cultmath-tapes map: the Cycles cuts under cycles-kernel-reference-ruled (AVX2 single-rounding probe, documented bound)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Meta Vens 2026-10-14 02:38:35 +02:00
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@ -418,6 +418,30 @@ the two CultLib cuts (pass 3):
`interval-ops` (pass 4): `docs/cultmath-interval-ground-cut-interval-ops.r3.spec.json`;
`glsl-lowering` r2 and `site-ground` r3 now depend on it.
### The Cycles cuts (ruling `cycles-kernel-reference-ruled`)
- `cycles-converters` r2 is the fix batch for Soul's s1. Its specs are typed
documents in the mind, not files here.
- `cycles-noise` r1 waits on `cycles-converters` and reuses its oracle tool.
It inherits the ruling: its fixtures are the unfused SSE4.2 kernel's exact
witness, and every other build is held to the tolerance-class table that
`tools/cycles-oracle/README.md` holds.
Body fact, probed 2026-10-14 on Yggdrasil. The job script, log and model are
`job.sh`, `probe-avx2.log` and `model.py` in
`F:\Projects\eureka-handoff-aux-2026-10-14\imagination-cycles-converters-r2\`.
Blender 5.2.2 Linux was run on its default AVX2 kernel, with the oracle's
kernel check removed, over the committed `math.json` operands at e48f9488.
Results against the SSE4.2 fixture:
- `cycles_floored_modulo` differs on 151 of 1024 rows and `cycles_wrap` on 30.
- A single-rounding model, `fma(-floor(a / b), b, a)` (wrap:
`fma(-range, floor((value - min) / range), value)`), reproduces every one of
those rows bit for bit. So the contraction never moved the floor.
- The worst `|delta|` is 0.91 x 2^-24 (|a| + |b|) for floored modulo and
0.77 x 2^-24 (|value| + |min| + |range|) for wrap. Both fall within the
documented bound of 2^-23 times the same sum.
## Standing design decisions (means; Self may overrule)
- D1. Intervals are `float2(lo, hi)`. Affine arithmetic is not taken; the