Python rewrite of the Urb/Homemaker stack
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Claude f07b3865ef
No size cap on circulation: twice the corridor is twice as bad, and no worse
Owner's ruling: "as long as circulation is more expensive to build than it has
value then we have a linear ramp. a gaussian ramp is probably not appropriate
here as double the amount of corridor is simply twice as bad, so it should
score the same as two half size corridors".

Both halves check out. The linear ramp is already there -- value_circulation 50
against a build cost of 200, so every m2 of corridor is worth -150 and the
objective pushes for less of it without needing a cap. And the AMOUNT of
circulation is separately governed at building level by ratio_circulation
[0.00, 0.20], a gaussian on the circulation fraction, which is where that
question belongs. The per-leaf size gaussian was a third charge on the same
thing.

It was also the only one of the three that depended on how the corridor was cut
up. One 20 m2 corridor scored gaussian(20,0,14) = 0.360 and contributed 360;
two 10 m2 halves scored 0.775 each and contributed 775 between them. Splitting a
corridor in half multiplied its value by 2.15x -- an artefact of where the tree
happened to cut, rewarding the search for fragmenting its own spine. The
ruling's test (one 2A leaf must score as two A leaves) is exactly what a
gaussian on an amount cannot satisfy, and is now a test.

size_circulation = None; quality_size returns 1.0 for circulation and
shapecurve gives amin, amax = 0, inf.

BUG this exposed: get_space_params falls through to a habitable default when a
generic family key is missing and could not tell "missing" from "present but
null", so a corridor silently inherited a room's 16 m2 size target.
_generic_param now returns (found, value); pinned by a test. The same trap
applied to 39.22's proportion_circulation.

Fail-set effect of 39.22 and 39.23 together: 16 corridor size fails and 7
proportion fails removed, none added. harbor 33/43/42 -> 32/40/38, maple
54/73/55 -> 51/65/52, health-centre 4/9/5 -> 3/9/5, programme-house unchanged.
The layouts are identical -- these are failures the objective should never have
been reporting.

Two shape-curve tests moved fixture: both built an infeasible upper storey from
a 'C' leaf, infeasible precisely because of the bounds now removed. The fixture
is a cr1 leaf, whose infeasibility is a contradiction between two of its own
bounds (needs >= 180 m2 for its aspect bound, <= 101.5 m2 for its size bound
across the box's fixed 23.52 m span) rather than a tight fit. The invariants
they test are unchanged.

Left open on hxi: the rate gap, value_circulation 50 against value_inside 300
on identical build cost. Whether a corridor is worth a sixth of a room per m2
is a design judgement, and the linear ramp is only as steep as that number.

419 passed.

Refs homemaker-py-hxi.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MJ84Feep79Hhm3E4zZJmnB
2026-09-06 15:01:12 +00:00
.beads bd: retitle homemaker-py-hxi and correct its premise 2026-09-06 12:56:40 +00:00
.claude Scaffold homemaker-py with validated geometry port 2026-06-10 20:50:20 +01:00
examples A terrace is no longer worth more per m2 than a real internal room 2026-09-05 19:25:02 +00:00
experiments Remove the Perl oracle 2026-09-06 07:56:24 +00:00
src/homemaker_layout No size cap on circulation: twice the corridor is twice as bad, and no worse 2026-09-06 15:01:12 +00:00
tests No size cap on circulation: twice the corridor is twice as bad, and no worse 2026-09-06 15:01:12 +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 Remove the Perl oracle 2026-09-06 07:56:24 +00:00
DESIGN.md No size cap on circulation: twice the corridor is twice as bad, and no worse 2026-09-06 15:01:12 +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.