selproxy

confirmedshipPython · PyTorchModel behavior & reasoningJuly 22, 2026

the question

Is query-independent sparse-attention block selection faithful to each block's true attention mass?

what came out

No. The mean-logit proxy keeps mean(x) and drops exactly the concentration D in LSE=mean+log(B)+D. Worst case it ranks a flat block above a spike holding 99.65% of the mass; missed mass rises to 25-51% as logit std grows. Any query-independent summary is one facet of a B-facet envelope; Quest's bounding box upper-bounds on 100% of queries.

method & receipts

Result: confirmed
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/selproxy