pub fn lag1_autocorrelation(values: &[f64]) -> Option<f64>Expand description
The lag-1 autocorrelation of values in draw order: the sum of
products of each deviation from the mean with the next one, over the
sum of squared deviations.
A diagnostic: for independent draws it lies near -1 / n, within about
2 / √n, so ±0.45 for 20 renders. A drift over the sequence takes it
towards 1. Returns None for fewer than two values or values that do
not vary.