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.
231 lines
11 KiB
C++
231 lines
11 KiB
C++
// nisps/ml/storage.hpp — storage policies for the MLP core (fixed flavour).
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//
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// The MLP algorithms (nisps/ml/mlp.hpp `MLPCore<Storage>`) are written ONCE
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// against a storage concept; the storage supplies every dimension and every
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// buffer. Two models exist:
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//
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// * `FixedStorage<NIn, NH1, NH2, NH3, NOut, NMaxExamples, NMaxIterTrain>`
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// (this file) — all buffers are template-sized `std::array`, zero heap.
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// This is the firmware model; the classic
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// `MLP<...>` template is an alias over it and its compile-time constants
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// (`kInput`, `kHidden1..3`, `kOutput`, `weight_count()`) are preserved.
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//
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// * `DynamicStorage` (nisps/ml/dynamic_storage.hpp) — dimensions chosen at
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// construction, one arena allocation, no allocation after construction.
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// Compile-time EXCLUDED from embedded builds (see NISPS_TARGET_EMBEDDED
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// in nisps/core/perf.hpp).
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//
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// STORAGE SURFACE (both models; L is the layer index 0..3)
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// dims: n_in(), n_out(), fan_in_l<L>(), fan_out_l<L>(),
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// max_examples(), max_iter_train(), weight_count()
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// layers: weights_l<L>(), biases_l<L>(), pre_act_l<L>(), act_l<L>(),
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// grad_w_l<L>(), grad_b_l<L>(), delta_l<L>() [backprop scratch,
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// sized fan_in(L)], eval_act_l<L>() [const-eval scratch,
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// sized fan_out(L), mutable]
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// global: input_buf(), output_buf(), ds_features(), ds_labels(),
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// flat_buf(), loss_hist_buf(), copy_weights_to(dst)
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//
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// For `FixedStorage` every dim accessor is constexpr-foldable, so the
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// algorithms compile to the same fully-unrolled/constant-bound code the old
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// hand-fixed MLP produced (verified against the RP2350 `.text` budget —
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// chokepoint B of docs/specs/plans/one-core-engine-refactor.md).
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//
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// Bit-parity contract: for identical shapes and seeds, MLPCore over
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// FixedStorage and DynamicStorage must produce bit-identical results — the
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// algorithm code is shared and the buffers are just memory. A ctest enforces
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// this (tests/cpp/test_mlp_storage_parity.cpp).
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#pragma once
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#include <array>
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#include <cstddef>
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#include <span>
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#include "../core/perf.hpp"
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namespace nisps::ml {
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inline constexpr std::size_t kMlpNumLayers = 4u;
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// Default example-store capacity, named ONCE and shared by FixedStorage's
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// compile-time default (below) and DynamicStorage's runtime-default
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// constructor argument (nisps/ml/dynamic_storage.hpp). `nisps_ml_describe`
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// (nisps/wasm/bindings.cpp) reports the live instance's max_examples() so
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// the Manifold TS side (manifold/src/engine/wasm-iml.ts) can size its JS
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// Dataset mirror to match instead of hardcoding a second, divergent number
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// (see docs/specs/recon/simplification-audit-2026-07.md S35).
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inline constexpr std::size_t kDefaultMaxExamples = 128u;
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template <std::size_t NIn,
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std::size_t NHidden1,
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std::size_t NHidden2,
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std::size_t NHidden3,
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std::size_t NOut,
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std::size_t NMaxExamples = kDefaultMaxExamples,
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std::size_t NMaxIterTrain = 4096u>
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class FixedStorage {
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public:
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static constexpr std::size_t kInput = NIn;
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static constexpr std::size_t kHidden1 = NHidden1;
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static constexpr std::size_t kHidden2 = NHidden2;
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static constexpr std::size_t kHidden3 = NHidden3;
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static constexpr std::size_t kOutput = NOut;
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static constexpr std::size_t kMaxExamples = NMaxExamples;
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static constexpr std::size_t kMaxIterTrain = NMaxIterTrain;
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static constexpr std::size_t kNumLayers = kMlpNumLayers;
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static constexpr std::size_t weight_count() noexcept {
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return NIn * NHidden1 + NHidden1 * NHidden2 + NHidden2 * NHidden3 + NHidden3 * NOut
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+ NHidden1 + NHidden2 + NHidden3 + NOut;
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}
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// ---- dims -----------------------------------------------------------
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static constexpr std::size_t n_in() noexcept { return NIn; }
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static constexpr std::size_t n_out() noexcept { return NOut; }
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static constexpr std::size_t max_examples() noexcept { return NMaxExamples; }
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static constexpr std::size_t max_iter_train() noexcept { return NMaxIterTrain; }
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template <std::size_t L>
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static constexpr std::size_t fan_in_l() noexcept {
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static_assert(L < kNumLayers);
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if constexpr (L == 0u) return NIn;
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else if constexpr (L == 1u) return NHidden1;
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else if constexpr (L == 2u) return NHidden2;
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else return NHidden3;
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}
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template <std::size_t L>
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static constexpr std::size_t fan_out_l() noexcept {
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static_assert(L < kNumLayers);
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if constexpr (L == 0u) return NHidden1;
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else if constexpr (L == 1u) return NHidden2;
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else if constexpr (L == 2u) return NHidden3;
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else return NOut;
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}
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// ---- per-layer buffers ------------------------------------------------
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> weights_l() noexcept {
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if constexpr (L == 0u) return w0_; else if constexpr (L == 1u) return w1_;
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else if constexpr (L == 2u) return w2_; else return w3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<const float> weights_l() const noexcept {
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if constexpr (L == 0u) return w0_; else if constexpr (L == 1u) return w1_;
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else if constexpr (L == 2u) return w2_; else return w3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> biases_l() noexcept {
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if constexpr (L == 0u) return b0_; else if constexpr (L == 1u) return b1_;
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else if constexpr (L == 2u) return b2_; else return b3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<const float> biases_l() const noexcept {
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if constexpr (L == 0u) return b0_; else if constexpr (L == 1u) return b1_;
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else if constexpr (L == 2u) return b2_; else return b3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> pre_act_l() noexcept {
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if constexpr (L == 0u) return pa0_; else if constexpr (L == 1u) return pa1_;
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else if constexpr (L == 2u) return pa2_; else return pa3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> act_l() noexcept {
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if constexpr (L == 0u) return a0_; else if constexpr (L == 1u) return a1_;
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else if constexpr (L == 2u) return a2_; else return a3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<const float> act_l() const noexcept {
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if constexpr (L == 0u) return a0_; else if constexpr (L == 1u) return a1_;
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else if constexpr (L == 2u) return a2_; else return a3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> grad_w_l() noexcept {
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if constexpr (L == 0u) return gw0_; else if constexpr (L == 1u) return gw1_;
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else if constexpr (L == 2u) return gw2_; else return gw3_;
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}
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> grad_b_l() noexcept {
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if constexpr (L == 0u) return gb0_; else if constexpr (L == 1u) return gb1_;
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else if constexpr (L == 2u) return gb2_; else return gb3_;
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}
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// Backprop scratch (delta into layer L's input), sized fan_in(L).
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> delta_l() noexcept {
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if constexpr (L == 0u) return d0_; else if constexpr (L == 1u) return d1_;
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else if constexpr (L == 2u) return d2_; else return d3_;
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}
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// Const-eval scratch (activation of layer L), sized fan_out(L). Mutable
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// so `eval_loss() const` can run the shared forward code without touching
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// the real activation caches.
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template <std::size_t L> NISPS_FORCE_INLINE std::span<float> eval_act_l() const noexcept {
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if constexpr (L == 0u) return e0_; else if constexpr (L == 1u) return e1_;
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else if constexpr (L == 2u) return e2_; else return e3_;
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}
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// ---- global buffers ---------------------------------------------------
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NISPS_FORCE_INLINE std::span<float> input_buf() noexcept { return input_; }
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NISPS_FORCE_INLINE std::span<const float> input_buf() const noexcept { return input_; }
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NISPS_FORCE_INLINE std::span<float> output_buf() noexcept { return output_; }
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NISPS_FORCE_INLINE std::span<const float> output_buf() const noexcept { return output_; }
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NISPS_FORCE_INLINE std::span<float> ds_features() noexcept { return dsf_; }
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NISPS_FORCE_INLINE std::span<const float> ds_features() const noexcept { return dsf_; }
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NISPS_FORCE_INLINE std::span<float> ds_labels() noexcept { return dsl_; }
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NISPS_FORCE_INLINE std::span<const float> ds_labels() const noexcept { return dsl_; }
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NISPS_FORCE_INLINE std::span<float> flat_buf() noexcept { return flat_; }
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NISPS_FORCE_INLINE std::span<float> loss_hist_buf() noexcept { return lh_; }
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NISPS_FORCE_INLINE std::span<const float> loss_hist_buf() const noexcept { return lh_; }
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// Copies the live weights+biases directly into `dst` in the same flat
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// layout as MLPCore::get_weights() (weights layer-major, then biases
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// layer-major) — but writes straight from the layer buffers, with no
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// intermediate flat_/flat_buf() hop. `dst` must be at least
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// weight_count() long. Lets a caller that only needs a transient copy
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// (feedback.hpp's snapshot/undo/nudge ops) take a single copy instead of
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// double-copying through get_weights()'s scratch buffer.
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void copy_weights_to(std::span<float> dst) const noexcept {
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std::size_t k = 0u;
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for (float v : weights_l<0u>()) dst[k++] = v;
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for (float v : weights_l<1u>()) dst[k++] = v;
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for (float v : weights_l<2u>()) dst[k++] = v;
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for (float v : weights_l<3u>()) dst[k++] = v;
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for (float v : biases_l<0u>()) dst[k++] = v;
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for (float v : biases_l<1u>()) dst[k++] = v;
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for (float v : biases_l<2u>()) dst[k++] = v;
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for (float v : biases_l<3u>()) dst[k++] = v;
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}
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private:
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std::array<float, NIn * NHidden1> w0_{};
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std::array<float, NHidden1 * NHidden2> w1_{};
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std::array<float, NHidden2 * NHidden3> w2_{};
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std::array<float, NHidden3 * NOut> w3_{};
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std::array<float, NHidden1> b0_{};
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std::array<float, NHidden2> b1_{};
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std::array<float, NHidden3> b2_{};
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std::array<float, NOut> b3_{};
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std::array<float, NHidden1> pa0_{};
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std::array<float, NHidden2> pa1_{};
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std::array<float, NHidden3> pa2_{};
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std::array<float, NOut> pa3_{};
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std::array<float, NHidden1> a0_{};
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std::array<float, NHidden2> a1_{};
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std::array<float, NHidden3> a2_{};
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std::array<float, NOut> a3_{};
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std::array<float, NIn * NHidden1> gw0_{};
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std::array<float, NHidden1 * NHidden2> gw1_{};
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std::array<float, NHidden2 * NHidden3> gw2_{};
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std::array<float, NHidden3 * NOut> gw3_{};
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std::array<float, NHidden1> gb0_{};
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std::array<float, NHidden2> gb1_{};
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std::array<float, NHidden3> gb2_{};
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std::array<float, NOut> gb3_{};
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std::array<float, NIn> d0_{};
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std::array<float, NHidden1> d1_{};
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std::array<float, NHidden2> d2_{};
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std::array<float, NHidden3> d3_{};
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mutable std::array<float, NHidden1> e0_{};
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mutable std::array<float, NHidden2> e1_{};
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mutable std::array<float, NHidden3> e2_{};
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mutable std::array<float, NOut> e3_{};
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std::array<float, NIn> input_{};
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std::array<float, NOut> output_{};
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std::array<float, NMaxExamples * NIn> dsf_{};
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std::array<float, NMaxExamples * NOut> dsl_{};
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std::array<float, weight_count()> flat_{};
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std::array<float, NMaxIterTrain> lh_{};
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};
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} // namespace nisps::ml
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