get_BB_R Subroutine

public subroutine get_BB_R()

Uses

  • proc~~get_bb_r~~UsesGraph proc~get_bb_r get_BB_R module~w90_constants w90_constants proc~get_bb_r->module~w90_constants module~w90_parameters w90_parameters proc~get_bb_r->module~w90_parameters module~w90_postw90_common w90_postw90_common proc~get_bb_r->module~w90_postw90_common module~w90_io w90_io proc~get_bb_r->module~w90_io module~w90_comms w90_comms proc~get_bb_r->module~w90_comms module~w90_parameters->module~w90_constants module~w90_parameters->module~w90_io module~w90_postw90_common->module~w90_constants module~w90_postw90_common->module~w90_comms module~w90_io->module~w90_constants module~w90_comms->module~w90_constants module~w90_comms->module~w90_io

BB_a(R)=<0n|H(r-R)|Rm> is the Fourier transform of BB_a(k) = i (a=x,y,z)

Arguments

None

Calls

proc~~get_bb_r~~CallsGraph proc~get_bb_r get_BB_R proc~io_error io_error proc~get_bb_r->proc~io_error proc~get_win_min get_win_min proc~get_bb_r->proc~get_win_min proc~io_file_unit io_file_unit proc~get_bb_r->proc~io_file_unit

Called by

proc~~get_bb_r~~CalledByGraph proc~get_bb_r get_BB_R proc~gyrotropic_main gyrotropic_main proc~gyrotropic_main->proc~get_bb_r proc~k_path k_path proc~k_path->proc~get_bb_r proc~berry_main berry_main proc~berry_main->proc~get_bb_r proc~k_slice k_slice proc~k_slice->proc~get_bb_r

Contents

Source Code


Source Code

  subroutine get_BB_R
    !=====================================================
    !
    !! BB_a(R)=<0n|H(r-R)|Rm> is the Fourier transform of
    !! BB_a(k) = i<u|H|del_a u> (a=x,y,z)
    !
    !=====================================================

    use w90_constants, only: dp, cmplx_0, cmplx_i
    use w90_parameters, only: num_kpts, nntot, nnlist, num_wann, num_bands, &
      ndimwin, eigval, wb, bk, have_disentangled, &
      timing_level, nncell, scissors_shift
    use w90_postw90_common, only: nrpts, v_matrix
    use w90_io, only: stdout, io_file_unit, io_error, io_stopwatch, &
      seedname
    use w90_comms, only: on_root, comms_bcast

    integer          :: idir, n, m, nn, i, ii, j, jj, &
                        ik, ik2, inn, nnl, nnm, nnn, &
                        winmin_q, winmin_qb, ncount, &
                        nb_tmp, nkp_tmp, nntot_tmp, mmn_in

    complex(kind=dp), allocatable :: S_o(:, :)
    complex(kind=dp), allocatable :: BB_q(:, :, :, :)
    complex(kind=dp), allocatable :: H_q_qb(:, :)
    integer, allocatable          :: num_states(:)
    real(kind=dp)                 :: m_real, m_imag
    logical                       :: nn_found
    character(len=60)             :: header

    if (timing_level > 1 .and. on_root) call io_stopwatch('get_oper: get_BB_R', 1)
    if (.not. allocated(BB_R)) then
      allocate (BB_R(num_wann, num_wann, nrpts, 3))
    else
      if (timing_level > 1 .and. on_root) call io_stopwatch('get_oper: get_BB_R', 2)
      return
    end if

    if (on_root) then

      if (abs(scissors_shift) > 1.0e-7_dp) &
        call io_error('Error: scissors correction not yet implemented for BB_R')

      allocate (BB_q(num_wann, num_wann, num_kpts, 3))
      allocate (S_o(num_bands, num_bands))
      allocate (H_q_qb(num_wann, num_wann))

      allocate (num_states(num_kpts))
      do ik = 1, num_kpts
        if (have_disentangled) then
          num_states(ik) = ndimwin(ik)
        else
          num_states(ik) = num_wann
        endif
      enddo

      mmn_in = io_file_unit()
      open (unit=mmn_in, file=trim(seedname)//'.mmn', &
            form='formatted', status='old', action='read', err=103)
      write (stdout, '(/a)', advance='no') &
        ' Reading overlaps from '//trim(seedname)//'.mmn in get_BB_R   : '
      ! Read the comment line (header)
      read (mmn_in, '(a)', err=104, end=104) header
      write (stdout, '(a)') trim(header)
      ! Read the number of bands, k-points and nearest neighbours
      read (mmn_in, *, err=104, end=104) nb_tmp, nkp_tmp, nntot_tmp
      ! Checks
      if (nb_tmp .ne. num_bands) &
        call io_error(trim(seedname)//'.mmn has wrong number of bands')
      if (nkp_tmp .ne. num_kpts) &
        call io_error(trim(seedname)//'.mmn has wrong number of k-points')
      if (nntot_tmp .ne. nntot) &
        call io_error &
        (trim(seedname)//'.mmn has wrong number of nearest neighbours')

      BB_q = cmplx_0

      do ncount = 1, num_kpts*nntot
        !
        !Read from .mmn file the original overlap matrix
        ! S_o=<u_ik|u_ik2> between ab initio eigenstates
        !
        read (mmn_in, *, err=104, end=104) ik, ik2, nnl, nnm, nnn
        do n = 1, num_bands
          do m = 1, num_bands
            read (mmn_in, *, err=104, end=104) m_real, m_imag
            S_o(m, n) = cmplx(m_real, m_imag, kind=dp)
          enddo
        enddo
        nn = 0
        nn_found = .false.
        do inn = 1, nntot
          if ((ik2 .eq. nnlist(ik, inn)) .and. &
              (nnl .eq. nncell(1, ik, inn)) .and. &
              (nnm .eq. nncell(2, ik, inn)) .and. &
              (nnn .eq. nncell(3, ik, inn))) then
            if (.not. nn_found) then
              nn_found = .true.
              nn = inn
            else
              call io_error('Error reading '//trim(seedname)//'.mmn.&
                   & More than one matching nearest neighbour found')
            endif
          endif
        end do
        if (nn .eq. 0) then
          write (stdout, '(/a,i8,2i5,i4,2x,3i3)') &
            ' Error reading '//trim(seedname)//'.mmn:', &
            ncount, ik, ik2, nn, nnl, nnm, nnn
          call io_error('Neighbour not found')
        end if

        call get_win_min(ik, winmin_q)
        call get_win_min(nnlist(ik, nn), winmin_qb)
        call get_gauge_overlap_matrix( &
          ik, num_states(ik), &
          nnlist(ik, nn), num_states(nnlist(ik, nn)), &
          S_o, H=H_q_qb)
        do idir = 1, 3
          BB_q(:, :, ik, idir) = BB_q(:, :, ik, idir) &
                                 + cmplx_i*wb(nn)*bk(idir, nn, ik)*H_q_qb(:, :)
        enddo
      enddo !ncount

      close (mmn_in)

      call fourier_q_to_R(BB_q(:, :, :, 1), BB_R(:, :, :, 1))
      call fourier_q_to_R(BB_q(:, :, :, 2), BB_R(:, :, :, 2))
      call fourier_q_to_R(BB_q(:, :, :, 3), BB_R(:, :, :, 3))

    endif !on_root

    call comms_bcast(BB_R(1, 1, 1, 1), num_wann*num_wann*nrpts*3)

    if (timing_level > 1 .and. on_root) call io_stopwatch('get_oper: get_BB_R', 2)
    return

103 call io_error &
      ('Error: Problem opening input file '//trim(seedname)//'.mmn')
104 call io_error &
      ('Error: Problem reading input file '//trim(seedname)//'.mmn')

  end subroutine get_BB_R