allocate_arrays Subroutine

  subroutine allocate_arrays
    use gs2_io_grids, only:nc_grid_file_open
    use gs2_io_grids, only: nc_get_grid_sizes, nc_get_grid_scalars
    implicit none
    integer :: unit
    character(200) :: line
    logical :: ncsource_exist

    inquire(file=ncsource, exist=ncsource_exist)
    if (ncsource_exist) then
       call nc_grid_file_open(ncsource, "r")
       call nc_get_grid_sizes(nthetain, ntgridin, nperiodin)
       call nc_get_grid_scalars(shat, drhodpsi, kxfac, qval, rmaj)
    else
       call get_unused_unit(unit)
       open (unit=unit, file=trim(source), status="old")
       read (unit=unit, fmt="(a)") line
       read (unit=unit, fmt=*,err=10) ntgridin, nperiodin, nthetain, drhodpsi, rmaj, shat, kxfac, qval
10     continue
       close (unit=unit)
    end if

    allocate (thetain(nthetain+1),bmagin(nthetain+1),bmagsm(nthetain+1))
    allocate (thetaout(nthetaout),bmagout(nthetaout),alambdaout(nlambdaout))
    allocate (thetagrid(-ntgridin:ntgridin))
    allocate (gbdrift(-ntgridin:ntgridin))
    allocate (gradpar(-ntgridin:ntgridin))
    allocate (grho(-ntgridin:ntgridin))
    allocate (cvdrift(-ntgridin:ntgridin))
    allocate (gds2(-ntgridin:ntgridin))
    allocate (bmag(-ntgridin:ntgridin))
    allocate (gds21(-ntgridin:ntgridin))
    allocate (gds22(-ntgridin:ntgridin))
    allocate (cvdrift0(-ntgridin:ntgridin))
    allocate (gbdrift0(-ntgridin:ntgridin))
    allocate (Rplot(-ntgridin:ntgridin))
    allocate (Rprime(-ntgridin:ntgridin))
    allocate (Zplot(-ntgridin:ntgridin))
    allocate (Zprime(-ntgridin:ntgridin))
    allocate (aplot(-ntgridin:ntgridin))
    allocate (aprime(-ntgridin:ntgridin))
  end subroutine allocate_arrays