Parabolic SAR

ParabolicSAR(Min AF, Max AF)
PSAR(Min AF, Max AF)

Overview
Author Welles Wilder developed the Parabolic Stop and Reversal or simply Parabolic SAR. This indicator is always in the market (whenever a position is closed, an opposing position is taken). The Parabolic SAR indicator is most often used to set trailing price stops.

Interpretation
A stop and reversal (SAR) occurs when the price penetrates a Parabolic SAR
level. Recommended Parameters
Min AF (Accumulation Factor): 0.02
Max AF (Accumulation Factor): 0.2

Example
set BUY = CROSSOVER(CLOSE, PSAR(0.02, 0.2))
Evaluates to buy when the close recently crossed over the Parabolic SAR.