src/gromacs/awh/histogramsize.h

   1 /*
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   4  * Copyright (c) 2015,2016,2017,2018, by the GROMACS development team, led by
   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
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  35
  36 /*! \internal \file
  37  *
  38  * \brief
  39  * Declares the HistogramSize class.
  40  *
  41  * The data members of this class keep track of global size and update related
  42  * properties of the bias histogram and the evolution of the histogram size.
  43  * Initially histogramSize_ (and thus the convergence rate) is controlled
  44  * heuristically to get good initial estimates,  i.e. increase the robustness
  45  * of the method.
  46  *
  47  * \author Viveca Lindahl
  48  * \author Berk Hess <hess@kth.se>
  49  * \ingroup module_awh
  50  */
  51
  52 #ifndef GMX_AWH_HISTOGRAMSIZE_H
  53 #define GMX_AWH_HISTOGRAMSIZE_H
  54
  55 #include <cstdio>
  56
  57 #include <vector>
  58
  59 #include "gromacs/math/vectypes.h"
  60 #include "gromacs/utility/arrayref.h"
  61
  62 namespace gmx
  63 {
  64
  65 struct AwhBiasStateHistory;
  66 struct AwhBiasParams;
  67 class BiasParams;
  68 class PointState;
  69
  70 /*! \internal
  71  * \brief Tracks global size related properties of the bias histogram.
  72  *
  73  * Tracks the number of updates and the histogram size.
  74  * Also keep track of the stage (initial/final of the AWH method
  75  * and printing warnings about covering.
  76  *
  77  * \note Histogram sizes are floating-point values, since the histogram uses weighted
  78  *        entries and we can assign a floating-point scaling factor when changing it.
  79  */
  80 class HistogramSize
  81 {
  82     public:
  83         /*! \brief Constructor.
  84          *
  85          * \param[in] awhBiasParams         The Bias parameters from inputrec.
  86          * \param[in] histogramSizeInitial  The initial histogram size.
  87          */
  88         HistogramSize(const AwhBiasParams &awhBiasParams,
  89                       double               histogramSizeInitial);
  90
  91     private:
  92         /*! \brief
  93          * Returns the new size of the reference weight histogram in the initial stage.
  94          *
  95          * This function also takes care resetting the histogram used for covering checks
  96          * and for exiting the initial stage.
  97          *
  98          * \param[in]     params             The bias parameters.
  99          * \param[in]     t                  Time.
 100          * \param[in]     detectedCovering   True if we detected that the sampling interval has been sufficiently covered.
 101          * \param[in,out] weightsumCovering  The weight sum for checking covering.
 102          * \param[in,out] fplog              Log file.
 103          * \returns the new histogram size.
 104          */
 105         double newHistogramSizeInitialStage(const BiasParams &params,
 106                                             double            t,
 107                                             bool              detectedCovering,
 108                                             ArrayRef<double>  weightsumCovering,
 109                                             FILE             *fplog);
 110
 111     public:
 112         /*! \brief
 113          * Return the new reference weight histogram size for the current update.
 114          *
 115          * This function also takes care of checking for covering in the initial stage.
 116          *
 117          * \param[in]     params             The bias parameters.
 118          * \param[in]     t                  Time.
 119          * \param[in]     covered            True if the sampling interval has been covered enough.
 120          * \param[in]     pointStates        The state of the grid points.
 121          * \param[in,out] weightsumCovering  The weight sum for checking covering.
 122          * \param[in,out] fplog              Log file.
 123          * \returns the new histogram size.
 124          */
 125         double newHistogramSize(const BiasParams              &params,
 126                                 double                         t,
 127                                 bool                           covered,
 128                                 const std::vector<PointState> &pointStates,
 129                                 ArrayRef<double>               weightsumCovering,
 130                                 FILE                          *fplog);
 131
 132         /*! \brief Restores the histogram size from history.
 133          *
 134          * \param[in] stateHistory  The AWH bias state history.
 135          */
 136         void restoreFromHistory(const AwhBiasStateHistory &stateHistory);
 137
 138         /*! \brief Store the histogram size state in a history struct.
 139          *
 140          * \param[in,out] stateHistory  The AWH bias state history.
 141          */
 142         void storeState(AwhBiasStateHistory *stateHistory) const;
 143
 144         /*! \brief Returns the number of updates since the start of the simulation.
 145          */
 146         int numUpdates() const
 147         {
 148             return numUpdates_;
 149         }
 150
 151         /*! \brief Increments the number of updates by 1.
 152          */
 153         void incrementNumUpdates()
 154         {
 155             numUpdates_ += 1;
 156         }
 157
 158         /*! \brief Returns the histogram size.
 159          */
 160         double histogramSize() const
 161         {
 162             return histogramSize_;
 163         }
 164
 165         /*! \brief Sets the histogram size.
 166          *
 167          * \param[in] histogramSize                 The new histogram size.
 168          * \param[in] weightHistogramScalingFactor  The factor to scale the weight by.
 169          */
 170         void setHistogramSize(double histogramSize,
 171                               double weightHistogramScalingFactor);
 172
 173         /*! \brief Returns true if we are in the initial stage of the AWH method.
 174          */
 175         bool inInitialStage() const
 176         {
 177             return inInitialStage_;
 178         }
 179
 180         /*! \brief Returns The log of the current sample weight, scaled because of the histogram rescaling.
 181          */
 182         double logScaledSampleWeight() const
 183         {
 184             return logScaledSampleWeight_;
 185         }
 186
 187     private:
 188         int64_t numUpdates_; /**< The number of updates performed since the start of the simulation. */
 189
 190         /* The histogram size sets the update size and so controls the convergence rate of the free energy and bias. */
 191         double      histogramSize_; /**< Size of reference weight histogram. */
 192
 193         /* Values that control the evolution of the histogram size. */
 194         bool      inInitialStage_;           /**< True if in the intial stage. */
 195         bool      equilibrateHistogram_;     /**< True if samples are kept from accumulating until the sampled distribution is close enough to the target. */
 196         double    logScaledSampleWeight_;    /**< The log of the current sample weight, scaled because of the histogram rescaling. */
 197         double    maxLogScaledSampleWeight_; /**< Maximum sample weight obtained for previous (smaller) histogram sizes. */
 198
 199         /* Bool to avoid printing multiple, not so useful, messages to log */
 200         bool      havePrintedAboutCovering_; /**< True if we have printed about covering to the log while equilibrateHistogram==true */
 201 };
 202
 203 }      // namespace gmx
 204
 205 #endif /* GMX_AWH_HISTOGRAMSIZE_H */