faiss/tutorial/cpp/9-RefineComparison.cpp

105 lines
2.8 KiB
C++

/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <random>
#include <faiss/IndexPQFastScan.h>
#include <faiss/IndexRefine.h>
#include <faiss/index_factory.h>
using idx_t = faiss::idx_t;
int main() {
int d = 64; // dimension
int nb = 100000; // database size
int nq = 10000; // nb of queries
std::mt19937 rng;
std::uniform_real_distribution<> distrib;
float* xb = new float[(int)(d * nb)];
float* xq = new float[(int)(d * nq)];
for (int i = 0; i < nb; i++) {
for (int j = 0; j < d; j++) {
xb[d * i + j] = distrib(rng);
}
xb[d * i] += i / 1000.;
}
for (int i = 0; i < nq; i++) {
for (int j = 0; j < d; j++) {
xq[d * i + j] = distrib(rng);
}
xq[d * i] += i / 1000.;
}
// Constructing the refine PQ index with SQfp16 with index factory
faiss::Index* index_fp16;
index_fp16 = faiss::index_factory(
d, "PQ32x4fs,Refine(SQfp16)", faiss::METRIC_L2);
index_fp16->train(nb, xb);
index_fp16->add(nb, xb);
// Constructing the refine PQ index with SQ8
faiss::Index* index_sq8;
index_sq8 =
faiss::index_factory(d, "PQ32x4fs,Refine(SQ8)", faiss::METRIC_L2);
index_sq8->train(nb, xb);
index_sq8->add(nb, xb);
int k = 10;
{ // search xq
idx_t* I_fp16 = new idx_t[(int)(k * nq)];
float* D_fp16 = new float[(int)(k * nq)];
idx_t* I_sq8 = new idx_t[(int)(k * nq)];
float* D_sq8 = new float[(int)(k * nq)];
// Parameterization on k factor while doing search for index refinement
float k_factor = 3;
faiss::IndexRefineSearchParameters* params =
new faiss::IndexRefineSearchParameters();
params->k_factor = k_factor;
// Perform index search using different index refinement
index_fp16->search(nq, xq, k, D_fp16, I_fp16, params);
index_sq8->search(nq, xq, k, D_sq8, I_sq8, params);
printf("I_fp16=\n");
for (int i = nq - 5; i < nq; i++) {
for (int j = 0; j < k; j++) {
printf("%5zd ", I_fp16[i * k + j]);
}
printf("\n");
}
printf("I_sq8=\n");
for (int i = nq - 5; i < nq; i++) {
for (int j = 0; j < k; j++) {
printf("%5zd ", I_sq8[i * k + j]);
}
printf("\n");
}
delete[] I_fp16;
delete[] D_fp16;
delete[] I_sq8;
delete[] D_sq8;
delete params;
delete index_fp16;
delete index_sq8;
}
delete[] xb;
delete[] xq;
return 0;
}