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/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#include <gtest/gtest.h>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <fstream>
#include <iostream>
#include <random>
#include <vector>
#include <faiss/IndexBinaryFlat.h>
#include <faiss/IndexFlat.h>
#include <faiss/impl/io.h>
#include <faiss/index_io.h>
namespace {
std::vector<float> make_data(const size_t n, const size_t d, size_t seed) {
std::vector<float> database(n * d);
std::mt19937 rng(seed);
std::uniform_real_distribution<float> distrib;
for (size_t i = 0; i < n * d; i++) {
database[i] = distrib(rng);
}
return database;
}
std::vector<uint8_t> make_binary_data(
const size_t n,
const size_t d,
size_t seed) {
std::vector<uint8_t> database(n * d);
std::mt19937 rng(seed);
std::uniform_int_distribution<uint8_t> distrib(0, 255);
for (size_t i = 0; i < n * d; i++) {
database[i] = distrib(rng);
}
return database;
}
} // namespace
// the logic is the following:
// 1. generate two flatcodes-based indices, Index1 and Index2
// 2. serialize both indices into std::vector<> buffers, Buf1 and Buf2
// 3. save Buf1 into a temporary file, File1
// 4. deserialize Index1 using mmap feature on File1 into Index1MM
// 5. ensure that Index1MM acts as Index2 if we write the data from Buf2
// on top of the existing File1
// 6. ensure that Index1MM acts as Index1 if we write the data from Buf1
// on top of the existing File1 again
TEST(TestMmap, mmap_flatcodes) {
#ifdef _AIX
GTEST_SKIP() << "Skipping test on AIX.";
#endif
// generate data
const size_t nt = 1000;
const size_t nq = 10;
const size_t d = 32;
const size_t k = 25;
std::vector<float> xt1 = make_data(nt, d, 123);
std::vector<float> xt2 = make_data(nt, d, 456);
std::vector<float> xq = make_data(nq, d, 789);
// ensure that the data is different
ASSERT_NE(xt1, xt2);
// make index1 and create reference results
faiss::IndexFlatL2 index1(d);
index1.train(nt, xt1.data());
index1.add(nt, xt1.data());
std::vector<float> ref_dis_1(k * nq);
std::vector<faiss::idx_t> ref_ids_1(k * nq);
index1.search(nq, xq.data(), k, ref_dis_1.data(), ref_ids_1.data());
// make index2 and create reference results
faiss::IndexFlatL2 index2(d);
index2.train(nt, xt2.data());
index2.add(nt, xt2.data());
std::vector<float> ref_dis_2(k * nq);
std::vector<faiss::idx_t> ref_ids_2(k * nq);
index2.search(nq, xq.data(), k, ref_dis_2.data(), ref_ids_2.data());
// ensure that the results are different
ASSERT_NE(ref_dis_1, ref_dis_2);
ASSERT_NE(ref_ids_1, ref_ids_2);
// serialize both in a form of vectors
faiss::VectorIOWriter wr1;
faiss::write_index(&index1, &wr1);
faiss::VectorIOWriter wr2;
faiss::write_index(&index2, &wr2);
// generate a temporary file and write index1 into it
std::string tmpname = std::tmpnam(nullptr);
{
std::ofstream ofs(tmpname);
ofs.write((const char*)wr1.data.data(), wr1.data.size());
}
// create a mmap index
std::unique_ptr<faiss::Index> index1mm(
faiss::read_index(tmpname.c_str(), faiss::IO_FLAG_MMAP_IFC));
ASSERT_NE(index1mm, nullptr);
// perform a search
std::vector<float> cand_dis_1(k * nq);
std::vector<faiss::idx_t> cand_ids_1(k * nq);
index1mm->search(nq, xq.data(), k, cand_dis_1.data(), cand_ids_1.data());
// match vs ref1
ASSERT_EQ(ref_ids_1, cand_ids_1);
ASSERT_EQ(ref_dis_1, cand_dis_1);
// ok now, overwrite the internals of the file without recreating it
{
std::ofstream ofs(tmpname);
ofs.seekp(0, std::ios::beg);
ofs.write((const char*)wr2.data.data(), wr2.data.size());
}
// perform a search
std::vector<float> cand_dis_2(k * nq);
std::vector<faiss::idx_t> cand_ids_2(k * nq);
index1mm->search(nq, xq.data(), k, cand_dis_2.data(), cand_ids_2.data());
// match vs ref1
ASSERT_EQ(ref_ids_2, cand_ids_2);
ASSERT_EQ(ref_dis_2, cand_dis_2);
// write back data1
{
std::ofstream ofs(tmpname);
ofs.seekp(0, std::ios::beg);
ofs.write((const char*)wr1.data.data(), wr1.data.size());
}
// perform a search
std::vector<float> cand_dis_3(k * nq);
std::vector<faiss::idx_t> cand_ids_3(k * nq);
index1mm->search(nq, xq.data(), k, cand_dis_3.data(), cand_ids_3.data());
// match vs ref1
ASSERT_EQ(ref_ids_1, cand_ids_3);
ASSERT_EQ(ref_dis_1, cand_dis_3);
}
TEST(TestMmap, mmap_binary_flatcodes) {
#ifdef _AIX
GTEST_SKIP() << "Skipping test on AIX.";
#endif
// generate data
const size_t nt = 1000;
const size_t nq = 10;
// in bits
const size_t d = 64;
// in bytes
const size_t d8 = (d + 7) / 8;
const size_t k = 25;
std::vector<uint8_t> xt1 = make_binary_data(nt, d8, 123);
std::vector<uint8_t> xt2 = make_binary_data(nt, d8, 456);
std::vector<uint8_t> xq = make_binary_data(nq, d8, 789);
// ensure that the data is different
ASSERT_NE(xt1, xt2);
// make index1 and create reference results
faiss::IndexBinaryFlat index1(d);
index1.train(nt, xt1.data());
index1.add(nt, xt1.data());
std::vector<int32_t> ref_dis_1(k * nq);
std::vector<faiss::idx_t> ref_ids_1(k * nq);
index1.search(nq, xq.data(), k, ref_dis_1.data(), ref_ids_1.data());
// make index2 and create reference results
faiss::IndexBinaryFlat index2(d);
index2.train(nt, xt2.data());
index2.add(nt, xt2.data());
std::vector<int32_t> ref_dis_2(k * nq);
std::vector<faiss::idx_t> ref_ids_2(k * nq);
index2.search(nq, xq.data(), k, ref_dis_2.data(), ref_ids_2.data());
// ensure that the results are different
ASSERT_NE(ref_dis_1, ref_dis_2);
ASSERT_NE(ref_ids_1, ref_ids_2);
// serialize both in a form of vectors
faiss::VectorIOWriter wr1;
faiss::write_index_binary(&index1, &wr1);
faiss::VectorIOWriter wr2;
faiss::write_index_binary(&index2, &wr2);
// generate a temporary file and write index1 into it
std::string tmpname = std::tmpnam(nullptr);
{
std::ofstream ofs(tmpname);
ofs.write((const char*)wr1.data.data(), wr1.data.size());
}
// create a mmap index
std::unique_ptr<faiss::IndexBinary> index1mm(
faiss::read_index_binary(tmpname.c_str(), faiss::IO_FLAG_MMAP_IFC));
ASSERT_NE(index1mm, nullptr);
// perform a search
std::vector<int32_t> cand_dis_1(k * nq);
std::vector<faiss::idx_t> cand_ids_1(k * nq);
index1mm->search(nq, xq.data(), k, cand_dis_1.data(), cand_ids_1.data());
// match vs ref1
ASSERT_EQ(ref_ids_1, cand_ids_1);
ASSERT_EQ(ref_dis_1, cand_dis_1);
// ok now, overwrite the internals of the file without recreating it
{
std::ofstream ofs(tmpname);
ofs.seekp(0, std::ios::beg);
ofs.write((const char*)wr2.data.data(), wr2.data.size());
}
// perform a search
std::vector<int32_t> cand_dis_2(k * nq);
std::vector<faiss::idx_t> cand_ids_2(k * nq);
index1mm->search(nq, xq.data(), k, cand_dis_2.data(), cand_ids_2.data());
// match vs ref1
ASSERT_EQ(ref_ids_2, cand_ids_2);
ASSERT_EQ(ref_dis_2, cand_dis_2);
// write back data1
{
std::ofstream ofs(tmpname);
ofs.seekp(0, std::ios::beg);
ofs.write((const char*)wr1.data.data(), wr1.data.size());
}
// perform a search
std::vector<int32_t> cand_dis_3(k * nq);
std::vector<faiss::idx_t> cand_ids_3(k * nq);
index1mm->search(nq, xq.data(), k, cand_dis_3.data(), cand_ids_3.data());
// match vs ref1
ASSERT_EQ(ref_ids_1, cand_ids_3);
ASSERT_EQ(ref_dis_1, cand_dis_3);
}
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