Merge pull request #71 from MatteoMer/zolt-arith-fixtures-research

Add fixture-backed differential tests, benchmarks, squaring optimization, and fix G2 decompression

Author: MatteoMer

.github/workflows/ci.yml

@@ -225,6 +225,59 @@ jobs:
       - name: Verify with Jolt verifier
         run: ./jolt-verifier/target/release/jolt-verifier --proof proof.bin --preprocessing preprocessing.bin
 
+  # ─── zolt-arith: differential fixture tests ────────────────────
+  zolt-arith-diff:
+    name: Differential Fixture Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: mlugg/setup-zig@v2
+        with:
+          version: ${{ env.ZIG_VERSION }}
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: tools/zolt-arith-diff/arkworks-fixtures
+      - name: Run differential tests
+        run: zig build test-zolt-arith-diff -Doptimize=ReleaseSafe
+
+  # ─── zolt-arith: fixture freshness check ──────────────────────
+  zolt-arith-fixture-freshness:
+    name: Fixture Freshness Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: tools/zolt-arith-diff/arkworks-fixtures
+      - name: Regenerate fixtures
+        run: cargo run --release --manifest-path tools/zolt-arith-diff/arkworks-fixtures/Cargo.toml -- --out-dir testdata/zolt-arith-diff
+      - name: Check for drift
+        run: git diff --exit-code testdata/zolt-arith-diff/
+
+  # ─── zolt-arith: benchmark reporting (non-blocking) ───────────
+  zolt-arith-bench:
+    name: Arithmetic Benchmarks
+    runs-on: macos-15
+    steps:
+      - uses: actions/checkout@v4
+      - name: Verify ARM64
+        run: test "$(uname -m)" = "arm64"
+      - uses: mlugg/setup-zig@v2
+        with:
+          version: ${{ env.ZIG_VERSION }}
+      - name: Field microbench
+        run: zig build bench-zolt-arith-field 2>&1 | tee field_bench.txt
+      - name: Pairing microbench
+        run: zig build bench-zolt-arith-pairing 2>&1 | tee pairing_bench.txt
+      - name: Post benchmark summary
+        run: |
+          echo "## Benchmark Results" >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY
+          grep '\[BENCH\]' field_bench.txt pairing_bench.txt >> $GITHUB_STEP_SUMMARY || true
+          echo '```' >> $GITHUB_STEP_SUMMARY
+
   # ─── Gate: all required checks must pass ─────────────────────────
   ci-pass:
     name: CI Pass
@@ -240,6 +293,8 @@ jobs:
       - cli-smoke
       - prove-verify-linux
       - prove-verify-macos
+      - zolt-arith-diff
+      - zolt-arith-fixture-freshness
     runs-on: ubuntu-latest
     steps:
       - name: Check all jobs
@@ -255,6 +310,8 @@ jobs:
             "${{ needs.cli-smoke.result }}"
             "${{ needs.prove-verify-linux.result }}"
             "${{ needs.prove-verify-macos.result }}"
+            "${{ needs.zolt-arith-diff.result }}"
+            "${{ needs.zolt-arith-fixture-freshness.result }}"
           )
           for r in "${results[@]}"; do
             if [[ "$r" != "success" ]]; then

.gitignore

@@ -9,4 +9,5 @@ node_modules/
 jolt/
 bench/results/
 jolt-bench/target/
+tools/zolt-arith-diff/arkworks-fixtures/target/
 flamegraph.svg

bench/zolt_arith/bench_harness.zig

@@ -0,0 +1,139 @@
+//! Shared microbenchmark harness for zolt-arith.
+//! Zero external dependencies — only std.
+//!
+//! Usage:
+//!   const harness = @import("bench_harness.zig");
+//!   _ = harness.run("field_Fp", "mul", harness.Config.field, Fp, struct {
+//!       fn call(i: usize) Fp { return a[i % N].mul(b[i % N]); }
+//!   }.call);
+
+const std = @import("std");
+
+const MAX_SAMPLES: usize = 101;
+
+pub const Config = struct {
+    warmup_iters: usize = 5_000,
+    sample_count: usize = 21,
+    iters_per_sample: usize = 100_000,
+
+    pub const field: Config = .{
+        .warmup_iters = 20_000,
+        .sample_count = 21,
+        .iters_per_sample = 100_000,
+    };
+
+    pub const pairing: Config = .{
+        .warmup_iters = 10,
+        .sample_count = 21,
+        .iters_per_sample = 100,
+    };
+};
+
+pub const Stats = struct {
+    min_ns: f64,
+    median_ns: f64,
+    mean_ns: f64,
+    p99_ns: f64,
+    stddev_ns: f64,
+    sample_count: usize,
+    iters_per_sample: usize,
+};
+
+pub fn run(
+    comptime group: []const u8,
+    comptime op_name: []const u8,
+    config: Config,
+    comptime T: type,
+    comptime body: fn (usize) T,
+) Stats {
+    const n = @min(config.sample_count, MAX_SAMPLES);
+    const iters = config.iters_per_sample;
+
+    // --- Warmup ---
+    var sink: T = undefined;
+    for (0..config.warmup_iters) |i| {
+        sink = body(i);
+    }
+    std.mem.doNotOptimizeAway(&sink);
+
+    // --- Collect samples ---
+    var samples: [MAX_SAMPLES]f64 = undefined;
+    for (0..n) |s| {
+        var timer = std.time.Timer.start() catch unreachable;
+        for (0..iters) |i| {
+            sink = body(i);
+        }
+        std.mem.doNotOptimizeAway(&sink);
+        const elapsed_ns: u64 = timer.read();
+        samples[s] = @as(f64, @floatFromInt(elapsed_ns)) /
+            @as(f64, @floatFromInt(iters));
+    }
+
+    // --- Compute stats ---
+    const slice = samples[0..n];
+    std.sort.pdq(f64, slice, {}, lessThanF64);
+
+    var sum: f64 = 0;
+    for (slice) |v| sum += v;
+    const mean = sum / @as(f64, @floatFromInt(n));
+
+    var var_sum: f64 = 0;
+    for (slice) |v| {
+        const d = v - mean;
+        var_sum += d * d;
+    }
+    const stddev = @sqrt(var_sum / @as(f64, @floatFromInt(n)));
+
+    const median = if (n % 2 == 1)
+        slice[n / 2]
+    else
+        (slice[n / 2 - 1] + slice[n / 2]) / 2.0;
+
+    const p99_idx = @as(usize, @intFromFloat(@ceil(0.99 * @as(f64, @floatFromInt(n))))) - 1;
+
+    const stats = Stats{
+        .min_ns = slice[0],
+        .median_ns = median,
+        .mean_ns = mean,
+        .p99_ns = slice[p99_idx],
+        .stddev_ns = stddev,
+        .sample_count = n,
+        .iters_per_sample = iters,
+    };
+
+    printResult(group, op_name, stats);
+    return stats;
+}
+
+fn lessThanF64(_: void, a: f64, b: f64) bool {
+    return a < b;
+}
+
+const FmtTime = struct { val: f64, unit: []const u8 };
+
+fn formatTime(ns: f64) FmtTime {
+    if (ns >= 1_000_000.0) return .{ .val = ns / 1_000_000.0, .unit = "ms" };
+    if (ns >= 1_000.0) return .{ .val = ns / 1_000.0, .unit = "us" };
+    return .{ .val = ns, .unit = "ns" };
+}
+
+fn printResult(comptime group: []const u8, comptime op_name: []const u8, s: Stats) void {
+    const min_f = formatTime(s.min_ns);
+    const med_f = formatTime(s.median_ns);
+    const mean_f = formatTime(s.mean_ns);
+    const p99_f = formatTime(s.p99_ns);
+    const sd_f = formatTime(s.stddev_ns);
+
+    std.debug.print(
+        "[BENCH] group={s} op={s} min={d:.1}{s} median={d:.1}{s} mean={d:.1}{s} p99={d:.1}{s} stddev={d:.1}{s} samples={d}x{d}\n",
+        .{
+            group,          op_name,
+            min_f.val,      min_f.unit,
+            med_f.val,      med_f.unit,
+            mean_f.val,     mean_f.unit,
+            p99_f.val,      p99_f.unit,
+            sd_f.val,       sd_f.unit,
+            s.sample_count, s.iters_per_sample,
+        },
+    );
+}

bench/zolt_arith/field_micro.zig

@@ -0,0 +1,66 @@
+const std = @import("std");
+const zolt = @import("zolt");
+const harness = @import("bench_harness.zig");
+
+const Fr = zolt.field.BN254Scalar;
+const Fp = zolt.field.BN254BaseField;
+
+const ELEMENTS: usize = 128;
+
+fn fillFieldInputs(comptime F: type, a: *[ELEMENTS]F, b: *[ELEMENTS]F) void {
+    for (0..ELEMENTS) |i| {
+        a[i] = F.fromU64(@as(u64, @intCast(i + 1)) *% 0x9E3779B185EBCA87 +% 17);
+        b[i] = F.fromU64(@as(u64, @intCast(i + 1)) *% 0xD6E8FEB86659FD93 +% 29);
+    }
+}
+
+fn benchField(comptime F: type, comptime field_name: []const u8) void {
+    const Ctx = struct {
+        var a: [ELEMENTS]F = undefined;
+        var b: [ELEMENTS]F = undefined;
+
+        fn add(i: usize) F {
+            return a[i % ELEMENTS].add(b[i % ELEMENTS]);
+        }
+        fn sub(i: usize) F {
+            return a[i % ELEMENTS].sub(b[i % ELEMENTS]);
+        }
+        fn mul(i: usize) F {
+            return a[i % ELEMENTS].mul(b[i % ELEMENTS]);
+        }
+        fn square(i: usize) F {
+            return a[i % ELEMENTS].square();
+        }
+        fn inverse(i: usize) F {
+            return a[i % ELEMENTS].inverse() orelse F.zero();
+        }
+        fn toMontgomery(i: usize) F {
+            return a[i % ELEMENTS].fromMontgomery().toMontgomery();
+        }
+        fn fromMontgomery(i: usize) F {
+            return a[i % ELEMENTS].fromMontgomery();
+        }
+        fn sumOfProducts(i: usize) F {
+            const idx = i % ELEMENTS;
+            return F.sumOfProducts(.{ a[idx], b[idx] }, .{ b[idx], a[idx] });
+        }
+    };
+
+    fillFieldInputs(F, &Ctx.a, &Ctx.b);
+
+    const cfg = harness.Config.field;
+    _ = harness.run(field_name, "add", cfg, F, Ctx.add);
+    _ = harness.run(field_name, "sub", cfg, F, Ctx.sub);
+    _ = harness.run(field_name, "mul", cfg, F, Ctx.mul);
+    _ = harness.run(field_name, "square", cfg, F, Ctx.square);
+    _ = harness.run(field_name, "inverse", cfg, F, Ctx.inverse);
+    _ = harness.run(field_name, "toMontgomery", cfg, F, Ctx.toMontgomery);
+    _ = harness.run(field_name, "fromMontgomery", cfg, F, Ctx.fromMontgomery);
+    _ = harness.run(field_name, "sumOfProducts", cfg, F, Ctx.sumOfProducts);
+}
+
+pub fn main() !void {
+    std.debug.print("=== Zolt-Arith Field Microbench ===\n", .{});
+    benchField(Fp, "field_Fp");
+    benchField(Fr, "field_Fr");
+}

bench/zolt_arith/pairing_micro.zig

@@ -0,0 +1,75 @@
+const std = @import("std");
+const zolt = @import("zolt");
+const harness = @import("bench_harness.zig");
+
+const field = zolt.field;
+const p = field.pairing;
+
+const Fp = field.BN254BaseField;
+const Fp12 = p.Fp12;
+const G1PointFp = p.G1PointFp;
+const G2Point = p.G2Point;
+const G2Projective = p.G2Projective;
+const G2Prepared = p.G2Prepared;
+
+const NUM_PAIRS: usize = 4;
+
+// File-scope inputs populated by setupInputs().
+var g1_points: [NUM_PAIRS]G1PointFp = undefined;
+var g2_points: [NUM_PAIRS]G2Point = undefined;
+var g2_prepared: [NUM_PAIRS]G2Prepared = undefined;
+var fp12_inputs: [NUM_PAIRS]Fp12 = undefined;
+
+fn setupInputs() void {
+    // G1: use generator (1, 2) for all pairs — pairing cost is
+    // dominated by the fixed Miller loop, not the specific point.
+    for (0..NUM_PAIRS) |i| {
+        g1_points[i] = .{ .x = Fp.one(), .y = Fp.fromU64(2), .infinity = false };
+    }
+
+    // G2: varied points via repeated doubling of generator.
+    var g2_proj = G2Projective.fromAffine(G2Point.generator());
+    for (0..NUM_PAIRS) |i| {
+        g2_points[i] = g2_proj.toAffine();
+        g2_prepared[i] = G2Prepared.fromG2Point(g2_points[i]);
+        g2_proj = g2_proj.double();
+    }
+
+    // Fp12: Miller loop outputs for finalExponentiation benchmark.
+    for (0..NUM_PAIRS) |i| {
+        fp12_inputs[i] = p.millerLoopArkworks(g1_points[i], g2_points[i]);
+    }
+}
+
+// --- Benchmark bodies ---
+
+fn benchPairingFp(i: usize) Fp12 {
+    const idx = i % NUM_PAIRS;
+    return p.pairingFp(g1_points[idx], g2_points[idx]);
+}
+
+fn benchMillerLoop(i: usize) Fp12 {
+    const idx = i % NUM_PAIRS;
+    return p.millerLoopArkworks(g1_points[idx], g2_points[idx]);
+}
+
+fn benchMillerLoopPrepared(i: usize) Fp12 {
+    const idx = i % NUM_PAIRS;
+    return p.millerLoopPrepared(g1_points[idx], &g2_prepared[idx]);
+}
+
+fn benchFinalExp(i: usize) Fp12 {
+    const idx = i % NUM_PAIRS;
+    return p.finalExponentiation(fp12_inputs[idx]);
+}
+
+pub fn main() !void {
+    std.debug.print("=== Zolt-Arith Pairing Microbench ===\n", .{});
+    setupInputs();
+
+    const cfg = harness.Config.pairing;
+    _ = harness.run("pairing", "pairingFp", cfg, Fp12, benchPairingFp);
+    _ = harness.run("pairing", "millerLoop", cfg, Fp12, benchMillerLoop);
+    _ = harness.run("pairing", "millerLoopPrepared", cfg, Fp12, benchMillerLoopPrepared);
+    _ = harness.run("pairing", "finalExp", cfg, Fp12, benchFinalExp);
+}