src/gromacs/mdtypes/forcebuffers.h

   1 /*
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   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
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  35
  36 /*! \libinternal \file
  37  *
  38  * \brief
  39  * This file contains the definition of a container for force buffers.
  40  *
  41  * \author Berk Hess
  42  *
  43  * \inlibraryapi
  44  * \ingroup module_mdtypes
  45  */
  46
  47 #ifndef GMX_MDTYPES_FORCEBUFFERS_H
  48 #define GMX_MDTYPES_FORCEBUFFERS_H
  49
  50 #include "gromacs/gpu_utils/hostallocator.h"
  51 #include "gromacs/math/arrayrefwithpadding.h"
  52 #include "gromacs/math/vectypes.h"
  53 #include "gromacs/utility/arrayref.h"
  54 #include "gromacs/utility/classhelpers.h"
  55
  56 namespace gmx
  57 {
  58
  59 enum class PinningPolicy : int;
  60
  61 /*! \libinternal \brief A view of the force buffer
  62  *
  63  * This is used for read and/or write access to the force buffer.
  64  */
  65 class ForceBuffersView
  66 {
  67 public:
  68     //! Constructor, creates a view to \p force
  69     ForceBuffersView(const ArrayRefWithPadding<RVec>& force,
  70                      const ArrayRefWithPadding<RVec>& forceMtsCombined,
  71                      const bool                       useForceMtsCombined) :
  72         force_(force),
  73         forceMtsCombined_(forceMtsCombined),
  74         useForceMtsCombined_(useForceMtsCombined)
  75     {
  76     }
  77
  78     //! Copy constructor deleted to avoid creating non-const from const
  79     ForceBuffersView(const ForceBuffersView& o) = delete;
  80
  81     //! Move constructor deleted, but could be implemented
  82     ForceBuffersView(ForceBuffersView&& o) = delete;
  83
  84     ~ForceBuffersView() = default;
  85
  86     //! Copy assignment deleted to avoid creating non-const from const
  87     ForceBuffersView& operator=(const ForceBuffersView& v) = delete;
  88
  89     //! Move assignment, moves the view
  90     ForceBuffersView& operator=(ForceBuffersView&& v) = default;
  91
  92     //! Returns a const arrayref to the force buffer without padding
  93     ArrayRef<const RVec> force() const { return force_.unpaddedConstArrayRef(); }
  94
  95     //! Returns an arrayref to the force buffer without padding
  96     ArrayRef<RVec> force() { return force_.unpaddedArrayRef(); }
  97
  98     //! Returns an ArrayRefWithPadding to the force buffer
  99     ArrayRefWithPadding<RVec> forceWithPadding() { return force_; }
 100
 101     //! Returns a const arrayref to the MTS force buffer without padding
 102     ArrayRef<const RVec> forceMtsCombined() const
 103     {
 104         GMX_ASSERT(useForceMtsCombined_, "Need the MTS buffer");
 105         return forceMtsCombined_.unpaddedConstArrayRef();
 106     }
 107
 108     //! Returns an arrayref to the MTS force buffer without padding
 109     ArrayRef<RVec> forceMtsCombined()
 110     {
 111         GMX_ASSERT(useForceMtsCombined_, "Need the MTS buffer");
 112         return forceMtsCombined_.unpaddedArrayRef();
 113     }
 114
 115     //! Returns an ArrayRefWithPadding to the MTS force buffer
 116     ArrayRefWithPadding<RVec> forceMtsCombinedWithPadding()
 117     {
 118         GMX_ASSERT(useForceMtsCombined_, "Need the MTS buffer");
 119         return forceMtsCombined_;
 120     }
 121
 122 private:
 123     //! The force buffer
 124     ArrayRefWithPadding<RVec> force_;
 125     //! The force buffer for combined fast and slow forces with MTS
 126     ArrayRefWithPadding<RVec> forceMtsCombined_;
 127     //! Wether we use forceMtsCombined_
 128     bool useForceMtsCombined_;
 129 };
 130
 131 /*! \libinternal \brief Object that holds the force buffers
 132  *
 133  * Contains a normal force buffer and optionally a force buffer for combined fast and slow
 134  * forces for use with multiple time stepping.
 135  * More buffers can be added when needed. Those should also be added
 136  * to ForceBuffersView.
 137  * The force buffer (not forceMtsCombined) can be pinned for efficient transfer to/from GPUs.
 138  * All access happens through the ForceBuffersView object.
 139  */
 140 class ForceBuffers
 141 {
 142 public:
 143     //! Constructor, creates an empty force buffer with pinning not active and no MTS force buffer
 144     ForceBuffers();
 145
 146     /*! \brief Constructor, with options for using the MTS force buffer and the pinning policy
 147      *
 148      * \param[in] useForceMtsCombined  Whether to enable use of the forceMtsCombined buffer
 149      * \param[in] pinningPolicy        The pinning policy for the force (not MTS) buffer
 150      */
 151     ForceBuffers(bool useForceMtsCombined, PinningPolicy pinningPolicy);
 152
 153     //! Copy constructor deleted, but could be implemented
 154     ForceBuffers(const ForceBuffers& o) = delete;
 155
 156     //! Move constructor deleted, but could be implemented
 157     ForceBuffers(ForceBuffers&& o) = delete;
 158
 159     ~ForceBuffers();
 160
 161     //! Copy assignment operator, sets the pinning policy to CannotBePinned
 162     ForceBuffers& operator=(ForceBuffers const& o);
 163
 164     //! Move assignment operator, deleted but could be implemented
 165     ForceBuffers& operator=(ForceBuffers&& o) = delete;
 166
 167     //! Returns a const view to the force buffers
 168     const ForceBuffersView& view() const { return view_; }
 169
 170     //! Returns a view to the force buffer
 171     ForceBuffersView& view() { return view_; }
 172
 173     //! Resize the force buffer
 174     void resize(int numAtoms);
 175
 176     /*! \brief Returns the active pinning policy.
 177      *
 178      * Does not throw.
 179      */
 180     PinningPolicy pinningPolicy() const;
 181
 182 private:
 183     //! The force buffer
 184     PaddedHostVector<RVec> force_;
 185     //! Force buffer with combined fast and slow forces for use with multiple time stepping
 186     PaddedHostVector<RVec> forceMtsCombined_;
 187     //! The view to the force buffer
 188     ForceBuffersView view_;
 189     //! Wether we use forceMtsCombined_
 190     bool useForceMtsCombined_;
 191 };
 192
 193 } // namespace gmx
 194
 195 #endif