libdpf/test/tests/lut_union_test.cpp

#include <gtest/gtest.h>

#include "dpf/compose.hpp"
#include "dpf/verifiable.hpp"
#include "grotto/lut_union.hpp"

#include "simde/simde/x86/sse2.h"

#include <algorithm>
#include <cstdint>
#include <limits>
#include <stdexcept>
#include <vector>

namespace
{

using grotto::offset_horner_group_add;
using grotto::offset_horner_group_sub;

grotto::piecewise_lut<uint8_t> lut_a()
{
    grotto::piecewise_lut<uint8_t> lut;
    lut.knots = {0, 10, 50};
    lut.coeff = {{1, 0}, {0, 2}, {7, 1}};
    return lut;
}

grotto::piecewise_lut<uint8_t> lut_b()
{
    grotto::piecewise_lut<uint8_t> lut;
    lut.knots = {0, 4, 12, 80};
    lut.coeff = {{3, 0, 0}, {1, 0, 1}, {9, 2, 0}, {4, 1, 0}};
    return lut;
}

grotto::piecewise_lut<uint8_t> lut_c()
{
    grotto::piecewise_lut<uint8_t> lut;
    lut.knots = {0, 7, 90};
    lut.coeff = {{8, 1, 0}, {2, 0, 3}, {1, 1, 1}};
    return lut;
}

std::vector<uint64_t> open_union(const grotto::offset_poly_keys<uint8_t> & mat,
    const grotto::lut_union_plan<uint8_t> & plan)
{
    const auto s0 = grotto::lut_union_eval<0>(mat, plan);
    const auto s1 = grotto::lut_union_eval<1>(mat, plan);
    EXPECT_EQ(s0.size(), s1.size());
    std::vector<uint64_t> out(s0.size());
    for (std::size_t i = 0; i < s0.size(); ++i)
        out[i] = s0[i] + s1[i];
    return out;
}

template <typename InputT>
void expect_partition(const grotto::lut_union_plan<InputT> & plan)
{
    if (plan.knots.empty())
    {
        ADD_FAILURE() << "empty union";
        return;
    }
    for (const auto & func : plan.funcs)
    {
        std::vector<int> seen(plan.knots.size(), 0);
        for (const auto & span : func)
        {
            auto mark = [&](std::size_t j) {
                if (j >= seen.size())
                {
                    ADD_FAILURE() << "span index " << j;
                    return;
                }
                seen[j] += 1;
            };
            if (span.begin <= span.end)
            {
                for (std::size_t j = span.begin; j < span.end; ++j)
                    mark(j);
            }
            else
            {
                for (std::size_t j = span.begin; j < plan.knots.size(); ++j)
                    mark(j);
                for (std::size_t j = 0; j < span.end; ++j)
                    mark(j);
            }
        }
        for (int bit : seen)
            EXPECT_EQ(bit, 1);
    }
}

}  // namespace

TEST(LutUnion, WideDomainMapsTheWrapAcrossTheFront)
{
    grotto::piecewise_lut<uint64_t> a;
    a.knots = {10, 30};
    a.coeff = {{1}, {2}};
    grotto::piecewise_lut<uint64_t> b;
    b.knots = {0, 20};
    b.coeff = {{3}, {4}};
    const auto plan = grotto::make_lut_union_plan(
        std::vector<grotto::piecewise_lut<uint64_t>>{a, b}, uint64_t{0});

    ASSERT_EQ(plan.knots, (std::vector<uint64_t>{0, 10, 20, 30}));
    EXPECT_EQ(plan.comparisons, 1u);
    EXPECT_EQ(plan.prefix_walks, 1u);
    EXPECT_EQ(plan.depth, 64u);
    EXPECT_EQ(plan.geneval_rounds(), plan.depth);
    EXPECT_EQ(plan.degree, 0u);

    ASSERT_EQ(plan.funcs[0].size(), 2u);
    EXPECT_EQ(plan.funcs[0][0].begin, 1u);
    EXPECT_EQ(plan.funcs[0][0].end, 3u);
    EXPECT_EQ(plan.funcs[0][1].begin, 3u);
    EXPECT_EQ(plan.funcs[0][1].end, 1u);

    ASSERT_EQ(plan.funcs[1].size(), 2u);
    EXPECT_EQ(plan.funcs[1][0].begin, 0u);
    EXPECT_EQ(plan.funcs[1][0].end, 2u);
    EXPECT_EQ(plan.funcs[1][1].begin, 2u);
    EXPECT_EQ(plan.funcs[1][1].end, 0u);
    expect_partition(plan);
}

TEST(LutUnion, OneWalkMatchesEachLutOnItsOwnKnots)
{
    const auto a = lut_a();
    const auto b = lut_b();
    const uint8_t center = 12;
    const auto plan = grotto::make_lut_union_plan({a, b}, uint8_t{3});
    EXPECT_GT(plan.endpoints(), a.knots.size());
    EXPECT_EQ(plan.degree, 2u);
    EXPECT_EQ(plan.lanes, 3u);
    EXPECT_EQ(plan.depth, 8u);
    EXPECT_EQ(plan.comparisons, 1u);
    EXPECT_EQ(plan.prefix_walks, 1u);

    const auto mat = grotto::make_offset_poly_keys<uint8_t>(center, plan.degree);
    for (int eta = 0; eta < 256; eta += 17)
    {
        const auto e = static_cast<uint8_t>(eta);
        const auto here = grotto::make_lut_union_plan({a, b}, e);
        const auto got = open_union(mat, here);
        ASSERT_EQ(got.size(), 2u);
        EXPECT_EQ(got[0], grotto::offset_poly_clear<uint8_t>(center, a.knots, a.coeff, e))
            << eta;
        EXPECT_EQ(got[1], grotto::offset_poly_clear<uint8_t>(center, b.knots, b.coeff, e))
            << eta;
    }
}

TEST(LutUnion, GenevalPlanIsOneComparisonHoweverManyLuts)
{
    const uint8_t eta = 3;
    const auto few = grotto::make_lut_union_plan({lut_a(), lut_b()}, eta);
    const auto many = grotto::make_lut_union_plan({lut_a(), lut_b(), lut_c()}, eta);
    EXPECT_GT(many.endpoints(), few.endpoints());
    EXPECT_EQ(few.geneval_rounds(), many.geneval_rounds());
    EXPECT_EQ(few.funcs.size(), 2u);
    EXPECT_EQ(many.funcs.size(), 3u);

    dpf::protocol::composer c0(0);
    grotto::schedule_lut_union(c0, few);
    dpf::protocol::composer c1(0);
    grotto::schedule_lut_union(c1, many);
    const auto p0 = c0.default_plan();
    const auto p1 = c1.default_plan();
    EXPECT_EQ(p0.rounds(), few.depth);
    EXPECT_EQ(p1.rounds(), many.depth);
    EXPECT_EQ(p0.rounds(), p1.rounds());
    EXPECT_EQ(p0.slot_bytes(0), grotto::lut_union_slot_bytes(few.lanes));
    EXPECT_EQ(p1.slot_bytes(0), grotto::lut_union_slot_bytes(many.lanes));
}

TEST(LutUnion, GenevalXorAndAdditiveSharesMatchTheClearLuts)
{
    const uint8_t center = 12;
    const uint8_t eta = 3;
    const auto a = lut_a();
    const auto b = lut_b();
    const auto plan = grotto::make_lut_union_plan({a, b}, eta);
    const uint8_t share = 0x3c;
    const uint8_t other = static_cast<uint8_t>(center ^ share);

    const auto xor_got = grotto::geneval_lut_union(share, other, plan);
    EXPECT_EQ(xor_got.eta, eta);
    ASSERT_EQ(xor_got.value0.size(), 2u);
    EXPECT_EQ(xor_got.value0[0] + xor_got.value1[0],
        grotto::offset_poly_clear<uint8_t>(center, a.knots, a.coeff, eta));
    EXPECT_EQ(xor_got.value0[1] + xor_got.value1[1],
        grotto::offset_poly_clear<uint8_t>(center, b.knots, b.coeff, eta));

    const uint8_t c0 = 5;
    const uint8_t c1 = offset_horner_group_sub(center, c0);
    const auto add_got = grotto::geneval_lut_union(dpf::arith_input, c0, c1, plan);
    EXPECT_EQ(add_got.value0[0] + add_got.value1[0], xor_got.value0[0] + xor_got.value1[0]);
    EXPECT_EQ(add_got.value0[1] + add_got.value1[1], xor_got.value0[1] + xor_got.value1[1]);
}

TEST(LutUnion, EasyAndConstantLutsShareTheUnion)
{
    const auto relu = grotto::piecewise_from_easy(grotto::make_relu_lut<int8_t>());
    const auto clip = grotto::piecewise_from_easy(
        grotto::make_clip_lut<int8_t>(0, -2, 3));
    grotto::constant_lut<int8_t> sign;
    sign.bounds = {std::numeric_limits<int8_t>::min(), 0};
    sign.values = {-1, 1};
    const auto step = grotto::piecewise_from_constant(sign);

    const int8_t center = -20;
    const int8_t eta = 15;
    const auto plan = grotto::make_lut_union_plan(
        std::vector<grotto::piecewise_lut<int8_t>>{relu, clip, step}, eta);
    EXPECT_EQ(plan.comparisons, 1u);
    EXPECT_EQ(plan.prefix_walks, 1u);
    EXPECT_GT(plan.endpoints(), relu.knots.size());

    const auto mat = grotto::make_offset_poly_keys<int8_t>(center, plan.degree);
    const auto s0 = grotto::lut_union_eval<0>(mat, plan);
    const auto s1 = grotto::lut_union_eval<1>(mat, plan);
    const int8_t wrapped = offset_horner_group_add(center, eta);
    const uint64_t opened[3] = {s0[0] + s1[0], s0[1] + s1[1], s0[2] + s1[2]};
    EXPECT_EQ(opened[0], static_cast<uint64_t>(grotto::make_relu_lut<int8_t>()(wrapped)));
    EXPECT_EQ(opened[1], static_cast<uint64_t>(grotto::make_clip_lut<int8_t>(0, -2, 3)(wrapped)));
    EXPECT_EQ(opened[2], static_cast<uint64_t>(sign(wrapped)));
    EXPECT_EQ(opened[0], grotto::offset_poly_clear<int8_t>(center, relu.knots, relu.coeff, eta));
}

TEST(LutUnion, RejectsARoundingDenominatorAndANarrowKey)
{
    EXPECT_THROW(grotto::piecewise_from_easy(grotto::make_leaky_relu_lut<int8_t>(1)),
        std::invalid_argument);
    EXPECT_THROW(grotto::make_lut_union_plan(
        std::vector<grotto::piecewise_lut<uint8_t>>{}, uint8_t{0}),
        std::invalid_argument);

    const auto plan = grotto::make_lut_union_plan({lut_b()}, uint8_t{1});
    const auto narrow = grotto::make_offset_poly_keys<uint8_t>(4, 0);
    EXPECT_THROW(grotto::lut_union_eval<0>(narrow, plan), std::invalid_argument);

    grotto::piecewise_lut<uint8_t> unsorted;
    unsorted.knots = {0, 5, 3};
    unsorted.coeff = {{1}, {1}, {1}};
    EXPECT_THROW(grotto::make_lut_union_plan({unsorted}, uint8_t{0}), std::invalid_argument);

    grotto::piecewise_lut<uint8_t> ragged;
    ragged.knots = {0, 1};
    ragged.coeff = {{1}, {1, 2}};
    EXPECT_THROW(grotto::make_lut_union_plan({ragged}, uint8_t{0}), std::invalid_argument);

    grotto::piecewise_lut<uint8_t> empty_row;
    empty_row.knots = {0};
    empty_row.coeff = {{}};
    EXPECT_THROW(grotto::make_lut_union_plan({empty_row}, uint8_t{0}), std::invalid_argument);

    grotto::piecewise_lut<uint8_t> too_wide;
    too_wide.knots = {0};
    too_wide.coeff = {std::vector<uint64_t>(grotto::offset_poly_max_degree + 2, 1)};
    EXPECT_THROW(grotto::make_lut_union_plan({too_wide}, uint8_t{0}), std::invalid_argument);

    grotto::easy_lut<int8_t> broken;
    broken.bounds = {0};
    broken.c0 = {0};
    EXPECT_THROW(grotto::piecewise_from_easy(broken), std::invalid_argument);

    grotto::constant_lut<int8_t> bare;
    bare.bounds = {std::numeric_limits<int8_t>::min()};
    EXPECT_THROW(grotto::piecewise_from_constant(bare), std::invalid_argument);

    dpf::protocol::composer composer(0);
    EXPECT_THROW(grotto::schedule_lut_union(composer, grotto::lut_union_plan<uint8_t>{}),
        std::invalid_argument);
}

TEST(LutUnion, CoarsePieceCoversSeveralUnionKnots)
{
    const auto plan = grotto::make_lut_union_plan({lut_a(), lut_b()}, uint8_t{0});
    expect_partition(plan);
    ASSERT_EQ(plan.knots, (std::vector<uint8_t>{0, 4, 10, 12, 50, 80}));
    const auto & first = plan.funcs[0][0];
    EXPECT_EQ(first.end - first.begin, 2u);
    EXPECT_EQ(first.kappa, 0);
    EXPECT_EQ(first.coeff, (std::vector<uint64_t>{1, 0}));

    const uint8_t center = 200;
    const uint8_t eta = 100;
    const auto carried = grotto::make_lut_union_plan({lut_a(), lut_b()}, eta);
    expect_partition(carried);
    EXPECT_NE(std::find(carried.knots.begin(), carried.knots.end(), uint8_t{156}),
        carried.knots.end());
    const auto mat = grotto::make_offset_poly_keys<uint8_t>(center, carried.degree);
    const auto got = open_union(mat, carried);
    EXPECT_EQ(got[0], grotto::offset_poly_clear<uint8_t>(center, lut_a().knots, lut_a().coeff, eta));
    EXPECT_EQ(got[1], grotto::offset_poly_clear<uint8_t>(center, lut_b().knots, lut_b().coeff, eta));
}

TEST(LutUnion, EveryEtaMatchesASeparatePolynomialEval)
{
    const auto a = lut_a();
    const auto b = lut_b();
    const uint8_t center = 12;
    const auto probe = grotto::make_lut_union_plan({a, b}, uint8_t{0});
    const auto mat = grotto::make_offset_poly_keys<uint8_t>(center, probe.degree);
    const auto wide = grotto::make_offset_poly_keys<uint8_t>(center, probe.degree + 2);
    const auto alone_a = grotto::make_offset_poly_keys<uint8_t>(center, 1);
    const auto alone_b = grotto::make_offset_poly_keys<uint8_t>(center, 2);
    for (int eta = 0; eta < 256; ++eta)
    {
        const auto e = static_cast<uint8_t>(eta);
        const auto plan = grotto::make_lut_union_plan({a, b}, e);
        expect_partition(plan);
        const auto got = open_union(mat, plan);
        const auto again = open_union(mat, plan);
        EXPECT_EQ(got, again);
        EXPECT_EQ(got, open_union(wide, plan));
        const uint64_t a_alone = grotto::offset_poly_eval<0>(alone_a, a.knots, a.coeff, e)
            + grotto::offset_poly_eval<1>(alone_a, a.knots, a.coeff, e);
        const uint64_t b_alone = grotto::offset_poly_eval<0>(alone_b, b.knots, b.coeff, e)
            + grotto::offset_poly_eval<1>(alone_b, b.knots, b.coeff, e);
        EXPECT_EQ(got[0], a_alone) << eta;
        EXPECT_EQ(got[1], b_alone) << eta;
    }
}

TEST(LutUnion, OnePieceLutCoversTheWholeUnion)
{
    grotto::piecewise_lut<uint8_t> whole;
    whole.knots = {0};
    whole.coeff = {{5, 1}};
    const auto plan = grotto::make_lut_union_plan({whole, lut_a()}, uint8_t{0});
    expect_partition(plan);
    ASSERT_EQ(plan.funcs[0].size(), 1u);
    EXPECT_EQ(plan.funcs[0][0].begin, 0u);
    EXPECT_EQ(plan.funcs[0][0].end, plan.knots.size());

    // A nonzero eta inserts the carry cut, so the one public knot becomes two
    // refined pieces. They still partition the union.
    const uint8_t eta = 9;
    const auto split = grotto::make_lut_union_plan({whole, lut_a()}, eta);
    expect_partition(split);
    EXPECT_GT(split.funcs[0].size(), 1u);
    const uint8_t center = 40;
    const auto mat = grotto::make_offset_poly_keys<uint8_t>(center, split.degree);
    const auto got = open_union(mat, split);
    EXPECT_EQ(got[0], grotto::offset_poly_clear<uint8_t>(center, whole.knots, whole.coeff, eta));
    EXPECT_EQ(got[1], grotto::offset_poly_clear<uint8_t>(center, lut_a().knots, lut_a().coeff, eta));
}

TEST(LutUnion, IdenticalKnotsStayASingleCopy)
{
    const auto a = lut_a();
    const auto plan = grotto::make_lut_union_plan({a, a}, uint8_t{0});
    EXPECT_EQ(plan.knots, a.knots);
    EXPECT_EQ(plan.funcs.size(), 2u);
    EXPECT_EQ(plan.prefix_walks, 1u);
    expect_partition(plan);
}

TEST(LutUnion, VerifiableTokensCoverEveryLane)
{
    const auto a = lut_a();
    const auto b = lut_b();
    const uint8_t center = 12;
    const uint8_t eta = 5;
    const auto plan = grotto::make_lut_union_plan({a, b}, eta);
    const auto mat = grotto::make_offset_poly_keys<uint8_t>(center, plan.degree, dpf::verifiable{});
    std::vector<dpf::proof_token> tok0(plan.lanes), tok1(plan.lanes);
    const auto s0 = grotto::lut_union_eval<0>(mat, plan, tok0.data());
    const auto s1 = grotto::lut_union_eval<1>(mat, plan, tok1.data());
    EXPECT_EQ(s0[0] + s1[0], grotto::offset_poly_clear<uint8_t>(center, a.knots, a.coeff, eta));
    EXPECT_EQ(s0[1] + s1[1], grotto::offset_poly_clear<uint8_t>(center, b.knots, b.coeff, eta));
    for (std::size_t m = 0; m < plan.lanes; ++m)
        EXPECT_TRUE(dpf::verify(tok0[m], tok1[m])) << m;
    tok0[0][0] = simde_mm_xor_si128(tok0[0][0], simde_mm_set1_epi8(1));
    EXPECT_FALSE(dpf::verify(tok0[0], tok1[0]));
    EXPECT_TRUE(dpf::verify(tok0[1], tok1[1]));
}

TEST(LutUnion, ScheduleOnAnExistingSeedStaysOneWalk)
{
    const auto few = grotto::make_lut_union_plan({lut_a()}, uint8_t{1});
    const auto many = grotto::make_lut_union_plan({lut_a(), lut_b(), lut_c()}, uint8_t{1});
    EXPECT_EQ(few.lanes, 2u);
    EXPECT_EQ(grotto::lut_union_slot_bytes(1), 16u);
    EXPECT_EQ(grotto::lut_union_slot_bytes(few.lanes), 16u);
    EXPECT_EQ(grotto::lut_union_slot_bytes(many.lanes), 24u);

    dpf::protocol::composer composer(0);
    auto seed = composer.input(dpf::protocol::domain::fss, 16);
    grotto::schedule_lut_union(composer, seed, many);
    const auto scheduled = composer.default_plan();
    ASSERT_EQ(scheduled.rounds(), many.depth);
    for (std::uint16_t round = 0; round < scheduled.rounds(); ++round)
        EXPECT_EQ(scheduled.slot_bytes(round), grotto::lut_union_slot_bytes(many.lanes));
}

TEST(LutUnion, SignedDomainAndRealTables)
{
    const auto relu = grotto::piecewise_from_easy(grotto::make_relu_lut<int8_t>());
    const auto abs_lut = grotto::piecewise_from_easy(grotto::make_abs_lut<int8_t>());
    const auto square = grotto::piecewise_from_easy(grotto::make_squared_relu_lut<int8_t>(0));
    for (const auto & row : relu.coeff)
        EXPECT_EQ(row.size(), 2u);
    for (const auto & row : abs_lut.coeff)
        EXPECT_EQ(row.size(), 2u);
    for (const auto & row : square.coeff)
        EXPECT_EQ(row.size(), 3u);

    const int8_t center = -20;
    const auto probe = grotto::make_lut_union_plan(
        std::vector<grotto::piecewise_lut<int8_t>>{relu, abs_lut, square}, int8_t{0});
    EXPECT_EQ(probe.degree, 2u);
    EXPECT_EQ(probe.depth, 8u);
    const auto mat = grotto::make_offset_poly_keys<int8_t>(center, probe.degree);
    const auto relu_f = grotto::make_relu_lut<int8_t>();
    const auto abs_f = grotto::make_abs_lut<int8_t>();
    const auto sq_f = grotto::make_squared_relu_lut<int8_t>(0);
    for (int eta = -128; eta < 128; eta += 7)
    {
        const auto e = static_cast<int8_t>(eta);
        const auto plan = grotto::make_lut_union_plan(
            std::vector<grotto::piecewise_lut<int8_t>>{relu, abs_lut, square}, e);
        expect_partition(plan);
        const auto s0 = grotto::lut_union_eval<0>(mat, plan);
        const auto s1 = grotto::lut_union_eval<1>(mat, plan);
        const int8_t wrapped = offset_horner_group_add(center, e);
        EXPECT_EQ(s0[0] + s1[0], static_cast<uint64_t>(relu_f(wrapped))) << eta;
        EXPECT_EQ(s0[1] + s1[1], static_cast<uint64_t>(abs_f(wrapped))) << eta;
        EXPECT_EQ(s0[2] + s1[2], static_cast<uint64_t>(sq_f(wrapped))) << eta;
    }

    const int8_t share = 3;
    const int8_t other = static_cast<int8_t>(center ^ share);
    const auto plan = grotto::make_lut_union_plan(
        std::vector<grotto::piecewise_lut<int8_t>>{relu, abs_lut, square}, int8_t{-3});
    const auto got = grotto::geneval_lut_union(share, other, plan);
    const int8_t wrapped = offset_horner_group_add(center, int8_t{-3});
    EXPECT_EQ(got.value0[0] + got.value1[0], static_cast<uint64_t>(relu_f(wrapped)));
    EXPECT_EQ(got.value0[1] + got.value1[1], static_cast<uint64_t>(abs_f(wrapped)));
    EXPECT_EQ(got.value0[2] + got.value1[2], static_cast<uint64_t>(sq_f(wrapped)));
}

TEST(LutUnion, SixteenBitDomainKeepsOneComparison)
{
    grotto::piecewise_lut<uint16_t> left;
    left.knots = {0, 1000};
    left.coeff = {{3, 1}, {8, 0}};
    grotto::piecewise_lut<uint16_t> right;
    right.knots = {0, 400, 2000};
    right.coeff = {{1, 0, 2}, {9, 1, 0}, {4, 0, 1}};
    const uint16_t center = 50;
    const uint16_t eta = 40000;
    const auto plan = grotto::make_lut_union_plan({left, right}, eta);
    EXPECT_EQ(plan.depth, 16u);
    EXPECT_EQ(plan.geneval_rounds(), 16u);
    EXPECT_EQ(plan.comparisons, 1u);
    expect_partition(plan);
    const auto mat = grotto::make_offset_poly_keys<uint16_t>(center, plan.degree);
    const auto s0 = grotto::lut_union_eval<0>(mat, plan);
    const auto s1 = grotto::lut_union_eval<1>(mat, plan);
    EXPECT_EQ(s0[0] + s1[0], grotto::offset_poly_clear<uint16_t>(center, left.knots, left.coeff, eta));
    EXPECT_EQ(s0[1] + s1[1], grotto::offset_poly_clear<uint16_t>(center, right.knots, right.coeff, eta));

    dpf::protocol::composer composer(0);
    grotto::schedule_lut_union(composer, plan);
    EXPECT_EQ(composer.default_plan().rounds(), 16u);
}