Function minimal_explanation 

pub fn minimal_explanation(
    rules: &[NQuin],
    observations: &[u64],
    explains: u64,
    out: &mut [u64],
) -> usize

Minimal explanation generation (Peirce’s parsimony): the DISTINCT root hypotheses that together explain every observation in observations, written into out. A single hypothesis accounting for several observations appears once (the smallest covering set under the chain model). Observations with no explanation are skipped. Returns the count. Zero-heap.