https://github.com/aiez/skape

skape: a multi-objective optimizer that spends labels like they are expensive — because they are. Each level it labels a few rows, projects the whole pool onto a FastMap line (poles = the two most distant labelled rows, by x-distance, so unlabelled rows project too), keeps the better two-thirds, and recurses. The ~50 labels it buys then grow a tiny min-variance tree that sorts a held-out half. One stdlib file, zero dependencies: the nuff closure it needs (typed CSV, Sym/Num columns, distance, tree) is inlined.

python3 -B skape.py -file ../optimiz/auto93.csv   # -> a 0..100 win
python3 -B skape.py -budget 30 -keep 0.7          # tune any setting

Sections: NAME | DESIGN | USAGE | SETTINGS | STYLE | LICENSE | AUTHOR

Files: skape.py | test_skape.py | Makefile | pyproject.toml

NAME

skape - a FastMap landscape active learner (stdlib only)

DESIGN

The loop (landscape): poles in O(2N), keep the kept side.
  label `grow` rows  ->  the worst survivors of the last cut
  project the pool   ->  (d(a,r)^2 + c^2 - d(b,r)^2) / 2c, c=d(a,b)
  drop the worst 1/3 ->  recurse until `budget` labels are spent
Poles come only from the labels still inside the surviving
region (local poles). Distance is root-stable: norms and goals
are read off the whole data, so subtrees see no spurious splits.

The yardstick (holdout): split rows in half, acquire on one half,
grow a tree, sort the other half by the tree, check the top
`check`, take the best by true distance, score 0..100 vs the
data's own spread. Mean over `repeats`.

USAGE

python3 -B skape.py [-KEY VAL ...]
  -file F     dataset (CSV; `+`/`-`/`!` header suffix = goal/klass)
  prints      "WIN<tab>basename"  (WIN is the mean hold-out score)

make test     # smoke tests (needs ../optimiz)
make sh       # konfig dev shell

SETTINGS

seed 1234567891   grow 4     keep 0.66    budget 50
cap  1024         check 5    leaf 3       repeats 20

Any `-key val` on the CLI overrides; types follow the default.

STYLE

konfig house style (style_code.md): 2-space indent, short names,
one-line colon bodies, python3 -B. Promoted from sand-box/far.py;
the nuff primitives are inlined so the file stands alone.

LICENSE

MIT (c) 2026 Tim Menzies.

AUTHOR

Tim Menzies <timm@ieee.org>, https://timm.fyi

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