src/gromacs/mdtypes/iforceprovider.h

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  35 /*! \libinternal \file
  36  * \brief
  37  * Declares gmx::IForceProvider and ForceProviders.
  38  *
  39  * See \ref page_mdmodules for an overview of this and associated interfaces.
  40  *
  41  * \author Teemu Murtola <teemu.murtola@gmail.com>
  42  * \author Carsten Kutzner <ckutzne@gwdg.de>
  43  * \inlibraryapi
  44  * \ingroup module_mdtypes
  45  */
  46 #ifndef GMX_MDTYPES_IFORCEPROVIDER_H
  47 #define GMX_MDTYPES_IFORCEPROVIDER_H
  48
  49 #include "gromacs/math/vec.h"
  50 #include "gromacs/utility/arrayref.h"
  51 #include "gromacs/utility/classhelpers.h"
  52 #include "gromacs/utility/gmxassert.h"
  53
  54 struct gmx_enerdata_t;
  55 struct t_commrec;
  56 struct t_forcerec;
  57 struct t_mdatoms;
  58
  59 namespace gmx
  60 {
  61
  62 template <typename T>
  63 class ArrayRef;
  64 class ForceWithVirial;
  65
  66
  67 /*! \libinternal \brief
  68  * Helper struct that bundles data for passing it over to the force providers
  69  *
  70  * This is a short-lived container that bundles up all necessary input data for the
  71  * force providers. Its only purpose is to allow calling forceProviders->calculateForces()
  72  * with just two arguments, one being the container for the input data,
  73  * the other the container for the output data.
  74  *
  75  * Both ForceProviderInput as well as ForceProviderOutput only package existing
  76  * data structs together for handing it over to calculateForces(). Apart from the
  77  * POD entries they own nothing.
  78  */
  79 class ForceProviderInput
  80 {
  81     public:
  82         /*! \brief Constructor assembles all necessary force provider input data
  83          *
  84          * \param[in]  x        Atomic positions
  85          * \param[in]  cr       Communication record structure
  86          * \param[in]  box      The simulation box
  87          * \param[in]  time     The current time in the simulation
  88          * \param[in]  mdatoms  The atomic data
  89          */
  90         ForceProviderInput(ArrayRef<const RVec> x,
  91                            const t_mdatoms     &mdatoms,
  92                            double               time,
  93                            const matrix         box,
  94                            const t_commrec     &cr)
  95             : x_(x), mdatoms_(mdatoms), t_(time), cr_(cr)
  96         {
  97             copy_mat(box, box_);
  98         }
  99
 100         ArrayRef<const RVec> x_;                                        //!< The atomic positions
 101         const t_mdatoms     &mdatoms_;                                  //!< Atomic data
 102         double               t_;                                        //!< The current time in the simulation
 103         matrix               box_ = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};  //!< The simulation box
 104         const t_commrec     &cr_;                                       //!< Communication record structure
 105 };
 106
 107 /*! \brief Take pointer, check if valid, return reference
 108  */
 109 template <class T> T &makeRefFromPointer(T *ptr)
 110 {
 111     GMX_ASSERT(ptr != nullptr, "got null pointer");
 112     return *ptr;
 113 }
 114
 115 /*! \libinternal \brief
 116  * Helper struct bundling the output data of a force provider
 117  *
 118  * Same as for the ForceProviderInput class, but these variables can be written as well.
 119  */
 120 class ForceProviderOutput
 121 {
 122     public:
 123         /*! \brief Constructor assembles all necessary force provider output data
 124          *
 125          * \param[in,out]  forceWithVirial  Container for force and virial
 126          * \param[in,out]  enerd            Structure containing energy data
 127          */
 128         ForceProviderOutput(ForceWithVirial *forceWithVirial,
 129                             gmx_enerdata_t  *enerd)
 130             : forceWithVirial_(makeRefFromPointer(forceWithVirial)), enerd_(makeRefFromPointer(enerd))
 131         {
 132         }
 133
 134         ForceWithVirial &forceWithVirial_; //!< Container for force and virial
 135         gmx_enerdata_t  &enerd_;           //!< Structure containing energy data
 136 };
 137
 138
 139 /*! \libinternal \brief
 140  * Interface for a component that provides forces during MD.
 141  *
 142  * Modules implementing IMDModule generally implement this internally, and use
 143  * IMDModule::initForceProviders() to register their implementation in
 144  * ForceProviders.
 145  *
 146  * The interface most likely requires additional generalization for use in
 147  * other modules than the current electric field implementation.
 148  *
 149  * The forces that are produced by force providers are not taken into account
 150  * in the calculation of the virial. When applicable, the provider should
 151  * compute its own virial contribution.
 152  *
 153  * \inlibraryapi
 154  * \ingroup module_mdtypes
 155  */
 156 class IForceProvider
 157 {
 158     public:
 159         /*! \brief
 160          * Computes forces.
 161          *
 162          * \param[in]    forceProviderInput    struct that collects input data for the force providers
 163          * \param[in,out] forceProviderOutput   struct that collects output data of the force providers
 164          */
 165         virtual void calculateForces(const ForceProviderInput &forceProviderInput,
 166                                      ForceProviderOutput      *forceProviderOutput) = 0;
 167
 168     protected:
 169         ~IForceProvider() {}
 170 };
 171
 172 } // namespace gmx
 173
 174 /*! \libinternal \brief
 175  * Evaluates forces from a collection of gmx::IForceProvider.
 176  *
 177  * This class is a `struct` outside the `gmx` namespace to make it possible to
 178  * forward-declare it in forcerec.h, which still needs to compile when included
 179  * from the C group kernels.
 180  *
 181  * \inlibraryapi
 182  * \ingroup module_mdtypes
 183  */
 184 struct ForceProviders
 185 {
 186     public:
 187         ForceProviders();
 188         ~ForceProviders();
 189
 190         /*! \brief
 191          * Adds a provider.
 192          */
 193         void addForceProvider(gmx::IForceProvider *provider);
 194
 195         //! Whether there are modules added.
 196         bool hasForceProvider() const;
 197
 198         //! Computes forces.
 199         void calculateForces(const gmx::ForceProviderInput &forceProviderInput,
 200                              gmx::ForceProviderOutput      *forceProviderOutput) const;
 201
 202     private:
 203         class Impl;
 204
 205         gmx::PrivateImplPointer<Impl> impl_;
 206 };
 207
 208 #endif