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36 * \brief SHAKE and LINCS tests.
38 * \todo Better tests for virial are needed.
39 * \todo Tests for bigger systems to test threads synchronization,
40 * reduction, etc. on the GPU.
41 * \todo Tests for algorithms for derivatives.
42 * \todo Free-energy perturbation tests
44 * \author Artem Zhmurov <zhmurov@gmail.com>
45 * \ingroup module_mdlib
53 #include <unordered_map>
56 #include <gtest/gtest.h>
58 #include "gromacs/math/vec.h"
59 #include "gromacs/math/vectypes.h"
60 #include "gromacs/pbcutil/pbc.h"
61 #include "gromacs/utility/stringutil.h"
63 #include "testutils/test_hardware_environment.h"
64 #include "testutils/testasserts.h"
66 #include "constrtestdata.h"
67 #include "constrtestrunners.h"
69 //! Helper function to convert t_pbc into string and make test failure messages readable
70 static void PrintTo(const t_pbc& pbc, std::ostream* os)
72 *os << "PBC: " << c_pbcTypeNames[pbc.pbcType];
84 // Define the set of PBCs to run the test for
85 const std::vector<t_pbc> c_pbcs = [] {
86 std::vector<t_pbc> pbcs;
89 // Infinitely small box
90 matrix boxNone = { { 0, 0, 0 }, { 0, 0, 0 }, { 0, 0, 0 } };
91 set_pbc(&pbc, PbcType::No, boxNone);
92 pbcs.emplace_back(pbc);
95 matrix boxXyz = { { 10.0, 0.0, 0.0 }, { 0.0, 20.0, 0.0 }, { 0.0, 0.0, 15.0 } };
96 set_pbc(&pbc, PbcType::Xyz, boxXyz);
97 pbcs.emplace_back(pbc);
102 struct ConstraintsTestSystem
104 //! Human-friendly name of the system.
106 //! Number of atoms in the system.
108 //! Atom masses. Size of this vector should be equal to numAtoms.
109 std::vector<real> masses;
110 /*! \brief List of constraints, organized in triples of integers.
112 * First integer is the index of type for a constraint, second
113 * and third are the indices of constrained atoms. The types
114 * of constraints should be sequential but not necessarily
115 * start from zero (which is the way they normally are in
118 std::vector<int> constraints;
119 /*! \brief Target values for bond lengths for bonds of each type.
121 * The size of this vector should be equal to the total number of
122 * unique types in constraints vector.
124 std::vector<real> constraintsR0;
125 //! Coordinates before integration step.
127 //! Coordinates after integration step, but before constraining.
128 std::vector<RVec> xPrime;
129 //! Velocities before constraining.
132 //! Reference values for scaled virial tensor.
133 tensor virialScaledRef;
135 //! Target tolerance for SHAKE.
136 real shakeTolerance = 0.0001;
137 /*! \brief Use successive over-relaxation method for SHAKE iterations.
139 * The general formula is:
140 * x_n+1 = (1-omega)*x_n + omega*f(x_n),
141 * where omega = 1 if SOR is off and may be < 1 if SOR is on.
143 bool shakeUseSOR = false;
145 //! Number of iterations used to compute the inverse matrix.
147 //! The order for algorithm that adjusts the direction of the bond after constraints are applied.
148 int lincslincsExpansionOrder = 4;
149 //! The threshold value for the change in bond angle. When exceeded the program will issue a warning
150 real lincsWarnAngle = 30.0;
152 FloatingPointTolerance lengthTolerance = absoluteTolerance(0.0002);
153 FloatingPointTolerance comTolerance = absoluteTolerance(0.0001);
154 FloatingPointTolerance virialTolerance = absoluteTolerance(0.0001);
157 //! Helper function to convert ConstraintsTestSystem into string and make test failure messages readable
158 void PrintTo(const ConstraintsTestSystem& constraintsTestSystem, std::ostream* os)
160 *os << constraintsTestSystem.title << " - " << constraintsTestSystem.numAtoms << " atoms";
163 const std::vector<ConstraintsTestSystem> c_constraintsTestSystemList = [] {
164 std::vector<ConstraintsTestSystem> constraintsTestSystemList;
166 ConstraintsTestSystem constraintsTestSystem;
168 constraintsTestSystem.title = "one constraint (e.g. OH)";
169 constraintsTestSystem.numAtoms = 2;
171 constraintsTestSystem.masses = { 1.0, 12.0 };
172 constraintsTestSystem.constraints = { 0, 0, 1 };
173 constraintsTestSystem.constraintsR0 = { 0.1 };
175 real oneTenthOverSqrtTwo = 0.1_real / std::sqrt(2.0_real);
177 constraintsTestSystem.x = { { 0.0, oneTenthOverSqrtTwo, 0.0 }, { oneTenthOverSqrtTwo, 0.0, 0.0 } };
178 constraintsTestSystem.xPrime = { { 0.01, 0.08, 0.01 }, { 0.06, 0.01, -0.01 } };
179 constraintsTestSystem.v = { { 1.0, 2.0, 3.0 }, { 3.0, 2.0, 1.0 } };
181 tensor virialScaledRef = { { -5.58e-04, 5.58e-04, 0.00e+00 },
182 { 5.58e-04, -5.58e-04, 0.00e+00 },
183 { 0.00e+00, 0.00e+00, 0.00e+00 } };
185 memcpy(constraintsTestSystem.virialScaledRef, virialScaledRef, DIM * DIM * sizeof(real));
187 constraintsTestSystemList.emplace_back(constraintsTestSystem);
190 ConstraintsTestSystem constraintsTestSystem;
192 constraintsTestSystem.title = "two disjoint constraints";
193 constraintsTestSystem.numAtoms = 4;
194 constraintsTestSystem.masses = { 0.5, 1.0 / 3.0, 0.25, 1.0 };
195 constraintsTestSystem.constraints = { 0, 0, 1, 1, 2, 3 };
196 constraintsTestSystem.constraintsR0 = { 2.0, 1.0 };
199 constraintsTestSystem.x = { { 2.50, -3.10, 15.70 },
200 { 0.51, -3.02, 15.55 },
201 { -0.50, -3.00, 15.20 },
202 { -1.51, -2.95, 15.05 } };
204 constraintsTestSystem.xPrime = { { 2.50, -3.10, 15.70 },
205 { 0.51, -3.02, 15.55 },
206 { -0.50, -3.00, 15.20 },
207 { -1.51, -2.95, 15.05 } };
209 constraintsTestSystem.v = { { 0.0, 1.0, 0.0 }, { 1.0, 0.0, 0.0 }, { 0.0, 0.0, 1.0 }, { 0.0, 0.0, 0.0 } };
211 tensor virialScaledRef = { { 3.3e-03, -1.7e-04, 5.6e-04 },
212 { -1.7e-04, 8.9e-06, -2.8e-05 },
213 { 5.6e-04, -2.8e-05, 8.9e-05 } };
215 memcpy(constraintsTestSystem.virialScaledRef, virialScaledRef, DIM * DIM * sizeof(real));
217 constraintsTestSystemList.emplace_back(constraintsTestSystem);
220 ConstraintsTestSystem constraintsTestSystem;
222 constraintsTestSystem.title = "three atoms, connected longitudinally (e.g. CH2)";
223 constraintsTestSystem.numAtoms = 3;
224 constraintsTestSystem.masses = { 1.0, 12.0, 16.0 };
225 constraintsTestSystem.constraints = { 0, 0, 1, 1, 1, 2 };
226 constraintsTestSystem.constraintsR0 = { 0.1, 0.2 };
228 real oneTenthOverSqrtTwo = 0.1_real / std::sqrt(2.0_real);
229 real twoTenthsOverSqrtThree = 0.2_real / std::sqrt(3.0_real);
231 constraintsTestSystem.x = { { oneTenthOverSqrtTwo, oneTenthOverSqrtTwo, 0.0 },
233 { twoTenthsOverSqrtThree, twoTenthsOverSqrtThree, twoTenthsOverSqrtThree } };
235 constraintsTestSystem.xPrime = { { 0.08, 0.07, 0.01 }, { -0.02, 0.01, -0.02 }, { 0.10, 0.12, 0.11 } };
237 constraintsTestSystem.v = { { 1.0, 0.0, 0.0 }, { 0.0, 1.0, 0.0 }, { 0.0, 0.0, 1.0 } };
239 tensor virialScaledRef = { { 4.14e-03, 4.14e-03, 3.31e-03 },
240 { 4.14e-03, 4.14e-03, 3.31e-03 },
241 { 3.31e-03, 3.31e-03, 3.31e-03 } };
243 memcpy(constraintsTestSystem.virialScaledRef, virialScaledRef, DIM * DIM * sizeof(real));
245 constraintsTestSystemList.emplace_back(constraintsTestSystem);
248 ConstraintsTestSystem constraintsTestSystem;
250 constraintsTestSystem.title = "four atoms, connected longitudinally";
251 constraintsTestSystem.numAtoms = 4;
252 constraintsTestSystem.masses = { 0.5, 1.0 / 3.0, 0.25, 1.0 };
253 constraintsTestSystem.constraints = { 0, 0, 1, 1, 1, 2, 2, 2, 3 };
254 constraintsTestSystem.constraintsR0 = { 2.0, 1.0, 1.0 };
257 constraintsTestSystem.x = { { 2.50, -3.10, 15.70 },
258 { 0.51, -3.02, 15.55 },
259 { -0.50, -3.00, 15.20 },
260 { -1.51, -2.95, 15.05 } };
262 constraintsTestSystem.xPrime = { { 2.50, -3.10, 15.70 },
263 { 0.51, -3.02, 15.55 },
264 { -0.50, -3.00, 15.20 },
265 { -1.51, -2.95, 15.05 } };
267 constraintsTestSystem.v = {
268 { 0.0, 0.0, 2.0 }, { 0.0, 0.0, 3.0 }, { 0.0, 0.0, -4.0 }, { 0.0, 0.0, -1.0 }
271 tensor virialScaledRef = { { 1.15e-01, -4.20e-03, 2.12e-02 },
272 { -4.20e-03, 1.70e-04, -6.41e-04 },
273 { 2.12e-02, -6.41e-04, 5.45e-03 } };
275 memcpy(constraintsTestSystem.virialScaledRef, virialScaledRef, DIM * DIM * sizeof(real));
278 // Overriding default values since LINCS converges slowly for this system.
279 constraintsTestSystem.lincsNIter = 4;
280 constraintsTestSystem.lincslincsExpansionOrder = 8;
281 constraintsTestSystem.virialTolerance = absoluteTolerance(0.01);
283 constraintsTestSystemList.emplace_back(constraintsTestSystem);
286 ConstraintsTestSystem constraintsTestSystem;
288 constraintsTestSystem.title = "three atoms, connected to the central atom (e.g. CH3)";
289 constraintsTestSystem.numAtoms = 4;
290 constraintsTestSystem.masses = { 12.0, 1.0, 1.0, 1.0 };
291 constraintsTestSystem.constraints = { 0, 0, 1, 0, 0, 2, 0, 0, 3 };
292 constraintsTestSystem.constraintsR0 = { 0.1 };
295 constraintsTestSystem.x = {
296 { 0.00, 0.00, 0.00 }, { 0.10, 0.00, 0.00 }, { 0.00, -0.10, 0.00 }, { 0.00, 0.00, 0.10 }
299 constraintsTestSystem.xPrime = { { 0.004, 0.009, -0.010 },
300 { 0.110, -0.006, 0.003 },
301 { -0.007, -0.102, -0.007 },
302 { -0.005, 0.011, 0.102 } };
304 constraintsTestSystem.v = { { 1.0, 0.0, 0.0 }, { 1.0, 0.0, 0.0 }, { 1.0, 0.0, 0.0 }, { 1.0, 0.0, 0.0 } };
306 tensor virialScaledRef = { { 7.14e-04, 0.00e+00, 0.00e+00 },
307 { 0.00e+00, 1.08e-03, 0.00e+00 },
308 { 0.00e+00, 0.00e+00, 1.15e-03 } };
310 memcpy(constraintsTestSystem.virialScaledRef, virialScaledRef, DIM * DIM * sizeof(real));
312 constraintsTestSystemList.emplace_back(constraintsTestSystem);
315 ConstraintsTestSystem constraintsTestSystem;
317 constraintsTestSystem.title = "basic triangle (three atoms, connected to each other)";
318 constraintsTestSystem.numAtoms = 3;
319 constraintsTestSystem.masses = { 1.0, 1.0, 1.0 };
320 constraintsTestSystem.constraints = { 0, 0, 1, 2, 0, 2, 1, 1, 2 };
321 constraintsTestSystem.constraintsR0 = { 0.1, 0.1, 0.1 };
323 real oneTenthOverSqrtTwo = 0.1_real / std::sqrt(2.0_real);
325 constraintsTestSystem.x = { { oneTenthOverSqrtTwo, 0.0, 0.0 },
326 { 0.0, oneTenthOverSqrtTwo, 0.0 },
327 { 0.0, 0.0, oneTenthOverSqrtTwo } };
329 constraintsTestSystem.xPrime = { { 0.09, -0.02, 0.01 }, { -0.02, 0.10, -0.02 }, { 0.03, -0.01, 0.07 } };
331 constraintsTestSystem.v = { { 1.0, 1.0, 1.0 }, { -2.0, -2.0, -2.0 }, { 1.0, 1.0, 1.0 } };
333 tensor virialScaledRef = { { 6.00e-04, -1.61e-03, 1.01e-03 },
334 { -1.61e-03, 2.53e-03, -9.25e-04 },
335 { 1.01e-03, -9.25e-04, -8.05e-05 } };
337 memcpy(constraintsTestSystem.virialScaledRef, virialScaledRef, DIM * DIM * sizeof(real));
339 constraintsTestSystemList.emplace_back(constraintsTestSystem);
342 return constraintsTestSystemList;
346 /*! \brief Test fixture for constraints.
348 * The fixture uses following test systems:
349 * 1. Two atoms, connected with one constraint (e.g. NH).
350 * 2. Three atoms, connected consequently with two constraints (e.g. CH2).
351 * 3. Three atoms, constrained to the fourth atom (e.g. CH3).
352 * 4. Four atoms, connected by two independent constraints.
353 * 5. Three atoms, connected by three constraints in a triangle
354 * (e.g. H2O with constrained H-O-H angle).
355 * 6. Four atoms, connected by three consequential constraints.
357 * For all systems, the final lengths of the constraints are tested against the
358 * reference values, the direction of each constraint is checked.
359 * Test also verifies that the center of mass has not been
360 * shifted by the constraints and that its velocity has not changed.
361 * For some systems, the value for scaled virial tensor is checked against
364 class ConstraintsTest : public ::testing::TestWithParam<std::tuple<ConstraintsTestSystem, t_pbc>>
368 * The test on the final length of constrained bonds.
370 * Goes through all the constraints and checks if the final length of all the constraints is
371 * equal to the target length with provided tolerance.
373 * \param[in] tolerance Allowed tolerance in final lengths.
374 * \param[in] testData Test data structure.
375 * \param[in] pbc Periodic boundary data.
377 static void checkConstrainsLength(FloatingPointTolerance tolerance,
378 const ConstraintsTestData& testData,
382 // Test if all the constraints are satisfied
383 for (index c = 0; c < ssize(testData.constraints_) / 3; c++)
385 real r0 = testData.constraintsR0_.at(testData.constraints_.at(3 * c));
386 int i = testData.constraints_.at(3 * c + 1);
387 int j = testData.constraints_.at(3 * c + 2);
390 if (pbc.pbcType == PbcType::Xyz)
392 pbc_dx_aiuc(&pbc, testData.x_[i], testData.x_[j], xij0);
393 pbc_dx_aiuc(&pbc, testData.xPrime_[i], testData.xPrime_[j], xij1);
397 rvec_sub(testData.x_[i], testData.x_[j], xij0);
398 rvec_sub(testData.xPrime_[i], testData.xPrime_[j], xij1);
402 EXPECT_REAL_EQ_TOL(r0, d1, tolerance) << gmx::formatString(
403 "rij = %f, which is not equal to r0 = %f for constraint #%zd, between atoms %d "
405 " (before constraining rij was %f).",
416 * The test on the final length of constrained bonds.
418 * Goes through all the constraints and checks if the direction of constraint has not changed
419 * by the algorithm (i.e. the constraints algorithm arrived to the solution that is closest
420 * to the initial system conformation).
422 * \param[in] testData Test data structure.
423 * \param[in] pbc Periodic boundary data.
425 static void checkConstrainsDirection(const ConstraintsTestData& testData, t_pbc pbc)
428 for (index c = 0; c < ssize(testData.constraints_) / 3; c++)
430 int i = testData.constraints_.at(3 * c + 1);
431 int j = testData.constraints_.at(3 * c + 2);
433 if (pbc.pbcType == PbcType::Xyz)
435 pbc_dx_aiuc(&pbc, testData.x_[i], testData.x_[j], xij0);
436 pbc_dx_aiuc(&pbc, testData.xPrime_[i], testData.xPrime_[j], xij1);
440 rvec_sub(testData.x_[i], testData.x_[j], xij0);
441 rvec_sub(testData.xPrime_[i], testData.xPrime_[j], xij1);
444 real dot = xij0.dot(xij1);
446 EXPECT_GE(dot, 0.0) << gmx::formatString(
447 "The constraint %zd changed direction. Constraining algorithm might have "
448 "returned the wrong root "
449 "of the constraints equation.",
455 * The test on the coordinates of the center of the mass (COM) of the system.
457 * Checks if the center of mass has not been shifted by the constraints. Note,
458 * that this test does not take into account the periodic boundary conditions.
459 * Hence it will not work should the constraints decide to move atoms across
462 * \param[in] tolerance Allowed tolerance in COM coordinates.
463 * \param[in] testData Test data structure.
465 static void checkCOMCoordinates(FloatingPointTolerance tolerance, const ConstraintsTestData& testData)
468 RVec comPrime0({ 0.0, 0.0, 0.0 });
469 RVec comPrime({ 0.0, 0.0, 0.0 });
470 for (int i = 0; i < testData.numAtoms_; i++)
472 comPrime0 += testData.masses_[i] * testData.xPrime0_[i];
473 comPrime += testData.masses_[i] * testData.xPrime_[i];
476 comPrime0 /= testData.numAtoms_;
477 comPrime /= testData.numAtoms_;
479 EXPECT_REAL_EQ_TOL(comPrime[XX], comPrime0[XX], tolerance)
480 << "Center of mass was shifted by constraints in x-direction.";
481 EXPECT_REAL_EQ_TOL(comPrime[YY], comPrime0[YY], tolerance)
482 << "Center of mass was shifted by constraints in y-direction.";
483 EXPECT_REAL_EQ_TOL(comPrime[ZZ], comPrime0[ZZ], tolerance)
484 << "Center of mass was shifted by constraints in z-direction.";
488 * The test on the velocity of the center of the mass (COM) of the system.
490 * Checks if the velocity of the center of mass has not changed.
492 * \param[in] tolerance Allowed tolerance in COM velocity components.
493 * \param[in] testData Test data structure.
495 static void checkCOMVelocity(FloatingPointTolerance tolerance, const ConstraintsTestData& testData)
498 RVec comV0({ 0.0, 0.0, 0.0 });
499 RVec comV({ 0.0, 0.0, 0.0 });
500 for (int i = 0; i < testData.numAtoms_; i++)
502 comV0 += testData.masses_[i] * testData.v0_[i];
503 comV += testData.masses_[i] * testData.v_[i];
505 comV0 /= testData.numAtoms_;
506 comV /= testData.numAtoms_;
508 EXPECT_REAL_EQ_TOL(comV[XX], comV0[XX], tolerance)
509 << "Velocity of the center of mass in x-direction has been changed by constraints.";
510 EXPECT_REAL_EQ_TOL(comV[YY], comV0[YY], tolerance)
511 << "Velocity of the center of mass in y-direction has been changed by constraints.";
512 EXPECT_REAL_EQ_TOL(comV[ZZ], comV0[ZZ], tolerance)
513 << "Velocity of the center of mass in z-direction has been changed by constraints.";
517 * The test of virial tensor.
519 * Checks if the values in the scaled virial tensor are equal to pre-computed values.
521 * \param[in] tolerance Tolerance for the tensor values.
522 * \param[in] testData Test data structure.
524 static void checkVirialTensor(FloatingPointTolerance tolerance, const ConstraintsTestData& testData)
526 for (int i = 0; i < DIM; i++)
528 for (int j = 0; j < DIM; j++)
530 EXPECT_REAL_EQ_TOL(testData.virialScaledRef_[i][j], testData.virialScaled_[i][j], tolerance)
531 << gmx::formatString(
532 "Values in virial tensor at [%d][%d] are not within the "
533 "tolerance from reference value.",
539 //! Before any test is run, work out whether any compatible GPUs exist.
540 static std::vector<std::unique_ptr<IConstraintsTestRunner>> getRunners()
542 std::vector<std::unique_ptr<IConstraintsTestRunner>> runners;
543 // Add runners for CPU versions of SHAKE and LINCS
544 runners.emplace_back(std::make_unique<ShakeConstraintsRunner>());
545 runners.emplace_back(std::make_unique<LincsConstraintsRunner>());
546 // If supported, add runners for the GPU version of LINCS for each available GPU
547 const bool addGpuRunners = GPU_CONSTRAINTS_SUPPORTED;
550 for (const auto& testDevice : getTestHardwareEnvironment()->getTestDeviceList())
552 runners.emplace_back(std::make_unique<LincsDeviceConstraintsRunner>(*testDevice));
559 TEST_P(ConstraintsTest, ConstraintsTest)
561 auto params = GetParam();
562 ConstraintsTestSystem constraintsTestSystem = std::get<0>(params);
563 t_pbc pbc = std::get<1>(params);
565 ConstraintsTestData testData(constraintsTestSystem.title,
566 constraintsTestSystem.numAtoms,
567 constraintsTestSystem.masses,
568 constraintsTestSystem.constraints,
569 constraintsTestSystem.constraintsR0,
571 constraintsTestSystem.virialScaledRef,
576 constraintsTestSystem.x,
577 constraintsTestSystem.xPrime,
578 constraintsTestSystem.v,
579 constraintsTestSystem.shakeTolerance,
580 constraintsTestSystem.shakeUseSOR,
581 constraintsTestSystem.lincsNIter,
582 constraintsTestSystem.lincslincsExpansionOrder,
583 constraintsTestSystem.lincsWarnAngle);
585 // Cycle through all available runners
586 for (const auto& runner : getRunners())
588 SCOPED_TRACE(formatString("Testing %s with %s PBC using %s.",
589 testData.title_.c_str(),
590 c_pbcTypeNames[pbc.pbcType].c_str(),
591 runner->name().c_str()));
596 runner->applyConstraints(&testData, pbc);
598 checkConstrainsLength(constraintsTestSystem.lengthTolerance, testData, pbc);
599 checkConstrainsDirection(testData, pbc);
600 checkCOMCoordinates(constraintsTestSystem.comTolerance, testData);
601 checkCOMVelocity(constraintsTestSystem.comTolerance, testData);
602 checkVirialTensor(constraintsTestSystem.virialTolerance, testData);
606 INSTANTIATE_TEST_SUITE_P(WithParameters,
608 ::testing::Combine(::testing::ValuesIn(c_constraintsTestSystemList),
609 ::testing::ValuesIn(c_pbcs)));