Commit Graph
7 Commits
Author SHA1 Message Date
logaritmiskandClaude Opus 5 633a503900 refactor!: remove the factor-graph surface nothing used, add try_winner
Two decisions taken before cutting 0.5.0.

#42 — the `Schedule` trait was public API the engine never called. Its
only call site was `Game::custom`, itself `#[doc(hidden)]`, and
`EpsilonOrMax` was never constructed anywhere. Removing that surface
showed the problem was larger than the issue described: with `custom`
gone, the compiler found `Factor`, `BuiltinFactor`, `RankDiffFactor` and
`TeamSumFactor` all dead too.

`Game::run_chain` drives a local `DiffFactor` enum and bypasses the
whole T1 abstraction — it has done since it was written. So this is not
just an unused extension point but the machinery it was built on, and
`CLAUDE.md` was documenting it as live architecture.

Removed: `graph` module, `Schedule`, `EpsilonOrMax`, `ScheduleReport`,
`Game::custom`, `Factor`, `BuiltinFactor`, `RankDiffFactor`,
`TeamSumFactor`. `TruncFactor`, `MarginFactor`, `VarStore` and `VarId`
stay — inference uses those. The measurement behind choosing removal
over wiring is in #42: the within-game loop converges in 1 to 8
iterations against a cap of 30, so a `Residual` schedule has no headroom
to reclaim, and `Damped` already shipped as `ConvergenceOptions::alpha`.

#20 — `Outcome::winner` panicking on an out-of-range index. Kept, and
the reasoning is now on the method. It is the only constructor here that
validates, which looks inconsistent until you try deferring like its
siblings: `winner(5, 2)` produces ranks `[1, 1]`, an all-tied draw that
ingestion accepts without complaint when `p_draw > 0`. Asking "team 5
won" and silently getting "everyone drew" is the exact failure this
crate keeps removing, so the check belongs where the mistake is.

Adds `Outcome::try_winner` for indices that are computed or parsed
rather than written literally, following the `new`/`try_new` convention.
That is additive; the panicking form stays because every call site in
this repo, its tests and its README passes literals, where a `?` would
be noise.

BREAKING CHANGE: the `graph` module and everything it exported are
removed, as are `Game::custom` and `ScheduleReport`.

Closes #42. Closes #20.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
2026-09-08 02:14:43 +02:00
logaritmiskandClaude Opus 5 683813ec10 fix: correct erfc_inv's sign error and keep evidence in log space
A systematic scan for precision defects, following the tail-precision
work in 7341669. Three findings; the first is a correctness bug in a
released version.

1. `erfc_inv`'s initial guess had the wrong sign. Numerical Recipes'
   `inverfc` uses -0.70711 as the leading coefficient; this used
   +FRAC_1_SQRT_2. Since `rational - t` is negative, that put Newton on
   the mirror image of the root, and three fixed iterations could not
   cross back. Measured against exact standard-normal quantiles:

       p_draw   old rel err   new rel err
       0.50        1.46e-7       8.40e-8
       0.90        1.02e-1       8.63e-9
       0.95        3.06e-1       1.91e-8
       0.99        8.05e-1       5.89e-9

   `compute_margin` inherited it, so the draw margin was wrong for any
   `p_draw` above about 0.6 and *non-monotone* above 0.9 — it ran
   0.674, 1.476, 0.503, 0.982 as p_draw went 0.5, 0.9, 0.99, 0.999. A
   history configured for a 0.99 draw rate was being fitted at 0.385.
   Note it was slightly wrong everywhere, not only in the tail.

2. `MarginFactor` computed a density and clamped it. `pdf` underflows
   past ~38 sigma, so `ln` of the clamped zero reported -708 nats
   however far out the score actually was: 4292 nats adrift at 100
   sigma, and unbounded beyond. This is the same defect as the one
   fixed in `TruncFactor`, one file over, on the scored-outcome path.

3. `TruncFactor` still bottomed out past ~38 sigma even after 7341669
   removed the cancellation, because the linear probability itself
   underflows there.

2 and 3 are fixed the same way: factors cache a *log* evidence, built
from new `ln_pdf`, `ln_sf` and `ln_interval` helpers that factor the
shared exponential out analytically via the `erfcx` added earlier.
Nothing underflows, at any separation.

One golden moved. `test_1vs1vs1` runs at `p_draw = 0.5`, so it goes
through `compute_margin`; its 1e-6-place values shifted. Verified as
movement *toward* analytic truth by comparing both the old and new
inverse against exact quantiles, per the goldens policy in CLAUDE.md —
not re-baselined on faith.

Two test tolerances are asserted at 1e-6 rather than tighter because
above x = 2 `erfcx` uses a continued fraction accurate to ~1e-15 while
`erfc` carries ~1e-7, so the log path is the more accurate of the two
and they part company at `erfc`'s error. That floor is tracked in #41.

Refs #41

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
2026-09-07 21:45:03 +02:00
logaritmiskandClaude Opus 5 7341669d1a fix: stop destroying tail precision in evidence and truncation
`erfc` is sound — it holds ~1e-7 *relative* accuracy down to 1e-296 with
no tail degradation. Three expressions built on it threw that away by
subtracting quantities that both approach the same value.

1. `cavity_evidence` computed `1.0 - cdf(margin, ..)`, which is
   algebraically `sf(margin, ..)` and numerically a catastrophe: 7%
   error by eight sigma, and exactly zero past ~8.3, where the true
   probability is 1e-19 and perfectly representable. Clamped, that
   reached `log_evidence` as ln(f64::MIN_POSITIVE) = -708 whatever the
   truth was — off by 665 nats at nine sigma.

   `1 - cdf` is smallest precisely when the result contradicts the
   prior, so the model-comparison number was worst for upsets: the
   observation it exists to notice. Adds `sf`, the survival function,
   computed without the subtraction. The tie branch picks whichever tail
   keeps both of its terms small, for the same reason.

2. `v_w` computed the inverse Mills ratio as `pdf(-a) / cdf(-a)`. Both
   underflow together past about 39 sigma, giving `0 / 0` and putting
   NaN straight into the posterior. Adds `erfcx`, so the shared
   `exp(-alpha^2 / 2)` cancels analytically instead of being evaluated
   twice and divided.

3. With that fixed, `w = v * (v - alpha)` became the next casualty: `v`
   tends to `alpha`, so the gap lost every digit and drove `w` above 1,
   making `sqrt(1 - w)` NaN at alpha = 1e6. The gap now comes from its
   asymptotic series, which forms no difference at all. The tie branch
   had the same defect one expression over — `v * v - u` with both terms
   at 1e18 returned w = -128 — and a far-tail window is
   indistinguishable from a half-line, so it shares the asymptotic.

No public signature changes, and no existing golden moved: every one of
these only alters regions the old code got wrong. The two identity tests
are asserted at 1e-6 rather than tighter because `erfc` is not exactly
antisymmetric — `erfc(z) + erfc(-z)` differs from 2 by ~3e-8, and
`erfc(0)` returns 1.00000003. That floor is tracked separately.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
2026-09-07 15:28:35 +02:00
logaritmiskandClaude Opus 5 9b2c2b38c8 docs: complete the public API documentation contract
Closes the last open item in #25. `cargo clippy -W missing_errors_doc
-W missing_panics_doc -W must_use_candidate -W doc_markdown` went from 56
warnings to zero.

The 13 hand-written sections name the actual variants each function returns
rather than gesturing at "an error". Establishing that meant reading the error
paths — `Game::ranked` alone returns four distinct variants, and `record_draw`
can hit TieWithoutDrawProbability where `record_winner` provably cannot, since
a two-team decisive outcome has nothing to tie. Documenting those as
interchangeable would have been worse than leaving them undocumented, because
a reader would trust it.

Two existing doc comments already described panics in prose but not under a
`# Panics` heading, so neither rustdoc nor clippy surfaced them:
`Outcome::winner` and `EventBuilder::weights`. Both now carry the heading, and
`Outcome::winner` gained the note that it ties every loser, so `n >= 3` needs a
positive p_draw — the crate's easiest error to hit by accident.

The 43 mechanical fixes (31 `#[must_use]` on pure accessors, 11 missing
backticks) were applied with `cargo clippy --fix`. `#[must_use]` on Gaussian's
arithmetic and on `posteriors()` matters: discarding those results is always a
bug, and until now nothing said so.

Also documented why `[profile.release] debug = true` exists — cargo-flamegraph
needs the symbols, and library profile settings are ignored downstream, so it
reads as an oversight without the note.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T5SYDExxL4vZgvunrcNSMc
2026-08-27 17:43:31 +02:00
logaritmiskandClaude Opus 5 0f1a1b8911 fix(evidence): accumulate in log space and floor the per-link value
Per-link evidence was multiplied in linear space and logged only at the
end. Each link contributes a probability in (0, 1], so the product over an
n-team game decays geometrically: around a thousand links it flushes to
exactly 0.0 and `ln(0.0)` is `-inf`, which then propagates through the sum
in `History::log_evidence_internal` and takes the whole history with it.
`Game::free_for_all` builds one team per player, so this is reachable at
the competitor counts the T3 benchmarks target.

`Game`, `OwnedGame`, and `time_slice::Event` now carry `log_evidence`
directly, summed over links rather than multiplied then logged.

The cached per-link evidence is also floored at `f64::MIN_POSITIVE`. It
could legitimately reach zero or go negative: `1.0 - cdf(..)` rounds to
zero for a near-certain outcome, and the `erfc` approximation carries
~1e-7 error so `cdf` can exceed 1.0 and make the difference negative —
`ln` of which is NaN.

Existing log-evidence goldens are unchanged, confirming the accumulation
is numerically equivalent in the range where the old form worked.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DnsaJg74eNSva3PJjK2eej
2026-08-04 21:43:57 +02:00
logaritmisk fcfe0ffe37 feat(factor): add TruncFactor::propagate_with_alpha for EP damping
Inherent method that applies α-damping to the outgoing message via
Gaussian::damp_natural. The Factor trait impl delegates with α=1.0,
preserving today's behavior bit-equal. Variable write switched from
`trunc` to `cavity * damped` — algebraically identical when α=1.0
(cavity * new_msg = trunc by construction); reflects partial-update
math when α<1.0.
2026-05-08 15:02:09 +02:00
logaritmisk d2aab82c1e 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>
2026-04-24 11:20:04 +00:00