Trait coverage (#76), all additive:
History Debug is still absent - see below
HistoryBuilder + Debug (it derived Clone but not Debug)
Rating + PartialEq (Gaussian had it; Rating is a Gaussian
plus three scalars and had none)
Event/Team/Member + PartialEq (input value types with no way to compare
them, which made round-trip tests awkward)
ConvergenceReport + PartialEq
`#[must_use]` (#67). The coverage had no rule: `filtered_log_evidence`
had it and `log_evidence` did not; `rating` had it and `current_skill`
did not; `Rating::with_drift_scale` had it and `Member::with_drift_scale`
did not.
Now on the types — `EventBuilder`, `HistoryBuilder`, `Prediction`,
`Gaussian`, `OwnedGame` — which covers most method returns at once, plus
the `History` accessors individually.
`EventBuilder` gets a message, because a dropped builder is the worst
case in the set: measured, `h.event(1).team(["x"]).team(["y"]).winner(0)`
without `.commit()` leaves `time_slices_len() == 0` and every skill
`None`, with no warning at all.
And `ConvergenceReport`'s `#[must_use]` moves off the TYPE onto
`converge_partial`, where its stated reason is true. It read "from
`converge_partial` this may describe a fit that stopped at max_iter" but
fired on `converge` too — where that is false, since `converge` returns
`Err(NotConverged)` in exactly that case. So the crate's own front-page
example warned, and every quickstart had to write `let _ =`. Verified
from a consumer crate: `h.converge()?;` now compiles clean.
Marking the types made eight method-level attributes redundant, which
clippy's `double_must_use` caught — that is the type-level marker doing
its job, and the eight are removed.
Refs #76, #67
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
0.8.0 closed the sign-absorption defect at `HistoryBuilder::mu/sigma/beta`
and at both ingestion paths. It was still open one layer down, in the
constructors those paths call. Measured, all bit identical to their
positive counterparts:
Gaussian::from_ms(25.0, -8.33) == from_ms(25.0, +8.33)
Rating::new(_, -4.17, _) == Rating::new(_, +4.17, _)
ConstantDrift(-0.0833) == ConstantDrift(+0.0833)
sigma, beta and gamma enter only as squares, so the sign vanished without
comment. Worst of the set: `Rating::new(_, NaN, _)` reached `Game::ranked`
which returned **Ok** carrying `Gaussian { pi: NaN, tau: NaN }` — no
`converge` on that path to catch it.
`from_ms` and `Rating::new` now reject. `ConstantDrift` cannot: the field
is public and positional, so there is no constructor to intercept, and
sealing it would break every `ConstantDrift(x)` for a case whose resulting
model is perfectly valid. Documented instead. Its non-finite half IS
rejected — `converge` validates the drift variance each competitor
accumulates, which also covers a custom `Drift` impl.
Two things the tests caught that I had wrong:
NaN sigma must PASS `from_ms`. My first version rejected it, and two
existing tests went red immediately: a broken fit legitimately produces a
NaN sigma from `sqrt` of a negative truncated variance, and the design is
to propagate that to `NonFiniteResult`. Rejecting it turned the reporting
path into a panic inside inference. Written as
`sigma >= 0.0 || sigma.is_nan()` so the intent is explicit rather than
hidden in a negated comparison.
Very small sigma is also not rejected, and that is deliberate: `approx`
produces small truncated sigmas legitimately. `pi = 1/sigma^2` leaves
f64's range below ~1.5e-154 and `tau = mu*pi` overflows sooner, at a
threshold that depends on mu — so there is a band where pi is finite and
only tau is not. Both land on the existing point-mass representation.
Documented, including that such a Gaussian is not equal to itself and can
make two identical declarations report as conflicting.
BREAKING CHANGE: `Gaussian::from_ms` panics on a negative sigma, and
`Rating::new` panics unless beta is finite and non-negative. `converge`
returns `InvalidParameter` for a non-finite drift variance.
Closes#61
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
`tuple_max` compared with a plain `>`, which is false against NaN, so a
NaN accumulator was replaced by the next finite delta. The fold runs over
`TimeSlice::posteriors()`, a HashMap, so whether a NaN survived to `step`
depended on per-process hash order.
Measured before, four competitors in one slice with one pathological
pair, same binary and input, 30 separate processes:
16 Ok converged=true, iterations=1, a = Gaussian { pi: NaN, tau: NaN }
14 Err NonFiniteResult
After: 30/30 Err. A coin flip on whether a NaN fit was reported as an
error or as a successful, converged fit — inside the guard whose entire
purpose is "NaN is never convergence".
`f64::max` would not have fixed it. It also ignores NaN by design, which
is the same defect wearing a standard-library name, and a test pins that
we do not use it.
`Gaussian::delta` had to be fixed FIRST, and that ordering is the whole
subtlety. Two identical improper messages produced `(0.0, NaN)` — not
from `mu()`, which is guarded and returns 0.0, but from `inf - inf` in
the sigma component. That NaN is reachable in ordinary healthy inference:
once a pairing is more than about nine cavity-sigma apart the truncation
is a no-op and the chain compares one identity message against another.
Propagating NaN without fixing `delta` would therefore have turned
correct fits into NonFiniteResult errors. `delta` now answers the
identical-message case in natural space before touching the accessors.
My first version of the `delta` test asserted `mu()` was NaN. It is not;
the accessor guards `pi <= 0.0`. The test caught my own wrong premise,
and the doc comment is corrected to match.
BREAKING CHANGE: a fit that produced NaN in a non-final reduction
position previously returned `Ok` with `converged: true` and a NaN
posterior; it now returns `Err(NonFiniteResult)`. That was always the
documented intent.
Closes#58
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
Three issues from two downstream consumers, all small, all sharing a
theme: the crate had the information and would not hand it over.
#44 — `UnknownKey { team: 0, member: 0 }` did not say which key. A
consumer upgrading 0.1.2 -> 0.4.1 had every one of 5591 predictions
return this error, fell back to a neutral 0.5, and lost its entire
metadata model for a day. Nothing crashed and nothing logged; it was
found by sweeping an unrelated parameter and noticing the output did not
move. The 0.4.0 change that made unknown keys an error was right — the
error was just too anonymous to act on. It now carries the key's `Debug`
rendering, and its `Display` says what to do about it. The precondition
is documented on every prediction entry point, which the reporter said
would alone have saved the day.
#43 — `cdf` was `pub(crate)`, so a consumer asking "is this competitor
below the cutoff" approximated it with a `mu + z * sigma` band and had no
way to say what confidence any `z` bought. Adds
`Gaussian::probability_below` / `probability_above`. The second is
separate on purpose: `1 - cdf` collapses to exactly zero past ~8.3
sigma, and a stopping rule is evaluated precisely there. Both route
through the survival function added in 0.4.1, so this is visibility
rather than new numerics.
#50 — `ConvergenceReport` was not `#[must_use]`, so the one signal that
a fit stopped short was trivially discarded. It now is, and that
immediately found 78 sites doing exactly that — including this crate's
own ATP example, which was capped at 10 sweeps when the history needs
30. The example now reads the report and says so.
`ITERATIONS = 30` is documented as the floor it is, with the three
measurements to hand: 400 events over 100 competitors already stops
there at ~7e-3 against a 1e-6 tolerance, the ATP example needs 30 at a
much looser one, and a consumer's 2000-node model needs 76 to 161.
BREAKING CHANGE: `InferenceError::UnknownKey` gains a `key` field, and
the prediction methods now require `K: Debug` in order to fill it.
Closes#43, #50. Refs #44 — its third ask, an opt-in `UnknownKeys::Skip`
mode, is a live API question and deliberately not answered here.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
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
`Add`, `Sub`, `exclude` and `forget` combined variances by way of standard
deviations: `sigma()` takes a square root, `.powi(2)` squares it away,
`var.sqrt()` takes another, and `from_ms` squares that one back. Three roots
to compute a value that is `1/pi` all along.
They now go through `variance()` and a new `from_mv(mu, var)`, which skip
both conversions. `Sub` is the hot one — `RankDiffFactor::propagate` is
`a - b`, run for every adjacent team pair on every forward and backward
sweep of every EP iteration.
`run_chain` also stopped recomputing each team's weighted performance in the
likelihood loop; the fold is already in `arena.team_prior`, indexed by the
sorted position the loop has in hand. Each `performance()` is itself a
`forget`, so the duplicate cost scaled with players per team.
Measured on this machine, before and after, same fixtures:
Batch::iteration 23.57us -> 19.31us (-18%)
scored_history_60_events 1.071ms -> 983us (-8%)
The `Gaussian::add`/`sub` microbenchmarks cannot resolve the change: they
sit at ~234ps against a ~218ps floor that `mul`/`div` also hit, so the
harness overhead dominates a single operation.
One golden moved. Two identical competitors drawing must land on their
shared prior mean exactly, by symmetry; the root-free path now returns
25.0 where the reference transcription recorded 24.999999 — that value
rounded to six decimals. Asserting a six-decimal transcription at
epsilon 1e-6 left no headroom, so the expectation is now the exact value.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DnsaJg74eNSva3PJjK2eej
EP message cancellation can leave a Gaussian's precision (pi) a tiny
negative value — round-off of exactly zero. mu()/sigma() only special-cased
pi == 0, so sigma() computed 1/sqrt(pi) = NaN for pi < 0. That NaN flowed
through the moment-space Sub in the game diff-chain and poisoned every skill
in the slice once it grew past ~75 competitors, making converge() return
all-NaN on real-scale histories (regression vs 0.1.0, which stored sigma
directly). Guard pi <= 0.0 in both accessors (improper Gaussian: mu 0,
sigma infinite), matching the existing pi == 0 handling.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Computes α·new + (1−α)·self in natural-parameter space. Will be used
by TruncFactor and MarginFactor to support opt-in EP damping via
ConvergenceOptions::alpha.
logaritmiskandClaude Opus 5