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39 * Declares the DimParams struct and AWH vector types.
41 * This class holds the physical information for a dimension
42 * of the bias reaction-coordinate grid.
44 * \author Viveca Lindahl
45 * \author Berk Hess <hess@kth.se>
49 #ifndef GMX_AWH_DIMPARAMS_H
50 #define GMX_AWH_DIMPARAMS_H
55 #include "gromacs/math/vectypes.h"
56 #include "gromacs/utility/basedefinitions.h"
61 //! The maximum dimensionality of the AWH coordinate.
62 static const int c_biasMaxNumDim = 4;
64 //! A real vector in AWH coordinate space.
65 typedef double awh_dvec[c_biasMaxNumDim];
67 //! An integer vector in AWH coordinate space.
68 typedef int awh_ivec[c_biasMaxNumDim];
70 /*! \internal \brief Constant parameters for each dimension of the coordinate.
74 /*! \internal \brief Type for storing dimension parameters for pull type dimensions
78 const double k; /**< Force constant (kJ/mol/nm^2) for each coordinate dimension. */
79 const double betak; /**< Inverse variance (1/nm^2) for each coordinate dimension. */
80 const double userCoordUnitsToInternal; /**< Conversion factor coordinate units. */
83 /*! \internal \brief Type for storing dimension parameters for free-energy lamdba type dimensions
87 const double beta; /**< 1/(k_B T). */
88 const int numFepLambdaStates; /**< Number of lambda points in this dimension. */
93 * Private constructor called by public builder functions for PullDimParams and FepLambdaDimParams.
95 DimParams(double conversionFactor, std::variant<PullDimParams, FepDimParams> dimParams) :
96 dimParams(std::move(dimParams)),
97 userCoordUnitsToInternal(conversionFactor)
103 * Builder function for pull dimension parameters.
105 * \param[in] conversionFactor Conversion factor from user coordinate units to bias internal
106 * units (=DEG2RAD for angles).
107 * \param[in] forceConstant The harmonic force constant.
108 * \param[in] beta 1/(k_B T).
110 static DimParams pullDimParams(double conversionFactor, double forceConstant, double beta)
112 PullDimParams pullDimParams = { forceConstant, forceConstant * beta };
114 return DimParams(conversionFactor, pullDimParams);
118 * Builder function for FEP lambda dimension parameters.
120 * \param[in] numFepLambdaStates Number of lambda states in the system.
121 * \param[in] beta 1/(k_B T).
123 static DimParams fepLambdaDimParams(int numFepLambdaStates, double beta)
125 FepDimParams fepDimParams = { beta, numFepLambdaStates };
127 return DimParams(1.0, fepDimParams);
130 //! Returns whether this dimension is coupled to a pull coordinate.
131 bool isPullDimension() const { return std::holds_alternative<PullDimParams>(dimParams); }
133 //! Returns whether this dimension has lambda states and thereby is a dimension coupled to lambda.
134 bool isFepLambdaDimension() const { return std::holds_alternative<FepDimParams>(dimParams); }
136 //! Returns pull dimension parameters, only call for pull dimensions
137 const PullDimParams& pullDimParams() const { return std::get<PullDimParams>(dimParams); }
139 //! Returns FEP dimension parameters, only call for FEP dimensions
140 const FepDimParams& fepDimParams() const { return std::get<FepDimParams>(dimParams); }
142 /*! \brief Convert internal coordinate units to external, user coordinate units.
144 * \param[in] value Value to convert.
145 * \returns the converted value.
147 double scaleInternalToUserInput(double value) const { return value / userCoordUnitsToInternal; }
149 /*! \brief Convert external, user coordinate units to internal coordinate units.
151 * \param[in] value Value to convert.
152 * \returns the converted value.
154 double scaleUserInputToInternal(double value) const { return value * userCoordUnitsToInternal; }
156 //! Parameters for pull dimensions, either type pull or free-energy lambda
157 const std::variant<PullDimParams, FepDimParams> dimParams;
158 //! Conversion factor for ordinate units
159 const double userCoordUnitsToInternal;
164 #endif /* GMX_AWH_DIMPARAMS_H */