Phase 2, S35. Two real defects from one root cause, both confirmed by trace
rather than taken from the audit:
1. Divergence. WasmIML built its TS Dataset mirror with a cap of 100 while
every addExample() ALSO pushed into the C++ FIFO ring, capped at 128. Since
train() reads the C++ ring and trainAsync() reads the TS mirror, past 100
examples the two trained on different datasets — silently.
2. Latent OOB read. nisps_ml_train sizes its sample-weight span by the C++
side's example_count() (up to 128), but wasm-iml.ts allocates that heap
buffer from the TS dataset's size (<=100). Once the ring exceeds the mirror,
the span reads past the end of the caller's allocation.
Fix: name the capacity ONCE as nisps::ml::kDefaultMaxExamples = 128, used by
FixedStorage's default template arg, DynamicStorage's default ctor arg, and the
MLP<> alias (which is the only real FixedStorage instantiation path and carried
its own independent 128 literal — the last copy of this dual truth). Expose it
through nisps_ml_describe and have the TS side read it instead of hardcoding.
Dataset's constructor default is removed entirely: a default was what invited
this bug class, and the sole call site now always supplies the describe() value.
ABI NOTE: this extends nisps_ml_describe from a 6-int to a 7-int descriptor.
nisps_ml_describe always writes 7 ints regardless of the caller's buffer, so
every call site had to grow in the same change or it would overflow the WASM
heap by 4 bytes per call. All five sites updated: three in wasm-iml.ts (init
defaults, init per-instance, reshape re-describe — the finding said there were
two), one in wasm-worker.ts, one in tests/cpp/parity_wasm.mjs. The parity
harness's expected-dims check now also pins the new max_examples slot.
Regression test: tests/cpp/test_mlp_storage_defaults.cpp — pins the two storage
policies to one constant, and drives MLPCore<DynamicStorage> exactly as
bindings.cpp does past the old TS cap, asserting it saturates at 128 and not at
100. Fail-before/pass-after confirmed by temporarily setting the constant to
100: 2 failures, named. Reverted: green.
Audit correction: the cited dataset.ts:81 is the FIFO eviction check; the
hardcoded default was at dataset.ts:45.
Gates: run-all-tests.sh ALL GREEN, parity PASS.
Phase 1 group 4 (S33, S34, L54).
- S33: removed 12 dead entries across the full 5-layer registration chain
(bindings.cpp KEEPALIVE -> EXPORTED_FUNCTIONS -> the NispsModule declaration
table -> the WasmIML wrapper -> the EngineApi facade): nisps_ml_reset,
example_count, move_weights, feedback_learning_paused, feedback_drag,
jolt_lr_scale, jolt_tick_lr_ramp, pipeline_state_size/save_state/load_state,
feedback_placing and feedback_state. Each was grepped against manifold/src,
manifold/tests, the e2e specs, manifold/tests/wasm-load.ts and
tests/cpp/parity_wasm.mjs — the parity gate builds its own API via cwrap and
is a real consumer, so it counts.
KEPT deliberately: EXPORTED_RUNTIME's heap views + ccall/cwrap (the parity
harness and wasm-load.ts depend on them), and nisps_ml_feedback_static_output,
whose C export IS called directly by parity_wasm.mjs even though no TS
wrapper reaches it. Also dropped parity_wasm.mjs's moveWeights cwrap, which
was declared but never invoked.
- S34: deleted the publishWeights_ channel — EngineSink.setWeights,
Spine.setWeights/weights()/liveWeights and every call site. It ran a C->heap
copy plus a fresh Float32Array allocation at up to 200 Hz into a field
nothing read. getWeights survives for persistence and the debug probe.
- L54: worklet loader — deleted the unused imports object, the 'c' branch,
exMap and the duplicate second loop, and replaced the silent `() => 0` stub
with one that throws, so a missing import fails loudly instead of returning
plausible zeros into the audio path.
manifold/public/nisps.{js,wasm} rebuilt with the trimmed export list (emcc
3.1.69, the CI-pinned version) and committed — the freshness gate added in
Phase 0 requires it, and the webhook ships this artifact to production.
Gates: run-all-tests.sh ALL GREEN, parity 1273 floats within 1e-5.
- plan P2 marked landed (hardware timing spot-check deferred to the
chokepoint-B session on physical MEMLNaut)
- ALIGNMENT: defect #3 resolved by the runtime-shaped browser MLP
- MAP/AGENT-REFERENCE/nisps-wasm-README: describe the honoured-dims
create + reshape ABI; note per-mode dims become schema-real at P5
- fresh wasm artifacts from the gate run
Operator-approved ABI change (P2 stop-point). The WASM MLP is now
MLPCore<DynamicStorage>:
- nisps_ml_create(input, output, hidden[3], n, seed) honours its args;
non-positive/null fall back to the historical 32→[10,14,18]→126, so
every pre-P2 caller (manifold, worker, parity harness) stays
bit-identical. Invalid/oversized dims (>4096) → null.
- NEW nisps_ml_reshape(ml, in, out, hidden, n, spread): fresh net at the
new dims, warm-started via nisps/ml/warm_start.hpp (overlapping region
copied; rest keeps spread init); feedback controller re-created (state
resets — reset-on-reshape modal is the front-end contract). Failure
leaves the old net untouched.
- nisps_ml_describe(ml, out): takes the handle; null reports defaults.
- FeedbackController got the same storage split: algorithms in
FeedbackControllerCore<FbStorage>; FixedFeedbackStorage keeps firmware/
tests source-identical via the old alias; DynamicFeedbackStorage (one
arena) sizes to the runtime net. Firmware .text unchanged (122692).
- MLHandle: per-instance scratch vectors; dropped the dead 2MB
batch_out_scratch.
- TS: types.ts decls (+_nisps_ml_reshape), wasm-iml re-describes the
created instance, worker carries a shape-contract note for P2.3.
Verified: ctest 4/4 incl. new warm-start grow/shrink test; reshape ABI
smoke (dims honoured, overlap survives, invalid rejected, outputs
bounded); parity PASS unchanged (2.4e-7); lint clean; manifold 9 unit +
20 e2e green; firmware .text 122692 (+0.30% vs pre-P2 baseline).
Wire the modular input layer into the Console and reshape the browser
engine so input axes are genuine independent dimensions.
Inputs (manifold/src/inputs/):
- gamepad-source: emit press+release edges with standard-mapping labels
(enables hold-and-move); single/double-stick already present.
- midi-input-source: single-device selection + batch "MIDI Learn"
(every CC swept while armed becomes an axis); notes stay discrete.
- input-layer: compose() forwards each axis 1:1 (no mean-blend);
add onReducedInput so the manifold tracks gamepad/MIDI position.
- types: InputAction.phase, InputMode.
Console (manifold/src/console/):
- ConsoleApp: bind gamepad buttons to verdicts (RB up / LB down /
X randomise / Y nudge / B undo / A-hold reposition); mirror composed
position onto the manifold.
- Drawers: rebuilt Inputs drawer (source picker, gamepad legend, MIDI
device picker + batch-learn flow, learned-control meters).
Engine (nisps/wasm, manifold/src/engine):
- DefaultMLP widened MLP<2,..> -> MLP<32,..> (32 = MAX_AXES); each
active axis gets a dedicated slot, unused slots held at 0 (inert).
Rebuilt nisps.wasm (playground + manifold).
- spine/engine-api: setInputs writes the full N-D vector (was dropping
arr[2+]); primary pair keeps the 2-D pipeline; process() re-ticks the
whole vector via spine.reprocess().
Tests:
- parity_check/parity_wasm: ParityMLP -> 32 inputs, widen example bufs.
- CMakeLists: build parity binary with -ffp-contract=off so native
matches FMA-free WASM (training amplified the gap past 1e-5).
Inputs dock is still an exclusive picker; mixing toggles, reshape modal,
and the >2-D slider view (inputs-spec.md) are groundwork-laid but not
yet wired. See docs/redesign/midi-gamepad-inputs-worklog.md.
Stream 7 wires nisps/ml + nisps/engines into the playground via Emscripten.
Highlights:
- nisps/wasm/bindings.cpp: flat C API per architecture.md §6.2. Fixed-arch
MLP<2, 10, 14, 18, 126>; engine string→type dispatch table with NoOp
fallback.
- scripts/build-wasm.sh: emcc invocation, MODULARIZE=1, exports listed
explicitly; produces playground/public/nisps.{js,wasm}.
- playground/src/ml/wasm-iml.ts: main-thread MLP host (sync inference,
sync training, RL ops, weights I/O, layer stats, localStorage).
- playground/src/ml/wasm-worker.ts: disposable Web Worker for off-thread
async training, owns its own WASM instance.
- playground/src/ml/dataset.ts: Float32Array-backed FIFO with sample-weight
modes (uniform/global/local/combined). Port of legacy dataset.js.
- playground/src/audio/engine-host.ts: AudioContext + AudioWorkletNode
lifecycle, with start/stop/setEngine/setParams.
- playground/src/audio/worklet/nisps-processor.ts: WASM-loading
AudioWorkletProcessor that runs engine.process_block per 128-sample
block. Loads its own WASM instance from main-thread-supplied bytes
(no fetch in worklet).
- playground/src/stores/ml-store.ts: wired stub methods to WasmIML
singleton; lazy initialize().
- playground/src/debug/probe.ts: window.__nisps now calls real WasmIML
via the store; lazy-init on first use.
Verified:
- bash scripts/build-wasm.sh succeeds (94 KB nisps.wasm)
- bun run typecheck OK
- bun run build OK (production bundle)
- vite dev server serves /nisps.{js,wasm} with COOP/COEP
Known limitation: WASM is fixed at one MLP shape. Multi-arch deferred —
documented in nisps/wasm/README.md.
