mirror of https://gitlab.com/QEF/q-e.git
79 lines
2.4 KiB
Fortran
79 lines
2.4 KiB
Fortran
!
|
|
! Copyright (C) 2001 PWSCF group
|
|
! This file is distributed under the terms of the
|
|
! GNU General Public License. See the file `License'
|
|
! in the root directory of the present distribution,
|
|
! or http://www.gnu.org/copyleft/gpl.txt .
|
|
!
|
|
!-----------------------------------------------------------------------
|
|
subroutine rotate_and_add_dyn (phi, phi2, nat, isym, s, invs, irt, &
|
|
rtau, sxq)
|
|
!-----------------------------------------------------------------------
|
|
!! Rotates a dynamical matrix (\(\text{phi}\)) in crystal coordinates
|
|
!! according to the specified symmetry operation and add the rotated
|
|
!! matrix to \(\text{phi2}\). \(\text{phi}\) is left unmodified.
|
|
!
|
|
USE kinds, only : DP
|
|
USE constants, ONLY : tpi
|
|
implicit none
|
|
|
|
integer :: nat
|
|
!! number of atoms in the unit cell
|
|
integer :: isym
|
|
!! index of the symm.op.
|
|
integer :: s(3,3,48)
|
|
!! the symmetry operations
|
|
integer :: invs(48)
|
|
!! index of the inverse operations
|
|
integer :: irt(48,nat)
|
|
!! index of the rotated atom
|
|
|
|
complex(DP) :: phi(3,3,nat,nat)
|
|
!! the input dyn.mat. in crystal coordinates
|
|
complex(DP) :: phi2(3,3,nat,nat)
|
|
!! the rotated dyn.mat. in crystal coordinates
|
|
|
|
real(DP) :: rtau(3,48,nat)
|
|
!! for eaxh atom and rotation gives the R vector involved
|
|
real(DP) :: sxq(3)
|
|
!! the rotated q involved in this sym.op.
|
|
!
|
|
! ... local variables
|
|
!
|
|
integer :: na, nb, sna, snb, ism1, i, j, k, l
|
|
! counters on atoms
|
|
! indices of rotated atoms
|
|
! index of the inverse symm.op.
|
|
! generic counters
|
|
real(DP) :: arg
|
|
! argument of the phase
|
|
complex(DP) :: phase, work
|
|
|
|
|
|
ism1 = invs (isym)
|
|
do na = 1, nat
|
|
do nb = 1, nat
|
|
sna = irt (isym, na)
|
|
snb = irt (isym, nb)
|
|
arg = (sxq (1) * (rtau (1, isym, na) - rtau (1, isym, nb) ) &
|
|
+ sxq (2) * (rtau (2, isym, na) - rtau (2, isym, nb) ) + sxq (3) &
|
|
* (rtau (3, isym, na) - rtau (3, isym, nb) ) ) * tpi
|
|
phase = CMPLX(cos (arg), - sin (arg) ,kind=DP)
|
|
do i = 1, 3
|
|
do j = 1, 3
|
|
work = CMPLX(0.d0, 0.d0,kind=DP)
|
|
do k = 1, 3
|
|
do l = 1, 3
|
|
work = work + s (i, k, ism1) * s (j, l, ism1) * phi (k, l, na, nb) &
|
|
* phase
|
|
enddo
|
|
enddo
|
|
phi2 (i, j, sna, snb) = phi2 (i, j, sna, snb) + work
|
|
enddo
|
|
enddo
|
|
enddo
|
|
enddo
|
|
!
|
|
return
|
|
end subroutine rotate_and_add_dyn
|