beta_prime_range_high Subroutine

  subroutine beta_prime_range_high (x, x0)
    implicit none
    real, intent (out) :: x
    real, intent (in) :: x0

    do
100    continue
       call text
       call text ('Strongest gradient in scan: (positive number)')
       read (interactive_input, *, err=100) x
       x = -x
       if (x >= x0) then
          call try_again
       else
          return
       end if
    end do

  end subroutine beta_prime_range_high