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36 * \brief Tests for GROMACS tabulated normal distribution
38 * \author Erik Lindahl <erik.lindahl@gmail.com>
39 * \ingroup module_random
43 #include "gromacs/random/tabulatednormaldistribution.h"
45 #include <gtest/gtest.h>
47 #include "gromacs/random/threefry.h"
49 #include "testutils/refdata.h"
50 #include "testutils/testasserts.h"
58 TEST(TabulatedNormalDistributionTest, Output14)
60 gmx::test::TestReferenceData data;
61 gmx::test::TestReferenceChecker checker(data.rootChecker());
63 gmx::ThreeFry2x64<2> rng(123456, gmx::RandomDomain::Other);
64 gmx::TabulatedNormalDistribution<> dist(2.0, 5.0); // Use default 14-bit resolution
65 std::vector<float> result;
68 for (int i = 0; i < 10; i++)
70 result.push_back(dist(rng));
72 checker.checkSequence(result.begin(), result.end(), "TabulatedNormalDistribution14");
75 TEST(TabulatedNormalDistributionTest, Output16)
77 gmx::test::TestReferenceData data;
78 gmx::test::TestReferenceChecker checker(data.rootChecker());
80 gmx::ThreeFry2x64<2> rng(123456, gmx::RandomDomain::Other);
81 gmx::TabulatedNormalDistribution<float, 16> dist(2.0, 5.0); // Use larger 16-bit table
82 std::vector<float> result;
85 for (int i = 0; i < 10; i++)
87 result.push_back(dist(rng));
89 checker.checkSequence(result.begin(), result.end(), "TabulatedNormalDistribution16");
92 TEST(TabulatedNormalDistributionTest, OutputDouble14)
94 gmx::test::TestReferenceData data;
95 gmx::test::TestReferenceChecker checker(data.rootChecker());
97 gmx::ThreeFry2x64<2> rng(123456, gmx::RandomDomain::Other);
98 gmx::TabulatedNormalDistribution<double> dist(2.0, 5.0);
99 std::vector<double> result;
102 for (int i = 0; i < 10; i++)
104 result.push_back(dist(rng));
106 checker.checkSequence(result.begin(), result.end(), "TabulatedNormalDistributionDouble14");
109 TEST(TabulatedNormalDistributionTest, Logical)
111 gmx::ThreeFry2x64<2> rng(123456, gmx::RandomDomain::Other);
112 gmx::TabulatedNormalDistribution<> distA(2.0, 5.0);
113 gmx::TabulatedNormalDistribution<> distB(2.0, 5.0);
114 gmx::TabulatedNormalDistribution<> distC(3.0, 5.0);
115 gmx::TabulatedNormalDistribution<> distD(2.0, 4.0);
117 EXPECT_EQ(distA, distB);
118 EXPECT_NE(distA, distC);
119 EXPECT_NE(distA, distD);
123 TEST(TabulatedNormalDistributionTest, Reset)
125 gmx::ThreeFry2x64<2> rng(123456, gmx::RandomDomain::Other);
126 gmx::TabulatedNormalDistribution<> distA(2.0, 5.0);
127 gmx::TabulatedNormalDistribution<> distB(2.0, 5.0);
128 gmx::TabulatedNormalDistribution<>::result_type valA, valB;
138 EXPECT_REAL_EQ_TOL(valA, valB, gmx::test::ulpTolerance(0));
141 TEST(TabulatedNormalDistributionTest, AltParam)
143 gmx::ThreeFry2x64<2> rngA(123456, gmx::RandomDomain::Other);
144 gmx::ThreeFry2x64<2> rngB(123456, gmx::RandomDomain::Other);
145 gmx::TabulatedNormalDistribution<> distA(2.0, 5.0);
146 gmx::TabulatedNormalDistribution<> distB;
147 gmx::TabulatedNormalDistribution<>::param_type paramA(2.0, 5.0);
149 EXPECT_NE(distA(rngA), distB(rngB));
154 EXPECT_REAL_EQ_TOL(distA(rngA), distB(rngB, paramA), gmx::test::ulpTolerance(0));
157 TEST(TabulatedNormalDistributionTableTest, HasValidProperties)
159 auto table = TabulatedNormalDistribution<real>::makeTable();
161 EXPECT_EQ(table.size() % 2, 0) << "Table must have even number of entries";
163 size_t halfSize = table.size() / 2;
164 double sumOfSquares = 0.0;
165 // accept errors of a few ULP since the exact value of the summation
166 // below will depend on whether the compiler issues FMA instructions
167 auto tolerance = gmx::test::ulpTolerance(10);
168 for (size_t i = 0, iFromEnd = table.size() - 1; i < halfSize; ++i, --iFromEnd)
170 EXPECT_REAL_EQ_TOL(table.at(i), -table.at(iFromEnd), tolerance)
171 << "Table is not an odd-valued function for entries " << i << " and " << iFromEnd;
172 // Add up the squares of the table values in order of ascending
173 // magnitude (to minimize accumulation of round-off error).
174 sumOfSquares += table.at(i) * table.at(i) + table.at(iFromEnd) * table.at(iFromEnd);
177 double variance = sumOfSquares / table.size();
178 EXPECT_REAL_EQ_TOL(1.0, variance, tolerance) << "Table should have unit variance";