Detrended Synthetic Price is a function that is in phase with the dominant cycle of real price data. This DSP is computed by subtracting a half-cycle exponential moving average (EMA) from the quarter cycle exponential moving average. See "MESA and Trading Market Cycles" by John Ehlers pages 64 - 70.
You can change long to short in the Input Settings Please, use it only for learning or paper trading. Do not for real trading.