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ShockHash.h
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ShockHash.h
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#pragma once
/*
* Based on RecSplit, Copyright (C) 2019-2020 Emmanuel Esposito and Sebastiano Vigna
* Enhanced to use overloaded cuckoo hash tables in the leaves.
* For tiny space usages (~1.6 bit/object), ShockHash is faster than RecSplit.
*/
#include <array>
#include <cassert>
#include <chrono>
#include <cmath>
#include <string>
#include <vector>
#include <fstream>
#include <condition_variable>
#include <thread>
#include <sux/util/Vector.hpp>
#include <sux/function/DoubleEF.hpp>
#include <sux/function/RiceBitVector.hpp>
#include <sux/function/RecSplit.hpp>
#include <SimpleRibbon.h>
#include <Sorter.hpp>
#include "TinyBinaryCuckooHashTable.h"
#include "RiceBitVector.h"
namespace shockhash {
using namespace sux;
using namespace sux::function;
using namespace std;
using namespace std::chrono;
// Assumed *maximum* size of a bucket. Works with high probability up to average bucket size ~2000.
static const int MAX_BUCKET_SIZE = 3000;
static const int MAX_FANOUT = 32;
static const int MAX_LEAF_SIZE = 60;
#if defined(STATS)
static uint64_t bij_unary, bij_fixed;
static uint64_t split_unary, split_fixed;
static uint64_t time_bij;
static uint64_t time_split[MAX_LEVEL_TIME];
static double split_opt;
static double bij_opt;
#endif
// Starting seed at given distance from the root (extracted at random).
static constexpr uint64_t start_seed[] = {0x106393c187cae21a, 0x6453cec3f7376937, 0x643e521ddbd2be98, 0x3740c6412f6572cb, 0x717d47562f1ce470, 0x4cd6eb4c63befb7c, 0x9bfd8c5e18c8da73,
0x082f20e10092a9a3, 0x2ada2ce68d21defc, 0xe33cb4f3e7c6466b, 0x3980be458c509c59, 0xc466fd9584828e8c, 0x45f0aabe1a61ede6, 0xf6e7b8b33ad9b98d,
0x4ef95e25f4b4983d, 0x81175195173b92d3, 0x4e50927d8dd15978, 0x1ea2099d1fafae7f, 0x425c8a06fbaaa815, 0xcd4216006c74052a};
static constexpr int NUM_START_SEEDS = sizeof(start_seed) / sizeof(uint64_t);
// Optimal Golomb-Rice parameters for leaves.
static constexpr uint8_t bij_memo[MAX_LEAF_SIZE + 1] = {
0, 0, 0, 0, 0, 0, 1, 1, 2, 2, // 0..9
2, 3, 3, 4, 4, 4, 5, 5, 6, 6, // 10..19
7, 7, 8, 8, 9, 9, 9, 10, 10, 10, // 20..29
11, 11, 12, 12, 13, 13, 13, 14, 15, 15, // 30..39
15, 16, 16, 16, 17, 17, 18, 18, 19, 19, // 40..49
19, 20, 20, 20, 21, 21, 22, 22, 23, 23, // 50..59
23 // 60
};
template <size_t LEAF_SIZE> class SplittingStrategy {
public:
static constexpr size_t _leaf = LEAF_SIZE;
static_assert(_leaf >= 1);
static_assert(_leaf <= MAX_LEAF_SIZE);
//static constexpr size_t lower_aggr = _leaf * max(2, ceil(0.35 * _leaf + 1. / 2));
//static constexpr size_t upper_aggr = lower_aggr * (_leaf < 7 ? 2 : ceil(0.21 * _leaf + 9. / 10));
static constexpr size_t lower_aggr = _leaf * (_leaf > 24 ? 4 : 2);
static constexpr size_t upper_aggr = lower_aggr * (_leaf > 24 ? 3 : 2);
};
// Generates the precomputed table of 32-bit values holding the Golomb-Rice code
// of a splitting (upper 5 bits), the number of nodes in the associated subtree
// (following 11 bits) and the sum of the Golomb-Rice codelengths in the same
// subtree (lower 16 bits).
template <size_t LEAF_SIZE> static constexpr void _fill_golomb_rice(const size_t m, array<uint32_t, MAX_BUCKET_SIZE> *memo) {
array<int, MAX_FANOUT> k{0};
constexpr size_t lower_aggr = SplittingStrategy<LEAF_SIZE>::lower_aggr;
constexpr size_t upper_aggr = SplittingStrategy<LEAF_SIZE>::upper_aggr;
size_t fanout = 0, unit = 0;
if (m > upper_aggr) { // High-level aggregation (fanout 2)
unit = upper_aggr * (uint16_t(m / 2 + upper_aggr - 1) / upper_aggr);
fanout = 2;
} else if (m > lower_aggr) { // Second-level aggregation
unit = lower_aggr;
fanout = uint16_t(m + lower_aggr - 1) / lower_aggr;
} else { // First-level aggregation
unit = LEAF_SIZE;
fanout = uint16_t(m + LEAF_SIZE - 1) / LEAF_SIZE;
}
k[fanout - 1] = m;
for (size_t i = 0; i < fanout - 1; ++i) {
k[i] = unit;
k[fanout - 1] -= k[i];
}
double sqrt_prod = 1;
for (size_t i = 0; i < fanout; ++i) sqrt_prod *= sqrt(k[i]);
const double p = sqrt(m) / (pow(2 * M_PI, (fanout - 1.) / 2) * sqrt_prod);
auto golomb_rice_length = (uint32_t)ceil(log2(-log((sqrt(5) + 1) / 2) / log1p(-p))); // log2 Golomb modulus
assert(golomb_rice_length <= 0x1F); // Golomb-Rice code, stored in the 5 upper bits
(*memo)[m] = golomb_rice_length << 27;
for (size_t i = 0; i < fanout; ++i) golomb_rice_length += (*memo)[k[i]] & 0xFFFF;
assert(golomb_rice_length <= 0xFFFF); // Sum of Golomb-Rice codeslengths in the subtree, stored in the lower 16 bits
(*memo)[m] |= golomb_rice_length;
uint32_t nodes = 1;
for (size_t i = 0; i < fanout; ++i) nodes += ((*memo)[k[i]] >> 16) & 0x7FF;
assert(LEAF_SIZE < 3 || nodes <= 0x7FF); // Number of nodes in the subtree, stored in the middle 11 bits
(*memo)[m] |= nodes << 16;
}
template <size_t LEAF_SIZE> static constexpr array<uint32_t, MAX_BUCKET_SIZE> fill_golomb_rice() {
array<uint32_t, MAX_BUCKET_SIZE> memo{0};
size_t s = 0;
for (; s <= LEAF_SIZE; ++s) memo[s] = bij_memo[s] << 27 | (s > 1) << 16 | bij_memo[s];
for (; s < MAX_BUCKET_SIZE; ++s) _fill_golomb_rice<LEAF_SIZE>(s, &memo);
return memo;
}
#define first_hash(k, len) spooky(k, len, 0)
#define golomb_param(m) (memo[m] >> 27)
#define skip_bits(m) (memo[m] & 0xFFFF)
#define skip_nodes(m) ((memo[m] >> 16) & 0x7FF)
template <size_t LEAF_SIZE, bool ROTATION_FITTING = false>
class ShockHash {
static_assert(LEAF_SIZE <= MAX_LEAF_SIZE);
static constexpr AllocType AT = sux::util::AllocType::MALLOC;
static constexpr size_t _leaf = LEAF_SIZE;
static constexpr size_t lower_aggr = SplittingStrategy<LEAF_SIZE>::lower_aggr;
static constexpr size_t upper_aggr = SplittingStrategy<LEAF_SIZE>::upper_aggr;
static constexpr uint64_t GROUP_A_HF_MASK = (LEAF_SIZE > 32) ? 0b111ul : 0ul;
// For each bucket size, the Golomb-Rice parameter (upper 8 bits) and the number of bits to
// skip in the fixed part of the tree (lower 24 bits).
static constexpr array<uint32_t, MAX_BUCKET_SIZE> memo = fill_golomb_rice<LEAF_SIZE>();
size_t bucket_size;
size_t nbuckets;
size_t keys_count;
RiceBitVector<AT> descriptors;
DoubleEF<AT> ef;
using Ribbon = SimpleRibbon<1, (_leaf > 24) ? 128 : 64>;
Ribbon ribbon;
public:
ShockHash() {}
ShockHash(const vector<string> &keys, const size_t bucket_size, size_t num_threads = 1) {
this->bucket_size = bucket_size;
this->keys_count = keys.size();
hash128_t *h = (hash128_t *)malloc(this->keys_count * sizeof(hash128_t));
if (num_threads == 1) {
for (size_t i = 0; i < this->keys_count; ++i) {
h[i] = first_hash(keys[i].c_str(), keys[i].size());
}
} else {
size_t keysPerThread = this->keys_count / num_threads + 1;
std::vector<std::thread> threads;
for (size_t thread = 0; thread < num_threads; thread++) {
threads.emplace_back([&, thread] {
size_t from = thread * keysPerThread;
size_t to = std::min(this->keys_count, (thread + 1) * keysPerThread);
for (size_t i = from; i < to; ++i) {
h[i] = first_hash(keys[i].c_str(), keys[i].size());
}
});
}
for (std::thread &t : threads) {
t.join();
}
}
hash_gen(h, num_threads);
free(h);
}
ShockHash(vector<hash128_t> &keys, const size_t bucket_size, size_t num_threads = 1) {
this->bucket_size = bucket_size;
this->keys_count = keys.size();
hash_gen(&keys[0], num_threads);
}
/** Returns the value associated with the given 128-bit hash.
*
* Note that this method is mainly useful for benchmarking.
* @param hash a 128-bit hash.
* @return the associated value.
*/
size_t operator()(const hash128_t &hash) {
const size_t bucket = hash128_to_bucket(hash);
uint64_t cum_keys, cum_keys_next, bit_pos;
ef.get(bucket, cum_keys, cum_keys_next, bit_pos);
// Number of keys in this bucket
size_t m = cum_keys_next - cum_keys;
auto reader = descriptors.reader();
reader.readReset(bit_pos, skip_bits(m));
int level = 0;
while (m > upper_aggr) { // fanout = 2
const auto d = reader.readNext(golomb_param(m));
const size_t hmod = sux::remap16(sux::function::remix(hash.second + d + start_seed[level]), m);
const uint32_t split = ((uint16_t(m / 2 + upper_aggr - 1) / upper_aggr)) * upper_aggr;
if (hmod < split) {
m = split;
} else {
reader.skipSubtree(skip_nodes(split), skip_bits(split));
m -= split;
cum_keys += split;
}
level++;
}
if (m > lower_aggr) {
const auto d = reader.readNext(golomb_param(m));
const size_t hmod = sux::remap16(sux::function::remix(hash.second + d + start_seed[level]), m);
const int part = uint16_t(hmod) / lower_aggr;
m = min(lower_aggr, m - part * lower_aggr);
cum_keys += lower_aggr * part;
if (part) reader.skipSubtree(skip_nodes(lower_aggr) * part, skip_bits(lower_aggr) * part);
level++;
}
if (m > _leaf) {
const auto d = reader.readNext(golomb_param(m));
const size_t hmod = sux::remap16(sux::function::remix(hash.second + d + start_seed[level]), m);
const int part = uint16_t(hmod) / _leaf;
m = min(_leaf, m - part * _leaf);
cum_keys += _leaf * part;
if (part) reader.skipSubtree(part, skip_bits(_leaf) * part);
level++;
}
const auto b = reader.readNext(golomb_param(m));
// Begin: difference to RecSplit.
shockhash::HashedKey key(hash.second);
size_t hashFunctionIndex = ribbon.retrieve(hash.second);
if (ROTATION_FITTING && m == LEAF_SIZE) {
size_t r = b % LEAF_SIZE;
size_t x = b / LEAF_SIZE + start_seed[level];
TinyBinaryCuckooHashTable::CandidateCells candidateCells;
size_t cell;
if ((key.mhc & 1) == 0) {
// Group A
candidateCells = TinyBinaryCuckooHashTable::getCandidateCells<LEAF_SIZE>(key, x & (~GROUP_A_HF_MASK));
cell = hashFunctionIndex == 0 ? candidateCells.cell1 : candidateCells.cell2;
} else {
candidateCells = TinyBinaryCuckooHashTable::getCandidateCells<LEAF_SIZE>(key, x);
cell = hashFunctionIndex == 0 ? candidateCells.cell1 : candidateCells.cell2;
cell = (cell + r) % LEAF_SIZE;
}
return cum_keys + cell;
} else {
return cum_keys + shockhash::TinyBinaryCuckooHashTable::hashToCell(key, b + start_seed[level], m, hashFunctionIndex);
}
// End: difference to RecSplit.
}
/** Returns the value associated with the given key.
*
* @param key a key.
* @return the associated value.
*/
size_t operator()(const string &key) { return operator()(first_hash(key.c_str(), key.size())); }
/** Returns the number of keys used to build this RecSplit instance. */
inline size_t size() { return this->keys_count; }
/** Returns an estimate of the size in bits of this structure. */
size_t getBits() {
return ef.bitCountCumKeys() + ef.bitCountPosition()
+ descriptors.getBits() + 8 * ribbon.sizeBytes() + 8 * sizeof(ShockHash);
}
void printBits() {
std::cout<<"EF 1: "<<(double)ef.bitCountCumKeys()/keys_count<<std::endl;
std::cout<<"EF 2: "<<(double)ef.bitCountPosition()/keys_count<<std::endl;
std::cout<<"trees: "<<(double)descriptors.getBits()/keys_count<<std::endl;
std::cout<<"ribbon: "<<(double)(8 * ribbon.sizeBytes())/keys_count<<std::endl;
}
private:
// Maps a 128-bit to a bucket using the first 64-bit half.
inline uint64_t hash128_to_bucket(const hash128_t &hash) const { return remap128(hash.first, nbuckets); }
static constexpr uint64_t rotate(size_t l, uint64_t val, uint32_t x) {
return ((val << x) | (val >> (l - x))) & ((1ul << l) - 1);
}
void recSplit(vector<uint64_t> &bucket, vector<uint64_t> &temp, size_t start, size_t end,
typename RiceBitVector<AT>::Builder &builder, vector<uint32_t> &unary, const int level,
TinyBinaryCuckooHashTable &tinyBinaryCuckooHashTable,
std::vector<std::pair<uint64_t, uint8_t>> &ribbonInput) {
const auto m = end - start;
assert(m > 1);
uint64_t x = start_seed[level];
if (m <= _leaf) {
#ifdef STATS
auto start_time = high_resolution_clock::now();
#endif
// Begin: difference to RecSplit.
if (ROTATION_FITTING && m == LEAF_SIZE) {
constexpr uint64_t allSet = (1ul << LEAF_SIZE) - 1;
size_t r = 0;
size_t keysGroupA = 0;
size_t indexB = LEAF_SIZE - 1;
shockhash::HashedKey keys[LEAF_SIZE];
TinyBinaryCuckooHashTable::CandidateCells candidateCellsCache[LEAF_SIZE];
tinyBinaryCuckooHashTable.clear();
for (size_t i = 0; i < LEAF_SIZE; i++) {
auto key = shockhash::HashedKey(bucket[i + start]);
if ((key.mhc & 1) == 0) {
keys[keysGroupA] = key;
keysGroupA++;
} else {
keys[indexB] = key;
indexB--;
}
}
for (size_t i = 0; i < LEAF_SIZE; i++) {
tinyBinaryCuckooHashTable.prepare(keys[i]);
}
uint64_t a = 0;
uint64_t b = 0;
for (;;x++) {
if (a == 0 || (x & GROUP_A_HF_MASK) == 0) {
a = 0;
for (size_t i = 0; i < keysGroupA; i++) {
auto candidateCells = TinyBinaryCuckooHashTable::getCandidateCells<LEAF_SIZE>(keys[i], x & (~GROUP_A_HF_MASK));
candidateCellsCache[i] = candidateCells;
uint64_t candidatePowers = (1ull << candidateCells.cell1) | (1ull << candidateCells.cell2);
a |= candidatePowers;
}
}
b = 0;
for (size_t i = keysGroupA; i < LEAF_SIZE; i++) {
auto candidateCells = TinyBinaryCuckooHashTable::getCandidateCells<LEAF_SIZE>(keys[i], x);
candidateCellsCache[i] = candidateCells;
uint64_t candidatePowers = (1ull << candidateCells.cell1) | (1ull << candidateCells.cell2);
b |= candidatePowers;
}
for (r = 0; r < LEAF_SIZE; r++) {
if ((a | rotate(LEAF_SIZE, b, r)) != allSet) {
continue;
}
tinyBinaryCuckooHashTable.clearPlacement();
size_t i = 0;
for (i = 0; i < LEAF_SIZE; i++) {
auto candidateCells = candidateCellsCache[i];
if ((tinyBinaryCuckooHashTable.heap[i].hash.mhc & 1) == 1) {
// Set B
candidateCells.cell1 = (candidateCells.cell1 + r) % LEAF_SIZE;
candidateCells.cell2 = (candidateCells.cell2 + r) % LEAF_SIZE;
}
if (!tinyBinaryCuckooHashTable.insert(&tinyBinaryCuckooHashTable.heap[i], candidateCells)) {
break;
}
}
if (i == m) {
goto storeOrientation; // All got inserted, break outer loop
}
}
}
storeOrientation:
for (size_t i = 0; i < m; i++) {
auto hash = tinyBinaryCuckooHashTable.cells[i]->hash;
size_t cell = i;
if ((hash.mhc & 1) == 1) {
// Set B
cell = (cell - r + m) % m;
}
// Use fact that first hash function is < m/2 (see getCandidateCells)
ribbonInput.emplace_back(hash.mhc, (cell < m / 2) ? 0 : 1);
#ifndef NDEBUG
TinyBinaryCuckooHashTable::CandidateCells candidateCells;
if ((hash.mhc & 1) == 0) {
// Set A
candidateCells = TinyBinaryCuckooHashTable::getCandidateCells(hash, x & (~GROUP_A_HF_MASK), m);
} else {
// Set B
candidateCells = TinyBinaryCuckooHashTable::getCandidateCells(hash, x, m);
candidateCells.cell1 = (candidateCells.cell1 + r) % m;
candidateCells.cell2 = (candidateCells.cell2 + r) % m;
}
assert(i == candidateCells.cell1 || i == candidateCells.cell2);
#endif
}
x -= start_seed[level];
x = x * LEAF_SIZE + r;
} else {
tinyBinaryCuckooHashTable.clear();
for (size_t i = start; i < end; i++) {
tinyBinaryCuckooHashTable.prepare(shockhash::HashedKey(bucket[i]));
}
uint64_t allSet = (1ul << m) - 1;
uint64_t mask = 0;
for (;;) {
for (;;) {
mask = 0;
for (size_t i = start; i < end; i++) {
auto hash = TinyBinaryCuckooHashTable::getCandidateCells(HashedKey(bucket[i]), x, m);
mask |= (1ul << hash.cell1);
mask |= (1ul << hash.cell2);
}
if (mask == allSet) break;
x++;
}
if (tinyBinaryCuckooHashTable.construct(x)) break;
x++;
}
for (size_t i = 0; i < m; i++) {
// Use fact that first hash function is < m/2 (see getCandidateCells)
ribbonInput.emplace_back(tinyBinaryCuckooHashTable.cells[i]->hash.mhc, (i < m / 2) ? 0 : 1);
#ifndef NDEBUG
auto candidateCells = TinyBinaryCuckooHashTable::getCandidateCells(tinyBinaryCuckooHashTable.cells[i]->hash, x, m);
assert(i == candidateCells.cell1 || i == candidateCells.cell2);
#endif
}
x -= start_seed[level];
}
// End: difference to RecSplit.
const auto log2golomb = golomb_param(m);
builder.appendFixed(x, log2golomb);
unary.push_back(x >> log2golomb);
#ifdef STATS
bij_unary += 1 + (x >> log2golomb);
bij_fixed += log2golomb;
time_bij += duration_cast<nanoseconds>(high_resolution_clock::now() - start_time).count();
bij_opt += log2(x + 1);
#endif
} else {
#ifdef STATS
auto start_time = high_resolution_clock::now();
#endif
if (m > upper_aggr) { // fanout = 2
const size_t split = ((uint16_t(m / 2 + upper_aggr - 1) / upper_aggr)) * upper_aggr;
size_t count[2];
for (;;) {
count[0] = 0;
for (size_t i = start; i < end; i++) {
count[remap16(sux::function::remix(bucket[i] + x), m) >= split]++;
}
if (count[0] == split) break;
x++;
}
count[0] = 0;
count[1] = split;
for (size_t i = start; i < end; i++) {
temp[count[remap16(sux::function::remix(bucket[i] + x), m) >= split]++] = bucket[i];
}
copy(&temp[0], &temp[m], &bucket[start]);
x -= start_seed[level];
const auto log2golomb = golomb_param(m);
builder.appendFixed(x, log2golomb);
unary.push_back(x >> log2golomb);
#ifdef STATS
time_split[min(MAX_LEVEL_TIME, level)] += duration_cast<nanoseconds>(high_resolution_clock::now() - start_time).count();
split_opt += log2(x + 1);
#endif
recSplit(bucket, temp, start, start + split, builder, unary, level + 1, tinyBinaryCuckooHashTable, ribbonInput);
if (m - split > 1) recSplit(bucket, temp, start + split, end, builder, unary, level + 1, tinyBinaryCuckooHashTable, ribbonInput);
} else if (m > lower_aggr) { // 2nd aggregation level
const size_t fanout = uint16_t(m + lower_aggr - 1) / lower_aggr;
size_t count[fanout]; // Note that we never read count[fanout-1]
for (;;) {
memset(count, 0, sizeof count - sizeof *count);
for (size_t i = start; i < end; i++) {
count[uint16_t(remap16(sux::function::remix(bucket[i] + x), m)) / lower_aggr]++;
}
size_t broken = 0;
for (size_t i = 0; i < fanout - 1; i++) broken |= count[i] - lower_aggr;
if (!broken) break;
x++;
}
for (size_t i = 0, c = 0; i < fanout; i++, c += lower_aggr) count[i] = c;
for (size_t i = start; i < end; i++) {
temp[count[uint16_t(sux::function::remap16(sux::function::remix(bucket[i] + x), m)) / lower_aggr]++] = bucket[i];
}
copy(&temp[0], &temp[m], &bucket[start]);
x -= start_seed[level];
const auto log2golomb = golomb_param(m);
builder.appendFixed(x, log2golomb);
unary.push_back(x >> log2golomb);
#ifdef STATS
time_split[min(MAX_LEVEL_TIME, level)] += duration_cast<nanoseconds>(high_resolution_clock::now() - start_time).count();
split_opt += log2(x + 1);
#endif
size_t i;
for (i = 0; i < m - lower_aggr; i += lower_aggr) {
recSplit(bucket, temp, start + i, start + i + lower_aggr, builder, unary, level + 1, tinyBinaryCuckooHashTable, ribbonInput);
}
if (m - i > 1) recSplit(bucket, temp, start + i, end, builder, unary, level + 1, tinyBinaryCuckooHashTable, ribbonInput);
} else { // First aggregation level, m <= lower_aggr
const size_t fanout = uint16_t(m + _leaf - 1) / _leaf;
size_t count[fanout]; // Note that we never read count[fanout-1]
for (;;) {
memset(count, 0, sizeof count - sizeof *count);
for (size_t i = start; i < end; i++) {
count[uint16_t(remap16(sux::function::remix(bucket[i] + x), m)) / _leaf]++;
}
size_t broken = 0;
for (size_t i = 0; i < fanout - 1; i++) broken |= count[i] - _leaf;
if (!broken) break;
x++;
}
for (size_t i = 0, c = 0; i < fanout; i++, c += _leaf) count[i] = c;
for (size_t i = start; i < end; i++) {
temp[count[uint16_t(remap16(sux::function::remix(bucket[i] + x), m)) / _leaf]++] = bucket[i];
}
copy(&temp[0], &temp[m], &bucket[start]);
x -= start_seed[level];
const auto log2golomb = golomb_param(m);
builder.appendFixed(x, log2golomb);
unary.push_back(x >> log2golomb);
#ifdef STATS
time_split[min(MAX_LEVEL_TIME, level)] += duration_cast<nanoseconds>(high_resolution_clock::now() - start_time).count();
split_opt += log2(x + 1);
#endif
size_t i;
for (i = 0; i < m - _leaf; i += _leaf) {
recSplit(bucket, temp, start + i, start + i + _leaf, builder, unary, level + 1, tinyBinaryCuckooHashTable, ribbonInput);
}
if (m - i > 1) recSplit(bucket, temp, start + i, end, builder, unary, level + 1, tinyBinaryCuckooHashTable, ribbonInput);
}
#ifdef STATS
const auto log2golomb = golomb_param(m);
split_unary += 1 + (x >> log2golomb);
split_fixed += log2golomb;
#endif
}
}
void compute_thread(int tid, int num_threads, mutex &mtx, std::condition_variable &condition,
vector<uint64_t> &bucket_size_acc, vector<uint64_t> &bucket_pos_acc,
vector<uint64_t> &sorted_keys, int &next_thread_to_append_builder,
typename shockhash::RiceBitVector<AT>::Builder &builder,
std::vector<std::pair<uint64_t, uint8_t>> &ribbonInput) {
typename shockhash::RiceBitVector<AT>::Builder local_builder;
TinyBinaryCuckooHashTable tinyBinaryCuckooHashTable(LEAF_SIZE);
vector<uint32_t> unary;
vector<uint64_t> temp(MAX_BUCKET_SIZE);
size_t begin = tid * this->nbuckets / num_threads;
size_t end = std::min(this->nbuckets, (tid + 1) * this->nbuckets / num_threads);
if (tid == num_threads - 1) {
end = this->nbuckets;
}
for (size_t i = begin; i < end; ++i) {
const size_t s = bucket_size_acc[i + 1] - bucket_size_acc[i];
if (s > 1) {
recSplit(sorted_keys, temp, bucket_size_acc[i], bucket_size_acc[i + 1], local_builder,
unary, 0, tinyBinaryCuckooHashTable, ribbonInput);
local_builder.appendUnaryAll(unary);
unary.clear();
}
bucket_pos_acc[i + 1] = local_builder.getBits();
}
if (tid == 0) {
builder = std::move(local_builder);
lock_guard<mutex> lock(mtx);
next_thread_to_append_builder = 1;
condition.notify_all();
} else {
uint64_t prev_bucket_pos;
{
unique_lock<mutex> lock(mtx);
condition.wait(lock, [&] { return next_thread_to_append_builder == tid; });
prev_bucket_pos = builder.getBits();
builder.appendRiceBitVector(local_builder);
next_thread_to_append_builder = tid + 1;
condition.notify_all();
}
for (size_t i = begin + 1; i < end + 1; ++i) {
bucket_pos_acc[i] += prev_bucket_pos;
}
}
}
void hash_gen(hash128_t *hashes, size_t num_threads) {
#ifdef STATS
split_unary = split_fixed = 0;
bij_unary = bij_fixed = 0;
time_bij = 0;
memset(time_split, 0, sizeof time_split);
#endif
#ifndef __SIZEOF_INT128__
if (keys_count > (1ULL << 32)) {
fprintf(stderr, "For more than 2^32 keys, you need 128-bit integer support.\n");
abort();
}
#endif
nbuckets = max(1, (keys_count + bucket_size - 1) / bucket_size);
auto bucket_size_acc = vector<uint64_t>(nbuckets + 1);
auto bucket_pos_acc = vector<uint64_t>(nbuckets + 1);
auto sorted_keys = vector<uint64_t>(keys_count);
std::vector<std::pair<uint64_t, uint8_t>> ribbonInput;
ribbonInput.reserve(keys_count);
parallelPartition(hashes, sorted_keys, bucket_size_acc, num_threads, keys_count, nbuckets);
typename RiceBitVector<AT>::Builder builder;
vector<std::thread> threads;
threads.reserve(num_threads);
mutex mtx;
std::condition_variable condition;
int next_thread_to_append_builder = 0;
bucket_pos_acc[0] = 0;
if (num_threads == 1) {
compute_thread(0, num_threads, mtx, condition,
bucket_size_acc, bucket_pos_acc, sorted_keys,
next_thread_to_append_builder, builder, ribbonInput);
} else {
std::vector<std::vector<std::pair<uint64_t, uint8_t>>> ribbonInputs;
ribbonInputs.resize(num_threads);
for (int tid = 0; tid < num_threads; ++tid) {
ribbonInputs.at(tid).reserve(keys_count / num_threads);
threads.emplace_back([&, tid] {
compute_thread(tid, num_threads, mtx, condition,
bucket_size_acc, bucket_pos_acc, sorted_keys,
next_thread_to_append_builder, builder, ribbonInputs.at(tid));
});
}
for (int tid = 0; tid < num_threads; ++tid) {
threads.at(tid).join();
ribbonInput.insert(ribbonInput.end(), ribbonInputs.at(tid).begin(), ribbonInputs.at(tid).end());
}
}
builder.appendFixed(1, 1); // Sentinel (avoids checking for parts of size 1)
descriptors = builder.build();
ef = DoubleEF<AT>(vector<uint64_t>(bucket_size_acc.begin(), bucket_size_acc.end()), vector<uint64_t>(bucket_pos_acc.begin(), bucket_pos_acc.end()));
// Begin: difference to RecSplit.
ribbon = Ribbon(ribbonInput);
ribbonInput.clear();
// End: difference to RecSplit.
#ifdef STATS
// Evaluation purposes only
double ef_sizes = (double)ef.bitCountCumKeys() / keys_count;
double ef_bits = (double)ef.bitCountPosition() / keys_count;
double rice_desc = (double)builder.getBits() / keys_count;
double retrieval = 8.0 * (double)ribbon.sizeBytes() / keys_count;
printf("Elias-Fano cumul sizes: %f bits/bucket\n", (double)ef.bitCountCumKeys() / nbuckets);
printf("Elias-Fano cumul bits: %f bits/bucket\n", (double)ef.bitCountPosition() / nbuckets);
printf("Elias-Fano cumul sizes: %f bits/key\n", ef_sizes);
printf("Elias-Fano cumul bits: %f bits/key\n", ef_bits);
printf("Rice-Golomb descriptors: %f bits/key\n", rice_desc);
printf("Retrieval: %f bits/key\n", retrieval);
printf("Total bits: %f bits/key\n", ef_sizes + ef_bits + rice_desc + retrieval);
printf("Split bits: %16.3f\n", ((double)split_fixed + split_unary) / keys_count);
printf("Split bits opt: %16.3f\n", split_opt / keys_count);
printf("Bij bits: %16.3f\n", ((double)bij_fixed + bij_unary) / keys_count);
printf("Bij bits opt: %16.3f\n", bij_opt / keys_count);
printf("\n");
printf("Bijections: %13.3f ms\n", time_bij * 1E-6);
for (int i = 0; i < MAX_LEVEL_TIME; i++) {
if (time_split[i] > 0) {
printf("Split level %d: %10.3f ms\n", i, time_split[i] * 1E-6);
}
}
#endif
}
};
} // namespace shockhash