Overview:
The Parabolic SAR was developed by Welles Wilder. 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. A stop and reversal (SAR) occurs when the price penetrates a Parabolic SAR level.

Parameters:
str Symbol
dbl Min AF (accumulation factor)
dbl Max AF (accumulation factor