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2-IVFFlat.cpp
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the CC-by-NC license found in the
* LICENSE file in the root directory of this source tree.
*/
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <faiss/IndexFlat.h>
#include <faiss/IndexIVF.h>
int main() {
int d = 64; // dimension
int nb = 100000; // database size
int nq = 10000; // nb of queries
float *xb = new float[d * nb];
float *xq = new float[d * nq];
for(int i = 0; i < nb; i++) {
for(int j = 0; j < d; j++)
xb[d * i + j] = drand48();
xb[d * i] += i / 1000.;
}
for(int i = 0; i < nq; i++) {
for(int j = 0; j < d; j++)
xq[d * i + j] = drand48();
xq[d * i] += i / 1000.;
}
int nlist = 100;
int k = 4;
faiss::IndexFlatL2 quantizer(d); // the other index
faiss::IndexIVFFlat index(&quantizer, d, nlist, faiss::METRIC_L2);
// here we specify METRIC_L2, by default it performs inner-product search
assert(!index.is_trained);
index.train(nb, xb);
assert(index.is_trained);
index.add(nb, xb);
{ // search xq
long *I = new long[k * nq];
float *D = new float[k * nq];
index.search(nq, xq, k, D, I);
printf("I=\n");
for(int i = nq - 5; i < nq; i++) {
for(int j = 0; j < k; j++)
printf("%5ld ", I[i * k + j]);
printf("\n");
}
index.nprobe = 10;
index.search(nq, xq, k, D, I);
printf("I=\n");
for(int i = nq - 5; i < nq; i++) {
for(int j = 0; j < k; j++)
printf("%5ld ", I[i * k + j]);
printf("\n");
}
delete [] I;
delete [] D;
}
delete [] xb;
delete [] xq;
return 0;
}
faiss::IndexFlatL2
Definition: IndexFlat.h:79
faiss::IndexIVFFlat
Definition: IndexIVF.h:132