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TestUtils.cpp
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 // Copyright 2004-present Facebook. All Rights Reserved.
10
11 #include "../test/TestUtils.h"
12 #include "../../utils.h"
13 #include <cmath>
14 #include <gtest/gtest.h>
15 #include <set>
16 #include <sstream>
17 #include <time.h>
18 #include <unordered_map>
19
20 namespace faiss { namespace gpu {
21
22 inline float relativeError(float a, float b) {
23 return std::abs(a - b) / (0.5f * (std::abs(a) + std::abs(b)));
24 }
25
26 // This seed is also used for the faiss float_rand API; in a test it
27 // is all within a single thread, so it is ok
28 long s_seed = 1;
29
30 void newTestSeed() {
31 struct timespec t;
32 clock_gettime(CLOCK_REALTIME, &t);
33
34 setTestSeed(t.tv_nsec);
35 }
36
37 void setTestSeed(long seed) {
38 printf("testing with random seed %ld\n", seed);
39
40 srand48(seed);
41 s_seed = seed;
42 }
43
44 int randVal(int a, int b) {
45 EXPECT_GE(a, 0);
46 EXPECT_LE(a, b);
47
48 return a + (lrand48() % (b + 1 - a));
49 }
50
51 bool randBool() {
52 return randSelect<bool>({true, false});
53 }
54
55 std::vector<float> randVecs(size_t num, size_t dim) {
56 std::vector<float> v(num * dim);
57 static bool first = true;
58
59 faiss::float_rand(v.data(), v.size(), s_seed);
60 // unfortunately we generate separate sets of vectors, and don't
61 // want the same values
62 ++s_seed;
63
64 return v;
65 }
66
67 void compareIndices(faiss::Index& refIndex,
68 faiss::Index& testIndex,
69 int numQuery, int dim, int k,
70 const std::string& configMsg,
71 float maxRelativeError,
72 float pctMaxDiff1,
73 float pctMaxDiffN) {
74 auto queries = faiss::gpu::randVecs(numQuery, dim);
75
76 // Compare
77 std::vector<float> refDistance(numQuery * k, 0);
78 std::vector<faiss::Index::idx_t> refIndices(numQuery * k, -1);
79 refIndex.search(numQuery, queries.data(),
80 k, refDistance.data(), refIndices.data());
81
82 std::vector<float> testDistance(numQuery * k, 0);
83 std::vector<faiss::Index::idx_t> testIndices(numQuery * k, -1);
84 testIndex.search(numQuery, queries.data(),
85 k, testDistance.data(), testIndices.data());
86
87 faiss::gpu::compareLists(refDistance.data(),
88 refIndices.data(),
89 testDistance.data(),
90 testIndices.data(),
91 numQuery, k,
92 configMsg,
93 true, false, true,
94 maxRelativeError, pctMaxDiff1, pctMaxDiffN);
95 }
96
97 template <typename T>
98 inline T lookup(const T* p, int i, int j, int /*dim1*/, int dim2) {
99 return p[i * dim2 + j];
100 }
101
102 void compareLists(const float* refDist,
103 const faiss::Index::idx_t* refInd,
104 const float* testDist,
105 const faiss::Index::idx_t* testInd,
106 int dim1, int dim2,
107 const std::string& configMsg,
108 bool printBasicStats, bool printDiffs, bool assertOnErr,
109 float maxRelativeError,
110 float pctMaxDiff1,
111 float pctMaxDiffN) {
112
113 float maxAbsErr = 0.0f;
114 for (int i = 0; i < dim1 * dim2; ++i) {
115 maxAbsErr = std::max(maxAbsErr, std::abs(refDist[i] - testDist[i]));
116 }
117 int numResults = dim1 * dim2;
118
119 // query -> {index -> result position}
120 std::vector<std::unordered_map<faiss::Index::idx_t, int>> refIndexMap;
121
122 for (int query = 0; query < dim1; ++query) {
123 std::unordered_map<faiss::Index::idx_t, int> indices;
124
125 for (int result = 0; result < dim2; ++result) {
126 indices[lookup(refInd, query, result, dim1, dim2)] = result;
127 }
128
129 refIndexMap.emplace_back(std::move(indices));
130 }
131
132 // See how far off the indices are
133 // Keep track of the difference for each entry
134 std::vector<std::vector<int>> indexDiffs;
135
136 int diff1 = 0; // index differs by 1
137 int diffN = 0; // index differs by >1
138 int diffInf = 0; // index not found in the other
139 int nonUniqueIndices = 0;
140
141 double avgDiff = 0.0;
142 int maxDiff = 0;
143 float maxRelErr = 0.0f;
144
145 for (int query = 0; query < dim1; ++query) {
146 std::vector<int> diffs;
147 std::set<faiss::Index::idx_t> uniqueIndices;
148
149 auto& indices = refIndexMap[query];
150
151 for (int result = 0; result < dim2; ++result) {
152 auto t = lookup(testInd, query, result, dim1, dim2);
153
154 // All indices reported within a query should be unique; this is
155 // a serious error if is otherwise the case
156 bool uniqueIndex = uniqueIndices.count(t) == 0;
157 if (assertOnErr) {
158 EXPECT_TRUE(uniqueIndex) << configMsg
159 << " " << query
160 << " " << result
161 << " " << t;
162 }
163
164 if (!uniqueIndex) {
165 ++nonUniqueIndices;
166 } else {
167 uniqueIndices.insert(t);
168 }
169
170 auto it = indices.find(t);
171 if (it != indices.end()) {
172 int diff = std::abs(result - it->second);
173 diffs.push_back(diff);
174
175 if (diff == 1) {
176 ++diff1;
177 maxDiff = std::max(diff, maxDiff);
178 } else if (diff > 1) {
179 ++diffN;
180 maxDiff = std::max(diff, maxDiff);
181 }
182
183 avgDiff += (double) diff;
184 } else {
185 ++diffInf;
186 diffs.push_back(-1);
187 // don't count this for maxDiff
188 }
189
190 auto refD = lookup(refDist, query, result, dim1, dim2);
191 auto testD = lookup(testDist, query, result, dim1, dim2);
192
193 float relErr = relativeError(refD, testD);
194
195 if (assertOnErr) {
196 EXPECT_LE(relErr, maxRelativeError) << configMsg
197 << " (" << query << ", " << result
198 << ") refD: " << refD
199 << " testD: " << testD;
200 }
201
202 maxRelErr = std::max(maxRelErr, relErr);
203 }
204
205 indexDiffs.emplace_back(std::move(diffs));
206 }
207
208 if (assertOnErr) {
209 EXPECT_LE((float) (diff1 + diffN + diffInf),
210 (float) numResults * pctMaxDiff1) << configMsg;
211
212 // Don't count diffInf because that could be diff1 as far as we
213 // know
214 EXPECT_LE((float) diffN, (float) numResults * pctMaxDiffN) << configMsg;
215 }
216
217 avgDiff /= (double) numResults;
218
219 if (printBasicStats) {
220 if (!configMsg.empty()) {
221 printf("Config\n"
222 "----------------------------\n"
223 "%s\n",
224 configMsg.c_str());
225 }
226
227 printf("Result error and differences\n"
228 "----------------------------\n"
229 "max abs diff %.7f rel diff %.7f\n"
230 "idx diff avg: %.5g max: %d\n"
231 "idx diff of 1: %d (%.3f%% of queries)\n"
232 "idx diff of >1: %d (%.3f%% of queries)\n"
233 "idx diff not found: %d (%.3f%% of queries)"
234 " [typically a last element inversion]\n"
235 "non-unique indices: %d (a serious error if >0)\n",
236 maxAbsErr, maxRelErr,
237 avgDiff, maxDiff,
238 diff1, 100.0f * (float) diff1 / (float) numResults,
239 diffN, 100.0f * (float) diffN / (float) numResults,
240 diffInf, 100.0f * (float) diffInf / (float) numResults,
241 nonUniqueIndices);
242 }
243
244 if (printDiffs) {
245 printf("differences:\n");
246 printf("==================\n");
247 for (int query = 0; query < dim1; ++query) {
248 for (int result = 0; result < dim2; ++result) {
249 long refI = lookup(refInd, query, result, dim1, dim2);
250 long testI = lookup(testInd, query, result, dim1, dim2);
251
252 if (refI != testI) {
253 float refD = lookup(refDist, query, result, dim1, dim2);
254 float testD = lookup(testDist, query, result, dim1, dim2);
255
256 float maxDist = std::max(refD, testD);
257 float delta = std::abs(refD - testD);
258
259 float relErr = delta / maxDist;
260
261 if (refD == testD) {
262 printf("(%d, %d [%d]) (ref %ld tst %ld dist ==)\n",
263 query, result,
264 indexDiffs[query][result],
265 refI, testI);
266 } else {
267 printf("(%d, %d [%d]) (ref %ld tst %ld abs %.8f "
268 "rel %.8f ref %a tst %a)\n",
269 query, result,
270 indexDiffs[query][result],
271 refI, testI, delta, relErr, refD, testD);
272 }
273 }
274 }
275 }
276 }
277 }
278
279 } }
faiss::Index::idx_t
long idx_t
all indices are this type
Definition: Index.h:62
faiss::Index::search
virtual void search(idx_t n, const float *x, idx_t k, float *distances, idx_t *labels) const =0
faiss::Index
Definition: Index.h:60