Trailing-window length.
Annualisation factor (252 daily, 52 weekly, 12 monthly, 1 = no annualisation).
Minimum acceptable return (only deviations below this contribute to the denominator).
https://screamer.readthedocs.io/en/latest/ for the Python reference and full details.
Annualised Sortino ratio: Sharpe with downside-only deviation.