/
hnsw.cc
932 lines (850 loc) · 33.7 KB
/
hnsw.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
// Copyright 2017 Kakao Corp. <http://www.kakaocorp.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <algorithm>
#include <chrono>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <queue>
#include <stdexcept>
#include <string>
#include <unordered_set>
#include <vector>
#include <thread>
#include "n2/hnsw.h"
#include "n2/hnsw_node.h"
#include "n2/distance.h"
#include "n2/min_heap.h"
#define MERGE_BUFFER_ALGO_SWITCH_THRESHOLD 100
namespace n2 {
using std::endl;
using std::fstream;
using std::max;
using std::min;
using std::mutex;
using std::ofstream;
using std::ifstream;
using std::pair;
using std::priority_queue;
using std::setprecision;
using std::string;
using std::stof;
using std::stoi;
using std::to_string;
using std::unique_lock;
using std::unordered_set;
using std::vector;
thread_local VisitedList* visited_list_ = nullptr;
Hnsw::Hnsw() {
logger_ = spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
metric_ = DistanceKind::ANGULAR;
dist_cls_ = new AngularDistance();
}
Hnsw::Hnsw(int dim, string metric) : data_dim_(dim) {
logger_ = spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
if(metric == "L2") {
metric_ = DistanceKind::L2;
dist_cls_ = new L2Distance();
} else if (metric == "angular") {
metric_ = DistanceKind::ANGULAR;
dist_cls_ = new AngularDistance();
} else {
throw std::runtime_error("[Error] Invalid configuration value for DistanceMethod: " + metric);
}
}
Hnsw::Hnsw(const Hnsw& other) {
logger_= spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
model_byte_size_ = other.model_byte_size_;
model_ = new char[model_byte_size_];
std::copy(other.model_, other.model_ + model_byte_size_, model_);
SetValuesFromModel(model_);
search_list_.reset(new VisitedList(num_nodes_));
if(metric_ == DistanceKind::ANGULAR) {
dist_cls_ = new AngularDistance();
} else if (metric_ == DistanceKind::L2) {
dist_cls_ = new L2Distance();
}
}
Hnsw::Hnsw(Hnsw& other) {
logger_= spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
model_byte_size_ = other.model_byte_size_;
model_ = new char[model_byte_size_];
std::copy(other.model_, other.model_ + model_byte_size_, model_);
SetValuesFromModel(model_);
search_list_.reset(new VisitedList(num_nodes_));
if(metric_ == DistanceKind::ANGULAR) {
dist_cls_ = new AngularDistance();
} else if (metric_ == DistanceKind::L2) {
dist_cls_ = new L2Distance();
}
}
Hnsw::Hnsw(Hnsw&& other) {
logger_= spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
model_byte_size_ = other.model_byte_size_;
model_ = other.model_;
other.model_ = nullptr;
model_mmap_ = other.model_mmap_;
other.model_mmap_ = nullptr;
SetValuesFromModel(model_);
search_list_.reset(new VisitedList(num_nodes_));
if(metric_ == DistanceKind::ANGULAR) {
dist_cls_ = new AngularDistance();
} else if (metric_ == DistanceKind::L2) {
dist_cls_ = new L2Distance();
}
}
Hnsw& Hnsw::operator=(const Hnsw& other) {
logger_= spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
if(model_) {
delete [] model_;
model_ = nullptr;
}
if(dist_cls_) {
delete dist_cls_;
dist_cls_ = nullptr;
}
model_byte_size_ = other.model_byte_size_;
model_ = new char[model_byte_size_];
std::copy(other.model_, other.model_ + model_byte_size_, model_);
SetValuesFromModel(model_);
search_list_.reset(new VisitedList(num_nodes_));
if(metric_ == DistanceKind::ANGULAR) {
dist_cls_ = new AngularDistance();
} else if (metric_ == DistanceKind::L2) {
dist_cls_ = new L2Distance();
}
return *this;
}
Hnsw& Hnsw::operator=(Hnsw&& other) {
logger_= spdlog::get("n2");
if (logger_ == nullptr) {
logger_ = spdlog::stdout_logger_mt("n2");
}
if(model_mmap_) {
delete model_mmap_;
model_mmap_ = nullptr;
} else {
delete [] model_;
model_ = nullptr;
}
if(dist_cls_) {
delete dist_cls_;
dist_cls_ = nullptr;
}
model_byte_size_ = other.model_byte_size_;
model_ = other.model_;
other.model_ = nullptr;
model_mmap_ = other.model_mmap_;
other.model_mmap_ = nullptr;
SetValuesFromModel(model_);
search_list_.reset(new VisitedList(num_nodes_));
if(metric_ == DistanceKind::ANGULAR) {
dist_cls_ = new AngularDistance();
} else if (metric_ == DistanceKind::L2) {
dist_cls_ = new L2Distance();
}
return *this;
}
Hnsw::~Hnsw() {
if (model_mmap_) {
delete model_mmap_;
} else {
if (model_)
delete[] model_;
}
for (size_t i = 0; i < nodes_.size(); ++i) {
delete nodes_[i];
}
if (default_rng_) {
delete default_rng_;
}
if (dist_cls_) {
delete dist_cls_;
}
if (selecting_policy_cls_) {
delete selecting_policy_cls_;
}
if (post_policy_cls_) {
delete post_policy_cls_;
}
}
void Hnsw::SetConfigs(const vector<pair<string, string> >& configs) {
bool is_levelmult_set = false;
for (const auto& c : configs) {
if (c.first == "M") {
MaxM_ = M_ = (size_t)stoi(c.second);
} else if (c.first == "MaxM0") {
MaxM0_ = (size_t)stoi(c.second);
} else if (c.first == "efConstruction") {
efConstruction_ = (size_t)stoi(c.second);
} else if (c.first == "NumThread") {
num_threads_ = stoi(c.second);
} else if (c.first == "Mult") {
levelmult_ = stof(c.second);
is_levelmult_set = true;
} else if (c.first == "NeighborSelecting") {
if(selecting_policy_cls_) delete selecting_policy_cls_;
if (c.second == "heuristic") {
selecting_policy_cls_ = new HeuristicNeighborSelectingPolicies(false);
is_naive_ = false;
} else if (c.second == "heuristic_save_remains") {
selecting_policy_cls_ = new HeuristicNeighborSelectingPolicies(true);
is_naive_ = false;
} else if (c.second == "naive") {
selecting_policy_cls_ = new NaiveNeighborSelectingPolicies();
is_naive_ = true;
} else {
throw std::runtime_error("[Error] Invalid configuration value for NeighborSelecting: " + c.second);
}
} else if (c.first == "GraphMerging") {
if (c.second == "skip") {
post_ = GraphPostProcessing::SKIP;
} else if (c.second == "merge_level0") {
post_ = GraphPostProcessing::MERGE_LEVEL0;
} else {
throw std::runtime_error("[Error] Invalid configuration value for GraphMerging: " + c.second);
}
} else if (c.first == "EnsureK") {
if (c.second == "true") {
ensure_k_ = true;
} else {
ensure_k_ = false;
}
} else {
throw std::runtime_error("[Error] Invalid configuration key: " + c.first);
}
}
if (!is_levelmult_set) {
levelmult_ = 1 / log(1.0*M_);
}
}
int Hnsw::DrawLevel(bool use_default_rng) {
if (use_default_rng) {
return (int)(-log(uniform_distribution_(*default_rng_)) * levelmult_);
} else {
double r = uniform_distribution_(rng_);
if (r < std::numeric_limits<double>::epsilon())
r = 1.0;
return (int)(-log(r) * levelmult_);
}
}
void Hnsw::Build(int M, int MaxM0, int ef_construction, int n_threads, float mult, NeighborSelectingPolicy neighbor_selecting, GraphPostProcessing graph_merging, bool ensure_k) {
bool is_levelmult_set = false;
if ( M > 0 ) MaxM_ = M_ = M;
if ( MaxM0 > 0 ) MaxM0_ = MaxM0;
if ( efConstruction_ > 0 ) efConstruction_ = ef_construction;
if ( n_threads > 0 ) num_threads_ = n_threads;
levelmult_ = mult > 0 ? mult : 1 / log(1.0*M_);
if (selecting_policy_cls_) delete selecting_policy_cls_;
if (neighbor_selecting == NeighborSelectingPolicy::HEURISTIC) {
selecting_policy_cls_ = new HeuristicNeighborSelectingPolicies(false);
is_naive_ = false;
} else if (neighbor_selecting == NeighborSelectingPolicy::HEURISTIC_SAVE_REMAINS) {
selecting_policy_cls_ = new HeuristicNeighborSelectingPolicies(true);
is_naive_ = false;
} else if (neighbor_selecting == NeighborSelectingPolicy::NAIVE) {
selecting_policy_cls_ = new NaiveNeighborSelectingPolicies();
is_naive_ = true;
}
post_ = graph_merging;
ensure_k_ = ensure_k;
Fit();
}
void Hnsw::Fit() {
if (data_.size() == 0) throw std::runtime_error("[Error] No data to fit. Load data first.");
if (default_rng_ == nullptr)
default_rng_ = new std::default_random_engine(100);
rng_.seed(rng_seed_);
BuildGraph(false);
if (post_ == GraphPostProcessing::MERGE_LEVEL0) {
vector<HnswNode*> nodes_backup;
nodes_backup.swap(nodes_);
BuildGraph(true);
MergeEdgesOfTwoGraphs(nodes_backup);
for (size_t i = 0; i < nodes_backup.size(); ++i) {
delete nodes_backup[i];
}
nodes_backup.clear();
}
long long totalLevel = 0;
for(size_t i = 0; i < nodes_.size(); ++i) {
totalLevel += nodes_[i]->GetLevel();
}
enterpoint_id_ = enterpoint_->GetId();
num_nodes_ = nodes_.size();
long long model_config_size = GetModelConfigSize();
memory_per_node_higher_level_ = sizeof(int) * (1 + MaxM_); // "1" for saving num_links
long long higher_level_size = memory_per_node_higher_level_ * totalLevel;
memory_per_data_ = sizeof(float) * data_dim_;
memory_per_link_level0_ = sizeof(int) * (1 + 1 + MaxM0_); // "1" for offset pos, 1" for saving num_links
memory_per_node_level0_ = memory_per_link_level0_ + memory_per_data_;
long long level0_size = memory_per_node_level0_ * data_.size();
model_byte_size_ = model_config_size + level0_size + higher_level_size;
model_ = new char[model_byte_size_];
if (model_ == NULL) {
throw std::runtime_error("[Error] Fail to allocate memory for optimised index (size: "
+ to_string(model_byte_size_ / (1024 * 1024)) + " MBytes)");
}
memset(model_, 0, model_byte_size_);
model_level0_ = model_ + model_config_size;
model_higher_level_ = model_level0_ + level0_size;
SaveModelConfig(model_);
int higher_offset = 0;
for (size_t i = 0; i < nodes_.size(); ++i) {
int level = nodes_[i]->GetLevel();
if(level > 0) {
nodes_[i]->CopyDataAndLevel0LinksToOptIndex(model_level0_ + i * memory_per_node_level0_, higher_offset, MaxM0_);
nodes_[i]->CopyHigherLevelLinksToOptIndex(model_higher_level_ + memory_per_node_higher_level_*higher_offset, memory_per_node_higher_level_);
higher_offset += nodes_[i]->GetLevel();
} else {
nodes_[i]->CopyDataAndLevel0LinksToOptIndex(model_level0_ + i * memory_per_node_level0_, 0, MaxM0_);
}
}
for (size_t i = 0; i < nodes_.size(); ++i) {
delete nodes_[i];
}
nodes_.clear();
data_.clear();
}
void Hnsw::BuildGraph(bool reverse) {
nodes_.resize(data_.size());
int level = DrawLevel(use_default_rng_);
HnswNode* first = new HnswNode(0, &(data_[0]), level, MaxM_, MaxM0_);
nodes_[0] = first;
maxlevel_ = level;
enterpoint_ = first;
if (reverse) {
#pragma omp parallel num_threads(num_threads_)
{
visited_list_ = new VisitedList(data_.size());
#pragma omp for schedule(dynamic,128)
for (size_t i = data_.size() - 1; i >= 1; --i) {
level = DrawLevel(use_default_rng_);
HnswNode* qnode = new HnswNode(i, &data_[i], level, MaxM_, MaxM0_);
nodes_[i] = qnode;
Insert(qnode);
}
delete visited_list_;
visited_list_ = nullptr;
}
} else {
#pragma omp parallel num_threads(num_threads_)
{
visited_list_ = new VisitedList(data_.size());
#pragma omp for schedule(dynamic,128)
for (size_t i = 1; i < data_.size(); ++i) {
level = DrawLevel(use_default_rng_);
HnswNode* qnode = new HnswNode(i, &data_[i], level, MaxM_, MaxM0_);
nodes_[i] = qnode;
Insert(qnode);
}
delete visited_list_;
visited_list_ = nullptr;
}
}
search_list_.reset(new VisitedList(data_.size()));
}
bool Hnsw::SaveModel(const string& fname) const {
ofstream b_stream(fname.c_str(), fstream::out|fstream::binary);
if (b_stream) {
b_stream.write(model_, model_byte_size_);
return (b_stream.good());
} else {
throw std::runtime_error("[Error] Failed to save model to file: " + fname);
}
return false;
}
bool Hnsw::LoadModel(const string& fname, const bool use_mmap) {
if(!use_mmap) {
ifstream in;
in.open(fname, fstream::in|fstream::binary|fstream::ate);
if(in.is_open()) {
size_t size = in.tellg();
in.seekg(0, fstream::beg);
model_ = new char[size];
model_byte_size_ = size;
in.read(model_, size);
in.close();
} else {
throw std::runtime_error("[Error] Failed to load model to file: " + fname+ " not found!");
}
} else {
model_mmap_ = new Mmap(fname.c_str());
model_byte_size_ = model_mmap_->GetFileSize();
model_ = model_mmap_->GetData();
}
char* ptr = model_;
ptr = GetValueAndIncPtr<size_t>(ptr, M_);
ptr = GetValueAndIncPtr<size_t>(ptr, MaxM_);
ptr = GetValueAndIncPtr<size_t>(ptr, MaxM0_);
ptr = GetValueAndIncPtr<size_t>(ptr, efConstruction_);
ptr = GetValueAndIncPtr<float>(ptr, levelmult_);
ptr = GetValueAndIncPtr<int>(ptr, maxlevel_);
ptr = GetValueAndIncPtr<int>(ptr, enterpoint_id_);
ptr = GetValueAndIncPtr<int>(ptr, num_nodes_);
ptr = GetValueAndIncPtr<DistanceKind>(ptr, metric_);
size_t model_data_dim = *((size_t*)(ptr));
if (data_dim_ > 0 && model_data_dim != data_dim_) {
throw std::runtime_error("[Error] index dimension(" + to_string(data_dim_)
+ ") != model dimension(" + to_string(model_data_dim) + ")");
}
ptr = GetValueAndIncPtr<size_t>(ptr, data_dim_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_data_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_link_level0_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_node_level0_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_node_higher_level_);
ptr = GetValueAndIncPtr<long long>(ptr, higher_level_offset_);
ptr = GetValueAndIncPtr<long long>(ptr, level0_offset_);
long long level0_size = memory_per_node_level0_ * num_nodes_;
long long model_config_size = GetModelConfigSize();
model_level0_ = model_ + model_config_size;
model_higher_level_ = model_level0_ + level0_size;
search_list_.reset(new VisitedList(num_nodes_));
if(dist_cls_) {
delete dist_cls_;
}
switch (metric_) {
case DistanceKind::ANGULAR:
dist_cls_ = new AngularDistance();
break;
case DistanceKind::L2:
dist_cls_ = new L2Distance();
break;
default:
throw std::runtime_error("[Error] Unknown distance metric. ");
}
return true;
}
void Hnsw::UnloadModel() {
if (model_mmap_ != nullptr) {
model_mmap_->UnMap();
delete model_mmap_;
model_mmap_ = nullptr;
model_ = nullptr;
model_higher_level_ = nullptr;
model_level0_ = nullptr;
}
search_list_.reset(nullptr);
if (visited_list_ != nullptr) {
delete visited_list_;
visited_list_ = nullptr;
}
}
void Hnsw::AddData(const std::vector<float>& data) {
if (model_ != nullptr) {
throw std::runtime_error("[Error] This index already has a trained model. Adding an item is not allowed.");
}
if (data.size() != data_dim_) {
throw std::runtime_error("[Error] Invalid dimension data inserted: " + to_string(data.size()) + ", Predefined dimension: " + to_string(data_dim_));
}
if(metric_ == DistanceKind::ANGULAR) {
vector<float> data_copy(data);
NormalizeVector(data_copy);
data_.emplace_back(data_copy);
} else {
data_.emplace_back(data);
}
}
void Hnsw::Insert(HnswNode* qnode) {
int cur_level = qnode->GetLevel();
unique_lock<mutex> *lock = nullptr;
if (cur_level > maxlevel_) lock = new unique_lock<mutex>(max_level_guard_);
int maxlevel_copy = maxlevel_;
HnswNode* enterpoint = enterpoint_;
const std::vector<float>& qvec = qnode->GetData();
const float* qraw = &qvec[0];
float PORTABLE_ALIGN32 TmpRes[8];
if (cur_level < maxlevel_copy) {
_mm_prefetch(&dist_cls_, _MM_HINT_T0);
HnswNode* cur_node = enterpoint;
float d = dist_cls_->Evaluate(qraw, (float*)&cur_node->GetData()[0], data_dim_, TmpRes);
float cur_dist = d;
for (int i = maxlevel_copy; i > cur_level; --i) {
bool changed = true;
while (changed) {
changed = false;
unique_lock<mutex> local_lock(cur_node->access_guard_);
const vector<HnswNode*>& neighbors = cur_node->GetFriends(i);
for (auto iter = neighbors.begin(); iter != neighbors.end(); ++iter) {
_mm_prefetch((char*)&((*iter)->GetData()), _MM_HINT_T0);
}
for (auto iter = neighbors.begin(); iter != neighbors.end(); ++iter) {
d = dist_cls_->Evaluate(qraw, &(*iter)->GetData()[0], data_dim_, TmpRes);
if (d < cur_dist) {
cur_dist = d;
cur_node = (*iter);
changed = true;
}
}
}
}
enterpoint = cur_node;
}
_mm_prefetch(&selecting_policy_cls_, _MM_HINT_T0);
for (int i = std::min(maxlevel_copy, cur_level); i >= 0; --i) {
priority_queue<FurtherFirst> temp_res;
SearchAtLayer(qvec, enterpoint, i, efConstruction_, temp_res);
selecting_policy_cls_->Select(M_, temp_res, data_dim_, dist_cls_);
while (temp_res.size() > 0) {
auto* top_node = temp_res.top().GetNode();
temp_res.pop();
Link(top_node, qnode, i, is_naive_, data_dim_);
Link(qnode, top_node, i, is_naive_, data_dim_);
}
}
if (cur_level > enterpoint_->GetLevel()) {
maxlevel_ = cur_level;
enterpoint_ = qnode;
}
if (lock != nullptr) delete lock;
}
void Hnsw::Link(HnswNode* source, HnswNode* target, int level, bool is_naive, size_t dim) {
std::unique_lock<std::mutex> lock(source->access_guard_);
std::vector<HnswNode*>& neighbors = source->friends_at_layer_[level];
neighbors.push_back(target);
bool shrink = (level > 0 && neighbors.size() > source->maxsize_) || (level <= 0 && neighbors.size() > source->maxsize0_);
if (!shrink) return;
float PORTABLE_ALIGN32 TmpRes[8];
if (is_naive) {
float max = dist_cls_->Evaluate((float*)&source->GetData()[0], (float*)&neighbors[0]->GetData()[0], dim, TmpRes);
int maxi = 0;
for (size_t i = 1; i < neighbors.size(); ++i) {
float curd = dist_cls_->Evaluate((float*)&source->GetData()[0], (float*)&neighbors[i]->GetData()[0], dim, TmpRes);
if (curd > max) {
max = curd;
maxi = i;
}
}
neighbors.erase(neighbors.begin() + maxi);
} else {
std::priority_queue<FurtherFirst> tempres;
for (auto iter = neighbors.begin(); iter != neighbors.end(); ++iter) {
_mm_prefetch((char*)&((*iter)->GetData()), _MM_HINT_T0);
}
for (auto iter = neighbors.begin(); iter != neighbors.end(); ++iter) {
tempres.emplace((*iter), dist_cls_->Evaluate((float*)&source->data_->GetData()[0], (float*)&(*iter)->GetData()[0], dim, TmpRes));
}
selecting_policy_cls_->Select(tempres.size() - 1, tempres, dim, dist_cls_);
neighbors.clear();
while (tempres.size()) {
neighbors.emplace_back(tempres.top().GetNode());
tempres.pop();
}
}
}
void Hnsw::MergeEdgesOfTwoGraphs(const vector<HnswNode*>& another_nodes) {
#pragma omp parallel for schedule(dynamic,128) num_threads(num_threads_)
for (size_t i = 1; i < data_.size(); ++i) {
const vector<HnswNode*>& neighbors1 = nodes_[i]->GetFriends(0);
const vector<HnswNode*>& neighbors2 = another_nodes[i]->GetFriends(0);
unordered_set<int> merged_neighbor_id_set = unordered_set<int>();
for (HnswNode* cur : neighbors1) {
merged_neighbor_id_set.insert(cur->GetId());
}
for (HnswNode* cur : neighbors2) {
merged_neighbor_id_set.insert(cur->GetId());
}
priority_queue<FurtherFirst> temp_res;
const std::vector<float>& ivec = data_[i].GetData();
float PORTABLE_ALIGN32 TmpRes[8];
for (int cur : merged_neighbor_id_set) {
temp_res.emplace(nodes_[cur], dist_cls_->Evaluate((float*)&data_[cur].GetData()[0], (float*)&ivec[0], data_dim_, TmpRes));
}
// Post Heuristic
post_policy_cls_->Select(MaxM0_, temp_res, data_dim_, dist_cls_);
vector<HnswNode*> merged_neighbors = vector<HnswNode*>();
while (!temp_res.empty()) {
merged_neighbors.emplace_back(temp_res.top().GetNode());
temp_res.pop();
}
nodes_[i]->SetFriends(0, merged_neighbors);
}
}
void Hnsw::NormalizeVector(std::vector<float>& vec) {
float sum = std::inner_product(vec.begin(), vec.end(), vec.begin(), 0.0);
if (sum != 0.0) {
sum = 1 / sqrt(sum);
std::transform(vec.begin(), vec.end(), vec.begin(), std::bind1st(std::multiplies<float>(), sum));
}
}
void Hnsw::SearchById_(int cur_node_id, float cur_dist, const float* qraw, size_t k, size_t ef_search, vector<pair<int, float> >& result) {
MinHeap<float, int> dh;
dh.push(cur_dist, cur_node_id);
float PORTABLE_ALIGN32 TmpRes[8];
typedef typename MinHeap<float, int>::Item QueueItem;
std::queue<QueueItem> q;
search_list_->Reset();
unsigned int mark = search_list_->GetVisitMark();
unsigned int* visited = search_list_->GetVisited();
bool need_sort = false;
if (ensure_k_) {
if (!result.empty()) need_sort = true;
for (size_t i = 0; i < result.size(); ++i)
visited[result[i].first] = mark;
if (visited[cur_node_id] == mark) return;
}
visited[cur_node_id] = mark;
std::priority_queue<pair<float, int> > visited_nodes;
int tnum;
float d;
QueueItem e;
float maxKey = cur_dist;
size_t total_size = 1;
while (dh.size() > 0 && visited_nodes.size() < (ef_search >> 1)) {
e = dh.top();
dh.pop();
cur_node_id = e.data;
visited_nodes.emplace(e.key, e.data);
float topKey = maxKey;
int *data = (int*)(model_level0_ + cur_node_id*memory_per_node_level0_ + sizeof(int));
int size = *data;
for (int j = 1; j <= size; ++j) {
tnum = *(data + j);
_mm_prefetch(dist_cls_, _MM_HINT_T0);
if (visited[tnum] != mark) {
visited[tnum] = mark;
d = dist_cls_->Evaluate(qraw, (float*)(model_level0_ + tnum*memory_per_node_level0_ + memory_per_link_level0_), data_dim_, TmpRes);
if (d < topKey || total_size < ef_search) {
q.emplace(QueueItem(d, tnum));
++total_size;
}
}
}
while(!q.empty()) {
dh.push(q.front().key, q.front().data);
if (q.front().key > maxKey) maxKey = q.front().key;
q.pop();
}
}
vector<pair<float, int> > res_t;
while(dh.size() && res_t.size() < k) {
res_t.emplace_back(dh.top().key, dh.top().data);
dh.pop();
}
while (visited_nodes.size() > k) visited_nodes.pop();
while (!visited_nodes.empty()) {
res_t.emplace_back(visited_nodes.top());
visited_nodes.pop();
}
_mm_prefetch(&res_t[0], _MM_HINT_T0);
std::sort(res_t.begin(), res_t.end());
size_t sz;
if (ensure_k_) {
sz = min(k - result.size(), res_t.size());
} else {
sz = min(k, res_t.size());
}
for(size_t i = 0; i < sz; ++i)
result.push_back(pair<int, float>(res_t[i].second, res_t[i].first));
if (ensure_k_ && need_sort) {
_mm_prefetch(&result[0], _MM_HINT_T0);
sort(result.begin(), result.end(), [](const pair<int, float>& i, const pair<int, float>& j) {
return i.second<j.second; });
}
}
bool Hnsw::SetValuesFromModel(char* model) {
if(model) {
char* ptr = model;
ptr = GetValueAndIncPtr<size_t>(ptr, M_);
ptr = GetValueAndIncPtr<size_t>(ptr, MaxM_);
ptr = GetValueAndIncPtr<size_t>(ptr, MaxM0_);
ptr = GetValueAndIncPtr<size_t>(ptr, efConstruction_);
ptr = GetValueAndIncPtr<float>(ptr, levelmult_);
ptr = GetValueAndIncPtr<int>(ptr, maxlevel_);
ptr = GetValueAndIncPtr<int>(ptr, enterpoint_id_);
ptr = GetValueAndIncPtr<int>(ptr, num_nodes_);
ptr = GetValueAndIncPtr<DistanceKind>(ptr, metric_);
ptr += sizeof(size_t);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_data_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_link_level0_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_node_level0_);
ptr = GetValueAndIncPtr<long long>(ptr, memory_per_node_higher_level_);
ptr = GetValueAndIncPtr<long long>(ptr, higher_level_offset_);
ptr = GetValueAndIncPtr<long long>(ptr, level0_offset_);
long long level0_size = memory_per_node_level0_ * num_nodes_;
long long model_config_size = GetModelConfigSize();
model_level0_ = model_ + model_config_size;
model_higher_level_ = model_level0_ + level0_size;
return true;
}
return false;
}
void Hnsw::SearchByVector(const vector<float>& qvec, size_t k, size_t ef_search, vector<pair<int, float>>& result) {
if (model_ == nullptr) throw std::runtime_error("[Error] Model has not loaded!");
float PORTABLE_ALIGN32 TmpRes[8];
const float* qraw = nullptr;
if (ef_search < 0) {
ef_search = 50 * k;
}
vector<float> qvec_copy(qvec);
if(metric_ == DistanceKind::ANGULAR) {
NormalizeVector(qvec_copy);
}
qraw = &qvec_copy[0];
_mm_prefetch(&dist_cls_, _MM_HINT_T0);
int maxlevel = maxlevel_;
int cur_node_id = enterpoint_id_;
float cur_dist = dist_cls_->Evaluate(qraw, (float *)(model_level0_ + cur_node_id*memory_per_node_level0_ + memory_per_link_level0_), data_dim_, TmpRes);
float d;
vector<pair<int, float> > path;
if (ensure_k_) path.emplace_back(cur_node_id, cur_dist);
bool changed;
for (int i = maxlevel; i > 0; --i) {
changed = true;
while (changed) {
changed = false;
char* level_offset = model_level0_ + cur_node_id*memory_per_node_level0_;
int offset = *((int*)(level_offset));
char* level_base_offset = model_higher_level_ + offset * memory_per_node_higher_level_;
int *data = (int*)(level_base_offset + (i-1) * memory_per_node_higher_level_);
int size = *data;
for (int j = 1; j <= size; ++j) {
int tnum = *(data + j);
d = (dist_cls_->Evaluate(qraw, (float *)(model_level0_ + tnum*memory_per_node_level0_ + memory_per_link_level0_), data_dim_, TmpRes));
if (d < cur_dist) {
cur_dist = d;
cur_node_id = tnum;
offset = *((int*)(model_level0_ + cur_node_id*memory_per_node_level0_));
changed = true;
if (ensure_k_) path.emplace_back(cur_node_id, cur_dist);
}
}
}
}
if (ensure_k_) {
while (result.size() < k && !path.empty()) {
cur_node_id = path.back().first;
cur_dist = path.back().second;
path.pop_back();
SearchById_(cur_node_id, cur_dist, qraw, k, ef_search, result);
}
} else {
SearchById_(cur_node_id, cur_dist, qraw, k, ef_search, result);
}
}
void Hnsw::SearchById(int id, size_t k, size_t ef_search, vector<pair<int, float> >& result) {
if (ef_search < 0) {
ef_search = 50 * k;
}
SearchById_(id, 0.0, (const float*)(model_level0_ + id * memory_per_node_level0_ + memory_per_link_level0_), k, ef_search, result);
}
void Hnsw::SearchAtLayer(const std::vector<float>& qvec, HnswNode* enterpoint, int level, size_t ef, priority_queue<FurtherFirst>& result) {
// TODO: check Node 12bytes => 8bytes
_mm_prefetch(&dist_cls_, _MM_HINT_T0);
float PORTABLE_ALIGN32 TmpRes[8];
const float* qraw = &qvec[0];
priority_queue<CloserFirst> candidates;
float d = dist_cls_->Evaluate(qraw, (float*)&(enterpoint->GetData()[0]), data_dim_, TmpRes);
result.emplace(enterpoint, d);
candidates.emplace(enterpoint, d);
visited_list_->Reset();
unsigned int mark = visited_list_->GetVisitMark();
unsigned int* visited = visited_list_->GetVisited();
visited[enterpoint->GetId()] = mark;
while(!candidates.empty()) {
const CloserFirst& cand = candidates.top();
float lowerbound = result.top().GetDistance();
if (cand.GetDistance() > lowerbound) break;
HnswNode* cand_node = cand.GetNode();
unique_lock<mutex> lock(cand_node->access_guard_);
const vector<HnswNode*>& neighbors = cand_node->GetFriends(level);
candidates.pop();
for (size_t j = 0; j < neighbors.size(); ++j) {
_mm_prefetch((char*)&(neighbors[j]->GetData()), _MM_HINT_T0);
}
for (size_t j = 0; j < neighbors.size(); ++j) {
int fid = neighbors[j]->GetId();
if (visited[fid] != mark) {
_mm_prefetch((char*)&(neighbors[j]->GetData()), _MM_HINT_T0);
visited[fid] = mark;
d = dist_cls_->Evaluate(qraw, (float*)&neighbors[j]->GetData()[0], data_dim_, TmpRes);
if (result.size() < ef || result.top().GetDistance() > d) {
result.emplace(neighbors[j], d);
candidates.emplace(neighbors[j], d);
if (result.size() > ef) result.pop();
}
}
}
}
}
size_t Hnsw::GetModelConfigSize() const {
size_t ret = 0;
ret += sizeof(M_);
ret += sizeof(MaxM_);
ret += sizeof(MaxM0_);
ret += sizeof(efConstruction_);
ret += sizeof(levelmult_);
ret += sizeof(maxlevel_);
ret += sizeof(enterpoint_id_);
ret += sizeof(num_nodes_);
ret += sizeof(data_dim_);
ret += sizeof(memory_per_data_);
ret += sizeof(memory_per_link_level0_);
ret += sizeof(memory_per_node_level0_);
ret += sizeof(memory_per_node_higher_level_);
ret += sizeof(higher_level_offset_);
ret += sizeof(level0_offset_);
return ret;
}
void Hnsw::SaveModelConfig(char* ptr) {
ptr = SetValueAndIncPtr<size_t>(ptr, M_);
ptr = SetValueAndIncPtr<size_t>(ptr, MaxM_);
ptr = SetValueAndIncPtr<size_t>(ptr, MaxM0_);
ptr = SetValueAndIncPtr<size_t>(ptr, efConstruction_);
ptr = SetValueAndIncPtr<float>(ptr, levelmult_);
ptr = SetValueAndIncPtr<int>(ptr, maxlevel_);
ptr = SetValueAndIncPtr<int>(ptr, enterpoint_id_);
ptr = SetValueAndIncPtr<int>(ptr, num_nodes_);
ptr = SetValueAndIncPtr<DistanceKind>(ptr, metric_);
ptr = SetValueAndIncPtr<size_t>(ptr, data_dim_);
ptr = SetValueAndIncPtr<long long>(ptr, memory_per_data_);
ptr = SetValueAndIncPtr<long long>(ptr, memory_per_link_level0_);
ptr = SetValueAndIncPtr<long long>(ptr, memory_per_node_level0_);
ptr = SetValueAndIncPtr<long long>(ptr, memory_per_node_higher_level_);
ptr = SetValueAndIncPtr<long long>(ptr, higher_level_offset_);
ptr = SetValueAndIncPtr<long long>(ptr, level0_offset_);
}
void Hnsw::PrintConfigs() const {
logger_->info("HNSW configurations & status: M({}), MaxM({}), MaxM0({}), efCon({}), levelmult({}), maxlevel({}), #nodes({}), dimension of data({}), memory per data({}), memory per link level0({}), memory per node level0({}), memory per node higher level({}), higher level offset({}), level0 offset({})", M_, MaxM_, MaxM0_, efConstruction_, levelmult_, maxlevel_, num_nodes_, data_dim_, memory_per_data_, memory_per_link_level0_, memory_per_node_level0_, memory_per_node_higher_level_, higher_level_offset_, level0_offset_);
}
void Hnsw::PrintDegreeDist() const {
logger_->info("* Degree distribution");
vector<int> degrees(MaxM0_ + 2, 0);
for (size_t i = 0; i < nodes_.size(); ++i) {
degrees[nodes_[i]->GetFriends(0).size()]++;
}
for (size_t i = 0; i < degrees.size(); ++i) {
logger_->info("degree: {}, count: {}", i, degrees[i]);
}
}
} // namespace n2