feat(hpc): Codec8 — compile-time 8-bit codec (phase a, scalar) + ratified plan by AdaWorldAPI · Pull Request #370 · AdaWorldAPI/ndarray

AdaWorldAPI · 2026-10-24T09:51:02Z

What

Phase (a) of .claude/plans/quantized-codec8-v2.md (content v3, ratified by a 5+3 council). The earlier runtime-scale prototype on this branch is gone (backed out in 62c43c9).

src/hpc/codec8.rs adds one codec, Codec8<Storage, CodeSpace, Rounding, NanPolicy>, built from sealed marker types. The calibration is a marker type passed to each call, and nothing is selected at run time.

parameter	markers
storage	`I8`, `U8` (u8 = i8 ^ 0x80 for Asym/Sym, the raw code for UnitFull)
code space	`Asym` (-128..127), `Sym` (-127..127), `UnitFull` (c/255)
rounding	`TiesAway`, `TiesEven`, `Floor`
NaN policy	`NoNaN`, `NaNAtMin` (only with `Sym`, where -128 means NaN)

Combinations that don't compile: Asym + NaNAtMin and I8 + UnitFull are E0277; doctests pin both.
Encode: a true division, because a precomputed reciprocal changes codes at half-ties. The zero point is added as an integer.
Calibration check: const assertions reject a non-positive or non-finite scale, or a zero point outside the code space. They run on encode and on decode, so code that only decodes is covered too; a compile_fail,E0080 doctest pins the decode-only path.
Integer rounding: div_round works from the quotient and remainder, so it does not overflow for any u128 operands.
Checking: the checked encode/decode validate once per slice. The unchecked bodies are pub(crate) and give a defined result for every input.
Aliases: TfliteAct, TfliteWeight, OnnxQ, SpoFcTruth. NativeLane is held back until its rounding is decided (plan §8 item 1).
Clippy: codec8.rs opts back into clippy::all, because pub mod hpc allows it.

Also in this PR:

examples/codec8_asm_probe.rs and scripts/codec8_asm_diff.sh, the assembly and timing probe.
The plan, and .claude/knowledge/coresearch-2026-10-24-i8-codec8-map.md.
A blackboard entry.

Tests and gates

cargo test --release --lib hpc::codec8: 16 passed.
cargo test --release --doc hpc::codec8: 11 passed. This includes two compile_fail,E0277 doctests and one compile_fail,E0080 doctest.
Codex findings: both are fixed and disable-checked. Removing the decode-path assertion makes the E0080 doctest compile, so it fails. Restoring (2n + d)/(2d) fails the large-operand test.
G2 byte identity: TfliteAct with the fitted scale bits equals quantize_f32_to_i8, including NaN and ±inf.
G13 spoFC: encode_ratio with Floor equals the spoFC encoder over the evidence grid.
Clippy (-D warnings) and cargo fmt --check are clean.
G5 assembly: on x86-64-v3 and -v4, the generic and hand-written kernels compile to identical code (vectorised, vdivps). The negative control differs.
G6 timing: not met as written. Repeated runs of identical machine code vary by up to 17% on this host, so a 2% band can't be resolved. G5 is the evidence that the parameters cost nothing.

Not in this PR

(b) The codegen check on every arm, which follows in its own PR.
(c) The certified tables and their generator.
(d) Code laws.
(e) Head-to-head probes.
(f) The lance-graph facades.

Plan §8 lists the decisions still open.

🤖 Generated with Claude Code

https://claude.ai/code/session_01G22yT6htkcdyXsihxxXdrg

…paths with endpoint gates

coderabbitai · 2026-10-24T09:51:11Z

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AdaWorldAPI · 2026-10-24T12:08:19Z

Being refactored. Do not merge or review this version.

This branch was pushed without being compiled. CI fails because of a missing doc comment (src/hpc/quantized.rs:576, denied by -D missing-docs) and unformatted code. The design is also being replaced:

Scale and zero point are runtime arguments here. In the refactor, calibration is a compile-time marker. Runtime calibration exists only behind a lab-calibration Cargo feature.
Every element is checked and the result is collected into a Result<Vec<_>, _>. Validation moves to the boundary, so the hot path is a hoisted, vectorisable loop.
Each mode has its own function. The refactor has a single Codec8<Storage, CodeSpace, Rounding, NaN> over marker types, with I8 and U8 storage.
There are no tanh tables. The refactor adds const 256-entry tables written by a certified offline generator, plus a test that regenerates them.
The refactor adds gates: generic and hand-written code must compile to identical assembly, plus timing checks.

The edge-case test inputs carry over: signed zero, both saturations, negative half-ties, and all 256 codes. Before the next push I will run cargo fmt, clippy -D warnings, the docs lint and cargo test --release locally.

Generated by Claude Code

…runtime-scale prototype - .claude/plans/quantized-codec8-v2.md: one compile-time Codec8<Storage, CodeSpace, Rounding, NanPolicy>, calibration as a marker type, prepare vs execute, certified const tables, edge cases, measured results, checklist, open items, superseded designs named once. Goes through /5plus3 next. - .claude/knowledge/coresearch-2026-10-24-i8-codec8-map.md: the /coresearch exploration map, banked so it survives the container. - the staged prompt is marked superseded (kept for provenance). - src/hpc/quantized.rs: back to master. The per-mode runtime-scale functions contradicted the compile-time ruling and never compiled under -D missing-docs; their edge-case inputs carry over into the v2 checklist. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G22yT6htkcdyXsihxxXdrg

The plan file keeps its name; its content is now v3. Changes from the council: true division in encode (a precomputed reciprocal changes codes at half-ties), exact scale bits for the byte-identity gate, a concrete compile_fail with a compiling twin, a clippy opt-in in codec8 (pub mod hpc allows clippy::all), the table generator in tools/ instead of a crate, SIMD primitives landing first, XOR storage scoped to Asym/Sym, UnitOdd/UnitMidrise test-only, NativeLane held until its rounding is decided, a per-mode table inventory, separate data and table rounding gates, spoFC byte and three-mode head-to-head gates, and restore conditions for parked arms. Blackboard entry added in the same commit. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G22yT6htkcdyXsihxxXdrg

One `Codec8<Storage, CodeSpace, Rounding, NanPolicy>` over sealed marker types, with calibration as a marker type (plan .claude/plans/quantized-codec8-v2.md, ratified by a 5+3 council). Nothing is selected at run time. - Storage I8 / U8 (u8 = i8 ^ 0x80 for Asym/Sym, raw for UnitFull); code spaces Asym, Sym, UnitFull; rounding TiesAway / TiesEven / Floor; NaNAtMin only for Sym (Asym + NaNAtMin and I8 + UnitFull are E0277, pinned by doctests). - Encode uses a true division (a reciprocal changes codes at half-ties) and adds the zero point as an integer; const assertions reject a bad calibration. - Checked encode/decode validate once per slice; the unchecked bodies are pub(crate) and total. - Aliases: TfliteAct, TfliteWeight, OnnxQ, SpoFcTruth. NativeLane waits for the operator's rounding decision. - codec8.rs opts back into clippy::all (pub mod hpc allows it). Gates: 14 unit tests and 10 doctests pass; G2 byte identity with quantize_f32_to_i8; G13 spoFC floor encoder equality; clippy -D warnings and fmt clean. G5: generic and hand-written kernels compile to identical asm on x86-64-v3 and -v4, negative control differs (scripts/codec8_asm_diff.sh, examples/codec8_asm_probe.rs). G6's 2% timing band is not resolvable on this host (identical code varies up to 17%) and is recorded as not met. Blackboard and plan updated in the same commit. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G22yT6htkcdyXsihxxXdrg

chatgpt-codex-connector · 2026-10-24T13:37:57Z

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📝 Code Review	✅ Completed 2026-10-24T13:39:43.978366Z	`4c82adf`	Draft marked ready

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Codex review on #370: - The SCALE/ZERO_POINT const asserts lived only in encode_one, so a consumer that only decoded never instantiated them; SCALE = -1.0 compiled and decoded. Both directions now call assert_calibration, pinned by a compile_fail,E0080 doctest on the decode-only path. - TiesAway::div_round computed 2n + d and 2d, TiesEven compared 2r with d; both wrap for large u128 operands. Both now use quotient and remainder with the half test as r vs d - r. Tests at 2^127 and u128::MAX, plus small-operand tie tables. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G22yT6htkcdyXsihxxXdrg

research(quantized): add independent full-range and symmetric RNE i8 …

bd64f9c

…paths with endpoint gates

AdaWorldAPI added 2 commits October 24, 2026 12:22

research(quantized): reserve -128 as NaN in opt-in symmetric i8 leg

5d4210c

docs(research): staged three-mode ndarray i8 NaN and ONNX cross-check…

cf0d579

… prompt

AdaWorldAPI changed the title ~~research(quantized): dual explicit-scale signed-i8 RNE range contracts~~ research(quantized): U8 / i8-asym / i8-sym+NaN contracts and staged probe Oct 24, 2026

AdaWorldAPI added 2 commits October 24, 2026 12:26

test(quantized): avoid false exact-midpoint assumption in legacy u8 f…

8e509ce

…32 path

docs(research): reflect f32 midpoint precision in staged U8 audit

b9b1d4e

AdaWorldAPI changed the title ~~research(quantized): U8 / i8-asym / i8-sym+NaN contracts and staged probe~~ [BEING REFACTORED — do not merge] research(quantized): U8 / i8-asym / i8-sym+NaN contracts and staged probe Oct 24, 2026

claude added 3 commits October 24, 2026 13:03

AdaWorldAPI changed the title ~~[BEING REFACTORED — do not merge] research(quantized): U8 / i8-asym / i8-sym+NaN contracts and staged probe~~ feat(hpc): Codec8 — compile-time 8-bit codec (phase a, scalar) + ratified plan Oct 24, 2026

AdaWorldAPI marked this pull request as ready for review October 24, 2026 13:37

chatgpt-codex-connector Bot reviewed Oct 24, 2026

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Comment thread src/hpc/codec8.rs

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AdaWorldAPI merged commit be18d17 into master Oct 24, 2026
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AdaWorldAPI mentioned this pull request Oct 24, 2026

feat(hpc): codec8 phase (b) — keep ties-away encode vector on wasm #371

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feat(hpc): Codec8 — compile-time 8-bit codec (phase a, scalar) + ratified plan - #370

feat(hpc): Codec8 — compile-time 8-bit codec (phase a, scalar) + ratified plan#370
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