Commodity Channel Index (CCI)

CommodityChannelIndex(Periods, MA Type)
CCI(Periods, MA Type)

Overview
Donald Lambert developed the CCI indicator. Although the purpose of this
indicator is to identify cyclical turns in commodities, it is often used for securities.

Interpretation
This indicator oscillates between an overbought and oversold condition and
works best in a sideways market.

Recommended Parameters
Periods: 21
MA Type: SIMPLE

Example
set CCI12 = CCI(12, SIMPLE)
set BUY = CCI12 > 0 AND REF(CCI12 , 1) < 0
Evaluates to buy when the CCI has just moved into positive territory.