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1-Flat.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 <faiss/IndexFlat.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.;
}
faiss::IndexFlatL2 index(d); // call constructor
printf("is_trained = %s\n", index.is_trained ? "true" : "false");
index.add(nb, xb); // add vectors to the index
printf("ntotal = %ld\n", index.ntotal);
int k = 4;
{ // sanity check: search 5 first vectors of xb
long *I = new long[k * 5];
float *D = new float[k * 5];
index.search(5, xb, k, D, I);
// print results
printf("I=\n");
for(int i = 0; i < 5; i++) {
for(int j = 0; j < k; j++)
printf("%5ld ", I[i * k + j]);
printf("\n");
}
printf("D=\n");
for(int i = 0; i < 5; i++) {
for(int j = 0; j < k; j++)
printf("%7g ", D[i * k + j]);
printf("\n");
}
delete [] I;
delete [] D;
}
{ // search xq
long *I = new long[k * nq];
float *D = new float[k * nq];
index.search(nq, xq, k, D, I);
// print results
printf("I (5 first results)=\n");
for(int i = 0; i < 5; i++) {
for(int j = 0; j < k; j++)
printf("%5ld ", I[i * k + j]);
printf("\n");
}
printf("I (5 last results)=\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