------------------------------------------------------
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! Rotates a dynamical matrix (phi) in crystal coordinates according
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! to the specified symmetry operation and add the rotated matrix
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! to phi2. phi is left unmodified.
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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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! input variables
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integer :: nat, isym, s (3, 3, 48), invs (48), irt (48, nat)
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! number of atoms in the unit cell
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! index of the symm.op.
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! the symmetry operations
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! index of the inverse operations
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! index of the rotated atom
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complex(kind=DP) :: phi (3, 3, nat, nat), phi2 (3, 3, nat, nat)
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! the input dyn.mat. in crystal coordinates
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! the rotated dyn.mat. in crystal coordinates
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real(kind=DP) :: rtau (3, 48, nat), sxq (3)
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! for eaxh atom and rotation gives the R vector
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!involved
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! the rotated q involved in this sym.op.
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! local variables
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integer :: na, nb, sna, snb, ism1, i, j, k, l
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! counters on atoms
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! indices of rotated atoms
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! index of the inverse symm.op.
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! generic counters
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real(kind=DP) :: arg
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! argument of the phase
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complex(kind=DP) :: phase, work
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! auxiliary variable
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!
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real(kind=DP) :: tpi
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parameter (tpi = 2.d0 * 3.14159265358979d0)
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ism1 = invs (isym)
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do na = 1, nat
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do nb = 1, nat
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sna = irt (isym, na)
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snb = irt (isym, nb)
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arg = (sxq (1) * (rtau (1, isym, na) - rtau (1, isym, nb) ) &
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+ sxq (2) * (rtau (2, isym, na) - rtau (2, isym, nb) ) + sxq (3) &
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* (rtau (3, isym, na) - rtau (3, isym, nb) ) ) * tpi
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phase = DCMPLX (cos (arg), - sin (arg) )
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do i = 1, 3
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do j = 1, 3
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work = DCMPLX (0.d0, 0.d0)
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do k = 1, 3
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do l = 1, 3
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work = work + s (i, k, ism1) * s (j, l, ism1) * phi (k, l, na, nb) &
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* phase
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enddo
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enddo
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phi2 (i, j, sna, snb) = phi2 (i, j, sna, snb) + work
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enddo
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enddo
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enddo
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enddo
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!
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return
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end subroutine rotate_and_add_dyn
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