sketch_histogram.nx

sketch_histogram.nx -- fixed-bin histogram with quantile + merge. Linear-bin histogram over a CALLER-DECLARED range [min, max). Each of N buckets holds an exact count. Out-of-range values land in under_count or over_count. COMPLEMENTS the quantile sketches: - sketch_kll: provable uniform rank-error; small footprint - sketch_tdigest: tail-tight; small footprint - sketch_histogram: EXACT bucket counts within declared range; memory = N * 8 bytes (no compression) Caller picks: histogram for known bounded ranges with audit-grade counts, sketches for unbounded streams with bounded error. USE CASES: - HTTP status code distribution (range [200, 600), 1 bucket per code) - Latency distribution with known SLA (range [0, 1000ms)) - Score distribution (range [0, 100)) MERGE: count-wise addition across matched ranges. Refused if ranges differ. LOSSLESS-LANGUAGE DISCIPLINE: nx_hist_query_count(value): NX_ENV_ABS with param_a = 0 if in-range, meaning exact count. For out-of-range we report the under/over counts honestly. nx_hist_query_quantile(p): NX_ENV_RANK_ERROR with param_a = bucket resolution = (max - min) / N expressed in ppb relative to range. MaturityClass = Production (exact within budget).