mirror of https://gitlab.com/QEF/q-e.git
74 lines
1.8 KiB
Fortran
74 lines
1.8 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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!-----------------------------------------------------------------------
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subroutine trntnsc (phi, at, bg, iflg)
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!-----------------------------------------------------------------------
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!! Transforms a COMPLEX tensor (like the dynamical matrix) from
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!! crystal to cartesian axis (\(\text{iflg}\geq 1\)) or viceversa
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!! (\(\text{iflg} \leq -1\)).
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!
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USE kinds, only : DP
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!
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implicit none
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!
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integer :: iflg
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!! input: gives the versus of the trans
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complex(DP) :: phi(3,3)
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!! inp/out: the matrix to transform
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real(DP) :: at(3,3)
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!! input: the direct lattice vectors
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real(DP) :: bg(3,3)
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!! input: the reciprocal lattice
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!
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! ... local variables
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!
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integer :: i, j, k, l
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!
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! counters on polarizations
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! /
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!/
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complex(DP) :: wrk (3, 3)
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! a working array
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if (iflg.gt.0) then
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!
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! forward transformation (crystal to cartesian axis)
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!
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call zcopy (9, phi, 1, wrk, 1)
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do i = 1, 3
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do j = 1, 3
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phi (i, j) = (0.d0, 0.d0)
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do k = 1, 3
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do l = 1, 3
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phi (i, j) = phi (i, j) + wrk (k, l) * bg (i, k) * bg (j, l)
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enddo
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enddo
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enddo
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enddo
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else
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!
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! backward transformation (cartesian to crystal axis)
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!
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do i = 1, 3
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do j = 1, 3
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wrk (i, j) = (0.d0, 0.d0)
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do k = 1, 3
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do l = 1, 3
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wrk (i, j) = wrk (i, j) + phi (k, l) * at (k, i) * at (l, j)
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enddo
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enddo
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enddo
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enddo
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call zcopy (9, wrk, 1, phi, 1)
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endif
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return
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end subroutine trntnsc
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