src/gromacs/awh/pointstate.cpp

   1 /*
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   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,
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  35
  36 /*! \internal \file
  37  * \brief
  38  * Implements the one method of the PointState class called only for one point per step.
  39  *
  40  * \author Viveca Lindahl
  41  * \author Berk Hess <hess@kth.se>
  42  * \ingroup module_awh
  43  */
  44
  45 #include "gmxpre.h"
  46
  47 #include "pointstate.h"
  48
  49 namespace gmx
  50 {
  51
  52 namespace
  53 {
  54
  55 /*! \brief Returns the exponent c where exp(c) = exp(a) + exp(b).
  56  *
  57  * \param[in] a  First exponent.
  58  * \param[in] b  Second exponent.
  59  * \returns c.
  60  */
  61 double expSum(double a,
  62               double b)
  63 {
  64     return (a > b ? a : b) + std::log1p(std::exp(-std::fabs(a - b)));
  65 }
  66
  67 }   // namespace
  68
  69 void PointState::samplePmf(double convolvedBias)
  70 {
  71     if (inTargetRegion())
  72     {
  73         logPmfSum_           = expSum(logPmfSum_, -convolvedBias);
  74         numVisitsIteration_ += 1;
  75     }
  76 }
  77
  78 } // namespace gmx