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GpuDistance.h
1 /**
2 * Copyright (c) Facebook, Inc. and its affiliates.
3 *
4 * This source code is licensed under the MIT license found in the
5 * LICENSE file in the root directory of this source tree.
6 */
7
8
9 #pragma once
10
11 #include "../Index.h"
12
13 namespace faiss { namespace gpu {
14
15 class GpuResources;
16
17 /// A wrapper for gpu/impl/Distance.cuh to expose direct brute-force k-nearest
18 /// neighbor searches on an externally-provided region of memory (e.g., from a
19 /// pytorch tensor).
20 /// The data (vectors, queries, outDistances, outIndices) can be resident on the
21 /// GPU or the CPU, but all calculations are performed on the GPU. If the result
22 /// buffers are on the CPU, results will be copied back when done.
23 ///
24 /// All GPU computation is performed on the current CUDA device, and ordered
25 /// with respect to resources->getDefaultStreamCurrentDevice().
26 ///
27 /// For each vector in `queries`, searches all of `vectors` to find its k
28 /// nearest neighbors with respect to the given metric
29 void bruteForceKnn(GpuResources* resources,
30 faiss::MetricType metric,
31 // If vectorsRowMajor is true, this is
32 // numVectors x dims, with dims innermost; otherwise,
33 // dims x numVectors, with numVectors innermost
34 const float* vectors,
35 bool vectorsRowMajor,
36 int numVectors,
37 // If queriesRowMajor is true, this is
38 // numQueries x dims, with dims innermost; otherwise,
39 // dims x numQueries, with numQueries innermost
40 const float* queries,
41 bool queriesRowMajor,
42 int numQueries,
43 int dims,
44 int k,
45 // A region of memory size numQueries x k, with k
46 // innermost (row major)
47 float* outDistances,
48 // A region of memory size numQueries x k, with k
49 // innermost (row major)
50 faiss::Index::idx_t* outIndices);
51
52 } } // namespace
faiss::Index::idx_t
long idx_t
all indices are this type
Definition: Index.h:62
faiss::MetricType
MetricType
Some algorithms support both an inner product version and a L2 search version.
Definition: Index.h:44