Rolling Min
What it measures: The lowest value in an N-bar window (includes the current bar)
When to use it: Finding short-term support / breakdown levels. Can take in-series, e.g. the min of ATR
Typical period: 20
Caution: Includes the current bar — to compare "price breaking the prior low" you need to route it through Lag(1), or use Swing Low instead
Formula the engine actually uses
series.rolling(period).min()
smoothing: None (raw window min) · warmup: period