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test_merge.cpp
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD+Patents license found in the
* LICENSE file in the root directory of this source tree.
*/
#include <cstdio>
#include <cstdlib>
#include <gtest/gtest.h>
#include <faiss/IndexIVFFlat.h>
#include <faiss/IndexIVFPQ.h>
#include <faiss/IndexFlat.h>
#include <faiss/MetaIndexes.h>
#include <faiss/FaissAssert.h>
#include <faiss/VectorTransform.h>
#include <faiss/OnDiskInvertedLists.h>
#include <faiss/IVFlib.h>
namespace {
struct Tempfilename {
static pthread_mutex_t mutex;
std::string filename;
Tempfilename (const char *prefix = nullptr) {
pthread_mutex_lock (&mutex);
char *cfname = tempnam (nullptr, prefix);
filename = cfname;
free(cfname);
pthread_mutex_unlock (&mutex);
}
~Tempfilename () {
if (access (filename.c_str(), F_OK)) {
unlink (filename.c_str());
}
}
const char *c_str() {
return filename.c_str();
}
};
pthread_mutex_t Tempfilename::mutex = PTHREAD_MUTEX_INITIALIZER;
// parameters to use for the test
int d = 64;
size_t nb = 1000;
size_t nq = 100;
int nindex = 4;
int k = 10;
int nlist = 40;
typedef faiss::Index::idx_t idx_t;
struct CommonData {
std::vector <float> database;
std::vector <float> queries;
std::vector<idx_t> ids;
faiss::IndexFlatL2 quantizer;
CommonData(): database (nb * d), queries (nq * d), ids(nb), quantizer (d) {
for (size_t i = 0; i < nb * d; i++) {
database[i] = drand48();
}
for (size_t i = 0; i < nq * d; i++) {
queries[i] = drand48();
}
for (int i = 0; i < nb; i++) {
ids[i] = 123 + 456 * i;
}
{ // just to train the quantizer
faiss::IndexIVFFlat iflat (&quantizer, d, nlist);
iflat.train(nb, database.data());
}
}
};
CommonData cd;
/// perform a search on shards, then merge and search again and
/// compare results.
int compare_merged (faiss::IndexShards *index_shards, bool shift_ids,
bool standard_merge = true)
{
std::vector<idx_t> refI(k * nq);
std::vector<float> refD(k * nq);
index_shards->search(nq, cd.queries.data(), k, refD.data(), refI.data());
Tempfilename filename;
std::vector<idx_t> newI(k * nq);
std::vector<float> newD(k * nq);
if (standard_merge) {
for (int i = 1; i < nindex; i++) {
faiss::ivflib::merge_into(
index_shards->at(0), index_shards->at(i),
shift_ids);
}
index_shards->sync_with_shard_indexes();
} else {
std::vector<const faiss::InvertedLists *> lists;
faiss::IndexIVF *index0 = nullptr;
size_t ntotal = 0;
for (int i = 0; i < nindex; i++) {
auto index_ivf = dynamic_cast< faiss::IndexIVF*>(index_shards->at(i));
assert (index_ivf);
if (i == 0) {
index0 = index_ivf;
}
lists.push_back (index_ivf->invlists);
ntotal += index_ivf->ntotal;
}
auto il = new faiss::OnDiskInvertedLists(
index0->nlist, index0->code_size,
filename.c_str());
il->merge_from(lists.data(), lists.size());
index0->replace_invlists(il, true);
index0->ntotal = ntotal;
}
// search only on first index
index_shards->at(0)->search(nq, cd.queries.data(),
k, newD.data(), newI.data());
size_t ndiff = 0;
for (size_t i = 0; i < k * nq; i++) {
if (refI[i] != newI[i]) {
ndiff ++;
}
}
return ndiff;
}
} // namespace
// test on IVFFlat with implicit numbering
TEST(MERGE, merge_flat_no_ids) {
faiss::IndexShards index_shards(d);
index_shards.own_fields = true;
for (int i = 0; i < nindex; i++) {
index_shards.add_shard (
new faiss::IndexIVFFlat (&cd.quantizer, d, nlist));
}
EXPECT_TRUE(index_shards.is_trained);
index_shards.add(nb, cd.database.data());
size_t prev_ntotal = index_shards.ntotal;
int ndiff = compare_merged(&index_shards, true);
EXPECT_EQ (prev_ntotal, index_shards.ntotal);
EXPECT_EQ(0, ndiff);
}
// test on IVFFlat, explicit ids
TEST(MERGE, merge_flat) {
faiss::IndexShards index_shards(d, false, false);
index_shards.own_fields = true;
for (int i = 0; i < nindex; i++) {
index_shards.add_shard (
new faiss::IndexIVFFlat (&cd.quantizer, d, nlist));
}
EXPECT_TRUE(index_shards.is_trained);
index_shards.add_with_ids(nb, cd.database.data(), cd.ids.data());
int ndiff = compare_merged(&index_shards, false);
EXPECT_GE(0, ndiff);
}
// test on IVFFlat and a VectorTransform
TEST(MERGE, merge_flat_vt) {
faiss::IndexShards index_shards(d, false, false);
index_shards.own_fields = true;
// here we have to retrain because of the vectorTransform
faiss::RandomRotationMatrix rot(d, d);
rot.init(1234);
faiss::IndexFlatL2 quantizer (d);
{ // just to train the quantizer
faiss::IndexIVFFlat iflat (&quantizer, d, nlist);
faiss::IndexPreTransform ipt (&rot, &iflat);
ipt.train(nb, cd.database.data());
}
for (int i = 0; i < nindex; i++) {
faiss::IndexPreTransform * ipt = new faiss::IndexPreTransform (
new faiss::RandomRotationMatrix (rot),
new faiss::IndexIVFFlat (&quantizer, d, nlist)
);
ipt->own_fields = true;
index_shards.add_shard (ipt);
}
EXPECT_TRUE(index_shards.is_trained);
index_shards.add_with_ids(nb, cd.database.data(), cd.ids.data());
size_t prev_ntotal = index_shards.ntotal;
int ndiff = compare_merged(&index_shards, false);
EXPECT_EQ (prev_ntotal, index_shards.ntotal);
EXPECT_GE(0, ndiff);
}
// put the merged invfile on disk
TEST(MERGE, merge_flat_ondisk) {
faiss::IndexShards index_shards(d, false, false);
index_shards.own_fields = true;
Tempfilename filename;
for (int i = 0; i < nindex; i++) {
auto ivf = new faiss::IndexIVFFlat (&cd.quantizer, d, nlist);
if (i == 0) {
auto il = new faiss::OnDiskInvertedLists (
ivf->nlist, ivf->code_size,
filename.c_str());
ivf->replace_invlists(il, true);
}
index_shards.add_shard (ivf);
}
EXPECT_TRUE(index_shards.is_trained);
index_shards.add_with_ids(nb, cd.database.data(), cd.ids.data());
int ndiff = compare_merged(&index_shards, false);
EXPECT_EQ(ndiff, 0);
}
// now use ondisk specific merge
TEST(MERGE, merge_flat_ondisk_2) {
faiss::IndexShards index_shards(d, false, false);
index_shards.own_fields = true;
for (int i = 0; i < nindex; i++) {
index_shards.add_shard (
new faiss::IndexIVFFlat (&cd.quantizer, d, nlist));
}
EXPECT_TRUE(index_shards.is_trained);
index_shards.add_with_ids(nb, cd.database.data(), cd.ids.data());
int ndiff = compare_merged(&index_shards, false, false);
EXPECT_GE(0, ndiff);
}
faiss::IndexIVF
Definition: IndexIVF.h:91
faiss::RandomRotationMatrix
Randomly rotate a set of vectors.
Definition: VectorTransform.h:116
faiss::IndexShards::add_with_ids
void add_with_ids(idx_t n, const float *x, const long *xids) override
Definition: MetaIndexes.cpp:428
faiss::IndexFlatL2
Definition: IndexFlat.h:78
faiss::IndexShards::search
void search(idx_t n, const float *x, idx_t k, float *distances, idx_t *labels) const override
Definition: MetaIndexes.cpp:489
faiss::IndexPreTransform
Definition: VectorTransform.h:253
faiss::IndexIVFFlat
Definition: IndexIVFFlat.h:25
faiss::IndexShards::add
void add(idx_t n, const float *x) override
supported only for sub-indices that implement add_with_ids
Definition: MetaIndexes.cpp:422
faiss::Index::idx_t
long idx_t
all indices are this type
Definition: Index.h:64
faiss::IndexIVF::replace_invlists
void replace_invlists(InvertedLists *il, bool own=false)
replace the inverted lists, old one is deallocated if own_invlists
Definition: IndexIVF.cpp:486
faiss::Index::ntotal
idx_t ntotal
total nb of indexed vectors
Definition: Index.h:67
faiss::Index::search
virtual void search(idx_t n, const float *x, idx_t k, float *distances, idx_t *labels) const =0
faiss::IndexPreTransform::own_fields
bool own_fields
! the sub-index
Definition: VectorTransform.h:258
faiss::OnDiskInvertedLists
Definition: OnDiskInvertedLists.h:52
faiss::IndexShards
Definition: MetaIndexes.h:85
faiss::Index::is_trained
bool is_trained
set if the Index does not require training, or if training is done already
Definition: Index.h:71
faiss::Level1Quantizer::nlist
size_t nlist
number of possible key values
Definition: IndexIVF.h:34
faiss::IndexIVF::code_size
size_t code_size
code size per vector in bytes
Definition: IndexIVF.h:96