Fast Non‐Uniform Quantisation via FP12 Demotion and Constant‐Time Predecessor Tables

We present a practical ‐per‐query method for non‐uniform scalar quantisation in the static‐boundary regime. Real‐valued boundaries are demoted to an FP12 universe () and indexed by a compact van Emde Boas–style predecessor structure, so predecessor retrieval uses a constant number of table lookups independent of the number of bins. A bounded local check against neighbouring original boundaries recovers the exact bin. Experiments show the core predecessor lookup achieves up to speedup over binary search for high‐volume workloads; end‐to‐end time depends on the cost of forming and is dominated by demotion in our reference implementation.