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37 * \brief Implements update and constraints class using CUDA.
39 * The class combines Leap-Frog integrator with LINCS and SETTLE constraints.
41 * \todo The computational procedures in members should be integrated to improve
42 * computational performance.
44 * \author Artem Zhmurov <zhmurov@gmail.com>
46 * \ingroup module_mdlib
50 #include "update_constrain_cuda_impl.h"
59 #include "gromacs/gpu_utils/cudautils.cuh"
60 #include "gromacs/gpu_utils/devicebuffer.h"
61 #include "gromacs/gpu_utils/gputraits.cuh"
62 #include "gromacs/gpu_utils/vectype_ops.cuh"
63 #include "gromacs/mdlib/leapfrog_cuda.cuh"
64 #include "gromacs/mdlib/lincs_cuda.cuh"
65 #include "gromacs/mdlib/settle_cuda.cuh"
66 #include "gromacs/mdlib/update_constrain_cuda.h"
71 void UpdateConstrainCuda::Impl::integrate(const real dt,
72 const bool updateVelocities,
73 const bool computeVirial,
75 const bool doTempCouple,
76 gmx::ArrayRef<const t_grp_tcstat> tcstat,
77 const bool doPressureCouple,
78 const float dtPressureCouple,
79 const matrix velocityScalingMatrix)
81 // Clearing virial matrix
82 // TODO There is no point in having separate virial matrix for constraints
85 // The integrate should save a copy of the current coordinates in d_xp_ and write updated once into d_x_.
86 // The d_xp_ is only needed by constraints.
87 integrator_->integrate(d_x_, d_xp_, d_v_, d_f_, dt,
89 doPressureCouple, dtPressureCouple, velocityScalingMatrix);
90 // Constraints need both coordinates before (d_x_) and after (d_xp_) update. However, after constraints
91 // are applied, the d_x_ can be discarded. So we intentionally swap the d_x_ and d_xp_ here to avoid the
92 // d_xp_ -> d_x_ copy after constraints. Note that the integrate saves them in the wrong order as well.
93 lincsCuda_->apply(d_xp_, d_x_,
94 updateVelocities, d_v_, 1.0/dt,
95 computeVirial, virial);
96 settleCuda_->apply(d_xp_, d_x_,
97 updateVelocities, d_v_, 1.0/dt,
98 computeVirial, virial);
100 // scaledVirial -> virial (methods above returns scaled values)
101 float scaleFactor = 0.5f/(dt*dt);
102 for (int i = 0; i < DIM; i++)
104 for (int j = 0; j < DIM; j++)
106 virial[i][j] = scaleFactor*virial[i][j];
110 coordinatesReady_.markEvent(commandStream_);
115 UpdateConstrainCuda::Impl::Impl(const t_inputrec &ir,
116 const gmx_mtop_t &mtop,
117 const void *commandStream)
119 commandStream != nullptr ? commandStream_ = *static_cast<const CommandStream*>(commandStream) : commandStream_ = nullptr;
121 integrator_ = std::make_unique<LeapFrogCuda>(commandStream_);
122 lincsCuda_ = std::make_unique<LincsCuda>(ir.nLincsIter, ir.nProjOrder, commandStream_);
123 settleCuda_ = std::make_unique<SettleCuda>(mtop, commandStream_);
127 UpdateConstrainCuda::Impl::~Impl()
131 void UpdateConstrainCuda::Impl::set(DeviceBuffer<float> d_x,
132 DeviceBuffer<float> d_v,
133 const DeviceBuffer<float> d_f,
136 const int numTempScaleValues)
138 GMX_ASSERT(d_x != nullptr, "Coordinates device buffer should not be null.");
139 GMX_ASSERT(d_v != nullptr, "Velocities device buffer should not be null.");
140 GMX_ASSERT(d_f != nullptr, "Forces device buffer should not be null.");
142 d_x_ = reinterpret_cast<float3*>(d_x);
143 d_v_ = reinterpret_cast<float3*>(d_v);
144 d_f_ = reinterpret_cast<float3*>(d_f);
148 reallocateDeviceBuffer(&d_xp_, numAtoms_, &numXp_, &numXpAlloc_, nullptr);
150 reallocateDeviceBuffer(&d_inverseMasses_, numAtoms_,
151 &numInverseMasses_, &numInverseMassesAlloc_, nullptr);
153 // Integrator should also update something, but it does not even have a method yet
154 integrator_->set(md, numTempScaleValues, md.cTC);
155 lincsCuda_->set(idef, md);
156 settleCuda_->set(idef, md);
159 void UpdateConstrainCuda::Impl::setPbc(const t_pbc *pbc)
161 setPbcAiuc(pbc->ndim_ePBC, pbc->box, &pbcAiuc_);
162 integrator_->setPbc(pbc);
163 lincsCuda_->setPbc(pbc);
164 settleCuda_->setPbc(pbc);
167 void UpdateConstrainCuda::Impl::waitCoordinatesReadyOnDevice()
169 coordinatesReady_.waitForEvent();
172 void *UpdateConstrainCuda::Impl::getCoordinatesReadySync()
174 return static_cast<void*> (&coordinatesReady_);
177 UpdateConstrainCuda::UpdateConstrainCuda(const t_inputrec &ir,
178 const gmx_mtop_t &mtop,
179 const void *commandStream)
180 : impl_(new Impl(ir, mtop, commandStream))
184 UpdateConstrainCuda::~UpdateConstrainCuda() = default;
186 void UpdateConstrainCuda::integrate(const real dt,
187 const bool updateVelocities,
188 const bool computeVirial,
190 const bool doTempCouple,
191 gmx::ArrayRef<const t_grp_tcstat> tcstat,
192 const bool doPressureCouple,
193 const float dtPressureCouple,
194 const matrix velocityScalingMatrix)
196 impl_->integrate(dt, updateVelocities, computeVirial, virialScaled,
197 doTempCouple, tcstat,
198 doPressureCouple, dtPressureCouple, velocityScalingMatrix);
201 void UpdateConstrainCuda::set(DeviceBuffer<float> d_x,
202 DeviceBuffer<float> d_v,
203 const DeviceBuffer<float> d_f,
206 const int numTempScaleValues)
208 impl_->set(d_x, d_v, d_f, idef, md, numTempScaleValues);
211 void UpdateConstrainCuda::setPbc(const t_pbc *pbc)
216 void UpdateConstrainCuda::waitCoordinatesReadyOnDevice()
218 impl_->waitCoordinatesReadyOnDevice();
221 void* UpdateConstrainCuda::getCoordinatesReadySync()
223 return impl_->getCoordinatesReadySync();