if (is_numeric($multiplier)) {
        $g_defname = $rrd['ds'] . '_cdef';
        $rrd_options .= ' CDEF:' . $g_defname . $i . '=' . $rrd['ds'] . $i . ',' . $multiplier . ',*';
        $rrd_options .= ' CDEF:' . $g_defname . $i . 'min=' . $rrd['ds'] . $i . 'min,' . $multiplier . ',*';
        $rrd_options .= ' CDEF:' . $g_defname . $i . 'max=' . $rrd['ds'] . $i . 'max,' . $multiplier . ',*';