mirror of https://gitlab.com/QEF/q-e.git
91 lines
2.5 KiB
Fortran
91 lines
2.5 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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logical function lchk_tauxk (nvec, vec, trmat)
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!-----------------------------------------------------------------------
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!
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! This routine tests that the atomic coordinates and/or k-points
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! are different (except for a lattice translation).
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!
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! Last revision 15 June 1995 by A. Di Pomponio
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!
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#include "f_defs.h"
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!
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USE kinds
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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 :: nvec
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! input: number of vectors (atom. pos. or k-p
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real(kind=DP) :: vec (3, nvec), trmat (3, 3)
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! input: cryst./cart. coord. of the vectors
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! (atom. pos. or k-points)
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! input: transf. matrix
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! ( = bg , basis of the real-space lat
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! for atoms or
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! = at , basis of the rec.-space lat
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! for k-points
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!
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! here the local variables
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!
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integer :: nv1, nv2, kpol
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! first counter on vectors
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! second counter on vectors
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! counter on polarizations
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real(kind=DP), allocatable :: vaux (:,:)
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! auxiliary vectors (atom. coord. or k-points in cryst. units)
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real(kind=DP) :: vdf (3)
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! auxiliary vector
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!
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! Here, set the value of the acceptance parameter
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!
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real(kind=DP), parameter :: accep = 1.0d-5
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!
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!
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! allocate work space
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!
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allocate (vaux( 3 , nvec))
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!
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! The vectors are in cart. coordinates; they are transformed
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! in crystall. units
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!
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do nv1 = 1, nvec
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do kpol = 1, 3
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vaux (kpol, nv1) = trmat (1, kpol) * vec (1, nv1) + trmat (2, &
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kpol) * vec (2, nv1) + trmat (3, kpol) * vec (3, nv1)
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enddo
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enddo
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!
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! Test that all the atomic coordinates and/or k-points are different
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! (if true, set the logical function lchk_tauxk as .true.)
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!
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do nv1 = 1, nvec - 1
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do nv2 = nv1 + 1, nvec
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do kpol = 1, 3
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vdf (kpol) = vaux (kpol, nv2) - vaux (kpol, nv1)
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vdf (kpol) = abs (vdf (kpol) - dble (nint (vdf (kpol) ) ) )
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enddo
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if ( (vdf (1) < accep) .and. (vdf (2) < accep) .and. &
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(vdf (3) < accep) ) then
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lchk_tauxk = .false.
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goto 10
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endif
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enddo
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enddo
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!
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lchk_tauxk = .true.
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!
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! deallocate work space
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!
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10 deallocate(vaux)
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return
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end function lchk_tauxk
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