./65_paw/pawpolev.F90

ABINIT/pawpolev

ABINIT/pawpolev [ Functions ]

NAME

 pawpolev

FUNCTION

 Compute the PAW term for polarization, named expected value term

 Copyright (C) 1998-2018 ABINIT group (FJ, PH)
 This file is distributed under the terms of the
 GNU General Public License, see ~abinit/COPYING
 or http://www.gnu.org/copyleft/gpl.txt .
 For the initials of contributors, see ~abinit/doc/developers/contributors.txt.

INPUTS

  comm_atom=--optional-- MPI communicator over atoms
  my_natom=number of atoms treated by current processor
  natom=number of atoms in cell.
  ntypat = number of atom types
  pawrhoij(natom) <type(pawrhoij_type)>= paw rhoij occupancies and related data
  pawtab(ntypat) <type(pawtab_type)>=paw tabulated starting data

OUTPUT

  pelev(3)= electronic polarisation. expectation value term (PAW only)

PARENTS

      berryphase_new

CHILDREN

      timab,xmpi_sum

SOURCE

 35 #if defined HAVE_CONFIG_H
 36 #include "config.h"
 37 #endif
 38 
 39 #include "abi_common.h"
 40 
 41 subroutine pawpolev(my_natom,natom,ntypat,pawrhoij,pawtab,pelev,&
 42 &                   comm_atom) ! optional argument (parallelism)
 43 
 44  use defs_basis
 45  use m_profiling_abi
 46  use m_errors
 47 
 48  use m_xmpi, only : xmpi_sum
 49  use m_pawtab,   only : pawtab_type
 50  use m_pawrhoij, only : pawrhoij_type
 51 
 52 !This section has been created automatically by the script Abilint (TD).
 53 !Do not modify the following lines by hand.
 54 #undef ABI_FUNC
 55 #define ABI_FUNC 'pawpolev'
 56  use interfaces_18_timing
 57 !End of the abilint section
 58 
 59  implicit none
 60 
 61 !Arguments ---------------------------------------------
 62 !scalars
 63  integer,intent(in) :: my_natom,natom,ntypat
 64  integer,optional,intent(in) :: comm_atom
 65 !arrays
 66  real(dp),intent(out) :: pelev(3)
 67  type(pawrhoij_type),intent(in) :: pawrhoij(my_natom)
 68  type(pawtab_type),intent(in) :: pawtab(ntypat)
 69 
 70 
 71 !Local variables ---------------------------------------
 72 !scalars
 73  integer :: iatom,idir,ierr,irhoij,ispden,itypat,jrhoij,klmn
 74  logical :: paral_atom
 75  real(dp) :: c1,ro_dlt
 76 !arrays
 77  integer,dimension(3) :: idirindx = (/4,2,3/)
 78  real(dp) :: tsec(2)
 79 
 80 
 81 ! *************************************************************************
 82 
 83  DBG_ENTER("COLL")
 84 
 85  call timab(560,1,tsec)
 86 
 87 !Check for parallelism over atoms
 88  paral_atom=(present(comm_atom).and.(my_natom/=natom))
 89 
 90 !note that when vector r is expanded in real spherical harmonics, the factor
 91 !sqrt(four_pi/three) appears, as in the following
 92 !x = sqrt(four_pi/three)*r*S_{1,1}
 93 !y = sqrt(four_pi/three)*r*S_{1,-1}
 94 !z = sqrt(four_pi/three)*r*S_{1,0}
 95 !
 96 !the moments pawtab()%qijl do not include such normalization factors
 97 !see pawinit.F90 for their definition and computation
 98 
 99  c1=sqrt(four_pi/three)
100 
101  pelev=zero
102  do idir=1,3
103    do iatom=1,my_natom
104      itypat=pawrhoij(iatom)%itypat
105      do ispden=1,pawrhoij(iatom)%nspden
106        jrhoij=1
107        do irhoij=1,pawrhoij(iatom)%nrhoijsel
108          klmn=pawrhoij(iatom)%rhoijselect(irhoij)
109          ro_dlt=pawrhoij(iatom)%rhoijp(jrhoij,ispden)*pawtab(itypat)%dltij(klmn)
110          pelev(idir)=pelev(idir)+ro_dlt*c1*pawtab(itypat)%qijl(idirindx(idir),klmn)
111          jrhoij=jrhoij+pawrhoij(iatom)%cplex
112        end do
113      end do
114    end do
115  end do
116 
117  if (paral_atom) then
118    call xmpi_sum(pelev,comm_atom,ierr)
119  end if
120 
121  call timab(560,2,tsec)
122 
123  DBG_EXIT("COLL")
124 
125 end subroutine pawpolev

TABLE OF CONTENTS

ABINIT/pawpolev [ Functions ]