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!
! Copyright (C) 2010-2016 Quantum ESPRESSO group
! 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 .
!
!=----------------------------------------------------------------------------=!
MODULE gvecw
!=----------------------------------------------------------------------------=!
USE kinds, ONLY: DP
IMPLICIT NONE
SAVE
PRIVATE
PUBLIC :: ngw, ngw_g, ngwx, ecutwfc, gcutw, ekcut, gkcut
PUBLIC :: g2kin, ecfixed, qcutz, q2sigma
PUBLIC :: gvecw_init, g2kin_init, deallocate_gvecw
! ... G vectors less than the wave function cut-off ( ecutwfc )
INTEGER :: ngw = 0 ! local number of G vectors
INTEGER :: ngw_g= 0 ! in parallel execution global number of G vectors,
! in serial execution this is equal to ngw
INTEGER :: ngwx = 0 ! maximum local number of G vectors
REAL(DP) :: ecutwfc = 0.0_DP
REAL(DP) :: gcutw = 0.0_DP
! values for costant cut-off computations
REAL(DP) :: ecfixed=0.0_DP ! value of the constant cut-off
REAL(DP) :: qcutz = 0.0_DP ! height of the penalty function (above ecfix)
REAL(DP) :: q2sigma=0.0_DP ! spread of the penalty function around ecfix
! augmented cut-off for k-point calculation
REAL(DP) :: ekcut = 0.0_DP
REAL(DP) :: gkcut = 0.0_DP
! array of G vectors module plus penalty function for constant cut-off
! simulation.
! g2kin = g + ( agg / tpiba**2 ) * ( 1 + erf( ( tpiba2*g - e0gg ) / sgg ) )
REAL(DP), ALLOCATABLE :: g2kin(:)
CONTAINS
SUBROUTINE gvecw_init( ngw_ , comm )
!
USE mp, ONLY: mp_max, mp_sum
IMPLICIT NONE
INTEGER, INTENT(IN) :: ngw_
INTEGER, INTENT(IN) :: comm
!
ngw = ngw_
!
! calculate maximum over all processors
!
ngwx = ngw
CALL mp_max( ngwx, comm )
!
! calculate sum over all processors
!
ngw_g = ngw
CALL mp_sum( ngw_g, comm )
!
! allocate kinetic energy
!
ALLOCATE( g2kin(ngw) )
!
RETURN
END SUBROUTINE gvecw_init
SUBROUTINE g2kin_init( gg, tpiba2 )
!
IMPLICIT NONE
REAL(DP), INTENT(IN) :: gg(:), tpiba2
REAL(DP), EXTERNAL :: qe_erf
REAL(DP) :: gcutz
INTEGER :: ig
!
! initialize kinetic energy
!
gcutz = qcutz / tpiba2
IF( gcutz > 0.0d0 ) THEN
DO ig=1,ngw
g2kin(ig) = gg(ig) + gcutz * &
( 1.0d0 + qe_erf( ( tpiba2 *gg(ig) - ecfixed )/q2sigma ) )
ENDDO
ELSE
g2kin( 1 : ngw ) = gg( 1 : ngw )
END IF
RETURN
END SUBROUTINE g2kin_init
SUBROUTINE deallocate_gvecw
IF( ALLOCATED( g2kin ) ) DEALLOCATE( g2kin )
END SUBROUTINE deallocate_gvecw
!=----------------------------------------------------------------------------=!
END MODULE gvecw
!=----------------------------------------------------------------------------=!
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