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test_ivfpq_indexing.cpp
1 /**
2 * Copyright (c) 2015-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under the BSD+Patents license found in the
6 * LICENSE file in the root directory of this source tree.
7 */
8
9
10 #include <cstdio>
11 #include <cstdlib>
12
13 #include <gtest/gtest.h>
14
15 #include <faiss/IndexIVFPQ.h>
16 #include <faiss/IndexFlat.h>
17 #include <faiss/index_io.h>
18
19 TEST(IVFPQ, accuracy) {
20
21 // dimension of the vectors to index
22 int d = 64;
23
24 // size of the database we plan to index
25 size_t nb = 1000;
26
27 // make a set of nt training vectors in the unit cube
28 // (could be the database)
29 size_t nt = 1500;
30
31 // make the index object and train it
32 faiss::IndexFlatL2 coarse_quantizer (d);
33
34 // a reasonable number of cetroids to index nb vectors
35 int ncentroids = 25;
36
37 faiss::IndexIVFPQ index (&coarse_quantizer, d,
38 ncentroids, 16, 8);
39
40 // index that gives the ground-truth
41 faiss::IndexFlatL2 index_gt (d);
42
43 srand48 (35);
44
45 { // training
46
47 std::vector <float> trainvecs (nt * d);
48 for (size_t i = 0; i < nt * d; i++) {
49 trainvecs[i] = drand48();
50 }
51 index.verbose = true;
52 index.train (nt, trainvecs.data());
53 }
54
55 { // populating the database
56
57 std::vector <float> database (nb * d);
58 for (size_t i = 0; i < nb * d; i++) {
59 database[i] = drand48();
60 }
61
62 index.add (nb, database.data());
63 index_gt.add (nb, database.data());
64 }
65
66 int nq = 200;
67 int n_ok;
68
69 { // searching the database
70
71 std::vector <float> queries (nq * d);
72 for (size_t i = 0; i < nq * d; i++) {
73 queries[i] = drand48();
74 }
75
76 std::vector<faiss::Index::idx_t> gt_nns (nq);
77 std::vector<float> gt_dis (nq);
78
79 index_gt.search (nq, queries.data(), 1,
80 gt_dis.data(), gt_nns.data());
81
82 index.nprobe = 5;
83 int k = 5;
84 std::vector<faiss::Index::idx_t> nns (k * nq);
85 std::vector<float> dis (k * nq);
86
87 index.search (nq, queries.data(), k, dis.data(), nns.data());
88
89 n_ok = 0;
90 for (int q = 0; q < nq; q++) {
91
92 for (int i = 0; i < k; i++)
93 if (nns[q * k + i] == gt_nns[q])
94 n_ok++;
95 }
96 EXPECT_GT(n_ok, nq * 0.4);
97 }
98
99 }
faiss::IndexFlatL2
Definition: IndexFlat.h:78
faiss::IndexIVFPQ
Definition: IndexIVFPQ.h:35