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GpuIndexFlat.h
1 /**
2 * Copyright (c) 2015-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under the CC-by-NC license found in the
6 * LICENSE file in the root directory of this source tree.
7 */
8
9 // Copyright 2004-present Facebook. All Rights Reserved.
10
11 #pragma once
12
13 #include "GpuIndex.h"
14
15 namespace faiss {
16
17 struct IndexFlat;
18 struct IndexFlatL2;
19 struct IndexFlatIP;
20
21 }
22
23 namespace faiss { namespace gpu {
24
25 struct FlatIndex;
26
27 struct GpuIndexFlatConfig : public GpuIndexConfig {
28 inline GpuIndexFlatConfig()
29 : useFloat16(false),
30 useFloat16Accumulator(false),
31 storeTransposed(false) {
32 }
33
34 /// Whether or not data is stored as float16
35 bool useFloat16;
36
37 /// Whether or not all math is performed in float16, if useFloat16 is
38 /// specified. If true, we use cublasHgemm, supported only on CC
39 /// 5.3+. Otherwise, we use cublasSgemmEx.
40 bool useFloat16Accumulator;
41
42 /// Whether or not data is stored (transparently) in a transposed
43 /// layout, enabling use of the NN GEMM call, which is ~10% faster.
44 /// This will improve the speed of the flat index, but will
45 /// substantially slow down any add() calls made, as all data must
46 /// be transposed, and will increase storage requirements (we store
47 /// data in both transposed and non-transposed layouts).
48 bool storeTransposed;
49 };
50
51 /// Wrapper around the GPU implementation that looks like
52 /// faiss::IndexFlat; copies over centroid data from a given
53 /// faiss::IndexFlat
54 class GpuIndexFlat : public GpuIndex {
55 public:
56 /// Construct from a pre-existing faiss::IndexFlat instance, copying
57 /// data over to the given GPU
58 GpuIndexFlat(GpuResources* resources,
59 const faiss::IndexFlat* index,
60 GpuIndexFlatConfig config = GpuIndexFlatConfig());
61
62 /// Construct an empty instance that can be added to
63 GpuIndexFlat(GpuResources* resources,
64 int dims,
65 faiss::MetricType metric,
66 GpuIndexFlatConfig config = GpuIndexFlatConfig());
67
68 ~GpuIndexFlat() override;
69
70 /// Set the minimum data size for searches (in MiB) for which we use
71 /// CPU -> GPU paging
72 void setMinPagingSize(size_t size);
73
74 /// Returns the current minimum data size for paged searches
75 size_t getMinPagingSize() const;
76
77 /// Initialize ourselves from the given CPU index; will overwrite
78 /// all data in ourselves
79 void copyFrom(const faiss::IndexFlat* index);
80
81 /// Copy ourselves to the given CPU index; will overwrite all data
82 /// in the index instance
83 void copyTo(faiss::IndexFlat* index) const;
84
85 /// Returns the number of vectors we contain
86 size_t getNumVecs() const;
87
88 /// Clears all vectors from this index
89 void reset() override;
90
91 /// This index is not trained, so this does nothing
92 void train(Index::idx_t n, const float* x) override;
93
94 /// Overrides to avoid excessive copies
95 void add(faiss::Index::idx_t, const float* x) override;
96
97 /// `x`, `distances` and `labels` can be resident on the CPU or any
98 /// GPU; copies are performed as needed
99 /// We have our own implementation here which handles CPU async
100 /// copies; searchImpl_ is not called
101 /// FIXME: move paged impl into GpuIndex
102 void search(
103 faiss::Index::idx_t n,
104 const float* x,
105 faiss::Index::idx_t k,
106 float* distances,
107 faiss::Index::idx_t* labels) const override;
108
109 /// Reconstruction methods; prefer the batch reconstruct as it will
110 /// be more efficient
111 void reconstruct(faiss::Index::idx_t key, float* out) const override;
112
113 /// Batch reconstruction method
114 void reconstruct_n(
115 faiss::Index::idx_t i0,
116 faiss::Index::idx_t num,
117 float* out) const override;
118
119 /// For internal access
120 inline FlatIndex* getGpuData() { return data_; }
121
122 protected:
123 /// Called from GpuIndex for add
124 void addImpl_(
125 faiss::Index::idx_t n,
126 const float* x,
127 const faiss::Index::idx_t* ids) override;
128
129 /// Should not be called (we have our own implementation)
130 void searchImpl_(
131 faiss::Index::idx_t n,
132 const float* x,
133 faiss::Index::idx_t k,
134 float* distances,
135 faiss::Index::idx_t* labels) const override;
136
137 /// Called from search when the input data is on the CPU;
138 /// potentially allows for pinned memory usage
139 void searchFromCpuPaged_(int n,
140 const float* x,
141 int k,
142 float* outDistancesData,
143 int* outIndicesData) const;
144
145 void searchNonPaged_(int n,
146 const float* x,
147 int k,
148 float* outDistancesData,
149 int* outIndicesData) const;
150
151 private:
152 /// Checks user settings for consistency
153 void verifySettings_() const;
154
155 protected:
156 /// Our config object
157 const GpuIndexFlatConfig config_;
158
159 /// Size above which we page copies from the CPU to GPU
160 size_t minPagedSize_;
161
162 /// Holds our GPU data containing the list of vectors
163 FlatIndex* data_;
164 };
165
166 /// Wrapper around the GPU implementation that looks like
167 /// faiss::IndexFlatL2; copies over centroid data from a given
168 /// faiss::IndexFlat
169 class GpuIndexFlatL2 : public GpuIndexFlat {
170 public:
171 /// Construct from a pre-existing faiss::IndexFlatL2 instance, copying
172 /// data over to the given GPU
173 GpuIndexFlatL2(GpuResources* resources,
174 faiss::IndexFlatL2* index,
175 GpuIndexFlatConfig config = GpuIndexFlatConfig());
176
177 /// Construct an empty instance that can be added to
178 GpuIndexFlatL2(GpuResources* resources,
179 int dims,
180 GpuIndexFlatConfig config = GpuIndexFlatConfig());
181
182 /// Initialize ourselves from the given CPU index; will overwrite
183 /// all data in ourselves
184 void copyFrom(faiss::IndexFlatL2* index);
185
186 /// Copy ourselves to the given CPU index; will overwrite all data
187 /// in the index instance
188 void copyTo(faiss::IndexFlatL2* index);
189 };
190
191 /// Wrapper around the GPU implementation that looks like
192 /// faiss::IndexFlatIP; copies over centroid data from a given
193 /// faiss::IndexFlat
194 class GpuIndexFlatIP : public GpuIndexFlat {
195 public:
196 /// Construct from a pre-existing faiss::IndexFlatIP instance, copying
197 /// data over to the given GPU
198 GpuIndexFlatIP(GpuResources* resources,
199 faiss::IndexFlatIP* index,
200 GpuIndexFlatConfig config = GpuIndexFlatConfig());
201
202 /// Construct an empty instance that can be added to
203 GpuIndexFlatIP(GpuResources* resources,
204 int dims,
205 GpuIndexFlatConfig config = GpuIndexFlatConfig());
206
207 /// Initialize ourselves from the given CPU index; will overwrite
208 /// all data in ourselves
209 void copyFrom(faiss::IndexFlatIP* index);
210
211 /// Copy ourselves to the given CPU index; will overwrite all data
212 /// in the index instance
213 void copyTo(faiss::IndexFlatIP* index);
214 };
215
216 } } // namespace
faiss::IndexFlat
Definition: IndexFlat.h:23
faiss::gpu::GpuIndexFlatConfig::useFloat16Accumulator
bool useFloat16Accumulator
Definition: GpuIndexFlat.h:40
faiss::gpu::GpuIndexFlatConfig::storeTransposed
bool storeTransposed
Definition: GpuIndexFlat.h:48
faiss::gpu::GpuIndexFlatL2::copyFrom
void copyFrom(faiss::IndexFlatL2 *index)
Definition: GpuIndexFlat.cu:562
faiss::gpu::GpuIndexFlat::copyTo
void copyTo(faiss::IndexFlat *index) const
Definition: GpuIndexFlat.cu:120
faiss::gpu::GpuIndexFlat::reconstruct_n
void reconstruct_n(faiss::Index::idx_t i0, faiss::Index::idx_t num, float *out) const override
Batch reconstruction method.
Definition: GpuIndexFlat.cu:508
faiss::gpu::GpuIndexFlat::getMinPagingSize
size_t getMinPagingSize() const
Returns the current minimum data size for paged searches.
Definition: GpuIndexFlat.cu:82
faiss::gpu::FlatIndex
Holder of GPU resources for a particular flat index.
Definition: FlatIndex.cuh:23
faiss::gpu::GpuIndexFlat::getGpuData
FlatIndex * getGpuData()
For internal access.
Definition: GpuIndexFlat.h:120
faiss::gpu::GpuIndexFlatL2::copyTo
void copyTo(faiss::IndexFlatL2 *index)
Definition: GpuIndexFlat.cu:567
faiss::IndexFlatL2
Definition: IndexFlat.h:79
faiss::gpu::GpuIndexFlat::searchFromCpuPaged_
void searchFromCpuPaged_(int n, const float *x, int k, float *outDistancesData, int *outIndicesData) const
Definition: GpuIndexFlat.cu:319
faiss::gpu::GpuIndexFlat::addImpl_
void addImpl_(faiss::Index::idx_t n, const float *x, const faiss::Index::idx_t *ids) override
Called from GpuIndex for add.
Definition: GpuIndexFlat.cu:180
faiss::gpu::GpuIndexFlat::searchImpl_
void searchImpl_(faiss::Index::idx_t n, const float *x, faiss::Index::idx_t k, float *distances, faiss::Index::idx_t *labels) const override
Should not be called (we have our own implementation)
Definition: GpuIndexFlat.cu:288
faiss::gpu::GpuIndexFlat::getNumVecs
size_t getNumVecs() const
Returns the number of vectors we contain.
Definition: GpuIndexFlat.cu:143
faiss::gpu::GpuResources
Definition: GpuResources.h:23
faiss::gpu::GpuIndexFlat::GpuIndexFlat
GpuIndexFlat(GpuResources *resources, const faiss::IndexFlat *index, GpuIndexFlatConfig config=GpuIndexFlatConfig())
Definition: GpuIndexFlat.cu:33
faiss::IndexFlatIP
Definition: IndexFlat.h:73
faiss::gpu::GpuIndexFlat::setMinPagingSize
void setMinPagingSize(size_t size)
Definition: GpuIndexFlat.cu:77
faiss::gpu::GpuIndexFlatConfig::useFloat16
bool useFloat16
Whether or not data is stored as float16.
Definition: GpuIndexFlat.h:35
faiss::gpu::GpuIndex
Definition: GpuIndex.h:35
faiss::gpu::GpuIndexFlatL2::GpuIndexFlatL2
GpuIndexFlatL2(GpuResources *resources, faiss::IndexFlatL2 *index, GpuIndexFlatConfig config=GpuIndexFlatConfig())
Definition: GpuIndexFlat.cu:549
faiss::gpu::GpuIndexFlatConfig
Definition: GpuIndexFlat.h:27
faiss::gpu::GpuIndexFlat::reconstruct
void reconstruct(faiss::Index::idx_t key, float *out) const override
Definition: GpuIndexFlat.cu:491
faiss::gpu::GpuIndexFlatIP::copyTo
void copyTo(faiss::IndexFlatIP *index)
Definition: GpuIndexFlat.cu:593
faiss::gpu::GpuIndexFlatIP::GpuIndexFlatIP
GpuIndexFlatIP(GpuResources *resources, faiss::IndexFlatIP *index, GpuIndexFlatConfig config=GpuIndexFlatConfig())
Definition: GpuIndexFlat.cu:575
faiss::Index::idx_t
long idx_t
all indices are this type
Definition: Index.h:62
faiss::gpu::GpuIndexFlatIP
Definition: GpuIndexFlat.h:194
faiss::gpu::GpuIndexFlat::copyFrom
void copyFrom(const faiss::IndexFlat *index)
Definition: GpuIndexFlat.cu:87
faiss::gpu::GpuIndexFlat::minPagedSize_
size_t minPagedSize_
Size above which we page copies from the CPU to GPU.
Definition: GpuIndexFlat.h:160
faiss::gpu::GpuIndexFlat::config_
const GpuIndexFlatConfig config_
Our config object.
Definition: GpuIndexFlat.h:157
faiss::gpu::GpuIndexFlatL2
Definition: GpuIndexFlat.h:169
faiss::gpu::GpuIndexConfig
Definition: GpuIndex.h:20
faiss::gpu::GpuIndexFlat::add
void add(faiss::Index::idx_t, const float *x) override
Overrides to avoid excessive copies.
Definition: GpuIndexFlat.cu:162
faiss::gpu::GpuIndexFlat
Definition: GpuIndexFlat.h:54
faiss::gpu::GpuIndexFlat::reset
void reset() override
Clears all vectors from this index.
Definition: GpuIndexFlat.cu:148
faiss::gpu::GpuIndexFlatIP::copyFrom
void copyFrom(faiss::IndexFlatIP *index)
Definition: GpuIndexFlat.cu:588
faiss::gpu::GpuIndexFlat::search
void search(faiss::Index::idx_t n, const float *x, faiss::Index::idx_t k, float *distances, faiss::Index::idx_t *labels) const override
Definition: GpuIndexFlat.cu:205
faiss::gpu::GpuIndexFlat::train
void train(Index::idx_t n, const float *x) override
This index is not trained, so this does nothing.
Definition: GpuIndexFlat.cu:157
faiss::MetricType
MetricType
Some algorithms support both an inner product vetsion and a L2 search version.
Definition: Index.h:43
faiss::gpu::GpuIndexFlat::data_
FlatIndex * data_
Holds our GPU data containing the list of vectors.
Definition: GpuIndexFlat.h:163