memlnaut-nisps/nisps/ml/feedback.hpp
monkey-w1n5t0n ec3118004d fix(ml): re-base the geometric dislike on upstream e291192 — delete the taper
geo_push.hpp and replay.hpp cited memllib @ 0a541cc. upstream/main pins
e291192, where the same code had been deliberately redesigned — and because
InterfaceRL was not in the tree (fixed one commit ago), we carried the
superseded version for months. Three changes, all upstream's:

  kGeometricPushScale   0.5 -> 1.0    (InterfaceRL.hpp:409)
  kNegLRBase            0.5 -> 1.5    (InterfaceRL.hpp:410)
  /(1+len) taper        deleted       (InterfaceRL.tpp:724)

Upstream's own comment on the taper: "a 'no' should clearly move the mapping
away even from a sound already far from the liked region (the taper used to
kill exactly that case)". The direction is already a unit vector, so the
taper only ever shrank the push for exactly the sounds a user is most likely
to be rejecting.

Cold start is folded into the same path. Upstream's useRandom is
`!havePositives || len <= 1e-4`: with nothing liked yet there is no centroid
to push away from, so every dim goes in a random direction. Ours instead
kept the older 0a541cc fallback — train AWAY from the heard action at a
NEGATIVE lr — which was inert whenever the heard action equalled the net's
own output, i.e. in the common case. One path now, and a "no" moves the
mapping before any likes exist (ml_bench E1: 0 -> 2.3e-3). The
GeometricColdStart action is still reported so callers keep their "like a
few sounds first" prompt; only the training changed.

Measured (ml_bench, one dislike at a point):
  A4  0.0157 -> 0.0533 at-point displacement (3.4x), so end to end across
      this and the RMSProp fix: 5.3e-5 -> 5.3e-2, ~1000x. The gap to the
      legacy Diffuse design closes from ~4100x to ~4.2x.
  D1  effective_lr 4.7e-4 -> 1.5e-3; 10 presses now reach 0.34, 100 reach
      the full intended push.
  A5  compounding 0.87 -> 0.96 (a second press at the same spot is no
      longer noticeably weaker than the first).
  A7  damage_ratio essentially unchanged (0.87-1.57) — the collateral
      damage to protected positives scales with the push and is NOT
      addressed here; it is the negative-feedback design question.

NOT adopted, deliberately: upstream's per-tick batch retraining over all
live negatives, and its fixed kDislikeLifetimeMs=2500 in place of our
proportional decay. Both need something the core does not have — a per-tick
call site and a millisecond clock inside nisps/ml — so they change
FeedbackControllerCore's interface rather than its constants. Recorded in
ALIGNMENT's deferred-debt entry alongside the existing one-press-one-step
divergence, and filed as its own task.

test_mlp_geo_dislike.cpp: the taper test now pins its ABSENCE (equal
displacement near and far), the cold-start test pins movement where it used
to pin inertness, and a new test covers the random-direction branch.

ALIGNMENT defect 6b resolved. Gates: build-cpp-tests 139 tests / ctest 4/4,
parity-check PASS (WASM rebuilt), lint-cpp clean, firmware slpworkshop
SUCCESS.
2026-07-25 11:22:15 +02:00

818 lines
40 KiB
C++

// nisps/ml/feedback.hpp — the "Down Action" negative-feedback controller.
//
// Ported from the firmware InterfaceRL FEEDBACK_MODE state machine (upstream
// branch feat/feedback-explore-modes) into the shared nisps/ core so the SAME
// logic compiles to both WASM (browser) and RP2350 firmware.
//
// Four FeedbackMode behaviours for the "down" (thumbs-down) gesture:
// * ExploreAndPlace — the DEFAULT product mode (docs/adr/rl-feedback-design.md).
// Idle→Exploring→Placing→Idle scratchpad lifecycle: down
// snapshots the real net aside and auditions a random
// scratchpad; up freezes the heard output and lets the
// user place it at a new input before committing (+1
// example, real net restored, trained toward the
// placement). See ExploreState below for the full
// granular API (firmware maps buttons directly to it).
// * Avoid — "down" trains AWAY from the heard action, via one of
// two AvoidStyle sub-modes:
// - Geometric (DEFAULT) — the ported firmware k-NN
// centroid push-away, backed by the controller's
// own ReplayMemory (see dislike_geometric() below).
// Cold-starts with a negative-LR fallback until the
// first positive is stored. The old "geometric push
// not ported" note is stale — it IS ported.
// - Diffuse — the pre-P3 undirected MLP::move_weights
// perturb. Deliberately-retained research reserve,
// not the product default (see its definition below
// and docs/adr/rl-feedback-design.md).
// * RandomiseOutputs — deliberately-retained research reserve (see its
// definition below): bypasses the MLP and holds a
// static random output vector; each subsequent down
// re-rolls it (focus-aware). Up commits the held output
// as a +1 example at the current input, then resumes.
// * RandomiseMlp — deliberately-retained research reserve (see its
// definition below): snapshots the live weights and
// randomises the net (draw_weights) so the user
// auditions a random mapping by moving the joystick.
// Down again cancels (restore). Up/drag commits the
// auditioned output as a +1 example then restores the
// original net (the kept example then trains the
// original net toward the audition).
//
// STORAGE POLICY (one-core-engine-refactor P2): like MLPCore, the controller
// algorithms are written once in `FeedbackControllerCore<FbStorage>` against a
// storage surface. Two models:
// * `FixedFeedbackStorage<NOut, NWeights, UndoDepth>` — std::array, zero
// heap. The classic `FeedbackController<MLP_T, UndoDepth>` alias derives
// the sizes from the fixed MLP type; firmware + tests compile unchanged.
// * `DynamicFeedbackStorage` (nisps/ml/dynamic_storage.hpp) — sizes at
// construction for the runtime-shaped browser MLP. Non-embedded only.
//
// Design: the controller does NOT own the MLP — every mutating method takes
// the MLP by reference (method-level template, so fixed and dynamic MLPs both
// work). It owns only the exploration state, with its OWN per-instance Rng so
// re-rolling outputs is deterministic and never perturbs the MLP's RNG stream.
// Honours the RP2350 perf contract in the fixed model: no heap, no virtual
// dispatch, deterministic per-instance RNG.
//
// The C++/JS boundary: the controller decides *what transition happened*
// (returns a FeedbackAction); the caller decides *what to persist* (add example,
// grow noise, train). All inherently-UI state (pins, pipeline outputs, display)
// stays in the caller.
#pragma once
#include <array>
#include <cstddef>
#include <cstdint>
#include <span>
#include "../core/perf.hpp"
#include "../core/rng.hpp"
#include "geo_push.hpp"
#include "replay.hpp"
namespace nisps::ml {
enum class FeedbackMode : std::uint8_t {
Avoid = 0, // down → geometric push-away (or legacy Diffuse — see AvoidStyle).
// NOTE (2026-07, S20): RandomiseOutputs and RandomiseMlp have no current
// product caller — firmware/browser both default to ExploreAndPlace.
// They are DELIBERATELY RETAINED as research reserve: building blocks for
// experimenting with how different instruments feel under different
// down-gesture behaviours, not dead code awaiting deletion. Do not re-flag.
RandomiseOutputs = 1, // down → bypass MLP, hold static random vector; re-roll each down.
RandomiseMlp = 2, // down → snapshot + draw_weights live net; down-again cancels.
ExploreAndPlace = 3, // Idle→Exploring→Placing→Idle scratchpad lifecycle (default product mode).
};
// How the Avoid mode realises a dislike (rl-feedback-design §2.1). Geometric
// (DEFAULT) is the ported firmware behaviour (replay-backed k-NN centroid
// push-away).
//
// NOTE (2026-07, S20): Diffuse (the pre-P3 undirected move_weights) has no
// current product caller. It is DELIBERATELY RETAINED as research reserve —
// a building block for experimenting with how different instruments feel
// under different down-gesture behaviours, not dead code awaiting deletion.
// Do not re-flag.
enum class AvoidStyle : std::uint8_t {
Geometric = 0,
Diffuse = 1,
};
// The explicit lifecycle state for FeedbackMode::ExploreAndPlace. The whole
// mode is a three-state machine; granular methods drive the transitions
// (firmware maps buttons to them directly), while on_down/on_up implement the
// SOFTWARE default policy (browser) on top of the same machine.
// Idle — the real (trained) net is live; no scratchpad.
// Exploring — real net snapshotted aside; a random SCRATCHPAD net is live and
// the user auditions it (reroll / nudge / undo). NEVER trained.
// Placing — the user liked the current scratchpad sound; its output vector
// is FROZEN in placed_out and held while they choose WHERE to
// place it. The caller drives inference at the chosen input but
// the audition stays the frozen vector.
enum class ExploreState : std::uint8_t {
Idle = 0,
Exploring = 1,
Placing = 2,
};
// What a press resolved to. The caller (JS runtime / firmware glue) performs the
// replay-memory / training side effect; the controller owns the in-core state
// machine and the weight snapshot/restore.
enum class FeedbackAction : std::uint8_t {
None = 0,
AvoidPerturb = 1, // move_weights already applied; caller grows exploration noise.
LikeStore = 2, // caller: add +1 example at (input, output) + train.
EnterExplore = 3, // entered a RANDOMISE_* exploration (UI: show "exploring").
Reroll = 4, // re-rolled within a RandomiseOutputs exploration.
CommitStore = 5, // caller: add +1 example at (input, captured output); explore ended.
Cancel = 6, // exploration discarded; net restored (RandomiseMlp).
Restore = 7, // exploration kept via drag; net restored (caller already stored).
// ---- ExploreAndPlace (append-only; never renumber the TS↔C++ contract) ----
ScratchReroll = 8, // scratchpad re-randomised (Exploring); pure audition, no store.
ScratchNudge = 9, // scratchpad nudged (bounded perturb, Exploring); undoable.
ScratchUndo = 10, // last reroll/nudge undone (Exploring).
BeginPlace = 11, // Exploring→Placing; placed_out captured + frozen (no store yet).
CommitPlace = 12, // Placing→Idle; real net restored. CALLER adds +1 (input→placed_output) + trains.
CancelPlace = 13, // Placing→Exploring; backed out of placing (no store).
// ---- Geometric dislike (append-only) ----
GeometricPush = 14, // dislike trained toward the computed push-away target.
GeometricColdStart = 15, // no positives yet: negative-LR fallback ran; UI shows the cold-start prompt.
};
// ---------------------------------------------------------------------------
// Fixed feedback storage — std::array, zero heap. Sizes are compile-time.
// UndoDepth = number of scratchpad ops (reroll/nudge) that can be undone in
// ExploreAndPlace; each undo slot is NWeights floats. WASM historically used
// depth 4, firmware 2 (per rl-feedback-design §2.2 — SRAM budget).
// ---------------------------------------------------------------------------
template <std::size_t NOut, std::size_t NWeights, std::size_t UndoDepth = 4u,
std::size_t NIn = 2u, std::size_t ReplayCap = 32u>
class FixedFeedbackStorage {
public:
static constexpr std::size_t kNOut = NOut;
static constexpr std::size_t kWeights = NWeights;
static constexpr std::size_t kUndoDepth = UndoDepth;
static constexpr std::size_t kNIn = NIn;
static constexpr std::size_t kReplayCap = ReplayCap;
static constexpr std::size_t n_out() noexcept { return NOut; }
static constexpr std::size_t n_weights() noexcept { return NWeights; }
static constexpr std::size_t undo_cap() noexcept { return UndoDepth; }
static constexpr std::size_t n_in() noexcept { return NIn; }
static constexpr std::size_t replay_cap() noexcept { return ReplayCap; }
NISPS_FORCE_INLINE std::span<float> static_out() noexcept { return static_out_; }
NISPS_FORCE_INLINE std::span<const float> static_out() const noexcept { return static_out_; }
NISPS_FORCE_INLINE std::span<float> snapshot() noexcept { return snapshot_; }
NISPS_FORCE_INLINE std::span<const float> snapshot() const noexcept { return snapshot_; }
NISPS_FORCE_INLINE std::span<std::uint8_t> focus() noexcept { return focus_; }
NISPS_FORCE_INLINE std::span<const std::uint8_t> focus() const noexcept { return focus_; }
NISPS_FORCE_INLINE std::span<float> placed_out() noexcept { return placed_out_; }
NISPS_FORCE_INLINE std::span<const float> placed_out() const noexcept { return placed_out_; }
NISPS_FORCE_INLINE std::span<float> scratch_buf() noexcept { return scratch_buf_; }
NISPS_FORCE_INLINE std::span<float> undo_slot(std::size_t i) noexcept { return undo_ring_[i]; }
NISPS_FORCE_INLINE std::span<const float> undo_slot(std::size_t i) const noexcept {
return undo_ring_[i];
}
// Replay memory buffers (geometric dislike — nisps/ml/replay.hpp).
NISPS_FORCE_INLINE std::span<float> replay_inputs() noexcept { return replay_in_; }
NISPS_FORCE_INLINE std::span<float> replay_actions() noexcept { return replay_act_; }
NISPS_FORCE_INLINE std::span<float> replay_rewards() noexcept { return replay_rew_; }
// Centroid + push-target scratch (n_out each).
NISPS_FORCE_INLINE std::span<float> centroid_buf() noexcept { return centroid_; }
NISPS_FORCE_INLINE std::span<float> target_buf() noexcept { return target_; }
private:
std::array<float, NOut> static_out_{};
std::array<float, NWeights> snapshot_{};
std::array<std::uint8_t, NOut> focus_{};
std::array<float, NOut> placed_out_{};
std::array<std::array<float, NWeights>, UndoDepth> undo_ring_{};
std::array<float, NWeights> scratch_buf_{};
std::array<float, ReplayCap * NIn> replay_in_{};
std::array<float, ReplayCap * NOut> replay_act_{};
std::array<float, ReplayCap> replay_rew_{};
std::array<float, NOut> centroid_{};
std::array<float, NOut> target_{};
};
// ---------------------------------------------------------------------------
// The controller algorithms, written once against the feedback storage
// surface: n_out(), n_weights(), undo_cap(), static_out(), snapshot(),
// focus(), placed_out(), scratch_buf(), undo_slot(i).
// ---------------------------------------------------------------------------
template <typename FbStorage>
class FeedbackControllerCore : public FbStorage {
public:
template <typename... StorageArgs>
explicit FeedbackControllerCore(std::uint64_t seed, StorageArgs&&... storage_args) noexcept
: FbStorage(static_cast<StorageArgs&&>(storage_args)...), rng_(seed) {}
// ---- mode ---------------------------------------------------------------
// Switching mode mid-exploration cleanly tears down: restores the net (in
// RandomiseMlp) and resumes learning, so we never strand a randomised net.
template <typename M>
void set_mode(FeedbackMode m, M& mlp) noexcept {
if (explore_active_) abort_explore(mlp);
if (ep_state_ != ExploreState::Idle) abort_explore_place(mlp);
mode_ = m;
}
FeedbackMode mode() const noexcept { return mode_; }
// Avoid sub-mode: Geometric (default, the ported firmware behaviour) or
// Diffuse (legacy undirected move_weights — kept for A/B comparison).
void set_avoid_style(AvoidStyle s) noexcept { avoid_style_ = s; }
AvoidStyle avoid_style() const noexcept { return avoid_style_; }
// Base learning rate for the geometric push training (upstream
// InterfaceRL default 1e-3, pre-scaling).
void set_geo_lr(float lr) noexcept { geo_lr_ = lr; }
float geo_lr() const noexcept { return geo_lr_; }
// `exploring()` is true whenever a scratchpad net is live and learning is
// paused — for the legacy RANDOMISE_* modes, AND for ExploreAndPlace in
// either Exploring or Placing (the real net stays snapshotted aside the
// whole time). The TS/firmware UI uses it to show the "exploring" state.
bool exploring() const noexcept {
return explore_active_ || ep_state_ != ExploreState::Idle;
}
bool learning_paused() const noexcept { return learning_paused_; }
// ---- ExploreAndPlace state introspection --------------------------------
ExploreState explore_state() const noexcept { return ep_state_; }
bool placing() const noexcept { return ep_state_ == ExploreState::Placing; }
// True while a REPOSITION hold is active (grab→move→drop). Distinguishes a
// reposition (real net never set aside) from an Explore→Place (scratchpad +
// snapshot). Both sit in ExploreState::Placing and both hold placed_out via
// static_output(); only commit/teardown differ (reposition does NOT restore
// weights — there is nothing to restore).
bool repositioning() const noexcept { return reposition_; }
// Depth of the scratchpad undo ring currently available to pop (0..undo_cap).
std::size_t undo_depth() const noexcept { return undo_count_; }
// The output vector frozen at like()/begin-place time. Valid only while
// placing(); empty span otherwise. The caller adds this as the +1 example
// label at commit (input → placed_output).
std::span<const float> placed_output() const noexcept {
if (ep_state_ != ExploreState::Placing) return {};
return this->placed_out();
}
// ---- focus mask: 1 byte per output; 0 == frozen (unfocused). Copied into a
// fixed buffer (no heap, no dangling span). Empty ⇒ all outputs active.
void set_focus_mask(std::span<const std::uint8_t> mask) noexcept {
auto focus = this->focus();
focus_count_ = (mask.size() < focus.size()) ? mask.size() : focus.size();
for (std::size_t i = 0; i < focus_count_; ++i) focus[i] = mask[i];
}
void clear_focus_mask() noexcept { focus_count_ = 0; }
// ---- press handlers -----------------------------------------------------
// `current_out` is the live (post-pipeline) output the user is hearing
// (n_out floats). `pin_mask` may be empty. Returns the FeedbackAction the
// caller must act on.
template <typename M>
FeedbackAction on_down(M& mlp, std::span<const float> current_out,
float speed, float spread,
std::span<const std::uint8_t> pin_mask) noexcept {
switch (mode_) {
case FeedbackMode::Avoid:
if (avoid_style_ == AvoidStyle::Diffuse) {
mlp.move_weights(speed, spread, pin_mask);
return FeedbackAction::AvoidPerturb;
}
return dislike_geometric(mlp, current_out, geo_lr_);
case FeedbackMode::RandomiseOutputs:
if (!explore_active_) {
enter_randomise_outputs(current_out);
return FeedbackAction::EnterExplore;
}
roll_static_outputs();
return FeedbackAction::Reroll;
case FeedbackMode::RandomiseMlp:
if (!explore_active_) {
enter_randomise_mlp(mlp, spread);
return FeedbackAction::EnterExplore;
}
cancel_explore(mlp);
return FeedbackAction::Cancel;
case FeedbackMode::ExploreAndPlace:
// SOFTWARE DEFAULT POLICY (browser): down enters explore from
// Idle, else re-rolls the scratchpad. (Firmware maps its own
// buttons to the granular methods instead.)
switch (ep_state_) {
case ExploreState::Idle:
enter_explore(mlp, spread);
return FeedbackAction::EnterExplore;
case ExploreState::Exploring:
reroll(mlp, spread);
return FeedbackAction::ScratchReroll;
case ExploreState::Placing:
// Down while placing backs out to Exploring.
cancel_place();
return FeedbackAction::CancelPlace;
}
return FeedbackAction::None;
}
return FeedbackAction::None;
}
// Up = thumbs-up / "keep". While exploring it commits: the CALLER must have
// captured the heard output BEFORE calling this (on_up restores the original
// net in RandomiseMlp), then stores it as a +1 example at the current input.
template <typename M>
FeedbackAction on_up(M& mlp) noexcept {
if (mode_ == FeedbackMode::ExploreAndPlace) {
// SOFTWARE DEFAULT POLICY (browser): up begins place from
// Exploring (freeze the heard output), then commits from Placing
// (restore the real net; caller stores +1 (input→placed_output)).
switch (ep_state_) {
case ExploreState::Idle:
return FeedbackAction::LikeStore; // not exploring → plain like
case ExploreState::Exploring:
begin_place(mlp);
return FeedbackAction::BeginPlace;
case ExploreState::Placing:
commit_place(mlp);
return FeedbackAction::CommitPlace;
}
return FeedbackAction::None;
}
if (explore_active_ && (mode_ == FeedbackMode::RandomiseOutputs ||
mode_ == FeedbackMode::RandomiseMlp)) {
restore_after_explore(mlp);
return FeedbackAction::CommitStore;
}
if (mode_ == FeedbackMode::Avoid && avoid_style_ == AvoidStyle::Geometric) {
// A geometric-mode like also feeds the positive centroid (ADR
// §2.1); the caller still runs addExample + train as usual.
store_positive(mlp);
}
return FeedbackAction::LikeStore;
}
// Drag-store (joystick freeze→reposition→release). In RandomiseMlp this is
// the "reposition-commit": the caller has already stored the +1 at the new
// input; we just restore the original net and end exploration.
//
// NOTE (2026-07, S20): the RandomiseMlp branch below has no current
// product caller (ExploreAndPlace's own reposition path is
// begin_reposition/commit_reposition, not on_drag). DELIBERATELY RETAINED
// as research reserve alongside RandomiseMlp itself — not dead code
// awaiting deletion. Do not re-flag.
template <typename M>
FeedbackAction on_drag(M& mlp) noexcept {
if (explore_active_ && mode_ == FeedbackMode::RandomiseMlp) {
restore_after_explore(mlp);
return FeedbackAction::Restore;
}
return FeedbackAction::LikeStore;
}
// Inference hook: fills `out` with the held static vector and returns true
// when RandomiseOutputs is bypassing the MLP; else returns false (the caller
// should run mlp.process() normally). `out` should hold at least n_out.
bool static_output(std::span<float> out) const noexcept {
const std::size_t n_out = this->n_out();
// ExploreAndPlace: while PLACING, the audition is the frozen vector the
// user liked, held steady as they aim at a location.
if (mode_ == FeedbackMode::ExploreAndPlace && ep_state_ == ExploreState::Placing) {
const auto placed = this->placed_out();
const std::size_t n = (out.size() < n_out) ? out.size() : n_out;
for (std::size_t i = 0; i < n; ++i) out[i] = placed[i];
return true;
}
if (!(mode_ == FeedbackMode::RandomiseOutputs && explore_active_)) return false;
const auto held = this->static_out();
const std::size_t n = (out.size() < n_out) ? out.size() : n_out;
for (std::size_t i = 0; i < n; ++i) out[i] = held[i];
return true;
}
void seed(std::uint64_t s) noexcept { rng_.seed(s); }
// =========================================================================
// Geometric dislike (rl-feedback-design §2.1) — the press-time half and
// the async optimise() half of upstream InterfaceRL collapsed into ONE
// synchronous call (nisps has no background optimise driver).
// =========================================================================
std::size_t replay_size() const noexcept { return replay_count_; }
std::size_t positive_count() noexcept { return replay_().positive_count(); }
std::size_t negative_count() noexcept { return replay_().negative_count(); }
// Store a positive (like) into the replay so the k-NN centroid sees it.
// `current_out` may be empty ⇒ the MLP's live output vector is used. The
// input is the MLP's current input vector.
template <typename M>
void store_positive(M& mlp, std::span<const float> current_out = {}) noexcept {
std::span<const float> a = current_out.empty()
? std::span<const float>(mlp.outputs())
: current_out;
replay_().store(1.f, std::span<const float>(mlp.input_buf()), a);
}
// Thumbs-down at the MLP's CURRENT input with heard action `current_out`
// (empty ⇒ the MLP's live outputs). Runs the full upstream sequence:
// 1. deepen-or-store the negative (dedup radius 0.05).
// 2. k-NN(4) positive centroid — or zeros when nothing is liked yet —
// → push-away target → train toward it at lr * negLRRatio, gated by
// the focus/solo mask. With no positives the push direction is
// random per dim, which is upstream's cold start (there is no
// separate negative-LR branch any more; see the body).
// 3. proportional decay + eviction of expired negatives.
template <typename M>
FeedbackAction dislike_geometric(M& mlp, std::span<const float> current_out,
float lr) noexcept {
auto replay = replay_();
const std::size_t n_out = this->n_out();
std::span<const float> a_neg = current_out.empty()
? std::span<const float>(mlp.outputs())
: current_out;
std::span<const float> x_neg(mlp.input_buf());
// 1. store/deepen the negative (InterfaceRL.cpp:42-66).
replay.deepen_or_store_negative(x_neg, a_neg);
const std::size_t pos_total = replay.positive_count();
const std::size_t neg_total = replay.negative_count();
const float avg_neg = replay.avg_negative_reward();
// 2+3. ONE path, as upstream (InterfaceRL.tpp:696-761). With no likes
// stored there is no centroid to push away from, so the centroid is
// zeros and `have_positives=false` sends every dim in a random
// direction — upstream's `useRandom = !havePositives || ...`. We still
// report GeometricColdStart so the caller can show its "like a few
// sounds first" prompt, but the TRAINING is the same push at the same
// LR either way. (Until 2026-07-25 the cold start instead trained AWAY
// from the heard action at a NEGATIVE lr — a port of the older
// `0a541cc` fallback that upstream has since replaced.)
auto mean = this->centroid_buf();
const bool have_positives = (pos_total > 0u);
if (have_positives) {
(void)replay.knn_positive_centroid(x_neg, kCentroidK, mean);
} else {
for (std::size_t j = 0; j < n_out; ++j) mean[j] = 0.f;
}
auto target = this->target_buf();
compute_push_target(a_neg.subspan(0, (a_neg.size() < n_out) ? a_neg.size() : n_out),
std::span<const float>(mean.data(), n_out),
focus_span_(), geo_push_step(avg_neg), have_positives,
rng_, target);
const float ratio = geo_neg_lr_ratio(neg_total, pos_total);
mlp.train_targets(x_neg, std::span<const float>(target.data(), n_out),
lr * ratio, focus_span_());
const FeedbackAction action = have_positives
? FeedbackAction::GeometricPush
: FeedbackAction::GeometricColdStart;
// 4. decay + evict expired negatives (InterfaceRL.cpp:752-760).
replay.decay_negatives();
return action;
}
// =========================================================================
// ExploreAndPlace — granular lifecycle methods (firmware maps buttons to
// these directly; on_down/on_up call them for the browser default policy).
//
// CONTRACT: the controller owns the WEIGHT snapshot/restore and all scratch
// state; the CALLER owns example-storage + training. On commit_place the
// controller restores the real net and the caller does add_example(current
// input → placed_output()) + train (warm-start to interpolate all anchors).
// =========================================================================
// Idle→Exploring. Snapshot the real (trained) net aside, randomise a
// scratchpad net the user auditions. No-op if not Idle.
template <typename M>
void enter_explore(M& mlp, float spread) noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Idle) return;
take_snapshot(mlp);
learning_paused_ = true;
ep_state_ = ExploreState::Exploring;
undo_count_ = 0u;
undo_head_ = 0u;
mlp.draw_weights(spread); // first scratchpad candidate
}
// Exploring→Idle. Restore the real net, discard the scratchpad. No example
// stored. (The hardware "enter/exit explore toggle" off-path.)
template <typename M>
void exit_explore(M& mlp) noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ == ExploreState::Idle) return;
restore_real_net(mlp);
}
// Exploring scratchpad op: re-randomise the scratchpad. Undoable.
template <typename M>
void reroll(M& mlp, float spread) noexcept {
if (!can_scratch_op()) return;
push_undo(mlp);
mlp.draw_weights(spread);
}
// Exploring scratchpad op: small bounded perturbation of the scratchpad via
// the controller's OWN Rng (move_weights uses the MLP's Rng; to keep the
// controller's Rng stream out of the MLP stream we draw the perturbation
// here and apply it). Undoable. `amount` is the noise stddev (e.g. 0.05).
template <typename M>
void nudge(M& mlp, float amount) noexcept {
if (!can_scratch_op()) return;
push_undo(mlp);
auto scratch = this->scratch_buf();
const std::size_t n_weights = this->n_weights();
mlp.copy_weights_to(scratch); // single copy — see take_snapshot.
for (std::size_t i = 0; i < n_weights; ++i) {
scratch[i] += rng_.next_float_gaussian(amount);
}
mlp.set_weights(std::span<const float>(scratch.data(), n_weights));
}
// Exploring scratchpad op: undo the last reroll/nudge (bounded ring).
template <typename M>
void undo(M& mlp) noexcept {
if (!can_scratch_op()) return;
if (undo_count_ == 0u) return;
const std::size_t cap = this->undo_cap();
undo_head_ = (undo_head_ + cap - 1u) % cap;
--undo_count_;
const auto slot = this->undo_slot(undo_head_);
mlp.set_weights(std::span<const float>(slot.data(), this->n_weights()));
}
// Exploring→Placing. Capture + FREEZE the current scratchpad output the user
// is auditioning. The caller MUST have run mlp.process() at the audition
// input first; pass that output here. While placing, static_output() holds
// this vector and the caller chooses WHERE to place it.
template <typename M>
void begin_place(M& mlp, std::span<const float> current_out) noexcept {
(void)mlp;
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Exploring) return;
capture_placed(current_out);
ep_state_ = ExploreState::Placing;
}
// Convenience: freeze the scratchpad's output at its CURRENT input (runs the
// forward pass on the live scratchpad net). Equivalent to process()+capture.
template <typename M>
void begin_place(M& mlp) noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Exploring) return;
mlp.process();
capture_placed(mlp.outputs());
ep_state_ = ExploreState::Placing;
}
// Placing→Idle. Restore the real net. The CALLER then adds a +1 example at
// (chosen input → placed_output()) and trains.
template <typename M>
void commit_place(M& mlp) noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Placing) return;
// Restore the real net but KEEP placed_out valid for the caller until
// it transitions to Idle; expose via a separate accessor that does not
// gate on Placing.
restore_snapshot(mlp);
last_placed_valid_ = true; // placed_out holds the just-committed vector
learning_paused_ = false;
ep_state_ = ExploreState::Idle;
undo_count_ = 0u;
}
// The output vector committed by the most recent commit_place, valid until
// the next enter_explore/begin_place. Lets the caller add the +1 example
// AFTER commit_place has restored the real net.
std::span<const float> committed_output() const noexcept {
if (!last_placed_valid_) return {};
return this->placed_out();
}
// Placing→Exploring. Back out of placing without storing; resume auditioning
// the scratchpad (which is still live — begin_place did not touch weights).
// A reposition hold has no scratchpad to return to, so it backs out to Idle.
void cancel_place() noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Placing) return;
if (reposition_) {
reposition_ = false;
learning_paused_ = false;
ep_state_ = ExploreState::Idle;
return;
}
ep_state_ = ExploreState::Exploring;
}
// =========================================================================
// Reposition (grab → move → drop) — relocate an EXISTING positive example's
// output to a new input position. Distinct from Explore→Place: there is NO
// scratchpad and NO weight snapshot — the real (trained) net stays live the
// whole time. We only FREEZE the currently-heard output and hold it (via
// static_output) while the user moves to a new input, then the caller adds
// a +1 example (new input → carried output) and trains. This is the new
// core's home for the upstream "drag-store / reposition-commit" gesture.
// =========================================================================
// Idle→Placing(reposition). Freeze `current_out` — the output the user is
// hearing from the TRAINED net — and hold it. No-op unless Idle.
void begin_reposition(std::span<const float> current_out) noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Idle) return;
capture_placed(current_out);
reposition_ = true;
learning_paused_ = true;
last_placed_valid_ = false;
ep_state_ = ExploreState::Placing;
}
// Convenience: capture the trained net's output at its CURRENT input
// (process + capture). Equivalent to begin_reposition(mlp.outputs()).
template <typename M>
void begin_reposition(M& mlp) noexcept {
if (mode_ != FeedbackMode::ExploreAndPlace) return;
if (ep_state_ != ExploreState::Idle) return;
mlp.process();
capture_placed(mlp.outputs());
reposition_ = true;
learning_paused_ = true;
last_placed_valid_ = false;
ep_state_ = ExploreState::Placing;
}
// Placing(reposition)→Idle. NO weight restore (the net was never set aside).
// committed_output() then holds the carried vector so the caller can add the
// +1 example at the new input and train. No-op unless repositioning.
void commit_reposition() noexcept {
if (!reposition_ || ep_state_ != ExploreState::Placing) return;
reposition_ = false;
last_placed_valid_ = true; // committed_output() valid for the caller
learning_paused_ = false;
ep_state_ = ExploreState::Idle;
undo_count_ = 0u;
}
private:
// The replay view over the storage-owned buffers.
ReplayView replay_() noexcept {
return ReplayView(this->replay_inputs(), this->replay_actions(),
this->replay_rewards(), this->n_in(), this->n_out(),
this->replay_cap(), replay_count_);
}
// The focus mask as the geometric active-dims gate (empty ⇒ all active).
std::span<const std::uint8_t> focus_span_() const noexcept {
if (focus_count_ == 0u) return {};
const auto focus = this->focus();
return focus.subspan(0, focus_count_);
}
void capture_placed(std::span<const float> src) noexcept {
auto placed = this->placed_out();
const std::size_t n = (src.size() < placed.size()) ? src.size() : placed.size();
for (std::size_t i = 0; i < n; ++i) placed[i] = src[i];
}
template <typename M>
void take_snapshot(M& mlp) noexcept {
// copy_weights_to writes the live flat weights+biases straight into
// the snapshot slot — a single copy (no intermediate hop through
// get_weights()'s flat_ scratch buffer; see storage.hpp L28).
mlp.copy_weights_to(this->snapshot());
}
template <typename M>
void restore_snapshot(M& mlp) noexcept {
const auto snap = this->snapshot();
mlp.set_weights(std::span<const float>(snap.data(), this->n_weights()));
}
void enter_randomise_outputs(std::span<const float> seed_out) noexcept {
explore_active_ = true;
learning_paused_ = true;
// Seed every dim with the live output the user is hearing, so unfocused
// (frozen) dims hold that value through the exploration — matching the
// firmware `staticRandomOut_ = action; _roll_static_outputs();`. The
// CALLER CONTRACT is to pass the full n_out live output. Any dims beyond
// a short seed keep their previous static value (we have no live value
// to freeze them to); they are only observable if a focus mask freezes
// a dim the short seed did not cover — an out-of-contract corner.
auto held = this->static_out();
const std::size_t n = (seed_out.size() < held.size()) ? seed_out.size() : held.size();
for (std::size_t i = 0; i < n; ++i) held[i] = seed_out[i];
roll_static_outputs();
}
void roll_static_outputs() noexcept {
auto held = this->static_out();
const auto focus = this->focus();
for (std::size_t i = 0; i < held.size(); ++i) {
const bool active = (focus_count_ == 0u) || (i < focus_count_ && focus[i] != 0u);
if (active) held[i] = rng_.next_float_uniform(); // [0, 1)
// inactive dims keep their seeded entry value
}
}
template <typename M>
void enter_randomise_mlp(M& mlp, float spread) noexcept {
explore_active_ = true;
learning_paused_ = true;
take_snapshot(mlp);
mlp.draw_weights(spread); // randomise the live net
}
template <typename M>
void restore_after_explore(M& mlp) noexcept {
if (mode_ == FeedbackMode::RandomiseMlp) {
restore_snapshot(mlp);
}
learning_paused_ = false;
explore_active_ = false;
}
// Cancel and abort share restore semantics; the caller stores nothing.
template <typename M>
void cancel_explore(M& mlp) noexcept { restore_after_explore(mlp); }
template <typename M>
void abort_explore(M& mlp) noexcept { restore_after_explore(mlp); }
// ---- ExploreAndPlace helpers --------------------------------------------
bool can_scratch_op() const noexcept {
return mode_ == FeedbackMode::ExploreAndPlace &&
ep_state_ == ExploreState::Exploring;
}
// Push the CURRENT scratchpad weights onto the bounded undo ring before a
// mutating op, so undo() restores the pre-op candidate.
template <typename M>
void push_undo(M& mlp) noexcept {
auto slot = this->undo_slot(undo_head_);
mlp.copy_weights_to(slot); // single copy — see take_snapshot.
const std::size_t cap = this->undo_cap();
undo_head_ = (undo_head_ + 1u) % cap;
if (undo_count_ < cap) ++undo_count_;
}
// Restore the set-aside real net and return to Idle. Shared by exit_explore
// and abort_explore_place. No example stored.
template <typename M>
void restore_real_net(M& mlp) noexcept {
restore_snapshot(mlp);
learning_paused_ = false;
ep_state_ = ExploreState::Idle;
undo_count_ = 0u;
last_placed_valid_ = false;
}
template <typename M>
void abort_explore_place(M& mlp) noexcept {
if (ep_state_ == ExploreState::Idle) return;
if (reposition_) {
// A reposition never set the real net aside, so there is nothing to
// restore — clearing snapshot into the net here would CLOBBER the
// live trained weights. Just drop the hold.
reposition_ = false;
learning_paused_ = false;
ep_state_ = ExploreState::Idle;
undo_count_ = 0u;
last_placed_valid_ = false;
return;
}
restore_real_net(mlp);
}
FeedbackMode mode_ = FeedbackMode::Avoid;
AvoidStyle avoid_style_ = AvoidStyle::Geometric;
bool explore_active_ = false;
bool learning_paused_ = false;
std::size_t focus_count_ = 0; // 0 ⇒ all active
// ---- Geometric dislike state ---------------------------------------------
std::size_t replay_count_ = 0u;
float geo_lr_ = 0.001f; // upstream InterfaceRL.hpp:312
// ---- ExploreAndPlace state ----------------------------------------------
ExploreState ep_state_ = ExploreState::Idle;
bool last_placed_valid_ = false;
bool reposition_ = false; // grab→move→drop hold; net NOT set aside
std::size_t undo_head_ = 0u; // next write slot
std::size_t undo_count_ = 0u; // valid entries (0..undo_cap)
Rng rng_;
};
// The classic fixed-size controller over a compile-time MLP type — the
// firmware model and the default for tests. Sizes derive from the MLP.
// ReplayCap 32 is the firmware SRAM-budget default (rl-feedback-design §4);
// the browser's DynamicFeedbackStorage uses 64.
template <typename MLP_T, std::size_t UndoDepth = 4u, std::size_t ReplayCap = 32u>
using FeedbackController = FeedbackControllerCore<
FixedFeedbackStorage<MLP_T::kOutput, MLP_T::weight_count(), UndoDepth,
MLP_T::kInput, ReplayCap>>;
} // namespace nisps::ml