mirror of https://gitlab.com/QEF/q-e.git
67 lines
1.7 KiB
Fortran
67 lines
1.7 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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!---------------------------------------------------------------------
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subroutine sort_gvec( ng, g2, mill )
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!---------------------------------------------------------------------
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!
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! first the input variables
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!
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use kinds, ONLY: dbl
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use constants, ONLY: eps8
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implicit none
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INTEGER, INTENT(IN) :: ng
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REAL(dbl) :: g2( ng )
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INTEGER :: mill( 3, ng )
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REAL(dbl), ALLOCATABLE :: gsort( : )
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INTEGER, ALLOCATABLE :: index( : )
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INTEGER :: ig, icurr, it, im
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REAL(dbl) :: gsq
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ALLOCATE( gsort( ng ) )
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ALLOCATE( index( ng ) )
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DO ig = 1, ng
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IF ( g2(ig) > eps8 ) THEN
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gsort(ig) = g2(ig)
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ELSE
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gsort(ig) = 0.d0
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END IF
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END DO
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index(1) = 0
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CALL hpsort_eps( ng, gsort( 1 ), index( 1 ), eps8 )
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! ... sort indices accordingly
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DO ig = 1, ng-1
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icurr = ig
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30 IF( index(icurr) /= ig ) THEN
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! ... swap g-vec indices
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im = mill(1,icurr); mill(1,icurr) = mill(1,index(icurr)); mill(1,index(icurr)) = im
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im = mill(2,icurr); mill(2,icurr) = mill(2,index(icurr)); mill(2,index(icurr)) = im
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im = mill(3,icurr); mill(3,icurr) = mill(3,index(icurr)); mill(3,index(icurr)) = im
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! ... swap modules
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gsq = g2( icurr ); g2( icurr ) = g2( index(icurr) ); g2( index(icurr) ) = gsq
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! ... swap indices
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it = icurr; icurr = index(icurr); index(it) = it
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IF( index(icurr) == ig ) THEN
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index(icurr) = icurr
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ELSE
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GOTO 30
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END IF
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END IF
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END DO
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DEALLOCATE( gsort )
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DEALLOCATE( index )
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return
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end subroutine
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