src/gromacs/awh/coordstate.h

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2015,2016,2017, 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 /*! \internal \file
  37  *
  38  * \brief
  39  * Declares the CoordState class.
  40  *
  41  * It sets and holds the current coordinate value and corresponding closest
  42  * grid point index. These are (re)set at every step.
  43  * With umbrella potential type, this class also holds and updates the umbrella
  44  * potential reference location, which is a state variable that presists over
  45  * the duration of an AWH sampling interval.
  46  *
  47  * \author Viveca Lindahl
  48  * \author Berk Hess <hess@kth.se>
  49  * \ingroup module_awh
  50  */
  51
  52 #ifndef GMX_AWH_COORDSTATE_H
  53 #define GMX_AWH_COORDSTATE_H
  54
  55 #include <vector>
  56
  57 #include "gromacs/utility/arrayref.h"
  58
  59 #include "dimparams.h"
  60
  61 namespace gmx
  62 {
  63
  64 struct AwhBiasParams;
  65 struct AwhBiasStateHistory;
  66 class BiasParams;
  67 class Grid;
  68
  69 /*! \internal \brief Keeps track of the current coordinate value, grid index and umbrella location.
  70  */
  71 class CoordState
  72 {
  73     public:
  74         /*! \brief Constructor.
  75          *
  76          * \param[in] awhBiasParams  The Bias parameters from inputrec.
  77          * \param[in] dimParams      The dimension Parameters.
  78          * \param[in] grid           The grid.
  79          */
  80         CoordState(const AwhBiasParams          &awhBiasParams,
  81                    const std::vector<DimParams> &dimParams,
  82                    const Grid                   &grid);
  83
  84         /*! \brief
  85          * Sample a new umbrella reference point given the current coordinate value.
  86          *
  87          * It is assumed that the probability distribution has been updated.
  88          *
  89          * \param[in] grid                The grid.
  90          * \param[in] gridpointIndex      The grid point, sets the neighborhood.
  91          * \param[in] probWeightNeighbor  Probability weights of the neighbors.
  92          * \param[in] step                Step number, needed for the random number generator.
  93          * \param[in] seed                Random seed.
  94          * \param[in] indexSeed           Second random seed, should be the bias Index.
  95          * \returns the index of the sampled point.
  96          */
  97         void sampleUmbrellaGridpoint(const Grid                  &grid,
  98                                      int                          gridpointIndex,
  99                                      gmx::ArrayRef<const double>  probWeightNeighbor,
 100                                      gmx_int64_t                  step,
 101                                      gmx_int64_t                  seed,
 102                                      int                          indexSeed);
 103
 104         /*! \brief Update the coordinate value with coordValue.
 105          *
 106          * \param[in] grid        The grid.
 107          * \param[in] coordValue  The new coordinate value.
 108          */
 109         void setCoordValue(const Grid     &grid,
 110                            const awh_dvec  coordValue);
 111
 112         /*! \brief Restores the coordinate state from history.
 113          *
 114          * \param[in] stateHistory  The AWH bias state history.
 115          */
 116         void restoreFromHistory(const AwhBiasStateHistory &stateHistory);
 117
 118         /*! \brief Returns the current coordinate value.
 119          */
 120         const awh_dvec &coordValue() const
 121         {
 122             return coordValue_;
 123         };
 124
 125         /*! \brief Returns the grid point index for the current coordinate value.
 126          */
 127         int gridpointIndex() const
 128         {
 129             return gridpointIndex_;
 130         }
 131
 132         /*! \brief Returns the index for the current reference grid point.
 133          */
 134         int umbrellaGridpoint() const
 135         {
 136             return umbrellaGridpoint_;
 137         };
 138
 139     private:
 140         awh_dvec coordValue_;        /**< Current coordinate value in (nm or rad) */
 141         int      gridpointIndex_;    /**< The grid point index for the current coordinate value */
 142         int      umbrellaGridpoint_; /**< Index for the current reference grid point for the umbrella, only used with umbrella potential type */
 143 };
 144
 145 }      // namespace gmx
 146
 147 #endif /* GMX_AWH_COORDSTATE_H */