Mass-spec structure splits drift as libraries grow: one component swallows 95.5% of 227,690 molecules, leaving a 4.5% holdout
The MCES-10 structure-disjoint split used to evaluate mass-spectrum structure prediction percolates once the public library grows from 29,000 to 227,690 molecules, so a single component holds 95.5% of the library, the usable holdout falls to 4.5%, and the surviving compounds are systematically heavier.