(PECL trader >= 0.2.0)
trader_minus_di — Minus Directional Indicator
$high
$low
$close
$timePeriod
high
高价，浮点数数组。
low
低价，浮点数数组。
close
收盘价，浮点数数组。
timePeriod
Number of period. Valid range from 2 to 100000.
Returns an array with calculated data or false on failure.
