Reverse RSI (price required for RSI to reach level)
len - lookback period
level - formula specifying the desired RSI level
This function can be used to calculate entry or exit limit prices based on RSI reaching a specific level.
Calculation uses the original Welles Wilder formula.
Wilder's exponential smoothing is equivalent to using 2*len-1 in a regular exponential moving average.
This indicator supports ultra-fast one-pass calculation when used in the Data Section with a non-variable length.