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GpuDistance.h
1 /**
2 * Copyright (c) 2015-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under the BSD+Patents license found in the
6 * LICENSE file in the root directory of this source tree.
7 */
8
9
10 #pragma once
11
12 #include "../Index.h"
13
14 namespace faiss { namespace gpu {
15
16 class GpuResources;
17
18 /// A wrapper for gpu/impl/Distance.cuh to expose direct brute-force k-nearest
19 /// neighbor searches on an externally-provided region of memory (e.g., from a
20 /// pytorch tensor).
21 /// The data (vectors, queries, outDistances, outIndices) can be resident on the
22 /// GPU or the CPU, but all calculations are performed on the GPU. If the result
23 /// buffers are on the CPU, results will be copied back when done.
24 ///
25 /// All GPU computation is performed on the current CUDA device, and ordered
26 /// with respect to resources->getDefaultStreamCurrentDevice().
27 ///
28 /// For each vector in `queries`, searches all of `vectors` to find its k
29 /// nearest neighbors with respect to the given metric
30 void bruteForceKnn(GpuResources* resources,
31 faiss::MetricType metric,
32 // A region of memory size numVectors x dims, with dims
33 // innermost
34 const float* vectors,
35 int numVectors,
36 // A region of memory size numQueries x dims, with dims
37 // innermost
38 const float* queries,
39 int numQueries,
40 int dims,
41 int k,
42 // A region of memory size numQueries x k, with k
43 // innermost
44 float* outDistances,
45 // A region of memory size numQueries x k, with k
46 // innermost
47 faiss::Index::idx_t* outIndices);
48
49 } } // namespace
faiss::Index::idx_t
long idx_t
all indices are this type
Definition: Index.h:64
faiss::MetricType
MetricType
Some algorithms support both an inner product version and a L2 search version.
Definition: Index.h:45