bvandeusen
65dd132b3d
Milestone #160 Opt 3 (temporal half). A new additive scoring term that boosts a candidate when its artist's play history concentrates in the CURRENT daypart × weekday-type cell, in the user's local timezone. - Migration 0046: recommendation_weight_profiles.context_time_weight (per-profile scoring weight, DEFAULT 1.0). - Query ListArtistContextPlayCountsForUser: per-artist completed-play counts split by the current cell (daypart night[22,5)/morning[5,12)/ afternoon[12,17)/evening[17,22) × weekday-vs-weekend) via started_at AT TIME ZONE users.timezone; 365-day window, skips excluded. - internal/recommendation/context.go: LoadContextAffinity computes each artist's shrunk cell-share minus the user's baseline share, clamped to [-1,1]; sparse artists shrink toward baseline (pseudo-count 5), unknown artists → 0 (cold-start neutral). - Score() gains context_affinity_score · ContextTimeWeight; both candidate loaders set it per candidate. - Tuning lab: ContextTimeWeight threaded through recsettings + admin API + web card ("Time-of-day weight" row) + Go/web tests. Shipped 1.0 both profiles (uniform start, re-bakeable). Device-class axis deferred to #1551 (needs a client_id → device-class mapping that doesn't exist yet). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
71 lines
2.5 KiB
Go
71 lines
2.5 KiB
Go
package recommendation
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import (
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"context"
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"github.com/jackc/pgx/v5/pgtype"
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"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
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)
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// contextAffinityShrinkage is the pseudo-count that pulls a low-play artist's
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// cell-share toward the user's baseline, so an artist with one or two plays
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// can't swing its affinity to ±1 on noise. At k plays the estimate sits
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// halfway between the raw cell-share and the baseline.
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const contextAffinityShrinkage = 5.0
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// ContextAffinity is the read-side map of per-artist time-of-day/weekday
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// affinity for the CURRENT context (#1531): artist_id → score in [-1, +1].
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// Absent artists (no play history) score 0, so cold-start candidates stay
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// neutral. The zero value is a valid all-neutral affinity.
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type ContextAffinity struct {
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byArtist map[pgtype.UUID]float64
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}
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// Affinity returns the artist's current-context affinity, or 0 if unknown.
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func (c ContextAffinity) Affinity(artistID pgtype.UUID) float64 {
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return c.byArtist[artistID]
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}
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// LoadContextAffinity computes each artist's affinity for the user's CURRENT
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// daypart × weekday cell. For every artist with completed plays in the window
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// it compares the share of that artist's plays that fall in the current cell
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// against the user's overall baseline share, shrinking sparse artists toward
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// the baseline. Returns an empty (all-neutral) affinity when the user has no
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// plays.
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func LoadContextAffinity(
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ctx context.Context, q *dbq.Queries, userID pgtype.UUID,
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) (ContextAffinity, error) {
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rows, err := q.ListArtistContextPlayCountsForUser(ctx, userID)
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if err != nil {
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return ContextAffinity{}, err
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}
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var totalPlays, cellPlays int64
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for _, r := range rows {
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totalPlays += r.TotalPlays
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cellPlays += r.CellPlays
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}
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out := ContextAffinity{byArtist: make(map[pgtype.UUID]float64, len(rows))}
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if totalPlays == 0 {
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return out, nil
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}
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baseline := float64(cellPlays) / float64(totalPlays)
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for _, r := range rows {
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out.byArtist[r.ArtistID] = contextAffinity(
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float64(r.CellPlays), float64(r.TotalPlays), baseline, contextAffinityShrinkage)
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}
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return out, nil
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}
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// contextAffinity returns an artist's shrunk cell-share minus the user's
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// baseline share, clamped to [-1, 1]. The shrinkage pseudo-count k pulls
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// low-play artists toward the baseline (→ 0 affinity) so noise can't dominate;
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// a heavily-played artist keeps close to its raw over/under-representation.
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func contextAffinity(cellPlays, totalPlays, baseline, k float64) float64 {
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if totalPlays == 0 {
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return 0
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}
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shrunk := (cellPlays + baseline*k) / (totalPlays + k)
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return clampUnit(shrunk - baseline)
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}
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