Files
the-daily-epub/src/curate/signals.rs
T
thalladaandClaude Fable 5.1 f71a4c2799 Keep the publication an article's page declares
Readability already reads og:site_name and JSON-LD publisher.name; carry
that through Page and Extracted and store it in articles.publication, the
same way the page byline is kept. `publication_label` is what the readers
will see after the feed name: the site name, else the domain, and nothing
when it would only repeat the feed's own title.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YWmCpUojfHXhSZ2129Z7Nv
2026-09-09 05:48:46 +00:00

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//! Cheap per-article ranking signals, the mid-rank percentile normalizer and the
//! preliminary blend (plan §9, §12.2, §12.4).
//!
//! Every signal is an `Option<f64>`: `None` means *absent*, which is never a
//! numeric zero. Absent signals are left out of the percentile computation and
//! of the blend, whose remaining weights are renormalized (§12.2, §12.4).
use std::collections::{BTreeMap, HashMap, HashSet};
use jiff::Timestamp;
use serde::{Deserialize, Serialize};
use crate::config::{PreliminaryWeights, RankingConfig, VoyageConfig};
use crate::curate::embedding::{dot, load_article_embeddings};
use crate::curate::prefilter;
use crate::db::Db;
use crate::types::{Article, ArticleId, FeedId, SourceKind};
/// Below this many embedded eligible articles the z-score is too noisy, so the
/// interest signal falls back to the raw top-1 cosine (§9.1).
pub const INTEREST_ZSCORE_MIN_ARTICLES: usize = 30;
/// Standard-deviation floor for the per-interest z-score (§9.1).
const ZSCORE_STD_FLOOR: f64 = 1e-3;
/// How many interests and rated neighbours `signals_json` records (§7.5).
const RECORDED_TOP: usize = 3;
/// Aggregators carried the link rather than authored the article, so they get
/// only a small share of an aggregator-only article's feed-affinity credit.
pub const AGGREGATOR_FEED_SHARE: f64 = 0.25;
/// The signal names that go through the percentile normalizer, in the order
/// they are rendered (§12.2). LLM scores (`triage`, `quality`, `fit`) are
/// absolute and arrive in steps 4–5.
pub const PERCENTILE_SIGNALS: [&str; 5] = ["interest", "knn", "feed", "social", "heuristic"];
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct TopInterest {
pub name: String,
pub z: f64,
pub cos: f64,
}
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct Neighbour {
pub article_id: ArticleId,
pub label: String,
pub cos: f64,
pub title: String,
}
/// Every cheap signal for one article, plus what the normalizer and the blend
/// derived from them (§9, §12.2, §12.4).
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct Signals {
pub interest: Option<f64>,
/// Raw top-1 cosine behind `interest`, recorded for `explain` (§7.5).
pub interest_top1_cos: Option<f64>,
pub knn: Option<f64>,
pub feed: Option<f64>,
pub social: Option<f64>,
pub heuristic: Option<f64>,
/// Mid-rank percentiles of the present signals (§12.2).
#[serde(default)]
pub norm: BTreeMap<String, f64>,
/// Effective preliminary weights after gating and renormalization (§12.4).
#[serde(default)]
pub weights: BTreeMap<String, f64>,
#[serde(default)]
pub top_interests: Vec<TopInterest>,
#[serde(default)]
pub neighbours: Vec<Neighbour>,
#[serde(default)]
pub notes: Vec<String>,
/// Preliminary blend on a 0–100 scale; `None` when nothing is present.
pub preliminary: Option<f64>,
/// The author has a current *AI slop* verdict (§9.3).
#[serde(default)]
pub slop_author: bool,
/// Gate ramps applied to the learned signals' weights (§9.2, §9.3).
#[serde(skip)]
pub knn_gate: f64,
#[serde(skip)]
pub feed_gate: f64,
/// `ranking.slop_author_penalty`, applied when `slop_author` is set.
#[serde(skip)]
pub slop_penalty: f64,
}
impl Signals {
/// The multiplier the slop-author penalty applies to the blend and the
/// utility: `1 − penalty` for a reported author, `1` otherwise (§9.3).
pub fn slop_factor(&self) -> f64 {
if self.slop_author {
(1.0 - self.slop_penalty).clamp(0.0, 1.0)
} else {
1.0
}
}
}
impl Signals {
/// The raw value of a named signal, `None` when absent or unknown.
pub fn raw(&self, name: &str) -> Option<f64> {
match name {
"interest" => self.interest,
"interest_top1_cos" => self.interest_top1_cos,
"knn" => self.knn,
"feed" => self.feed,
"social" => self.social,
"heuristic" => self.heuristic,
_ => None,
}
}
pub fn present(&self, name: &str) -> bool {
self.raw(name).is_some()
}
/// The signals every eligible article gets without embeddings or ratings.
pub fn baseline(article: &Article) -> Self {
Self {
social: (!article.social.is_empty()).then(|| article.social_score()),
heuristic: Some(prefilter::text_heuristic(article)),
..Self::default()
}
}
}
/// What the run log and the report say about the learned signals (§9.2, §15.4).
#[derive(Debug, Clone, Copy, Default, PartialEq)]
pub struct PreferenceSummary {
pub rated_with_embeddings: usize,
pub attributable_feed_ratings: usize,
pub knn_gate: f64,
pub feed_gate: f64,
}
/// One rated article with an embedding: the unit of the preference state (§9.2).
#[derive(Debug, Clone, PartialEq)]
pub struct RatedExample {
pub article_id: ArticleId,
pub label: String,
pub title: String,
/// The vote's value (`loved` 1.0, `good` 0.35, `not_for_me` −1.0).
pub value: f64,
/// `0.5 ^ (age_days / half_life_days)` at the time of the run.
pub decay: f64,
pub embedding: Vec<f32>,
/// Distinct direct feeds that carried the rated article (§9.3).
pub feeds: Vec<FeedId>,
/// Whitespace-normalized, lowercase author key (§9.3).
pub author: Option<String>,
/// Whether the article arrived only through link aggregators (§9.3).
pub aggregator_only: bool,
}
impl RatedExample {
/// `weight_i = value_i × decay_i` (§9.2).
pub fn weight(&self) -> f64 {
self.value * self.decay
}
}
#[derive(Debug, Clone, Copy, Default, PartialEq)]
struct FeedRate {
up: f64,
down: f64,
}
impl FeedRate {
/// Beta-smoothed rate `(up + 1) / (up + down + 2)` (§9.3).
fn rate(self) -> f64 {
(self.up + 1.0) / (self.up + self.down + 2.0)
}
}
/// Rated-neighbour and feed-affinity state, built once per run (§9.2, §9.3).
#[derive(Debug, Clone, Default)]
pub struct PreferenceState {
pub examples: Vec<RatedExample>,
feed_rates: HashMap<FeedId, FeedRate>,
author_rates: HashMap<String, FeedRate>,
/// Normalized keys of authors with a current *AI slop* verdict (§9.3).
slop_authors: HashSet<String>,
pub slop_author_penalty: f64,
pub attributable_feed_ratings: usize,
pub knn_gate: f64,
pub feed_gate: f64,
}
impl PreferenceState {
/// Build the state from already-loaded examples (pure; tests use this).
pub fn build(mut examples: Vec<RatedExample>, ranking: &RankingConfig) -> Self {
for example in &mut examples {
example.author = normalize_author(example.author.as_deref());
}
let (feed_rates, author_rates, attributable_feed_ratings) = feed_rates(&examples);
Self {
knn_gate: gate(examples.len(), ranking.knn_floor, ranking.knn_full),
feed_gate: gate(
attributable_feed_ratings,
ranking.feed_floor,
ranking.feed_full,
),
examples,
feed_rates,
author_rates,
slop_authors: HashSet::new(),
slop_author_penalty: ranking.slop_author_penalty,
attributable_feed_ratings,
}
}
/// Register the authors whose current verdict is *AI slop*; keys are
/// normalized like [`normalize_author`] and empty ones are dropped.
pub fn with_slop_authors<I, S>(mut self, authors: I) -> Self
where
I: IntoIterator<Item = S>,
S: AsRef<str>,
{
self.slop_authors = authors
.into_iter()
.filter_map(|author| normalize_author(Some(author.as_ref())))
.collect();
self
}
/// Whether the article's author has a current *AI slop* verdict (§9.3).
pub fn is_slop_author(&self, article: &Article) -> bool {
normalize_author(article.author.as_deref())
.is_some_and(|author| self.slop_authors.contains(&author))
}
pub fn slop_author_count(&self) -> usize {
self.slop_authors.len()
}
/// Load `db::current_ratings(rating_lookback_days)` joined to
/// `article_embeddings`; ratings without an embedding are skipped (§9.2).
pub async fn load(
db: &Db,
voyage: &VoyageConfig,
ranking: &RankingConfig,
now: Timestamp,
) -> anyhow::Result<Self> {
let ratings = db.current_ratings(ranking.rating_lookback_days).await?;
let ids = ratings
.iter()
.map(|rating| rating.article_id)
.collect::<Vec<_>>();
let embeddings = load_article_embeddings(db, voyage, &ids).await?;
let mut examples = Vec::new();
for rating in ratings {
let Some(embedding) = embeddings.get(&rating.article_id).cloned() else {
continue;
};
let article = db.get_article(rating.article_id).await?;
let feeds = article.as_ref().map(direct_feeds).unwrap_or_default();
let author = article
.as_ref()
.and_then(|article| normalize_author(article.author.as_deref()));
let aggregator_only = article
.as_ref()
.is_some_and(crate::discovery::aggregator_only);
let age_days = (now.as_second() - rating.event_at.as_second()).max(0) as f64 / 86_400.0;
examples.push(RatedExample {
article_id: rating.article_id,
label: rating.label,
title: rating.title,
value: rating.value,
decay: decay(age_days, ranking.rating_half_life_days),
embedding,
feeds,
author,
aggregator_only,
});
}
let slop_authors = db.slop_authors().await?;
Ok(Self::build(examples, ranking).with_slop_authors(slop_authors))
}
pub fn summary(&self) -> PreferenceSummary {
PreferenceSummary {
rated_with_embeddings: self.examples.len(),
attributable_feed_ratings: self.attributable_feed_ratings,
knn_gate: self.knn_gate,
feed_gate: self.feed_gate,
}
}
/// The once-per-run log line of §9.2.
pub fn log(&self, ranking: &RankingConfig) {
let feed_detail = if self.feed_gate > 0.0 {
format!("(n={})", self.attributable_feed_ratings)
} else {
format!(
"(n={} < {})",
self.attributable_feed_ratings, ranking.feed_floor
)
};
tracing::info!(
rated_with_embeddings = self.examples.len(),
knn_gate = self.knn_gate,
feed_gate = self.feed_gate,
slop_authors = self.slop_authors.len(),
"preference: {} rated articles with embeddings → knn gate {:.2}; feed gate {:.1} {}; {} slop authors (penalty {:.2})",
self.examples.len(),
self.knn_gate,
self.feed_gate,
feed_detail,
self.slop_authors.len(),
self.slop_author_penalty
);
}
/// Signed rated-neighbour preference and the three nearest rated articles
/// (§9.2). Absent when the gate is closed or there are no examples.
pub fn knn(&self, candidate: &[f32], ranking: &RankingConfig) -> (Option<f64>, Vec<Neighbour>) {
if self.knn_gate <= 0.0 || self.examples.is_empty() {
return (None, Vec::new());
}
let mut scored = self
.examples
.iter()
.filter_map(|example| {
dot(candidate, &example.embedding)
.ok()
.map(|s| (s, example))
})
.collect::<Vec<_>>();
scored.sort_by(|left, right| right.0.total_cmp(&left.0));
let side = |positive: bool| -> Option<f64> {
let chosen = scored
.iter()
.filter(|(_, example)| (example.weight() > 0.0) == positive)
.take(ranking.neighbour_k.max(1))
.collect::<Vec<_>>();
let denominator = chosen
.iter()
.map(|(_, example)| example.weight().abs())
.sum::<f64>();
(denominator > 0.0).then(|| {
chosen
.iter()
.map(|(similarity, example)| example.weight().abs() * similarity)
.sum::<f64>()
/ denominator
})
};
let positive = side(true);
let negative = side(false);
let knn = (positive.is_some() || negative.is_some()).then(|| {
positive.unwrap_or(0.0) - ranking.negative_coefficient * negative.unwrap_or(0.0)
});
let neighbours = scored
.iter()
.take(RECORDED_TOP)
.map(|(cos, example)| Neighbour {
article_id: example.article_id,
label: example.label.clone(),
cos: *cos,
title: example.title.clone(),
})
.collect();
(knn, neighbours)
}
/// Mean Beta-smoothed rate over the article's rated direct feeds and author
/// (§9.3).
pub fn feed(&self, article: &Article) -> Option<f64> {
if self.feed_gate <= 0.0 {
return None;
}
let mut rates = direct_feeds(article)
.into_iter()
.filter_map(|feed| self.feed_rates.get(&feed))
.map(|rate| rate.rate())
.collect::<Vec<_>>();
if let Some(rate) = normalize_author(article.author.as_deref())
.as_ref()
.and_then(|author| self.author_rates.get(author))
{
rates.push(rate.rate());
}
(!rates.is_empty()).then(|| rates.iter().sum::<f64>() / rates.len() as f64)
}
/// Per-feed `(up, down)` credit, exposed for tests of §9.3.
pub fn feed_credit(&self, feed: FeedId) -> Option<(f64, f64)> {
self.feed_rates.get(&feed).map(|rate| (rate.up, rate.down))
}
/// Per-author `(up, down)` credit, exposed for tests of §9.3.
pub fn author_credit(&self, author: &str) -> Option<(f64, f64)> {
normalize_author(Some(author))
.and_then(|author| self.author_rates.get(&author))
.map(|rate| (rate.up, rate.down))
}
}
/// `0.5 ^ (age_days / half_life_days)` (§9.2).
pub fn decay(age_days: f64, half_life_days: f64) -> f64 {
if half_life_days <= 0.0 {
return 1.0;
}
0.5f64.powf(age_days.max(0.0) / half_life_days)
}
/// `clamp((n − floor) / (full − floor), 0, 1)` (§9.2).
pub fn gate(n: usize, floor: usize, full: usize) -> f64 {
if n <= floor {
0.0
} else if n >= full || full <= floor {
1.0
} else {
(n - floor) as f64 / (full - floor) as f64
}
}
/// Distinct `SourceKind::Feed` feeds that carried the article; the best entry's
/// feed when there are none (§9.3).
pub fn direct_feeds(article: &Article) -> Vec<FeedId> {
let mut feeds = article
.sources
.iter()
.filter(|source| source.kind == SourceKind::Feed)
.map(|source| source.feed_id)
.collect::<HashSet<_>>()
.into_iter()
.collect::<Vec<_>>();
if feeds.is_empty() && article.feed_id != 0 {
feeds.push(article.feed_id);
}
feeds.sort_unstable();
feeds
}
fn normalize_author(author: Option<&str>) -> Option<String> {
let normalized = author?
.split_whitespace()
.collect::<Vec<_>>()
.join(" ")
.to_lowercase();
(!normalized.is_empty()).then_some(normalized)
}
fn feed_rates(
examples: &[RatedExample],
) -> (HashMap<FeedId, FeedRate>, HashMap<String, FeedRate>, usize) {
let mut feed_rates: HashMap<FeedId, FeedRate> = HashMap::new();
let mut author_rates: HashMap<String, FeedRate> = HashMap::new();
let mut attributable = 0;
for example in examples {
let weight = example.weight();
if !example.feeds.is_empty() {
let feed_weight = if example.aggregator_only {
weight * AGGREGATOR_FEED_SHARE
} else {
weight
};
let credit = feed_weight / example.feeds.len() as f64;
for feed in &example.feeds {
let rate = feed_rates.entry(*feed).or_default();
rate.up += credit.max(0.0);
rate.down += (-credit).max(0.0);
}
}
if let Some(author) = &example.author {
let rate = author_rates.entry(author.clone()).or_default();
rate.up += weight.max(0.0);
rate.down += (-weight).max(0.0);
}
if !example.feeds.is_empty() || example.author.is_some() {
attributable += 1;
}
}
(feed_rates, author_rates, attributable)
}
/// The interest match of §9.1 for one article.
#[derive(Debug, Clone, Default, PartialEq)]
pub struct InterestMatch {
pub score: f64,
pub top1_cos: f64,
pub top_interests: Vec<TopInterest>,
}
/// Z-scored standing-interest match for every embedded article (§9.1).
///
/// Below [`INTEREST_ZSCORE_MIN_ARTICLES`] embedded articles the score is the raw
/// top-1 cosine instead, and that is logged.
pub fn interest_matches(
articles: &HashMap<ArticleId, Vec<f32>>,
interests: &HashMap<String, Vec<f32>>,
) -> HashMap<ArticleId, InterestMatch> {
if articles.is_empty() || interests.is_empty() {
return HashMap::new();
}
let fallback = articles.len() < INTEREST_ZSCORE_MIN_ARTICLES;
if fallback {
tracing::info!(
embedded = articles.len(),
"fewer than {INTEREST_ZSCORE_MIN_ARTICLES} embedded articles; interest uses the raw top-1 cosine"
);
}
let mut matches: HashMap<ArticleId, Vec<TopInterest>> = HashMap::new();
for (name, interest) in interests {
let similarities = articles
.iter()
.filter_map(|(article_id, article)| {
dot(interest, article).ok().map(|cos| (*article_id, cos))
})
.collect::<Vec<_>>();
if similarities.is_empty() {
continue;
}
let n = similarities.len() as f64;
let mean = similarities.iter().map(|(_, cos)| cos).sum::<f64>() / n;
let variance = similarities
.iter()
.map(|(_, cos)| (cos - mean).powi(2))
.sum::<f64>()
/ n;
let std = variance.sqrt().max(ZSCORE_STD_FLOOR);
for (article_id, cos) in similarities {
matches.entry(article_id).or_default().push(TopInterest {
name: name.clone(),
z: (cos - mean) / std,
cos,
});
}
}
matches
.into_iter()
.map(|(article_id, mut all)| {
all.sort_by(|left, right| {
right
.z
.total_cmp(&left.z)
.then_with(|| left.name.cmp(&right.name))
});
let top1_cos = all
.iter()
.map(|item| item.cos)
.fold(f64::NEG_INFINITY, f64::max);
all.truncate(RECORDED_TOP);
let score = if fallback {
top1_cos
} else {
let top_mean = all.iter().map(|item| item.z).sum::<f64>() / all.len() as f64;
0.7 * all[0].z + 0.3 * top_mean
};
(
article_id,
InterestMatch {
score,
top1_cos,
top_interests: all,
},
)
})
.collect()
}
/// Every cheap signal for the eligible set, normalized and blended (§9, §12.2,
/// §12.4). Pure: the preference state is already loaded.
pub fn compute(
articles: &[Article],
article_embeddings: &HashMap<ArticleId, Vec<f32>>,
interest_embeddings: &HashMap<String, Vec<f32>>,
preference: &PreferenceState,
ranking: &RankingConfig,
) -> HashMap<ArticleId, Signals> {
let interests = interest_matches(article_embeddings, interest_embeddings);
let mut all = articles
.iter()
.map(|article| {
let mut signals = Signals::baseline(article);
signals.knn_gate = preference.knn_gate;
signals.feed_gate = preference.feed_gate;
if let Some(matched) = interests.get(&article.id) {
signals.interest = Some(matched.score);
signals.interest_top1_cos = Some(matched.top1_cos);
signals.top_interests = matched.top_interests.clone();
}
if let Some(embedding) = article_embeddings.get(&article.id) {
let (knn, neighbours) = preference.knn(embedding, ranking);
signals.knn = knn;
signals.neighbours = neighbours;
}
signals.feed = preference.feed(article);
if preference.is_slop_author(article) {
signals.slop_author = true;
signals.slop_penalty = preference.slop_author_penalty;
signals.notes.push(format!(
"author reported as AI slop: blend and utility × {:.2}",
signals.slop_factor()
));
}
if preference.knn_gate > 0.0 {
signals.notes.push(format!(
"knn gate {:.2} (n={} rated with embeddings)",
preference.knn_gate,
preference.examples.len()
));
}
signals
})
.collect::<Vec<_>>();
normalize(&mut all.iter_mut().collect::<Vec<_>>());
for signals in &mut all {
preliminary_blend(signals, &ranking.weights.preliminary);
}
articles.iter().map(|article| article.id).zip(all).collect()
}
/// [`compute`] with the preference state loaded from the database.
pub async fn compute_all(
db: &Db,
articles: &[Article],
article_embeddings: &HashMap<ArticleId, Vec<f32>>,
interest_embeddings: &HashMap<String, Vec<f32>>,
voyage: &VoyageConfig,
ranking: &RankingConfig,
now: Timestamp,
) -> anyhow::Result<(HashMap<ArticleId, Signals>, PreferenceSummary)> {
let preference = PreferenceState::load(db, voyage, ranking, now).await?;
preference.log(ranking);
Ok((
compute(
articles,
article_embeddings,
interest_embeddings,
&preference,
ranking,
),
preference.summary(),
))
}
/// Mid-rank percentiles over the present values of each signal (§12.2).
///
/// `p(x) = (count_below + (count_equal + 1) / 2) / n_present`; fewer than two
/// present values or all-equal values give 0.5. Article id never breaks ties.
pub fn normalize(signals: &mut [&mut Signals]) {
for name in PERCENTILE_SIGNALS {
let mut values = signals
.iter()
.filter_map(|signal| signal.raw(name))
.collect::<Vec<_>>();
if values.is_empty() {
continue;
}
values.sort_by(f64::total_cmp);
let n = values.len() as f64;
let constant = values.len() < 2 || values.first() == values.last();
for signal in signals.iter_mut() {
let Some(value) = signal.raw(name) else {
continue;
};
let percentile = if constant {
0.5
} else {
let below = values.partition_point(|other| *other < value);
let equal = values.partition_point(|other| *other <= value) - below;
(below as f64 + (equal as f64 + 1.0) / 2.0) / n
};
signal.norm.insert(name.to_string(), percentile);
}
}
}
/// The preliminary blend of §12.4 on a 0–100 scale: present-and-active
/// signals only, learned weights multiplied by their gate, renormalized to 1,
/// then scaled by the slop-author factor (§9.3).
pub fn preliminary_blend(signals: &mut Signals, configured: &PreliminaryWeights) -> Option<f64> {
let candidates = [
("interest", configured.interest, 1.0),
("knn", configured.knn, signals.knn_gate),
("heuristic", configured.heuristic, 1.0),
("feed", configured.feed, signals.feed_gate),
("social", configured.social, 1.0),
];
let active = candidates
.into_iter()
.filter_map(|(name, weight, gate)| {
let norm = *signals.norm.get(name)?;
let effective = weight * gate;
(effective > 0.0).then_some((name, effective, norm))
})
.collect::<Vec<_>>();
let total = active.iter().map(|(_, weight, _)| weight).sum::<f64>();
if total <= 0.0 {
signals.weights.clear();
signals.preliminary = None;
return None;
}
signals.weights = active
.iter()
.map(|(name, weight, _)| ((*name).to_string(), weight / total))
.collect();
let blend = active
.iter()
.map(|(_, weight, norm)| weight / total * norm)
.sum::<f64>()
* 100.0
* signals.slop_factor();
signals.preliminary = Some(blend);
Some(blend)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::types::{ExtractMethod, SourceRef};
fn ranking() -> RankingConfig {
RankingConfig::default()
}
fn unit(values: &[f32]) -> Vec<f32> {
let norm = values.iter().map(|v| v * v).sum::<f32>().sqrt();
values.iter().map(|v| v / norm).collect()
}
fn example(id: ArticleId, label: &str, value: f64, embedding: &[f32]) -> RatedExample {
RatedExample {
article_id: id,
label: label.into(),
title: format!("rated {id}"),
value,
decay: 1.0,
embedding: unit(embedding),
feeds: vec![id],
author: None,
aggregator_only: false,
}
}
fn article(id: ArticleId, feeds: &[FeedId]) -> Article {
Article {
id,
canonical_url: format!("https://example.com/{id}"),
title: format!("Article {id}"),
best_entry_id: id,
content_html: String::new(),
word_count: 1000,
excerpt_only: false,
image_count: 0,
sources: feeds
.iter()
.map(|feed| SourceRef {
entry_id: id,
feed_id: *feed,
feed_title: format!("feed {feed}"),
category: None,
kind: SourceKind::Feed,
})
.collect(),
first_seen: "2026-08-15T00:00:00Z".parse().unwrap(),
url: format!("https://example.com/{id}"),
author: None,
publication: None,
feed_id: feeds.first().copied().unwrap_or(0),
feed_title: String::new(),
category: None,
published_at: None,
comments_url: None,
image_urls: vec![],
social: vec![],
extract_method: ExtractMethod::Miniflux,
}
}
fn with_heuristic(value: Option<f64>) -> Signals {
Signals {
heuristic: value,
..Signals::default()
}
}
// --- §9.1 interest z-scores ---
fn interest_fixture(n: usize) -> (HashMap<ArticleId, Vec<f32>>, HashMap<String, Vec<f32>>) {
// Article 1 sits on axis x; the rest sit near axis y with a tiny spread.
let mut articles = HashMap::new();
articles.insert(1, unit(&[1.0, 0.0, 0.0]));
for id in 2..=n as ArticleId {
articles.insert(id, unit(&[0.0, 1.0, 0.001 * id as f32]));
}
// "Broad" is about equally close to everything; "Specific" matches only article 1.
let mut interests = HashMap::new();
interests.insert("Broad".to_string(), unit(&[1.0, 1.0, 0.0]));
interests.insert("Specific".to_string(), unit(&[1.0, 0.0, 0.0]));
(articles, interests)
}
#[test]
fn specific_interest_with_one_strong_match_beats_a_broad_one() {
let (articles, interests) = interest_fixture(40);
let matched = interest_matches(&articles, &interests);
let strong = &matched[&1];
assert_eq!(strong.top_interests[0].name, "Specific");
assert!(
strong.top_interests[0].z > 3.0,
"z = {}",
strong.top_interests[0].z
);
let others = (2..=40)
.map(|id| matched[&id].score)
.fold(f64::NEG_INFINITY, f64::max);
assert!(strong.score > others + 2.0, "{} vs {others}", strong.score);
// Raw cosine would have called Broad a near-tie everywhere (≈0.707).
assert!((matched[&2].top1_cos - 0.707).abs() < 0.01);
}
#[test]
fn interest_falls_back_to_raw_cosine_under_thirty_articles() {
let (articles, interests) = interest_fixture(10);
let matched = interest_matches(&articles, &interests);
for (id, m) in &matched {
assert!(
(m.score - m.top1_cos).abs() < 1e-9,
"article {id} should use raw top-1"
);
}
assert!((matched[&2].score - 0.707).abs() < 0.01);
}
// --- §9.2 preference ---
#[test]
fn one_loved_article_gives_a_positive_knn_to_a_near_neighbour() {
let mut ranking = ranking();
ranking.knn_floor = 0;
ranking.knn_full = 1;
let state = PreferenceState::build(vec![example(1, "loved", 1.0, &[1.0, 0.0])], &ranking);
let (knn, neighbours) = state.knn(&unit(&[0.9, 0.1]), &ranking);
assert!(knn.unwrap() > 0.9);
assert_eq!(neighbours.len(), 1);
assert_eq!(neighbours[0].label, "loved");
let (far, _) = state.knn(&unit(&[0.0, 1.0]), &ranking);
assert!(far.unwrap().abs() < 1e-6);
}
#[test]
fn two_unrelated_loved_clusters_both_score_high() {
let mut ranking = ranking();
ranking.knn_floor = 0;
ranking.knn_full = 1;
ranking.neighbour_k = 2;
let state = PreferenceState::build(
vec![
example(1, "loved", 1.0, &[1.0, 0.0, 0.0]),
example(2, "loved", 1.0, &[0.98, 0.02, 0.0]),
example(3, "loved", 1.0, &[0.0, 1.0, 0.0]),
example(4, "loved", 1.0, &[0.0, 0.98, 0.02]),
],
&ranking,
);
let (near_a, _) = state.knn(&unit(&[1.0, 0.0, 0.0]), &ranking);
let (near_b, _) = state.knn(&unit(&[0.0, 1.0, 0.0]), &ranking);
assert!(near_a.unwrap() > 0.95, "{near_a:?}");
assert!(near_b.unwrap() > 0.95, "{near_b:?}");
// A centroid would have put both at ~0.7.
}
#[test]
fn good_carries_a_third_of_loved() {
let loved = example(1, "loved", 1.0, &[1.0, 0.0]);
let good = example(2, "good", 0.35, &[1.0, 0.0]);
assert!((good.weight() / loved.weight() - 0.35).abs() < 1e-9);
// A mixed neighbourhood: the far example pulls the mean down by 0.35× as
// much weight when it is merely "good" as when it is "loved".
let mut ranking = ranking();
ranking.knn_floor = 0;
ranking.knn_full = 1;
let near = example(1, "loved", 1.0, &[1.0, 0.0]);
let candidate = unit(&[1.0, 0.0]);
let both_loved = PreferenceState::build(
vec![near.clone(), example(2, "loved", 1.0, &[0.0, 1.0])],
&ranking,
);
let one_good =
PreferenceState::build(vec![near, example(2, "good", 0.35, &[0.0, 1.0])], &ranking);
let pull_loved = 1.0 - both_loved.knn(&candidate, &ranking).0.unwrap();
let pull_good = 1.0 - one_good.knn(&candidate, &ranking).0.unwrap();
assert!(pull_good < pull_loved);
// Weighted means: 0.5 vs 1/1.35 → pulls 0.5 vs 0.35/1.35.
assert!((pull_good / pull_loved - 0.35 / 1.35 / 0.5).abs() < 1e-9);
}
#[test]
fn negatives_subtract_with_the_negative_coefficient() {
let mut ranking = ranking();
ranking.knn_floor = 0;
ranking.knn_full = 1;
let state =
PreferenceState::build(vec![example(1, "not_for_me", -1.0, &[1.0, 0.0])], &ranking);
let (knn, _) = state.knn(&unit(&[1.0, 0.0]), &ranking);
assert!((knn.unwrap() + ranking.negative_coefficient).abs() < 1e-9);
}
#[test]
fn decay_halves_at_the_half_life() {
assert!((decay(60.0, 60.0) - 0.5).abs() < 1e-12);
assert!((decay(0.0, 60.0) - 1.0).abs() < 1e-12);
assert!((decay(120.0, 60.0) - 0.25).abs() < 1e-12);
}
#[test]
fn gate_is_zero_below_floor_one_at_full_and_linear_between() {
assert_eq!(gate(0, 8, 25), 0.0);
assert_eq!(gate(8, 8, 25), 0.0);
assert_eq!(gate(25, 8, 25), 1.0);
assert_eq!(gate(100, 8, 25), 1.0);
assert!((gate(16, 8, 24) - 0.5).abs() < 1e-9);
assert!((gate(9, 8, 25) - 1.0 / 17.0).abs() < 1e-9);
}
#[test]
fn knn_is_absent_when_the_gate_is_closed() {
let ranking = ranking(); // knn_floor 8
let state = PreferenceState::build(vec![example(1, "loved", 1.0, &[1.0, 0.0])], &ranking);
assert_eq!(state.knn_gate, 0.0);
assert_eq!(state.knn(&unit(&[1.0, 0.0]), &ranking), (None, Vec::new()));
}
// --- §9.3 feed affinity ---
#[test]
fn feed_credit_sums_to_one_across_direct_feeds() {
let mut rated = example(1, "loved", 1.0, &[1.0, 0.0]);
rated.feeds = vec![10, 20, 30];
let state = PreferenceState::build(vec![rated], &ranking());
let total: f64 = [10, 20, 30]
.iter()
.map(|feed| state.feed_credit(*feed).unwrap().0)
.sum();
assert!((total - 1.0).abs() < 1e-9);
assert!((state.feed_credit(10).unwrap().0 - 1.0 / 3.0).abs() < 1e-9);
}
#[test]
fn feed_affinity_is_the_mean_over_rated_feeds() {
let mut ranking = ranking();
ranking.feed_floor = 0;
ranking.feed_full = 1;
let mut loved = example(1, "loved", 1.0, &[1.0, 0.0]);
loved.feeds = vec![10];
let mut down = example(2, "not_for_me", -1.0, &[1.0, 0.0]);
down.feeds = vec![20];
let state = PreferenceState::build(vec![loved, down], &ranking);
// feed 10: (1+1)/(1+0+2) = 2/3; feed 20: (0+1)/(0+1+2) = 1/3; unrated 99 ignored.
let both = state.feed(&article(7, &[10, 20, 99])).unwrap();
assert!((both - 0.5).abs() < 1e-9, "{both}");
let best = state.feed(&article(8, &[10])).unwrap();
assert!((best - 2.0 / 3.0).abs() < 1e-9);
assert_eq!(state.feed(&article(9, &[99])), None);
}
#[test]
fn aggregator_only_rating_splits_credit_between_feed_and_author() {
let mut rated = example(1, "loved", 1.0, &[1.0, 0.0]);
rated.decay = 0.4;
rated.feeds = vec![10];
rated.author = Some("example author".into());
rated.aggregator_only = true;
let state = PreferenceState::build(vec![rated], &ranking());
assert!((state.feed_credit(10).unwrap().0 - 0.25 * 0.4).abs() < 1e-9);
assert!((state.author_credit("example author").unwrap().0 - 0.4).abs() < 1e-9);
}
#[test]
fn author_affinity_applies_across_feeds_with_normalized_keys() {
let mut ranking = ranking();
ranking.feed_floor = 0;
ranking.feed_full = 1;
let mut rated = example(1, "loved", 1.0, &[1.0, 0.0]);
rated.feeds = vec![10];
rated.author = Some("Ada Lovelace".into());
let state = PreferenceState::build(vec![rated], &ranking);
let mut candidate = article(2, &[99]);
candidate.author = Some(" ADA lovelace ".into());
assert_eq!(state.examples[0].author.as_deref(), Some("ada lovelace"));
assert_eq!(state.feed_credit(99), None);
assert!((state.feed(&candidate).unwrap() - 2.0 / 3.0).abs() < 1e-9);
assert_eq!(state.author_credit(" ADA Lovelace "), Some((1.0, 0.0)));
}
#[test]
fn feed_affinity_means_rated_feed_and_rated_author() {
let mut ranking = ranking();
ranking.feed_floor = 0;
ranking.feed_full = 1;
let mut feed_loved = example(1, "loved", 1.0, &[1.0, 0.0]);
feed_loved.feeds = vec![10];
let mut author_down = example(2, "not_for_me", -1.0, &[1.0, 0.0]);
author_down.feeds.clear();
author_down.author = Some("writer".into());
let state = PreferenceState::build(vec![feed_loved, author_down], &ranking);
let mut candidate = article(3, &[10]);
candidate.author = Some("Writer".into());
assert!((state.feed(&candidate).unwrap() - 0.5).abs() < 1e-9);
}
#[test]
fn aggregator_only_without_author_keeps_feed_behavior_at_reduced_credit() {
let mut ranking = ranking();
ranking.feed_floor = 0;
ranking.feed_full = 1;
let mut rated = example(1, "not_for_me", -1.0, &[1.0, 0.0]);
rated.feeds = vec![10];
rated.aggregator_only = true;
let state = PreferenceState::build(vec![rated], &ranking);
assert_eq!(state.feed_credit(10), Some((0.0, 0.25)));
assert_eq!(state.author_credit(""), None);
assert!((state.feed(&article(2, &[10])).unwrap() - 1.0 / 2.25).abs() < 1e-9);
}
// --- §9.3 slop authors ---
#[test]
fn slop_authors_are_normalized_and_scale_the_preliminary_blend() {
let state = PreferenceState::build(Vec::new(), &ranking()).with_slop_authors([
" Content FARM ",
"",
" ",
]);
assert_eq!(state.slop_author_count(), 1);
let mut reported = article(1, &[10]);
reported.author = Some("content farm".into());
let mut other = article(2, &[10]);
other.author = Some("real writer".into());
let anonymous = article(3, &[10]);
assert!(state.is_slop_author(&reported));
assert!(!state.is_slop_author(&other));
assert!(!state.is_slop_author(&anonymous));
let articles = vec![reported, other, anonymous];
let computed = compute(
&articles,
&HashMap::new(),
&HashMap::new(),
&state,
&ranking(),
);
let reported = &computed[&1];
let other = &computed[&2];
assert!(reported.slop_author);
assert!(!other.slop_author);
// Identical heuristic/social inputs: the only difference is the factor.
assert!((reported.preliminary.unwrap() - other.preliminary.unwrap() * 0.25).abs() < 1e-9);
assert!(
reported
.notes
.iter()
.any(|note| note.contains("author reported as AI slop"))
);
assert!(!other.notes.iter().any(|note| note.contains("AI slop")));
}
#[test]
fn slop_factor_is_neutral_without_a_report_and_clamped_with_one() {
let mut signals = Signals {
slop_penalty: 0.75,
..Signals::default()
};
assert_eq!(signals.slop_factor(), 1.0);
signals.slop_author = true;
assert!((signals.slop_factor() - 0.25).abs() < 1e-9);
signals.slop_penalty = 1.0;
assert_eq!(signals.slop_factor(), 0.0);
signals.slop_penalty = 0.0;
assert_eq!(signals.slop_factor(), 1.0);
}
#[test]
fn feed_is_absent_when_the_gate_is_closed() {
let ranking = ranking(); // feed_floor 15
let mut loved = example(1, "loved", 1.0, &[1.0, 0.0]);
loved.feeds = vec![10];
let state = PreferenceState::build(vec![loved], &ranking);
assert_eq!(state.feed_gate, 0.0);
assert_eq!(state.feed(&article(7, &[10])), None);
}
#[test]
fn direct_feeds_fall_back_to_the_best_entry_feed() {
let mut a = article(1, &[]);
a.feed_id = 42;
assert_eq!(direct_feeds(&a), vec![42]);
assert_eq!(direct_feeds(&article(2, &[5, 3, 5])), vec![3, 5]);
}
// --- §12.2 normalization, §12.4 blend ---
#[test]
fn constant_signal_normalizes_to_half_for_everyone() {
let mut values = [with_heuristic(Some(7.0)), with_heuristic(Some(7.0))];
let mut refs = values.iter_mut().collect::<Vec<_>>();
normalize(&mut refs);
assert!(values.iter().all(|v| v.norm["heuristic"] == 0.5));
let mut single = [with_heuristic(Some(3.0))];
let mut refs = single.iter_mut().collect::<Vec<_>>();
normalize(&mut refs);
assert_eq!(single[0].norm["heuristic"], 0.5);
}
#[test]
fn ties_get_equal_percentiles_without_an_id_ramp() {
let mut values = (0..400)
.map(|_| with_heuristic(Some(0.0)))
.collect::<Vec<_>>();
let mut refs = values.iter_mut().collect::<Vec<_>>();
normalize(&mut refs);
assert!(values.iter().all(|v| v.norm["heuristic"] == 0.5));
let mut mixed = [
with_heuristic(Some(1.0)),
with_heuristic(Some(2.0)),
with_heuristic(Some(2.0)),
with_heuristic(Some(3.0)),
];
let mut refs = mixed.iter_mut().collect::<Vec<_>>();
normalize(&mut refs);
assert_eq!(mixed[0].norm["heuristic"], 0.25);
assert_eq!(mixed[1].norm["heuristic"], 0.625);
assert_eq!(mixed[2].norm["heuristic"], 0.625);
assert_eq!(mixed[3].norm["heuristic"], 1.0);
}
#[test]
fn absent_values_do_not_shift_present_values() {
let mut values = [
with_heuristic(Some(1.0)),
with_heuristic(Some(2.0)),
with_heuristic(None),
];
let mut refs = values.iter_mut().collect::<Vec<_>>();
normalize(&mut refs);
assert!(!values[2].norm.contains_key("heuristic"));
// n_present = 2: the absent third value does not widen the scale.
assert_eq!(values[0].norm["heuristic"], 0.5);
assert_eq!(values[1].norm["heuristic"], 1.0);
}
#[test]
fn effective_weights_sum_to_one_and_missing_signals_are_skipped() {
let mut signals = Signals {
interest: Some(1.0),
heuristic: Some(2.0),
norm: BTreeMap::from([("interest".into(), 0.8), ("heuristic".into(), 0.4)]),
..Signals::default()
};
let blend = preliminary_blend(&mut signals, &PreliminaryWeights::default()).unwrap();
assert!((signals.weights.values().sum::<f64>() - 1.0).abs() < 1e-9);
assert!(!signals.weights.contains_key("knn"));
assert!(!signals.weights.contains_key("social"));
// 0.35/0.55 × 0.8 + 0.20/0.55 × 0.4 = 0.6545…
assert!((blend - 65.4545).abs() < 0.01, "{blend}");
let mut only_heuristic = Signals {
heuristic: Some(2.0),
norm: BTreeMap::from([("heuristic".into(), 0.4)]),
..Signals::default()
};
let blend = preliminary_blend(&mut only_heuristic, &PreliminaryWeights::default());
assert!((blend.unwrap() - 40.0).abs() < 1e-9);
assert_eq!(only_heuristic.weights["heuristic"], 1.0);
}
#[test]
fn learned_weights_are_multiplied_by_their_gate() {
let mut signals = Signals {
knn: Some(0.5),
heuristic: Some(2.0),
knn_gate: 0.5,
norm: BTreeMap::from([("knn".into(), 1.0), ("heuristic".into(), 0.0)]),
..Signals::default()
};
preliminary_blend(&mut signals, &PreliminaryWeights::default());
// knn 0.25 × 0.5 = 0.125 against heuristic 0.20.
assert!((signals.weights["knn"] - 0.125 / 0.325).abs() < 1e-9);
}
#[test]
fn compute_scores_every_article_and_leaves_ungated_signals_absent() {
let articles = vec![article(1, &[10]), article(2, &[20]), article(3, &[30])];
let mut embeddings = HashMap::new();
embeddings.insert(1, unit(&[1.0, 0.0]));
embeddings.insert(2, unit(&[0.0, 1.0]));
let mut interests = HashMap::new();
interests.insert("Axis".to_string(), unit(&[1.0, 0.0]));
let state = PreferenceState::build(vec![example(9, "loved", 1.0, &[1.0, 0.0])], &ranking());
let signals = compute(&articles, &embeddings, &interests, &state, &ranking());
assert_eq!(signals.len(), 3);
assert!(signals[&1].interest.is_some());
assert!(signals[&3].interest.is_none(), "no embedding → absent");
assert!(
signals
.values()
.all(|s| s.knn.is_none() && s.feed.is_none())
);
assert!(
signals
.values()
.all(|s| s.heuristic.is_some() && s.preliminary.is_some())
);
}
}