ginit_kz0 Subroutine

  subroutine ginit_kz0
    use species, only: spec
    use theta_grid, only: ntgrid 
    use kt_grids, only: naky, ntheta0, aky, reality
    use le_grids, only: forbid
    use dist_fn_arrays, only: g, gnew, vpa, vperp2
    use gs2_layouts, only: g_lo, ik_idx, it_idx, il_idx, is_idx
    use array_utils, only: copy
    implicit none
    complex, dimension (-ntgrid:ntgrid,ntheta0,naky) :: phi
    logical :: right
    integer :: iglo
    integer :: ik, it, il, is

    right = .not. left

    phi = cmplx(refac,imfac)
    if (chop_side .and. left) phi(:-1,:,:) = 0.0
    if (chop_side .and. right) phi(1:,:,:) = 0.0
    
    if (reality) then
       phi(:,1,1) = 0.0

       if (naky > 1 .and. aky(1) == 0.0) then
          phi(:,:,1) = 0.0
       end if

! not used:
! reality condition for k_theta = 0 component:
       do it = 1, ntheta0/2
          phi(:,it+(ntheta0+1)/2,1) = conjg(phi(:,(ntheta0+1)/2+1-it,1))
       enddo
    end if

    do iglo = g_lo%llim_proc, g_lo%ulim_proc
       ik = ik_idx(g_lo,iglo)
       it = it_idx(g_lo,iglo)
       il = il_idx(g_lo,iglo)
       is = is_idx(g_lo,iglo)
       g(:,1,iglo) = -phi(:,it,ik)*spec(is)%z*phiinit*(den0 + sqrt(2.)*upar0*vpa(:,1,iglo) + tpar0*(vpa(:,1,iglo)**2-0.5) + tperp0*(vperp2(:,iglo)-1.))
       where (forbid(:,il)) g(:,1,iglo) = 0.0
       g(:,2,iglo) = -phi(:,it,ik)*spec(is)%z*phiinit*(den0 + sqrt(2.)*upar0*vpa(:,2,iglo) + tpar0*(vpa(:,2,iglo)**2-0.5) + tperp0*(vperp2(:,iglo)-1.))
    end do
    call copy(g, gnew)
  end subroutine ginit_kz0