timePeriod can be from 1 (not from 2)
Working correctly, and tis is common need to calculate change from previos period.
(PECL trader >= 0.2.0)
trader_rocr — Rate of change ratio: (price/prevPrice)
Array of real values.
Number of period. Valid range from 2 to 100000.
Returns an array with calculated data or false on failure.