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37 * Tests for Gaussian spreading
39 * \author Christian Blau <blau@kth.se>
40 * \ingroup module_math
44 #include "gromacs/math/gausstransform.h"
50 #include <gmock/gmock.h>
51 #include <gtest/gtest.h>
53 #include "gromacs/math/vec.h"
54 #include "gromacs/mdspan/extensions.h"
56 #include "testutils/testasserts.h"
57 #include "testutils/testmatchers.h"
68 TEST(GaussianOn1DLattice, sumsCloseToOne)
70 const int spreadWidth = 7;
71 const real sigma = 1.9;
72 const real shift = 0.1;
73 GaussianOn1DLattice gauss1d(spreadWidth, sigma);
74 const real amplitude = 1;
75 gauss1d.spread(amplitude, shift);
76 auto sumOverLattice = std::accumulate(std::begin(gauss1d.view()), std::end(gauss1d.view()), 0.);
78 FloatingPointTolerance tolerance(defaultFloatTolerance());
79 // The sum over the lattice should be roughly one
80 EXPECT_FLOAT_EQ_TOL(0.99993300437927246, sumOverLattice, tolerance);
83 TEST(GaussianOn1DLattice, isCorrect)
85 const int spreadWidth = 2;
86 const real sigma = 0.57;
87 const real shift = -0.2;
88 GaussianOn1DLattice gauss1d(spreadWidth, sigma);
89 const auto viewOnResult = gauss1d.view();
90 FloatingPointTolerance tolerance(defaultFloatTolerance());
91 const real amplitude = 1.0;
92 gauss1d.spread(amplitude, shift);
93 std::array<float, 2 * spreadWidth + 1> expected = { 0.0047816522419452667236328125,
94 0.2613909542560577392578125,
95 0.65811407566070556640625,
96 0.07631497085094451904296875,
97 0.000407583254855126142501831054688 };
98 EXPECT_THAT(expected, Pointwise(FloatEq(tolerance), viewOnResult));
101 TEST(GaussianOn1DLattice, complementaryAmplitudesSumToZero)
103 const int spreadWidth = 2;
104 const real sigma = 0.57;
105 const real shift = -0.2;
106 GaussianOn1DLattice gauss1d(spreadWidth, sigma);
107 const auto viewOnResult = gauss1d.view();
108 FloatingPointTolerance tolerance(defaultFloatTolerance());
109 const real amplitude = 2.0;
110 gauss1d.spread(amplitude, shift);
111 std::vector<float> sumOfComplementaryGaussians;
112 // keep a copy of the first Gaussian
113 std::copy(std::begin(viewOnResult), std::end(viewOnResult), std::back_inserter(sumOfComplementaryGaussians));
115 gauss1d.spread(-amplitude, shift);
116 // add the two spread Gaussians
117 std::transform(std::begin(viewOnResult),
118 std::end(viewOnResult),
119 std::begin(sumOfComplementaryGaussians),
120 std::begin(sumOfComplementaryGaussians),
123 std::array<float, 2 * spreadWidth + 1> expected = {};
124 EXPECT_THAT(expected, Pointwise(FloatEq(tolerance), sumOfComplementaryGaussians));
127 TEST(GaussianOn1DLattice, doesNotOverflowForLargeRange)
129 const int spreadWidth = 200;
130 const real sigma = 1;
131 const real shift = -0.5;
132 GaussianOn1DLattice gauss1d(spreadWidth, sigma);
133 const auto viewOnResult = gauss1d.view();
134 const real weightFirst = 1;
135 gauss1d.spread(weightFirst, shift);
137 for (size_t i = 0; i < 187; i++)
139 EXPECT_FLOAT_EQ(0, viewOnResult[i]);
142 std::array<float, 12> expectedResult = {
143 7.64165518045829568433117268116e-30, 4.57537550091150099862240391475e-25,
144 1.00779356059942059652096780012e-20, 8.1662360418003390174698785664e-17,
145 2.43432064870457987026952650922e-13, 2.66955679784075528004905208945e-10,
146 1.07697594842193211661651730537e-07, 1.59837418323149904608726501465e-05,
147 0.000872682663612067699432373046875, 0.01752830110490322113037109375,
148 0.12951759994029998779296875, 0.3520653247833251953125
151 for (size_t i = 188; i < 200; i++)
153 EXPECT_FLOAT_EQ(expectedResult[i - 188], viewOnResult[i]);
156 for (size_t i = 200; i < 212; i++)
158 EXPECT_FLOAT_EQ(expectedResult[211 - i], viewOnResult[i]);
161 EXPECT_FLOAT_EQ(4.69519506491195688717869977423e-35, viewOnResult[212]);
163 for (size_t i = 213; i < 2 * spreadWidth + 1; i++)
165 EXPECT_FLOAT_EQ(0, viewOnResult[i]);
169 class GaussTransformTest : public ::testing::Test
172 void isZeroWithinFloatTolerance()
174 for (const auto& x : gaussTransform_.constView())
176 EXPECT_FLOAT_EQ_TOL(0, x, tolerance_);
181 extents<dynamic_extent, dynamic_extent, dynamic_extent> latticeExtent_ = { 3, 3, 3 };
182 DVec sigma_ = { 1., 1., 1. };
184 GaussTransform3D gaussTransform_ = { latticeExtent_, { sigma_, nSigma_ } };
185 test::FloatingPointTolerance tolerance_ = test::defaultFloatTolerance();
186 const RVec latticeCenter_ = { 1, 1, 1 };
189 TEST_F(GaussTransformTest, isZeroUponConstruction)
191 isZeroWithinFloatTolerance();
194 TEST_F(GaussTransformTest, isZeroAddingZeroAmplitudeGauss)
196 gaussTransform_.add({ latticeCenter_, 0. });
197 isZeroWithinFloatTolerance();
200 TEST_F(GaussTransformTest, isZeroAfterSettingZero)
202 gaussTransform_.add({ latticeCenter_, 1. });
203 for (const auto value : gaussTransform_.constView())
207 gaussTransform_.setZero();
208 isZeroWithinFloatTolerance();
211 TEST_F(GaussTransformTest, isZeroWhenOutsideRangeinX)
213 DVec coordinateOutsideX(-nSigma_ * sigma_[XX], 0, 0);
214 gaussTransform_.add({ coordinateOutsideX.toRVec(), 1. });
215 isZeroWithinFloatTolerance();
218 TEST_F(GaussTransformTest, isZeroWhenOutsideRangeinY)
220 DVec coordinateOutsideY(0, -nSigma_ * sigma_[YY], 0);
221 gaussTransform_.add({ coordinateOutsideY.toRVec(), 1. });
222 isZeroWithinFloatTolerance();
225 TEST_F(GaussTransformTest, isZeroWhenOutsideRangeinZ)
227 RVec coordinateOutsideZ(0, 0, -nSigma_ * sigma_[ZZ]);
228 gaussTransform_.add({ coordinateOutsideZ.toRVec(), 1. });
229 isZeroWithinFloatTolerance();
232 TEST_F(GaussTransformTest, complementaryGaussAddToZero)
234 gaussTransform_.add({ latticeCenter_, -2.0 });
235 gaussTransform_.add({ latticeCenter_, 0.8 });
236 gaussTransform_.add({ latticeCenter_, 1.2 });
237 isZeroWithinFloatTolerance();
240 TEST_F(GaussTransformTest, centerGaussianInCubeHasExpectedValues)
242 gaussTransform_.add({ latticeCenter_, 1. });
243 const float center = 0.0634936392307281494140625; // center
244 const float f = 0.0385108403861522674560546875; // face
245 const float e = 0.0233580060303211212158203125; // edge
246 const float c = 0.014167346991598606109619140625; // corner
247 std::vector<float> expectedValues = { c, e, c, e, f, e, c, e, c,
249 e, f, e, f, center, f, e, f, e,
251 c, e, c, e, f, e, c, e, c };
252 // This assignment to std::vector is needed because the view() on the GaussTransform (aka basic_mdspan) does not provide size() needed by Pointwise
253 std::vector<float> gaussTransformVector;
254 gaussTransformVector.assign(gaussTransform_.constView().data(),
255 gaussTransform_.constView().data()
256 + gaussTransform_.constView().mapping().required_span_size());
257 EXPECT_THAT(expectedValues, testing::Pointwise(FloatEq(tolerance_), gaussTransformVector));
260 TEST_F(GaussTransformTest, view)
262 gaussTransform_.add({ latticeCenter_, 1. });
263 const float f = 0.0385108403861522674560546875; // face
264 const float e = 0.0233580060303211212158203125; // edge
265 const float c = 0.014167346991598606109619140625; // corner
266 std::vector<float> expectedValues = { c, e, c, e, f, e, c, e, c,
268 e, f, e, f, 0., f, e, f, e,
270 c, e, c, e, f, e, c, e, c };
272 gaussTransform_.view()[1][1][1] = 0;
273 // This assignment to std::vector is needed because the view() on the
274 // GaussTransform (aka basic_mdspan) does not provide size() that is
275 // needed by Pointwise
276 // \todo Update when mdspan functionality is extended
277 std::vector<float> gaussTransformVector;
278 gaussTransformVector.assign(
279 gaussTransform_.view().data(),
280 gaussTransform_.view().data() + gaussTransform_.view().mapping().required_span_size());
281 EXPECT_THAT(expectedValues, testing::Pointwise(FloatEq(tolerance_), gaussTransformVector));