The +10M library bonus was added directly to the popularity map,
which made it the maxPop normalization denominator. With maxPop=10M,
every non-library artist's log-normalized popularity collapsed to
near-zero, making their blended score purely 40% of MB relevance.
All non-indexed artists scored ~35 and ranked by MB noise.
New approach:
- Removed +10M from both GetPopularityBatch and boostWithPopularity
- GetPopularityBatch now returns PopularityBatchResult with separate
Popularity and InLibrary maps
- rerankArtists takes a libraryMBIDs set and applies a fixed +25
score bonus AFTER blended scoring and normalization
- maxPop reflects real popularity only, so log normalization works
correctly across all artists
Shannon Wright (766K listens) now properly outranks Shannon Kennedy
(95 listens) because the popularity scale isn't contaminated.