T0 + T1 + T2: engine redesign through new API surface (#1)

Implements tiers T0, T1, T2 of `docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md`. All three tiers have landed together on this branch because they build on one another; this PR rolls them up for a single review pass.

Per-tier plans:
- T0: `docs/superpowers/plans/2026-04-23-t0-numerical-parity.md`
- T1: `docs/superpowers/plans/2026-04-24-t1-factor-graph.md`
- T2: `docs/superpowers/plans/2026-04-24-t2-new-api-surface.md`

## Summary

### T0 — Numerical parity (internal)

- `Gaussian` switched to natural-parameter storage `(pi, tau)`; mul/div now ~7× faster (218 ps vs 1.57 ns).
- `HashMap<Index, _>` → dense `Vec<_>` keyed by `Index.0` (via `AgentStore<D>`, `SkillStore`).
- `ScratchArena` eliminates per-event allocations in `Game::likelihoods`.
- `InferenceError` seed type added (1 variant).
- 38 → 53 tests passing through T1.
- Benchmark: `Batch::iteration` 29.84 → 21.25 µs.

### T1 — Factor graph machinery (internal)

- `Factor` trait + `BuiltinFactor` enum (TeamSum / RankDiff / Trunc) driving within-game inference.
- `VarStore` flat storage for variable marginals.
- `Schedule` trait + `EpsilonOrMax` impl replacing the hand-rolled EP loop.
- `Game::likelihoods` rebuilt on the factor-graph machinery; iteration counts and goldens preserved to within 1e-6.
- 53 tests passing.
- Benchmark: `Batch::iteration` 23.01 µs (slight regression absorbed in T2).

### T2 — New API surface (breaking)

**Renames:**
- `IndexMap → KeyTable`, `Player → Rating`, `Agent → Competitor`, `Batch → TimeSlice`

**New types:**
- `Time` trait with `Untimed` ZST and `i64` impls; `Drift<T>`, `Rating<T, D>`, `Competitor<T, D>`, `TimeSlice<T>`, `History<T, D, O, K>` all generic.
- `Event<T, K>`, `Team<K>`, `Member<K>`, `Outcome` (`Ranked` variant; `#[non_exhaustive]`).
- `Observer<T>` trait + `NullObserver`.
- `ConvergenceOptions`, `ConvergenceReport`.
- `GameOptions`, `OwnedGame<T, D>`.

**Three-tier ingestion:**
- `history.record_winner(&K, &K, T)` / `record_draw(&K, &K, T)` — 1v1 convenience.
- `history.add_events(iter)` — typed bulk.
- `history.event(T).team([...]).weights([...]).ranking([...]).commit()` — fluent.

**Query API:** `current_skill`, `learning_curve`, `learning_curves` (keyed on `K`), `log_evidence`, `log_evidence_for`, `predict_quality`, `predict_outcome`.

**Game constructors:** `ranked`, `one_v_one`, `free_for_all`, `custom` — all returning `Result<_, InferenceError>`.

**`factors` module:** `Factor`, `Schedule`, `VarStore`, `VarId`, `BuiltinFactor`, `EpsilonOrMax`, `ScheduleReport`, `TeamSumFactor`, `RankDiffFactor`, `TruncFactor` now public.

**Errors:** `InferenceError` gains `MismatchedShape`, `InvalidProbability`, `ConvergenceFailed`; boundary panics converted to `Result`.

**Removed (breaking):** `History::convergence(iters, eps, verbose)`, `HistoryBuilder::gamma(f64)`, `HistoryBuilder::time(bool)`, `History.time: bool`, `learning_curves_by_index`, nested-Vec public `add_events`.

## Behavior change (documented in CHANGELOG)

`Time = Untimed` has `elapsed_to → 0`, so no drift accumulates between slices. The old `time=false` mode implicitly forced `elapsed=1` on reappearance via an `i64::MAX` sentinel — that quirk is not reproducible under a typed time axis. Tests that depended on it now use `History::<i64, _>` with explicit `1..=n` timestamps. One test (`test_env_ttt`) had 3 Gaussian goldens updated to reflect the corrected semantics; documented in commit `33a7d90`.

## Final numbers

| Metric | Before T0 | After T2 | Delta |
|---|---|---|---|
| `Batch::iteration` | 29.84 µs | 21.36 µs | **-28%** |
| `Gaussian::mul` | 1.57 ns | 219 ps | **-86%** |
| `Gaussian::div` | 1.57 ns | 219 ps | **-86%** |
| Tests passing | 38 | 90 | +52 |

All other Gaussian ops unchanged (~219 ps add/sub, ~264 ps pi/tau reads).

## Test plan

- [x] `cargo test --features approx` — 90/90 pass (68 lib + 10 api_shape + 6 game + 4 record_winner + 2 equivalence)
- [x] `cargo clippy --all-targets --features approx -- -D warnings` — clean
- [x] `cargo +nightly fmt --check` — clean
- [x] `cargo bench --bench batch` — 21.36 µs
- [x] `cargo bench --bench gaussian` — unchanged from T1
- [x] `cargo run --example atp --features approx` — rewritten in new API, runs clean
- [x] Historical Game-level goldens preserved in `tests/equivalence.rs`
- [x] Public API matches spec Section 4 (verified by integration tests in `tests/api_shape.rs`)

## Commit history

~45 commits total across T0 + T1 + T2. Each task is self-contained and individually tested; the branch is bisectable. See `git log main..t2-new-api-surface` for the full list.

## Deferred to later tiers

- `Outcome::Scored` + `MarginFactor` — T4
- `Damped` / `Residual` schedules — T4
- `Send + Sync` bounds + Rayon parallelism — T3
- N-team `predict_outcome` — T4
- `Game::custom` full ergonomics — T4

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: #1
Co-authored-by: Anders Olsson <anders.e.olsson@gmail.com>
Co-committed-by: Anders Olsson <anders.e.olsson@gmail.com>
This commit was merged in pull request #1.
This commit is contained in:
2026-04-24 11:20:04 +00:00
committed by logaritmisk
parent a14df02089
commit d2aab82c1e
44 changed files with 10541 additions and 1325 deletions
+39 -101
View File
@@ -1,30 +1,49 @@
use std::{
borrow::{Borrow, ToOwned},
cmp::Reverse,
collections::HashMap,
f64::consts::{FRAC_1_SQRT_2, FRAC_2_SQRT_PI, SQRT_2},
hash::Hash,
};
pub mod agent;
#[cfg(feature = "approx")]
mod approx;
pub mod batch;
pub(crate) mod arena;
mod time;
mod time_slice;
pub use time_slice::TimeSlice;
mod competitor;
mod convergence;
pub mod drift;
mod error;
mod event;
mod event_builder;
pub(crate) mod factor;
pub mod factors;
mod game;
pub mod gaussian;
mod history;
mod key_table;
mod matrix;
mod message;
pub mod player;
mod observer;
mod outcome;
mod rating;
pub(crate) mod schedule;
pub mod storage;
pub use competitor::Competitor;
pub use convergence::{ConvergenceOptions, ConvergenceReport};
pub use drift::{ConstantDrift, Drift};
pub use game::Game;
pub use error::InferenceError;
pub use event::{Event, Member, Team};
pub use event_builder::EventBuilder;
pub use game::{Game, GameOptions, OwnedGame};
pub use gaussian::Gaussian;
pub use history::History;
pub use key_table::KeyTable;
use matrix::Matrix;
use message::DiffMessage;
pub use player::Player;
pub use observer::{NullObserver, Observer};
pub use outcome::Outcome;
pub use rating::Rating;
pub use schedule::ScheduleReport;
pub use time::{Time, Untimed};
pub const BETA: f64 = 1.0;
pub const MU: f64 = 0.0;
@@ -49,61 +68,6 @@ impl From<usize> for Index {
}
}
pub struct IndexMap<K>(HashMap<K, Index>);
impl<K> IndexMap<K>
where
K: Eq + Hash,
{
pub fn new() -> Self {
Self(HashMap::new())
}
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<Index>
where
K: Borrow<Q>,
Q: Hash + Eq + ToOwned<Owned = K>,
{
self.0.get(k).cloned()
}
pub fn get_or_create<Q: ?Sized>(&mut self, k: &Q) -> Index
where
K: Borrow<Q>,
Q: Hash + Eq + ToOwned<Owned = K>,
{
if let Some(idx) = self.0.get(k) {
*idx
} else {
let idx = Index::from(self.0.len());
self.0.insert(k.to_owned(), idx);
idx
}
}
pub fn key(&self, idx: Index) -> Option<&K> {
self.0
.iter()
.find(|&(_, value)| *value == idx)
.map(|(key, _)| key)
}
pub fn keys(&self) -> impl Iterator<Item = &K> {
self.0.keys()
}
}
impl<K> Default for IndexMap<K>
where
K: Eq + Hash,
{
fn default() -> Self {
IndexMap::new()
}
}
fn erfc(x: f64) -> f64 {
let z = x.abs();
let t = 1.0 / (1.0 + z / 2.0);
@@ -158,7 +122,7 @@ fn compute_margin(p_draw: f64, sd: f64) -> f64 {
ppf(0.5 - p_draw / 2.0, 0.0, sd).abs()
}
fn cdf(x: f64, mu: f64, sigma: f64) -> f64 {
pub(crate) fn cdf(x: f64, mu: f64, sigma: f64) -> f64 {
let z = -(x - mu) / (sigma * SQRT_2);
0.5 * erfc(z)
@@ -203,9 +167,9 @@ fn trunc(mu: f64, sigma: f64, margin: f64, tie: bool) -> (f64, f64) {
}
pub(crate) fn approx(n: Gaussian, margin: f64, tie: bool) -> Gaussian {
let (mu, sigma) = trunc(n.mu, n.sigma, margin, tie);
let (mu, sigma) = trunc(n.mu(), n.sigma(), margin, tie);
Gaussian { mu, sigma }
Gaussian::from_ms(mu, sigma)
}
pub(crate) fn tuple_max(v1: (f64, f64), v2: (f64, f64)) -> (f64, f64) {
@@ -219,39 +183,18 @@ pub(crate) fn tuple_gt(t: (f64, f64), e: f64) -> bool {
t.0 > e || t.1 > e
}
pub(crate) fn sort_perm(x: &[f64], reverse: bool) -> Vec<usize> {
let mut v = x.iter().enumerate().collect::<Vec<_>>();
pub(crate) fn sort_time<T: Copy + Ord>(xs: &[T], reverse: bool) -> Vec<usize> {
let mut x: Vec<(usize, T)> = xs.iter().enumerate().map(|(i, &t)| (i, t)).collect();
if reverse {
v.sort_by(|(_, a), (_, b)| b.partial_cmp(a).unwrap());
x.sort_by_key(|&(_, t)| Reverse(t));
} else {
v.sort_by(|(_, a), (_, b)| a.partial_cmp(b).unwrap());
}
v.into_iter().map(|(i, _)| i).collect()
}
pub(crate) fn sort_time(xs: &[i64], reverse: bool) -> Vec<usize> {
let mut x = xs.iter().enumerate().collect::<Vec<_>>();
if reverse {
x.sort_by_key(|&(_, x)| Reverse(x));
} else {
x.sort_by_key(|&(_, x)| x);
x.sort_by_key(|&(_, t)| t);
}
x.into_iter().map(|(i, _)| i).collect()
}
pub(crate) fn evidence(d: &[DiffMessage], margin: &[f64], tie: &[bool], e: usize) -> f64 {
if tie[e] {
cdf(margin[e], d[e].prior.mu, d[e].prior.sigma)
- cdf(-margin[e], d[e].prior.mu, d[e].prior.sigma)
} else {
1.0 - cdf(margin[e], d[e].prior.mu, d[e].prior.sigma)
}
}
/// Calculates the match quality of the given rating groups. A result is the draw probability in the association
pub fn quality(rating_groups: &[&[Gaussian]], beta: f64) -> f64 {
let flatten_ratings = rating_groups
@@ -266,13 +209,13 @@ pub fn quality(rating_groups: &[&[Gaussian]], beta: f64) -> f64 {
let mut mean_matrix = Matrix::new(length, 1);
for (i, rating) in flatten_ratings.iter().enumerate() {
mean_matrix[(i, 0)] = rating.mu;
mean_matrix[(i, 0)] = rating.mu();
}
let mut variance_matrix = Matrix::new(length, length);
for (i, rating) in flatten_ratings.iter().enumerate() {
variance_matrix[(i, i)] = rating.sigma.powi(2);
variance_matrix[(i, i)] = rating.sigma().powi(2);
}
let mut rotated_a_matrix = Matrix::new(rating_groups.len() - 1, length);
@@ -320,14 +263,9 @@ mod tests {
use super::*;
#[test]
fn test_sort_perm() {
assert_eq!(sort_perm(&[0.0, 1.0, 2.0, 0.0], true), vec![2, 1, 0, 3]);
}
#[test]
fn test_sort_time() {
assert_eq!(sort_time(&[0, 1, 2, 0], true), vec![2, 1, 0, 3]);
assert_eq!(sort_time(&[0i64, 1, 2, 0], true), vec![2, 1, 0, 3]);
}
#[test]