q2krail

confirmedcertificateC++ · CPUInference & servingJuly 13, 2026

the question

Is the q2_K reference quantizer's unguarded scale and min nibble store, the only K-quant packer without a MIN/MAX clamp, a latent corruption or safe by construction?

what came out

Across an adversarial corpus of 4008 blocks plus a 20-million-sub-block hunt, every pre-store integer stays in [0,15] and no scale or min goes negative, so the missing clamp is a no-op. Safe by construction: the deducted-min formulation forces both values non-negative and bounded by their max.

method & receipts

Result: confirmed
Pre-registered — the prediction was written down and committed before the run.
Reproducible — one script re-runs the whole thing from scratch.
Tested — a correctness/benchmark suite ships alongside the code.

→ read the code and re-run it

github.com/v-code01/q2krail