Jānis Kacēns
968479ff51
- internal/sampling: ComputeWeight (Laplace-smoothed error rate + recency
multiplier, floor 0.15) and SelectWeighted (A-Res reservoir algorithm).
10k-run statistical test verifies weak questions appear >3x more often
than mastered, and mastered questions still appear (floor exercised).
- GET/POST /test/new: source filter with live available-count JS update,
n-questions input, weighted vs uniform mode radio.
- GET /test/{id}/q/{n}: deterministic answer shuffle per (test_id,
question_id), progress bar, mobile-friendly large tap targets.
- POST /test/{id}/q/{n}: records answer + upserts stat; advances to next
question or finishes test and redirects to results stub.
- GET /test/{id}/results: stub (Phase 7 will add full review).
- Ownership enforced: all test routes 404 for wrong user.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
42 lines
1.1 KiB
Go
42 lines
1.1 KiB
Go
package sampling
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import (
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"math"
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"time"
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"qbank/internal/models"
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)
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const (
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FloorWeight = 0.15 // mastered questions still appear at ~15% base rate
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RecencyCapDays = 30.0 // days until recency multiplier saturates
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RecencyMaxMult = 2.0 // peak recency multiplier
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UnseenBaseWeight = 0.5 // base weight for questions with no stats row
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)
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// ComputeWeight returns the sampling weight for a question given its per-user
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// stat. A nil stat means the question has never been seen.
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func ComputeWeight(stat *models.UserQuestionStat, now time.Time) float64 {
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if stat == nil {
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// Unseen: mid-range base + full recency = 1.0
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return UnseenBaseWeight * RecencyMaxMult
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}
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s := float64(stat.TimesSeen)
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c := float64(stat.TimesCorrect)
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// Laplace-smoothed error rate dampens noise from small samples.
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errorRate := (s - c + 1) / (s + 2)
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base := math.Max(FloorWeight, errorRate)
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var daysSince float64
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if stat.LastSeenAt.Valid {
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daysSince = now.Sub(stat.LastSeenAt.Time).Hours() / 24
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} else {
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daysSince = RecencyCapDays
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}
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recency := 1 + math.Min(daysSince/RecencyCapDays, 1.0)
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return base * recency
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}
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