hpc: HDR rolling floor — integer σ-lattice thresholds on demand

Cargo.toml

@@ -207,6 +207,10 @@ required-features = ["std"]
 name = "rolling_floor_probe"
 required-features = ["std"]
 
+[[example]]
+name = "hdr_rolling_floor_bench"
+required-features = ["std"]
+
 [[example]]
 name = "codec_overlap_probe"
 required-features = ["std"]

examples/hdr_rolling_floor_bench.rs

@@ -0,0 +1,148 @@
+//! Cost split of the HDR rolling floor: the per-observation hot path versus
+//! the periodic shape path.
+//!
+//! ```sh
+//! cargo run --release --example hdr_rolling_floor_bench
+//! ```
+//!
+//! Hot path, per observation:
+//!   1. popcount / Hamming distance of two 2048-byte vectors
+//!   2. exact moments update (`MomentsU32::observe`, and `moments_u32` batch)
+//!   3. reservoir update
+//!   4. full rolling-floor update (moments + reservoir + checkpoint test)
+//!
+//! Periodic path, once per 1000 observations:
+//!   5. shape evaluation (sort 1000 samples, median, kurtosis)
+//!   6. empirical shape: locate 8 σ-lattice levels
+//!
+//! Query path, on demand (nothing is stored):
+//!   7. Gaussian thresholds of 8 levels
+//!   8. shade of a response over 8 levels
+
+use ndarray::hpc::bitwise::hamming_distance_raw;
+use ndarray::hpc::rolling_floor::{quantile_of_sorted, EmpiricalShape, ReservoirU32, RollingFloor, SigmaLevel};
+use ndarray::hpc::statistics::{moments_u32, MomentsU32};
+use std::hint::black_box;
+use std::time::Instant;
+
+fn xorshift(n: usize, mut s: u64) -> Vec<u64> {
+    (0..n)
+        .map(|_| {
+            s ^= s << 13;
+            s ^= s >> 7;
+            s ^= s << 17;
+            s
+        })
+        .collect()
+}
+
+fn ns_per(label: &str, n: usize, f: impl FnOnce()) {
+    let t = Instant::now();
+    f();
+    let dt = t.elapsed();
+    println!("{label:<44} {:>9.2} ns/op  ({n} ops)", dt.as_nanos() as f64 / n as f64);
+}
+
+fn main() {
+    println!("avx512f={} avx2={}", cfg!(target_feature = "avx512f"), cfg!(target_feature = "avx2"));
+
+    const VBYTES: usize = 2048; // 16384-bit vectors
+    const N: usize = 2_000_000;
+    let words = xorshift(VBYTES / 8 * 65, 1);
+    let bytes: Vec<u8> = words.iter().flat_map(|w| w.to_le_bytes()).collect();
+    let query = &bytes[..VBYTES];
+    let db = &bytes[VBYTES..];
+    let dists: Vec<u32> = (0..N)
+        .map(|i| {
+            let j = i % 64;
+            hamming_distance_raw(query, &db[j * VBYTES..(j + 1) * VBYTES]) as u32
+        })
+        .collect();
+
+    println!("-- hot path, per observation --");
+    ns_per("1. popcount/Hamming (2048 B)", N, || {
+        let mut acc = 0u64;
+        for i in 0..N {
+            let j = i % 64;
+            acc += hamming_distance_raw(black_box(query), &db[j * VBYTES..(j + 1) * VBYTES]);
+        }
+        black_box(acc);
+    });
+    ns_per("2a. MomentsU32::observe (scalar)", N, || {
+        let mut m = MomentsU32::default();
+        for &d in &dists {
+            m.observe(black_box(d));
+        }
+        black_box(m);
+    });
+    ns_per("2b. moments_u32 (batch)", N, || {
+        black_box(moments_u32(black_box(&dists)));
+    });
+    ns_per("3. ReservoirU32::observe (cap 1000)", N, || {
+        let mut r = ReservoirU32::new(1000);
+        for &d in &dists {
+            r.observe(black_box(d));
+        }
+        black_box(r.len());
+    });
+    ns_per("4a. RollingFloor::observe (incl. checkpoints)", N, || {
+        let mut f = RollingFloor::for_width(16384);
+        for &d in &dists {
+            if let Some(s) = f.observe(black_box(d)) {
+                f.recalibrate(&s);
+            }
+        }
+        black_box(f.mu());
+    });
+    ns_per("4b. RollingFloor::observe_batch (incl. checkpoints)", N, || {
+        let mut f = RollingFloor::for_width(16384);
+        let mut rest: &[u32] = &dists;
+        while !rest.is_empty() {
+            let (used, s) = f.observe_batch(rest);
+            rest = &rest[used..];
+            if let Some(s) = s {
+                f.recalibrate(&s);
+            }
+        }
+        black_box(f.mu());
+    });
+
+    println!("-- periodic path, per checkpoint (every 1000 observations) --");
+    let mut r = ReservoirU32::new(1000);
+    dists[..5000].iter().for_each(|&d| r.observe(d));
+    const K: usize = 20_000;
+    ns_per("5. shape: sort + median + kurtosis", K, || {
+        for _ in 0..K {
+            let sorted = black_box(&r).sorted();
+            black_box(quantile_of_sorted(&sorted, 5000));
+            black_box(r.kurtosis(8192, 64));
+        }
+    });
+    let lattice = [4u8, 6, 7, 8, 9, 10, 11, 12].map(SigmaLevel);
+    let shape = EmpiricalShape::from_sample(r.samples()).unwrap();
+    ns_per("6. empirical: locate 8 lattice levels", K, || {
+        for _ in 0..K {
+            black_box(lattice.map(|l| black_box(&shape).locate(l, 8200, 70)));
+        }
+    });
+
+    println!("-- query path, on demand --");
+    let mut g = RollingFloor::for_width(16384);
+    dists[..3000].iter().for_each(|&d| {
+        if let Some(s) = g.observe(d) {
+            g.recalibrate(&s);
+        }
+    });
+    ns_per("7. Gaussian: thresholds of 8 levels", N, || {
+        for _ in 0..N {
+            black_box(black_box(&g).thresholds(&lattice));
+        }
+    });
+    ns_per("8. Gaussian: shade over 8 levels", N, || {
+        let mut acc = 0usize;
+        for &d in &dists {
+            acc += black_box(&g).shade(d, &lattice);
+        }
+        black_box(acc);
+    });
+}

src/hpc/mod.rs

@@ -25,6 +25,7 @@ pub mod blas_level2;
 pub mod blas_level3;
 pub mod reductions;
 pub mod statistics;
+pub mod rolling_floor;
 /// Reliability & validity statistics: Pearson r, Spearman ρ, Cronbach α, ICC.
 pub mod reliability;
 /// Entropy ladder: Staunen↔Wisdom coordinate over NARS truth + Pearl-2³ SPO.