https://zorro-project.com/manual/en/transform.htm Spearman(vars Data, int TimePeriod): var Spearman's rank correlation coefficient; correlation between the original Data series and the same series sorted in ascending order within TimePeriod (1..256). Returns the similarity to a steadily rising series and can be used to determine trend intensity and turning points. Range = -1..+1, lag = TimePeriod/2. For usage and details, see Stocks & Commodities magazine 2/2011. Source available in indicators.c.
What are those "arbitrary functions"? Already listed above?
