121 lines
3.0 KiB
C++
121 lines
3.0 KiB
C++
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD+Patents license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#include <cstdio>
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#include <cstdlib>
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#include <cassert>
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#include <faiss/IndexFlat.h>
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#include <faiss/gpu/GpuIndexFlat.h>
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#include <faiss/gpu/GpuIndexIVFFlat.h>
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#include <faiss/gpu/StandardGpuResources.h>
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int main() {
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int d = 64; // dimension
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int nb = 100000; // database size
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int nq = 10000; // nb of queries
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float *xb = new float[d * nb];
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float *xq = new float[d * nq];
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for(int i = 0; i < nb; i++) {
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for(int j = 0; j < d; j++)
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xb[d * i + j] = drand48();
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xb[d * i] += i / 1000.;
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}
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for(int i = 0; i < nq; i++) {
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for(int j = 0; j < d; j++)
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xq[d * i + j] = drand48();
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xq[d * i] += i / 1000.;
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}
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faiss::gpu::StandardGpuResources res;
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// Using a flat index
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faiss::gpu::GpuIndexFlatL2 index_flat(&res, d);
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printf("is_trained = %s\n", index_flat.is_trained ? "true" : "false");
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index_flat.add(nb, xb); // add vectors to the index
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printf("ntotal = %ld\n", index_flat.ntotal);
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int k = 4;
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{ // search xq
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long *I = new long[k * nq];
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float *D = new float[k * nq];
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index_flat.search(nq, xq, k, D, I);
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// print results
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printf("I (5 first results)=\n");
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for(int i = 0; i < 5; i++) {
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for(int j = 0; j < k; j++)
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printf("%5ld ", I[i * k + j]);
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printf("\n");
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}
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printf("I (5 last results)=\n");
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for(int i = nq - 5; i < nq; i++) {
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for(int j = 0; j < k; j++)
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printf("%5ld ", I[i * k + j]);
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printf("\n");
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}
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delete [] I;
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delete [] D;
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}
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// Using an IVF index
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int nlist = 100;
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faiss::gpu::GpuIndexIVFFlat index_ivf(&res, d, nlist, faiss::METRIC_L2);
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// here we specify METRIC_L2, by default it performs inner-product search
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assert(!index_ivf.is_trained);
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index_ivf.train(nb, xb);
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assert(index_ivf.is_trained);
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index_ivf.add(nb, xb); // add vectors to the index
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printf("is_trained = %s\n", index_ivf.is_trained ? "true" : "false");
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printf("ntotal = %ld\n", index_ivf.ntotal);
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{ // search xq
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long *I = new long[k * nq];
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float *D = new float[k * nq];
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index_ivf.search(nq, xq, k, D, I);
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// print results
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printf("I (5 first results)=\n");
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for(int i = 0; i < 5; i++) {
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for(int j = 0; j < k; j++)
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printf("%5ld ", I[i * k + j]);
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printf("\n");
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}
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printf("I (5 last results)=\n");
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for(int i = nq - 5; i < nq; i++) {
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for(int j = 0; j < k; j++)
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printf("%5ld ", I[i * k + j]);
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printf("\n");
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}
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delete [] I;
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delete [] D;
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}
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delete [] xb;
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delete [] xq;
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return 0;
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}
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