fn partition(
samples: &[(TreeSample, f64)],
feature: u8,
threshold: u64,
) -> (Vec<(TreeSample, f64)>, Vec<(TreeSample, f64)>)Expand description
Partition a node’s samples by a split, mirroring the walk’s <=
routing. feat_value <= threshold goes left. The recency weights
ride along with their samples.