src/gromacs/awh/coordstate.h

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  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                                      int64_t                      step,
 101                                      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 */