src/gromacs/mdlib/update_constrain_cuda_impl.h

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  35 /*! \internal \file
  36  *
  37  * \brief Declares CUDA implementation class for update and constraints.
  38  *
  39  * This header file is needed to include from both the device-side
  40  * kernels file, and the host-side management code.
  41  *
  42  * \author Artem Zhmurov <zhmurov@gmail.com>
  43  *
  44  * \ingroup module_mdlib
  45  */
  46 #ifndef GMX_MDLIB_UPDATE_CONSTRAIN_CUDA_IMPL_H
  47 #define GMX_MDLIB_UPDATE_CONSTRAIN_CUDA_IMPL_H
  48
  49 #include "gmxpre.h"
  50
  51 #include "gromacs/mdlib/leapfrog_cuda.cuh"
  52 #include "gromacs/mdlib/lincs_cuda.cuh"
  53 #include "gromacs/mdlib/settle_cuda.cuh"
  54 #include "gromacs/mdlib/update_constrain_cuda.h"
  55 #include "gromacs/mdtypes/inputrec.h"
  56
  57 namespace gmx
  58 {
  59
  60 /*! \internal \brief Class with interfaces and data for CUDA version of Update-Constraint. */
  61 class UpdateConstrainCuda::Impl
  62 {
  63
  64     public:
  65         /*! \brief Create Update-Constrain object
  66          *
  67          * \param[in] ir             Input record data: LINCS takes number of iterations and order of
  68          *                           projection from it.
  69          * \param[in] mtop           Topology of the system: SETTLE gets the masses for O and H atoms
  70          *                           and target O-H and H-H distances from this object.
  71          * \param[in] commandStream  GPU stream to use. Can be nullptr.
  72          */
  73         Impl(const t_inputrec     &ir,
  74              const gmx_mtop_t     &mtop,
  75              const void           *commandStream);
  76
  77         ~Impl();
  78
  79         /*! \brief Integrate
  80          *
  81          * Integrates the equation of motion using Leap-Frog algorithm and applies
  82          * LINCS and SETTLE constraints.
  83          * Updates d_xp_ and d_v_ fields of this object.
  84          * If computeVirial is true, constraints virial is written at the provided pointer.
  85          * doTempCouple should be true if:
  86          *   1. The temperature coupling is enabled.
  87          *   2. This is the temperature coupling step.
  88          * Parameters virial/lambdas can be nullptr if computeVirial/doTempCouple are false.
  89          *
  90          * \param[in]  dt                     Timestep.
  91          * \param[in]  updateVelocities       If the velocities should be constrained.
  92          * \param[in]  computeVirial          If virial should be updated.
  93          * \param[out] virial                 Place to save virial tensor.
  94          * \param[in]  doTempCouple           If the temperature coupling should be performed.
  95          * \param[in]  tcstat                 Temperature coupling data.
  96          * \param[in]  doPressureCouple       If the temperature coupling should be applied.
  97          * \param[in]  dtPressureCouple       Period between pressure coupling steps
  98          * \param[in]  velocityScalingMatrix  Parrinello-Rahman velocity scaling matrix
  99          */
 100         void integrate(real                              dt,
 101                        bool                              updateVelocities,
 102                        bool                              computeVirial,
 103                        tensor                            virial,
 104                        bool                              doTempCouple,
 105                        gmx::ArrayRef<const t_grp_tcstat> tcstat,
 106                        bool                              doPressureCouple,
 107                        float                             dtPressureCouple,
 108                        const matrix                      velocityScalingMatrix);
 109
 110         /*! \brief Set the pointers and update data-structures (e.g. after NB search step).
 111          *
 112          * \param[in,out]  d_x            Device buffer with coordinates.
 113          * \param[in,out]  d_v            Device buffer with velocities.
 114          * \param[in]      d_f            Device buffer with forces.
 115          * \param[in] idef                System topology
 116          * \param[in] md                  Atoms data.
 117          * \param[in] numTempScaleValues  Number of temperature scaling groups. Set zero for no temperature coupling.
 118          */
 119         void set(DeviceBuffer<float>        d_x,
 120                  DeviceBuffer<float>        d_v,
 121                  const DeviceBuffer<float>  d_f,
 122                  const t_idef              &idef,
 123                  const t_mdatoms           &md,
 124                  const int                  numTempScaleValues);
 125
 126         /*! \brief
 127          * Update PBC data.
 128          *
 129          * Converts PBC data from t_pbc into the PbcAiuc format and stores the latter.
 130          *
 131          * \param[in] pbc The PBC data in t_pbc format.
 132          */
 133         void setPbc(const t_pbc *pbc);
 134
 135     private:
 136
 137         //! CUDA stream
 138         CommandStream       commandStream_         = nullptr;
 139
 140         //! Periodic boundary data
 141         PbcAiuc             pbcAiuc_;
 142
 143         //! Number of atoms
 144         int                 numAtoms_;
 145
 146         //! Local copy of the pointer to the device positions buffer
 147         float3             *d_x_;
 148         //! Local copy of the pointer to the device velocities buffer
 149         float3             *d_v_;
 150         //! Local copy of the pointer to the device forces buffer
 151         float3             *d_f_;
 152
 153         //! Device buffer for intermediate positions (maintained internally)
 154         float3             *d_xp_;
 155         //! Number of elements in shifted coordinates buffer
 156         int                 numXp_                 = -1;
 157         //! Allocation size for the shifted coordinates buffer
 158         int                 numXpAlloc_            = -1;
 159
 160
 161         //! 1/mass for all atoms (GPU)
 162         real               *d_inverseMasses_;
 163         //! Number of elements in reciprocal masses buffer
 164         int                 numInverseMasses_      = -1;
 165         //! Allocation size for the reciprocal masses buffer
 166         int                 numInverseMassesAlloc_ = -1;
 167
 168         //! Leap-Frog integrator
 169         std::unique_ptr<LeapFrogCuda>        integrator_;
 170         //! LINCS CUDA object to use for non-water constraints
 171         std::unique_ptr<LincsCuda>           lincsCuda_;
 172         //! SETTLE CUDA object for water constrains
 173         std::unique_ptr<SettleCuda>          settleCuda_;
 174
 175 };
 176
 177 } // namespace gmx
 178
 179 #endif