mirror of https://gitlab.com/QEF/q-e.git
106 lines
3.1 KiB
Fortran
106 lines
3.1 KiB
Fortran
!
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! Copyright (C) 2010 Quantum ESPRESSO 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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MODULE gvecw
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!=----------------------------------------------------------------------------=!
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USE kinds, ONLY: DP
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IMPLICIT NONE
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SAVE
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PRIVATE
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PUBLIC :: ngw, ngw_g, ngwx, ecutwfc, gcutw, ekcut, gkcut
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PUBLIC :: ggp, ecfixed, qcutz, q2sigma
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PUBLIC :: gvecw_init, g2kin_init, deallocate_gvecw
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! ... G vectors less than the wave function cut-off ( ecutwfc )
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INTEGER :: ngw = 0 ! local number of G vectors
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INTEGER :: ngw_g= 0 ! in parallel execution global number of G vectors,
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! in serial execution this is equal to ngw
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INTEGER :: ngwx = 0 ! maximum local number of G vectors
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REAL(DP) :: ecutwfc = 0.0_DP
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REAL(DP) :: gcutw = 0.0_DP
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! values for costant cut-off computations
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REAL(DP) :: ecfixed=0.0_DP ! value of the constant cut-off
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REAL(DP) :: qcutz = 0.0_DP ! height of the penalty function (above ecfix)
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REAL(DP) :: q2sigma=0.0_DP ! spread of the penalty function around ecfix
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! augmented cut-off for k-point calculation
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REAL(DP) :: ekcut = 0.0_DP
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REAL(DP) :: gkcut = 0.0_DP
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! array of G vectors module plus penalty function for constant cut-off
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! simulation.
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! ggp = g + ( agg / tpiba**2 ) * ( 1 + erf( ( tpiba2 * g - e0gg ) / sgg ) )
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REAL(DP), ALLOCATABLE, TARGET :: ggp(:)
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CONTAINS
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SUBROUTINE gvecw_init( ngw_ , comm )
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!
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USE mp, ONLY: mp_max, mp_sum
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IMPLICIT NONE
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INTEGER, INTENT(IN) :: ngw_
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INTEGER, INTENT(IN) :: comm
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!
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ngw = ngw_
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!
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! calculate maximum over all processors
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!
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ngwx = ngw
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CALL mp_max( ngwx, comm )
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!
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! calculate sum over all processors
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!
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ngw_g = ngw
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CALL mp_sum( ngw_g, comm )
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!
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! allocate kinetic energy
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!
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ALLOCATE( ggp(ngw) )
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!
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RETURN
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END SUBROUTINE gvecw_init
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SUBROUTINE g2kin_init( gg, tpiba2 )
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!
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IMPLICIT NONE
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REAL(DP), INTENT(IN) :: gg(:), tpiba2
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REAL(DP), EXTERNAL :: qe_erf
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REAL(DP) :: gcutz
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INTEGER :: ig
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!
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! initialize kinetic energy
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!
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gcutz = qcutz / tpiba2
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IF( gcutz > 0.0d0 ) THEN
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DO ig=1,ngw
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ggp(ig) = gg(ig) + gcutz * &
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( 1.0d0 + qe_erf( ( tpiba2 *gg(ig) - ecfixed )/q2sigma ) )
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ENDDO
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ELSE
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ggp( 1 : ngw ) = gg( 1 : ngw )
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END IF
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RETURN
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END SUBROUTINE g2kin_init
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SUBROUTINE deallocate_gvecw
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IF( ALLOCATED( ggp ) ) DEALLOCATE( ggp )
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END SUBROUTINE deallocate_gvecw
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!=----------------------------------------------------------------------------=!
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END MODULE gvecw
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!=----------------------------------------------------------------------------=!
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