Python rewrite of the Urb/Homemaker stack
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Claude a76ed3b9b8
Quality aggregation: divide out how many questions a leaf was asked
39.17 left the search's storey choice unexplained and blamed value_rate. It is
not the rate, or not only.

Measured over the twelve baseline runs, value/cost by leaf kind: outside ground
7.40, roof terrace 2.69, room 0.34, circulation 0.02. A terrace returns 2.7x
its cost where a room returns a third of it, so filling upper storeys with
terrace is not the search leaving value on the table -- it is by a wide margin
the most profitable thing the objective offers. 7% of the corpus area produces
32% of its value.

Most of that gap is mean quality: 0.986 for a terrace against 0.223 for a
room. Quality is a PRODUCT of factors and the kinds are not asked the same
number of questions -- an outside leaf is exempt from size, crinkliness and
access, so 3 of 7 factors can ever bite it against a room's 6. Each exemption
is individually right (no programme size target; uncovered outside is lit by
definition; ground-level outside needs no access). The consequence is not: a
leaf exempt from the two harshest factors out-scores one judged on them and
doing well, purely by not being asked, and quality multiplies the value rate.

Stated generally, and this is not about outside space: under a product, adding
any new quality criterion mechanically devalues every leaf it applies to,
including leaves that score 1.0 on it. The objective's scale should not depend
on how many things it measures.

quality_aggregate="geometric_mean" (default OFF, "product" is stock) divides
that out. Computed in log space so six small factors cannot underflow the
product before the root is taken; a zero factor still gives zero, so a fully
buried leaf is worth nothing either way.

Telling "exempt" from "asked and scored 1.0" needs factor_is_asked, which
restates conditions that live inside the quality_* methods. That duplication
can drift, so tests/test_fitness_aggregate.py pins it against every leaf in the
corpus: wherever the predicate says exempt, the factor really is 1.0.

Fail set byte-identical everywhere, and for a stronger reason than 39.13/39.14
had: evaluate_leaf emits each fail from the factor itself before anything is
combined, so no aggregation can move one. Score effect +37% to +169%, reaching
all four programmes where the crinkliness changes reached two; room value/cost
0.34 -> 0.66, circulation 0.02 -> 0.07.

Deliberately not fixed: a terrace still out-earns a room 4:1, which is the
rates (value_supported = value_inside = 300 against costs of 110 and 200), not
the aggregation. That is a design judgement for the programme author, and
39.16 is a standing reminder that "this inherited constant looks wrong" has
been wrong twice already in this section. Left open on ecx with the numbers.

A/B running; verdict to follow.

Refs homemaker-py-ecx.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MJ84Feep79Hhm3E4zZJmnB
2026-09-05 18:57:00 +00:00
.beads bd: close homemaker-py-773; file ecx 2026-09-05 17:46:53 +00:00
.claude Scaffold homemaker-py with validated geometry port 2026-06-10 20:50:20 +01:00
examples coldstart maple-court seed 2 @ 500000: 55 fails (11h/44s) 2026-09-03 10:06:06 +01:00
experiments Quality aggregation: divide out how many questions a leaf was asked 2026-09-05 18:57:00 +00:00
src/homemaker_layout Quality aggregation: divide out how many questions a leaf was asked 2026-09-05 18:57:00 +00:00
tests Quality aggregation: divide out how many questions a leaf was asked 2026-09-05 18:57:00 +00:00
.gitignore Ignore the A/B harnesses' per-process shard files 2026-09-05 06:29:15 +00:00
AGENTS.md §39.7: access requirements become a declared usage: attribute (homemaker-py-sel) 2026-08-26 13:39:41 +00:00
CLAUDE.md §39.7: access requirements become a declared usage: attribute (homemaker-py-sel) 2026-08-26 13:39:41 +00:00
DESIGN.md Quality aggregation: divide out how many questions a leaf was asked 2026-09-05 18:57:00 +00:00
pyproject.toml homemaker-py-2g7.5: CP-SAT exact room-code assignment (seeder + reassign op) 2026-08-04 09:19:36 +01:00
README.md §39.7: access requirements become a declared usage: attribute (homemaker-py-sel) 2026-08-26 13:39:41 +00:00

homemaker-layout

Programme-driven building-layout search over slicing trees. A clean-room Python successor to the Perl Urb project, intended to eventually be 100% Python.

Why a rewrite

Urb represents a building as a binary slicing tree where room sizes are derived top-down from division ratios. That makes room area an emergent property of every cut above it, which:

  • gives the genome low locality (a cut near the root rescales every descendant),
  • makes target room sizes nearly impossible to hit, so the gaussian size penalty dominates fitness, and
  • defeats crossover (transplanted subtrees lose their proportions).

homemaker inverts this: leaves carry target dimensions from the programme and division ratios are solved bottom-up for a fixed topology. The evolutionary search then only explores topology + types + adjacency.

Phase plan

  1. Solver experiment: port Urb's geometry, re-solve ratios from programme targets, score the result against the original via the Perl oracle.
  2. Native Python fitness (retire the Perl oracle).
  3. Memetic search: canonical slicing genome + high-locality operators + Nelder-Mead inner loop.
  4. Penalty reshaping: lexicographic (-n_fails, fitness) outer-search comparison.
  5. Representation upgrade: canonical slicing encoding + bottom-up shape feasibility, scaled to larger programmes.
  6. Search-quality experiments (current): a long running series of opt-in levers tried against the harbor-house, health-centre, and programme-house example corpora — leaf-sharing, finish-time cell→room collapse, ruin-and-recreate LNS, 2-opt polish, multi-use/co-located leaves, adjacency-graph and bubble-diagram fitness signals, and more. Most of these are negative/null results kept as opt-in flags or reference code rather than defaults. See DESIGN.md §11 onward for the full, numbered experiment log with methodology and results for each.

Layout

  • src/homemaker_layout/dom.py — read/write Urb .dom YAML into a Node tree.
  • src/homemaker_layout/geometry.py — faithful port of Urb's top-down geometry.
  • src/homemaker_layout/programme.py — parse patterns.config space requirements.
  • src/homemaker_layout/solver.py — bottom-up ratio solve (scipy).
  • src/homemaker_layout/fitness.py — native Python fitness evaluator.
  • src/homemaker_layout/fitness_cmd.pyhomemaker-fitness CLI (drop-in for urb-fitness.pl).
  • src/homemaker_layout/collapse_cmd.pyhomemaker-collapse CLI: finish-time global cell→room relabel of a .dom.
  • src/homemaker_layout/graph.py — leaf-adjacency graph for programme-driven checks.
  • src/homemaker_layout/genome.py — topology genome: base-floor tree + per-storey deltas.
  • src/homemaker_layout/operators.py — high-locality mutation and subtree crossover.
  • src/homemaker_layout/innerloop.py — ratio optimisation inner loop (Nelder-Mead / CMA-ES).
  • src/homemaker_layout/driver.py — memetic search outer loop.
  • src/homemaker_layout/evolve.pyhomemaker-evolve CLI entry point.
  • src/homemaker_layout/oracle.py — legacy Perl shim, kept for cross-validation only.
  • src/homemaker_layout/bubble.py — 3D bubble-diagram adjacency fitness-signal prototype (DESIGN.md §27); validated null, not wired into fitness.py — reference only.

Room codes and reserved names

Leaf types live in three namespaces that share a first character. Only the first is enforced; the other two are conventions the fitness function reads, so a room's spelling can change how it is scored.

1. Generic structural types — C, O, S (reserved). The leaves the search itself creates: C circulation, O outside, S sahn (an outside court that also serves as circulation). Always uppercase. A programme code spelled exactly C, O or S is rejected at load.

2. Programme room codes — anything else, lowercase. k1, b1, cr1, of, and single-character codes like r or t. These may start with any letter: since DESIGN.md §39.4 the generic tests match C/O/S exactly, so naming a room cr1 no longer makes it circulation. (Before that fix it did — and silently dropped it from the required-space check entirely.)

3. Access requirements — the usage: attribute. Every space declares one of living, kitchen, bedroom, toilet, utility, none. Mandatory, no fallback, and a missing or unknown value is a load error. It replaced a first-character convention (b/t/l/k) under which a room silently inherited another room's connectivity rules from its spelling — la1 "Laundry Room" was trimmed as a living room (DESIGN.md §39.7).

spaces:
  la1:
    usage: utility          # controlled, drives engine behaviour
    name: Laundry Room      # free text, building-specific

A usage value exists only where the engine treats it differently, so the vocabulary is closed: a new access class means new code, not new config. Check a programme with:

python experiments/audit_programme_config.py

which reports reserved-name collisions, the usage class each code picks up, and whether each room's size/width/proportion/crinkliness targets are mutually satisfiable at all.