Refactor distance matrix calculation logic for consistency

Ensures that combined distance matrix calculations use the exact same site selection by retaining sampled data within Sankoff bundles. This involves refactoring post-sampling logic into shared functions, implementing `SankoffBundle` to reuse internal tally data, and adding validation to guarantee consistent site selection across all distance calculation paths.
2026-09-12 07:45:32 +02:00
parent be838da256
commit a8bcf5ffac
6 changed files with 196 additions and 33 deletions
@@ -202,6 +202,8 @@ A family is eligible for a genome pair $(i,j)$ only if both genomes carry exactl

 `--subsample`, `--free-loss`, `--no-ambiguity`, `--entropy`/`--entropy-sd` are shared by `--pseudo-alignment`, `--sankoff` (and everything it implies: `--tnt`/`--phyg`/`--iqtree`), and a `snp-*` `--distance` value — one draw feeds all of them in a single invocation. `--subsample` is mandatory for `--pseudo-alignment`/`--sankoff`; for a `snp-*` `--distance` value it is optional (omitted means every non-monomorphic family in the index, not an approximation).

+Combining `--sankoff` (or `--tnt`/`--phyg`/`--iqtree`) with a `snp-*` `--distance` value in the same command reuses that one draw for both — the distance and the Sankoff calibration/alignment are guaranteed to be computed from the *identical* set of sampled sites, never two independent samples, so the two outputs are directly comparable. This only holds within a single command; running them as two separate `obikmer phylo` invocations draws two independent samples even with the same flags.
+
 Without `--subsample`, every variable family (family size ≥ 2) is used. With `--subsample N`, roughly `N` families are kept instead, drawn in proportion to how many candidate families each part of the index actually holds, so the sample stays representative of the whole index. If the index has fewer than `N` candidate families, `--subsample` has no effect.

 ### `--shannon`: measuring how informative a family is