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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 <iostream>
#include <memory>
#include <vector>
#include <gtest/gtest.h>
#include <faiss/IndexPQFastScan.h>
#include <faiss/impl/ProductQuantizer.h>
#include <faiss/impl/pq4_fast_scan.h>
namespace {
const std::vector<uint64_t> random_vector(size_t s) {
std::vector<uint64_t> v(s, 0);
for (size_t i = 0; i < s; ++i) {
v[i] = rand();
}
return v;
}
const std::vector<float> random_vector_float(size_t s) {
std::vector<float> v(s, 0);
for (size_t i = 0; i < s; ++i) {
v[i] = rand();
}
return v;
}
} // namespace
TEST(PQEncoderGeneric, encode) {
const int nsubcodes = 97;
const int minbits = 1;
const int maxbits = 24;
const std::vector<uint64_t> values = random_vector(nsubcodes);
for (int nbits = minbits; nbits <= maxbits; ++nbits) {
std::cerr << "nbits = " << nbits << std::endl;
const uint64_t mask = (1ull << nbits) - 1;
std::unique_ptr<uint8_t[]> codes(
new uint8_t[(nsubcodes * maxbits + 7) / 8]);
// NOTE(hoss): Necessary scope to ensure trailing bits are flushed to
// mem.
{
faiss::PQEncoderGeneric encoder(codes.get(), nbits);
for (const auto& v : values) {
encoder.encode(v & mask);
}
}
faiss::PQDecoderGeneric decoder(codes.get(), nbits);
for (int i = 0; i < nsubcodes; ++i) {
uint64_t v = decoder.decode();
EXPECT_EQ(values[i] & mask, v);
}
}
}
TEST(PQEncoder8, encode) {
const int nsubcodes = 100;
const std::vector<uint64_t> values = random_vector(nsubcodes);
const uint64_t mask = 0xFF;
std::unique_ptr<uint8_t[]> codes(new uint8_t[nsubcodes]);
faiss::PQEncoder8 encoder(codes.get(), 8);
for (const auto& v : values) {
encoder.encode(v & mask);
}
faiss::PQDecoder8 decoder(codes.get(), 8);
for (int i = 0; i < nsubcodes; ++i) {
uint64_t v = decoder.decode();
EXPECT_EQ(values[i] & mask, v);
}
}
TEST(PQEncoder16, encode) {
const int nsubcodes = 100;
const std::vector<uint64_t> values = random_vector(nsubcodes);
const uint64_t mask = 0xFFFF;
std::unique_ptr<uint8_t[]> codes(new uint8_t[2 * nsubcodes]);
faiss::PQEncoder16 encoder(codes.get(), 16);
for (const auto& v : values) {
encoder.encode(v & mask);
}
faiss::PQDecoder16 decoder(codes.get(), 16);
for (int i = 0; i < nsubcodes; ++i) {
uint64_t v = decoder.decode();
EXPECT_EQ(values[i] & mask, v);
}
}
TEST(PQFastScan, set_packed_element) {
int d = 20, ntotal = 1000, M = 5, nbits = 4;
const std::vector<float> ds = random_vector_float(ntotal * d);
faiss::IndexPQFastScan index(d, M, nbits);
index.train(ntotal, ds.data());
index.add(ntotal, ds.data());
for (int j = 0; j < 10; j++) {
int vector_id = rand() % ntotal;
std::vector<uint8_t> old(ntotal * M);
std::vector<uint8_t> code(M);
for (int i = 0; i < ntotal; i++) {
for (int sq = 0; sq < M; sq++) {
old[i * M + sq] = faiss::pq4_get_packed_element(
index.codes.data(), index.bbs, M, i, sq);
}
}
for (int sq = 0; sq < M; sq++) {
faiss::pq4_set_packed_element(
index.codes.data(),
((old[vector_id * M + sq] + 3) % 16),
index.bbs,
M,
vector_id,
sq);
}
for (int i = 0; i < ntotal; i++) {
for (int sq = 0; sq < M; sq++) {
uint8_t newcode = faiss::pq4_get_packed_element(
index.codes.data(), index.bbs, M, i, sq);
uint8_t oldcode = old[i * M + sq];
if (i == vector_id) {
EXPECT_EQ(newcode, (oldcode + 3) % 16);
} else {
EXPECT_EQ(newcode, oldcode);
}
}
}
}
}
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