check_parameters Subroutine

  subroutine check_parameters
    use run_parameters, only: fapar
    use file_utils, only: error_unit
    use mp, only: proc0
    implicit none
    if ((gnostics%print_line .or. gnostics%write_line) .and. .not.(gnostics%write_fields.and.gnostics%write_omega)) then 
       if (proc0) write (error_unit(), *) 'print_line and write_line require both write_fields and write_omega... enabling'
       gnostics%write_fields = .true.
       gnostics%write_omega = .true.
    end if
    if ((gnostics%print_flux_line .or. gnostics%write_flux_line) .and. .not.gnostics%write_fields) then 
       if (proc0) write (error_unit(), *) 'print_flux_line and write_flux_line require both write_fields ... enabling'
       gnostics%write_fields = .true.
    end if
    if (gnostics%write_jext .and. .not. fapar .gt. epsilon(0.0)) then
       if (proc0) write (*,*) "ERROR: it doesn't make sense to switch on write_jext without apar"
       !SHOULD THIS BE MP_ABORT? COULD WE NOT JUST DISABLE THE DIAGNOSTIC?
       stop 1
    end if
    
  end subroutine check_parameters