Outcome::winner(i, n), Outcome::draw(n), Outcome::ranking(iter) are
the convenience constructors. Marked #[non_exhaustive] so Scored can
be added in T4 without breaking match exhaustiveness.
Adds smallvec = "1" as a direct dependency.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
The bool encoded 'no time axis' which is now expressed at the type
level (T = Untimed). The old !self.time branch generated sequential
i64 timestamps internally (1..=n) and bumped all agents' last_time at
every tick; tests that relied on this now pass those timestamps
explicitly and reflect the correct time=true elapsed semantics.
Collapsed `if self.time { A } else { B }` into the A branch everywhere
in add_events_with_prior. Removed the two !self.time blocks that
updated all agents' last_time at every slice regardless of participation.
sort_time is now generic over `T: Copy + Ord`.
HistoryBuilder::time(bool) removed. History<i64, ConstantDrift>
default remains, producing the same behavior as old .time(true).
The test_env_ttt Gaussian goldens are updated to reflect the correct
time=true semantics (b.elapsed=2 instead of 1 due to b skipping t=2);
this is a correction: the old !self.time last_time bump was an
implementation quirk that diverged from the Python reference.
55 tests pass. clippy clean. fmt clean.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Drift now takes &T -> &T and is generic over the time axis. Untimed
impls return elapsed=0. ConstantDrift impl covers all T via the Time
trait. An additional variance_for_elapsed(i64) method on the trait
serves callers that work with the pre-cached i64 elapsed count.
Competitor.last_time moves from i64 with MIN sentinel to Option<T>
with None sentinel. receive(&T) computes variance from last_time
dynamically; receive_for_elapsed(i64) uses a pre-cached elapsed count
(needed in convergence sweeps where last_time has already advanced).
TimeSlice.time changes from i64 to T. compute_elapsed is now generic
over T and takes Option<&T> for the last-seen time. new_forward_info
uses receive_for_elapsed to preserve the cached elapsed during sweeps.
History<D> becomes History<T, D>; HistoryBuilder<D> becomes
HistoryBuilder<T, D>; Game<D> becomes Game<T, D>. Defaults keep
existing call sites compiling with zero changes: T = i64,
D = ConstantDrift.
add_events / add_events_with_prior stay on impl History<i64, D> since
times: Vec<i64> is i64-specific (Task 8 will generalise this).
In !self.time mode the old i64::MAX sentinel guaranteed elapsed=1 for
every slice transition regardless of time gaps. Replaced by advancing
all previously-seen agents' last_time to Some(current_slice_time) at
the end of each slice; this preserves elapsed=1 between adjacent
slices in sequential-integer untimed mode.
The time: bool field on History and .time(bool) on HistoryBuilder are
NOT removed by this task — deferred to Task 8 so this commit is
purely a type-level generification.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Foundation for generic History time axis. Untimed is the ZST case
(no drift across slices); i64 is the standard timestamp case.
Additional impls (time::OffsetDateTime, chrono) can be added behind
feature flags in follow-up work.
The trait is not yet wired into History — that happens in Task 7
along with generifying Drift over T.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
TimeSlice says what it is: every event sharing one timestamp. The
History field .batches is renamed to .time_slices. Local variables
named `batch` referring to TimeSlice instances are renamed to
`time_slice`.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Competitor holds dynamic per-history state (message, last_time) for
someone competing; its configuration lives in a Rating.
AgentStore renamed to CompetitorStore to match. The internal
`clean()` free function's parameter name changed from `agents` to
`competitors` for consistency.
Local variable names (agent_idx, this_agent) inside history.rs are
left unchanged — they represent abstract identifiers, not Competitor
instances.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
The struct holds prior/beta/drift — a rating configuration, not a
person. The person-with-temporal-state is the Competitor (renamed in
the next task). Resolves Player/Agent ambiguity.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Address code review feedback from Task 2:
- key_table module doesn't need pub visibility; the KeyTable re-export
at lib.rs root already exposes the only public type. Matches the
error/history private-module pattern.
- Revert an incidental bench variable rename (index_map → index) that
wasn't part of the task scope.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The former name collided with the popular indexmap crate. KeyTable
lives in its own module. Public API unchanged beyond the rename.
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Move team_prior, lhood_lose, lhood_win, inv_buf into ScratchArena so
their Vec capacity is reused across games in a Batch. Eliminates 5
per-game heap allocations (the trunc Vec remains local due to borrow
constraints with arena.vars).
Batch::iteration: 23.0 µs (down from 27.0 µs with naive local Vecs;
8% above T0 21.253 µs baseline due to TruncFactor propagate overhead).
Game::likelihoods now uses VarStore (for diff vars) and TruncFactor
(for EP truncation + evidence caching) instead of TeamMessage and
DiffMessage. The EP loop structure is preserved exactly; VarId-keyed
diff vars live in the arena's VarStore (capacity reused per batch).
ScratchArena loses teams/diffs/ties/margins; gains VarStore and
sort_buf (sort_perm allocation eliminated). message.rs deleted.
Public API of Game (new, posteriors, likelihoods, evidence) unchanged.
EpsilonOrMax mirrors today's Game::likelihoods loop: sweep forward
then backward over iterating factors, capped at 10 iterations or
step <= 1e-6. Setup factors (TeamSum) run exactly once before the
loop begins.
ScheduleReport is the only public surface from this module.
EP truncation factor that operates on a diff variable. Stores its
outgoing message so the cavity computation produces the correct EP
message on each propagation. The first propagation caches the
evidence contribution (cdf-bounded probability) for log_evidence().
Promotes lib::cdf to pub(crate) so the factor can use it.
Maintains diff = team_a - team_b across three variables. On each
propagation, reads the team-perf marginals (which may have been
updated by neighboring factors) and computes the new diff via
Gaussian Sub (variance addition).
Computes the weighted sum of player performance Gaussians into a
team-performance variable. Runs once per game (no iteration needed).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the trait that all factors implement and the enum dispatcher
used by the schedule to drive heterogeneous factors without dynamic
dispatch in the hot loop.
The three built-in factors (TeamSum, RankDiff, Trunc) are stubbed
out; concrete implementations follow in tasks 4-6.
Foundation types for the T1 factor graph machinery. VarStore is a
flat Vec<Gaussian> indexed by VarId; variables are allocated by
alloc() and the store can be cleared between games to reuse capacity.
Part of T1 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Game::likelihoods previously allocated four Vecs (teams, diffs, ties,
margins) on every call. Batch now owns one ScratchArena reused across
all Game::new calls in the iteration loop; likelihoods() clears and
extends the arena buffers instead of allocating fresh.
For log_evidence (called infrequently), a local ScratchArena is created
per invocation so the method signature stays &self.
Also: add #[derive(Debug)] to TeamMessage and DiffMessage (required by
ScratchArena's own Debug derive).
Part of T0 engine redesign.
AgentStore<D> is a Vec<Option<Agent<D>>>-backed store indexed directly
by Index.0, eliminating per-iteration hashing in the cross-history
forward/backward sweep. Implements Index<Index>/IndexMut<Index> for
ergonomic agent access.
AgentStore is public (so benches/batch.rs can use it). SkillStore
remains pub(crate) since Skill is pub(crate) in batch.rs.
HashMap<Index, _> is now only used for the posteriors() return value
(temporary; will be replaced in T2 with a proper typed return) and
for the add_events_with_prior(priors: HashMap<Index, Player<D>>) API
(also T2 target).
Part of T0 engine redesign.
SkillStore is a Vec<Skill>-backed dense store with a parallel present
mask, indexed directly by Index.0. Eliminates per-iteration hashing
in the within-slice convergence loop; O(1) array lookup replaces O(1)
amortised hash lookup with better cache behaviour.
Iteration order is now ascending-by-Index (was arbitrary for HashMap);
EP fixed point is order-independent so posteriors are unchanged.
Part of T0 engine redesign.
mu_sigma was deleted as part of the Gaussian nat-param rewrite (its
only callers were the old Mul/Div impls). This commit adds the
InferenceError enum as a seed for the T2 API surface, with the
NegativePrecision variant that mu_sigma would have returned.
Part of T0 engine redesign.
Mul and Div become two f64 adds/subs with no sqrt in the hot path.
mu() and sigma() are computed on demand from stored pi/tau.
Key implementation notes:
- exclude() returns N00 when var <= 0 to avoid inf/inf = NaN when
two Gaussians have the same precision (ULP-level round-trip error
from the pi→sigma accessor).
- Mul<f64> by 0.0 returns N00 (point mass at 0), matching old behavior.
- from_ms(0, 0) == N00 {pi:inf, tau:0}; from_ms(0, inf) == N_INF {pi:0, tau:0}.
Golden values in test_1vs1vs1_draw updated: nat-param arithmetic
rounds mu to 25.0 (was 24.999999) and shifts sigma by ~3e-7.
Both differences are bounded and validated against the original Python
reference values.
Part of T0 engine redesign.
- Promotes Gaussian::pi and Gaussian::tau to public so benches/gaussian.rs
compiles, then captures baseline numbers for the T0 acceptance gate.
- Fixes the divide bench: g1/g2 panicked (g1 has lower precision than g2;
cavity requires pi_num >= pi_den). Swapped to g2/g1 (well-defined).
Baseline on Apple M5 Pro:
Batch::iteration 29.840 µs
Gaussian::mul 1.568 ns (vs ~220 ps for add/sub — hot path)
Gaussian::div 1.572 ns
