(PECL trader >= 0.2.0)
trader_minus_dm — Minus Directional Movement
$high, array $low, int $timePeriod = ?): array
high高價(jià)，浮點(diǎn)數數組。
low低價(jià)，浮點(diǎn)數數組。
timePeriodNumber of period. Valid range from 2 to 100000.
Returns an array with calculated data or false on failure.