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2-IVFFlat.cpp
1
2 /**
3 * Copyright (c) 2015-present, Facebook, Inc.
4 * All rights reserved.
5 *
6 * This source code is licensed under the CC-by-NC license found in the
7 * LICENSE file in the root directory of this source tree.
8 */
9
10 #include <cstdio>
11 #include <cstdlib>
12 #include <cassert>
13
14 #include <faiss/IndexFlat.h>
15 #include <faiss/IndexIVF.h>
16
17
18 int main() {
19 int d = 64; // dimension
20 int nb = 100000; // database size
21 int nq = 10000; // nb of queries
22
23 float *xb = new float[d * nb];
24 float *xq = new float[d * nq];
25
26 for(int i = 0; i < nb; i++) {
27 for(int j = 0; j < d; j++)
28 xb[d * i + j] = drand48();
29 xb[d * i] += i / 1000.;
30 }
31
32 for(int i = 0; i < nq; i++) {
33 for(int j = 0; j < d; j++)
34 xq[d * i + j] = drand48();
35 xq[d * i] += i / 1000.;
36 }
37
38
39 int nlist = 100;
40 int k = 4;
41
42 faiss::IndexFlatL2 quantizer(d); // the other index
43 faiss::IndexIVFFlat index(&quantizer, d, nlist, faiss::METRIC_L2);
44 // here we specify METRIC_L2, by default it performs inner-product search
45 assert(!index.is_trained);
46 index.train(nb, xb);
47 assert(index.is_trained);
48 index.add(nb, xb);
49
50 { // search xq
51 long *I = new long[k * nq];
52 float *D = new float[k * nq];
53
54 index.search(nq, xq, k, D, I);
55
56 printf("I=\n");
57 for(int i = nq - 5; i < nq; i++) {
58 for(int j = 0; j < k; j++)
59 printf("%5ld ", I[i * k + j]);
60 printf("\n");
61 }
62
63 index.nprobe = 10;
64 index.search(nq, xq, k, D, I);
65
66 printf("I=\n");
67 for(int i = nq - 5; i < nq; i++) {
68 for(int j = 0; j < k; j++)
69 printf("%5ld ", I[i * k + j]);
70 printf("\n");
71 }
72
73 delete [] I;
74 delete [] D;
75 }
76
77
78
79 delete [] xb;
80 delete [] xq;
81
82 return 0;
83 }
faiss::IndexFlatL2
Definition: IndexFlat.h:81
faiss::IndexIVFFlat
Definition: IndexIVF.h:128