faiss/tutorial/cpp/2-IVFFlat.cpp
Matthijs Douze a996a4a052 Put idx_t in the faiss namespace (#2582)
Summary:
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/2582

A few more or less cosmetic improvements
* Index::idx_t was in the Index object, which does not make much sense, this diff moves it to faiss::idx_t
* replace multiprocessing.dummy with multiprocessing.pool
* add Alexandr as a core contributor of Faiss in the README ;-)

```
for i in $( find . -name \*.cu -o -name \*.cuh -o -name \*.h -o -name \*.cpp ) ; do
  sed -i s/Index::idx_t/idx_t/ $i
done
```

For the fbcode deps:
```
for i in $( fbgs Index::idx_t --exclude fbcode/faiss -l ) ; do
   sed -i s/Index::idx_t/idx_t/ $i
done
```

Reviewed By: algoriddle

Differential Revision: D41437507

fbshipit-source-id: 8300f2a3ae97cace6172f3f14a9be3a83999fb89
2022-11-30 08:25:30 -08:00

83 lines
1.8 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/IndexFlat.h>
#include <faiss/IndexIVFFlat.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[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] = 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.;
}
int nlist = 100;
int k = 4;
faiss::IndexFlatL2 quantizer(d); // the other index
faiss::IndexIVFFlat index(&quantizer, d, nlist);
assert(!index.is_trained);
index.train(nb, xb);
assert(index.is_trained);
index.add(nb, xb);
{ // search xq
idx_t* I = new idx_t[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("%5zd ", 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("%5zd ", I[i * k + j]);
printf("\n");
}
delete[] I;
delete[] D;
}
delete[] xb;
delete[] xq;
return 0;
}