mirror of https://gitlab.com/QEF/q-e.git
93 lines
2.7 KiB
Fortran
93 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 rotate_and_add_d3 (phi, phi2, nat, isym, s, invs, irt, &
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rtau, sxq)
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!-----------------------------------------------------------------------
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! Rotates a third order 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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!
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! input variables
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!
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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 (DP) :: phi (3, 3, 3, nat, nat, nat), phi2 (3, 3, 3, nat, nat, nat)
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! the input d3dyn.mat.
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! in crystal coordinates
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! the rotated d3dyn.mat
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! in crystal coordinates
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real (DP) :: rtau (3, 48, nat), sxq (3)
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! for each atom and rotation gives
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! the R vector involved
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! the rotated q involved in this sym.op
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!
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! local variables
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!
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integer :: na, nb, nc, sna, snb, snc, ism1, i, j, k, l, m, n
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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 (DP) :: arg
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! argument of the phase
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complex (DP) :: phase, work
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! auxiliary variable
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real (DP) :: tpi
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parameter (tpi = 2.0_dp * 3.14159265358979_dp)
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ism1 = invs(isym)
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do nc = 1, nat
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snc = irt(isym,nc)
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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) ) &
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+ sxq (3) * (rtau(3,isym,na) - rtau(3,isym,nb) ) ) * tpi
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phase = CMPLX(cos(arg),-sin(arg))
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do m = 1, 3
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do i = 1, 3
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do j = 1, 3
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work = CMPLX(0.d0, 0.d0)
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do k = 1, 3
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do l = 1, 3
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do n = 1, 3
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work = work &
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+ s(m,n,ism1) * s(i,k,ism1) * s(j,l,ism1) &
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* phi(n,k,l,nc,na,nb) * phase
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enddo
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enddo
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enddo
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phi2(m,i,j,snc,sna,snb) = phi2(m,i,j,snc,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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enddo
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enddo
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return
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end subroutine rotate_and_add_d3
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