Answers homemaker-py-yql. §39.8 established the search is not PAID to sever
circulation; this establishes where connectivity actually goes.
CONSTRUCTED, THEN LOST -- at construction time, in the resize.
_assign_adjacency_aware picks circulation as a CONNECTED dominating set and
succeeds every time. _size_divisions_from_targets then moves every wall to hit
the programme's area targets and destroys it.
Measured over 20 constructed seeds per programme, fully-connected seeds:
harbor-house 1/20, health-centre 1/20, maple-court 0/20. The control -- same
seeds with proportion_aware=False, i.e. no resize -- is 100% connected on all
three. Mechanism confirmed on health-centre: 41 of 49 circulation-to-circulation
edges destroyed by the resize, surviving shared walls squeezed to 0.54-1.11 m
against door_width=1.2, so they stop counting as edges. This is the failure mode
§37.7 recorded for CP-SAT assignment, never looked for in connectivity, where it
costs 35-95 points.
§39.7 COST CHECK: zero. Identical rates under prefix-inferred vs declared
usages -- has_circulation never trims C-C edges, so last commit's usage change
could not and did not make connectivity harder to achieve.
REPAIR MEASURED NEGATIVE. operators.repair_circulation_settled applies §37.7's
own alternating-minimisation fix (re-connect against the settled geometry by
retyping the cheapest bridging leaves to C). It restores 100% connectivity on
all three programmes -- and is still the wrong trade: connectivity fails fall
0.8-1.7 per seed while missing-room fails rise 5.0-8.5, because every retyped
leaf displaces a required room at a 3-5 fail cascade (§38.5). Kept default off
with the write-up, per house style for a null lever, plus a byte-identical
default test and a test asserting it does reconnect every storey.
NEXT LEVER, FILED: preserve the connection during the resize (constrain
_size_divisions_from_targets so a shared C-C boundary cannot fall below
door_width) rather than rebuild it afterwards at the programme's expense --
a constraint on an existing solve, not a new repair pass. solver.py's existing
min_width_generic is the same idea applied to leaf width rather than to a shared
boundary, so it may belong beside it.
Adds experiments/diag_connectivity_yql.py (construct / cost / survive reports).
355 passed (+2 new), same 7 pre-existing fixture failures, lint unchanged.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MJ84Feep79Hhm3E4zZJmnB
