Python rewrite of the Urb/Homemaker stack
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Claude e92a96ac99
Correct 39.14/39.15: the crinkliness constant is Alexander 159
The owner supplied the provenance the analysis was missing. The constant is
Christopher Alexander, A Pattern Language 159, "Light on Two Sides of Every
Room", and it changes what the numbers mean.

1/crink = A/(L*h) is floor area per metre of ILLUMINATED wall over storey
height. It is not room depth -- it equals depth only for a room lit on one
side. So 5/6 * h = 2.5 m is 2.5 m of room depth PER WINDOW WALL: one side
allows 2.5 m at the peak and 4.86 m at the fail edge, two opposite sides allow
5.00 m and 9.72 m. A 4 m room scores 0.395 lit on one side and 0.902 lit on
two. The factor is the pattern stated as a ratio, and it is not
miscalibrated.

WITHDRAWN from 39.14: the "2.5 m absurd optimum" reading, and "the corpus's
realised median depth is 2.95 m, so the search built what it was paid for" --
2.95 was the median A/L, while the corpus's single-aspect leaves are a median
3.46 m deep and its two-opposite leaves 4.42 m. Ordinary rooms. Section
retitled, passage struck in place.

WITHDRAWN from 39.15: calling six specs "self-contradictory". They are large
rooms, and under Alexander a large room is supposed to need two aspects; the
audit's new column reports the pattern working, not a mis-specification. What
is real is the tension between that demand and what the plan form supplies.

SURVIVES, on a better argument: crinkliness_shape="daylight". 159 states a
MINIMUM, and a two-sided gaussian turns a minimum into a target -- 68% of the
133 leaves in the clipped region are lit on two or more sides, mean quality
0.770, docked for satisfying the pattern well, on top of the
exterior_wall/boundary_wall charge those windows already carry in cost.

New 39.16 records this and relocates the residual. Over the 430 graded
baseline leaves: unlit 77 (100% fail), one side 208 (15%), two-corner 87 (2%),
two-opposite 34 (0%), three/four 24 (4%). Light on two sides all but
guarantees a pass and only 33.7% of leaves get it, so the open question is why
a binary slicing tree on a convex plot can only give a third of its leaves two
aspects -- a plan-form question, not a scoring one. Filed as
homemaker-py-773; 39.11's courtyard finding is the same question from the
other side.

Both errors came from reading a dimensionless ratio as a length, so the
provenance and the interpretation now sit next to the constant in fitness.py,
not only in DESIGN.md.

405 passed, 72 skipped.

Refs homemaker-py-u5q.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MJ84Feep79Hhm3E4zZJmnB
2026-09-05 16:04:44 +00:00
.beads bd: close homemaker-py-9gj and homemaker-py-u5q; file k54 2026-09-05 15:11:19 +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 Record what the crinkliness examination found: 39.13, 39.14, 39.15 2026-09-05 15:11:11 +00:00
src/homemaker_layout Correct 39.14/39.15: the crinkliness constant is Alexander 159 2026-09-05 16:04:44 +00:00
tests Make the crinkliness factor one-sided: stop billing the daylit wall twice 2026-09-05 07:27:02 +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 Correct 39.14/39.15: the crinkliness constant is Alexander 159 2026-09-05 16:04:44 +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.