src/gromacs/mdtypes/forceoutput.h

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2019, by the GROMACS development team, led by
   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   6  * and including many others, as listed in the AUTHORS file in the
   7  * top-level source directory and at http://www.gromacs.org.
   8  *
   9  * GROMACS is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 2.1
  12  * of the License, or (at your option) any later version.
  13  *
  14  * GROMACS is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with GROMACS; if not, see
  21  * http://www.gnu.org/licenses, or write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
  23  *
  24  * If you want to redistribute modifications to GROMACS, please
  25  * consider that scientific software is very special. Version
  26  * control is crucial - bugs must be traceable. We will be happy to
  27  * consider code for inclusion in the official distribution, but
  28  * derived work must not be called official GROMACS. Details are found
  29  * in the README & COPYING files - if they are missing, get the
  30  * official version at http://www.gromacs.org.
  31  *
  32  * To help us fund GROMACS development, we humbly ask that you cite
  33  * the research papers on the package. Check out http://www.gromacs.org.
  34  */
  35
  36 /*! \libinternal \file
  37  *
  38  * \brief
  39  * This file contains the definition of a container for force and virial
  40  * output.
  41  *
  42  * Currently the only container defined here is one used in algorithms
  43  * that provide their own virial tensor contribution.
  44  * We can consider adding another containter for forces and shift forces.
  45  *
  46  * \author Berk Hess
  47  *
  48  * \inlibraryapi
  49  * \ingroup module_mdtypes
  50  */
  51
  52 #ifndef GMX_MDTYPES_FORCEOUTPUT_H
  53 #define GMX_MDTYPES_FORCEOUTPUT_H
  54
  55 #include "gromacs/math/vectypes.h"
  56 #include "gromacs/utility/arrayref.h"
  57
  58 namespace gmx
  59 {
  60
  61 /*! \libinternal \brief Container for force and virial for algorithms that provide their own virial tensor contribution
  62  *
  63  * \note The \p force_ data member is a reference to an external force buffer.
  64  */
  65 class ForceWithVirial
  66 {
  67     public:
  68         /*! \brief Constructor
  69          *
  70          * \param[in] force          A force buffer that will be used for storing forces
  71          * \param[in] computeVirial  True when algorithms are required to provide their virial contribution (for the current force evaluation)
  72          */
  73         ForceWithVirial(ArrayRef<RVec> force, bool computeVirial) :
  74             force_(force),
  75             computeVirial_(computeVirial)
  76         {
  77             for (int dim1 = 0; dim1 < DIM; dim1++)
  78             {
  79                 for (int dim2 = 0; dim2 < DIM; dim2++)
  80                 {
  81                     virial_[dim1][dim2] = 0;
  82                 }
  83             }
  84         }
  85
  86         /*! \brief Adds a virial contribution
  87          *
  88          * \note Can be called with \p computeVirial=false.
  89          * \note It is recommended to accumulate the virial contributions
  90          *       of a module internally before calling this method, as that
  91          *       will reduce rounding errors.
  92          *
  93          * \param[in] virial  The virial contribution to add
  94          */
  95         void addVirialContribution(const matrix virial)
  96         {
  97             if (computeVirial_)
  98             {
  99                 for (int dim1 = 0; dim1 < DIM; dim1++)
 100                 {
 101                     for (int dim2 = 0; dim2 < DIM; dim2++)
 102                     {
 103                         virial_[dim1][dim2] += virial[dim1][dim2];
 104                     }
 105                 }
 106             }
 107         }
 108
 109         /*! \brief Adds a virial diagonal contribution
 110          *
 111          * \note Can be called with \p computeVirial=false.
 112          * \note It is recommended to accumulate the virial contributions
 113          *       of a module internally before calling this method, as that
 114          *       will reduce rounding errors.
 115          *
 116          * \param[in] virial  The virial contribution to add
 117          */
 118         void addVirialContribution(const RVec virial)
 119         {
 120             if (computeVirial_)
 121             {
 122                 for (int dim = 0; dim < DIM; dim++)
 123                 {
 124                     virial_[dim][dim] += virial[dim];
 125                 }
 126             }
 127         }
 128
 129         /*! \brief Returns the accumulated virial contributions
 130          */
 131         const matrix &getVirial() const
 132         {
 133             return virial_;
 134         }
 135
 136         const ArrayRef<RVec> force_;         //!< Force accumulation buffer reference
 137         const bool           computeVirial_; //!< True when algorithms are required to provide their virial contribution (for the current force evaluation)
 138     private:
 139         matrix               virial_;        //!< Virial accumulation buffer
 140 };
 141
 142 /*! \libinternal \brief Force and virial output buffers for use in force computation
 143  *
 144  * TODO: Extend with shift forces
 145  */
 146 class ForceOutputs
 147 {
 148     public:
 149         //! Constructor
 150         ForceOutputs(rvec                 *f,
 151                      gmx::ForceWithVirial  forceWithVirial) :
 152             f_(f),
 153             forceWithVirial_(forceWithVirial) {}
 154
 155         //! Returns a, deprecated, rvec pointer to the force buffer for use with shift forces
 156         rvec *f()
 157         {
 158             return f_;
 159         }
 160
 161         //! Returns a reference to the force with virial object
 162         gmx::ForceWithVirial &forceWithVirial()
 163         {
 164             return forceWithVirial_;
 165         }
 166
 167     private:
 168         //! Force output buffer used by legacy modules (without SIMD padding)
 169         rvec                 *f_;
 170         //! Force with direct virial contribution (if there are any; without SIMD padding)
 171         gmx::ForceWithVirial  forceWithVirial_;
 172 };
 173
 174 }  // namespace gmx
 175
 176 #endif