quantum-espresso/PW/bp_strings.f90

81 lines
2.5 KiB
Fortran

!
! Copyright (C) 2004 Vanderbilt's group at Rutgers University, NJ
! 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 kp_strings ( nppstr, gdir, nrot, s, bg, npk, &
k1,k2,k3, nk1,nk2,nk3, nks, xk, wk )
#include "f_defs.h"
! --- Usage of modules ---
USE kinds, ONLY: dp
! --- No implicit definitions ---
IMPLICIT NONE
! --- Input arguments ---
INTEGER , INTENT(IN) :: k1
INTEGER , INTENT(IN) :: k2
INTEGER , INTENT(IN) :: k3
INTEGER , INTENT(IN) :: nk1
INTEGER , INTENT(IN) :: nk2
INTEGER , INTENT(IN) :: nk3
INTEGER , INTENT(IN) :: nppstr
INTEGER , INTENT(IN) :: npk
INTEGER , INTENT(IN) :: nrot
INTEGER , INTENT(IN) :: gdir
INTEGER , INTENT(IN) :: s(3,3,48)
REAL(dp) , INTENT(IN) :: bg(3,3)
! --- Output arguments ---
INTEGER , INTENT(OUT) :: nks
REAL(dp), INTENT(OUT) :: xk(3,npk)
REAL(dp), INTENT(OUT) :: wk(npk)
! --- Internal definitions ---
INTEGER :: ipar
INTEGER :: iort
INTEGER :: kindex
! time reversal and no magnetic symmetries assumed
INTEGER :: t_rev(48) = 0
LOGICAL :: time_reversal = .true.
REAL(dp) :: dk(3)
REAL(dp) :: xk0(3,npk)
REAL(dp) :: wk0(npk)
! --- Generate a k-point grid in the two dimensions other than gdir ---
IF (gdir == 1) THEN
CALL kpoint_grid (nrot, time_reversal, s, t_rev, bg, npk, &
k1,k2,k3, 1,nk2,nk3, nks, xk0, wk0 )
ELSE IF (gdir == 2) THEN
CALL kpoint_grid (nrot, time_reversal, s, t_rev, bg, npk, &
k1,k2,k3, nk1,1,nk3, nks, xk0, wk0 )
ELSE IF (gdir == 3) THEN
CALL kpoint_grid (nrot, time_reversal, s, t_rev, bg, npk, &
k1,k2,k3, nk1,nk2,1, nks, xk0, wk0 )
ELSE
CALL errore('kp_strings','gdir different from 1, 2, or 3',1)
END IF
! --- Generate a string of k-points for every k-point in the 2D grid ---
kindex=0
dk(1)=bg(1,gdir)/REAL(nppstr-1,dp)
dk(2)=bg(2,gdir)/REAL(nppstr-1,dp)
dk(3)=bg(3,gdir)/REAL(nppstr-1,dp)
DO iort=1,nks
DO ipar=1,nppstr
kindex=kindex+1
xk(1,kindex)=xk0(1,iort)+REAL(ipar-1,dp)*dk(1)
xk(2,kindex)=xk0(2,iort)+REAL(ipar-1,dp)*dk(2)
xk(3,kindex)=xk0(3,iort)+REAL(ipar-1,dp)*dk(3)
wk(kindex)=wk0(iort)/REAL(nppstr,dp)
END DO
END DO
nks=nks*nppstr
END SUBROUTINE kp_strings