ts_rank(ts_returns(close, 15), 30)
-ts_corr(ts_rank(close, 30), ts_rank(volume, 30), 10)
(close - ts_min(close, 20)) / (ts_max(close, 20) - ts_min(close, 20))
ts_rank(ts_delta(close, 3) / ts_delay(close, 3), 15)
-ts_std(ts_returns(close, 1), 30)