src/gromacs/mdtypes/multipletimestepping.h

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  35 #ifndef GMX_MULTIPLETIMESTEPPING_H
  36 #define GMX_MULTIPLETIMESTEPPING_H
  37
  38 #include <string>
  39 #include <vector>
  40
  41 #include <bitset>
  42
  43 #include "gromacs/utility/arrayref.h"
  44 #include "gromacs/utility/enumerationhelpers.h"
  45
  46 struct t_inputrec;
  47
  48 namespace gmx
  49 {
  50
  51 //! Force group available for selection for multiple time step integration
  52 enum class MtsForceGroups : int
  53 {
  54     LongrangeNonbonded, //!< PME-mesh or Ewald for electrostatics and/or LJ
  55     Nonbonded,          //!< Non-bonded pair interactions
  56     Pair,               //!< Bonded pair interactions
  57     Dihedral,           //!< Dihedrals, including cmap (not restraints)
  58     Angle,              //!< Bonded angle potentials (not restraints)
  59     Pull,               //!< COM pulling
  60     Awh,                //!< Accelerated weight histogram method
  61     Count               //!< The number of groups above
  62 };
  63
  64 //! Names for the MTS force groups
  65 static const gmx::EnumerationArray<MtsForceGroups, std::string> mtsForceGroupNames = {
  66     "longrange-nonbonded", "nonbonded", "pair", "dihedral", "angle", "pull", "awh"
  67 };
  68
  69 //! Setting for a single level for multiple time step integration
  70 struct MtsLevel
  71 {
  72     //! The force group selection for this level;
  73     std::bitset<static_cast<int>(MtsForceGroups::Count)> forceGroups;
  74     //! The factor between the base, fastest, time step and the time step for this level
  75     int stepFactor;
  76 };
  77
  78 /*! \brief Returns the MTS level at which a force group is to be computed
  79  *
  80  * \param[in] mtsLevels  List of force groups for each MTS level, can be empty without MTS
  81  * \param[in] mtsForceGroup  The force group to query the MTS level for
  82  */
  83 static inline int forceGroupMtsLevel(ArrayRef<const MtsLevel> mtsLevels, const MtsForceGroups mtsForceGroup)
  84 {
  85     GMX_ASSERT(mtsLevels.empty() || mtsLevels.size() == 2, "Only 0 or 2 MTS levels are supported");
  86
  87     return (mtsLevels.empty() || mtsLevels[0].forceGroups[static_cast<int>(mtsForceGroup)]) ? 0 : 1;
  88 };
  89
  90 /*! \brief Returns the interval in steps at which the non-bonded pair forces are calculated
  91  *
  92  * Note: returns 1 when multiple time-stepping is not activated.
  93  */
  94 int nonbondedMtsFactor(const t_inputrec& ir);
  95
  96 //! Struct for passing the MTS mdp options to setupMtsLevels()
  97 struct GromppMtsOpts
  98 {
  99     //! The number of MTS levels
 100     int numLevels = 0;
 101     //! The names of the force groups assigned by the user to level 2, internal index 1
 102     std::string level2Forces;
 103     //! The step factor assigned by the user to level 2, internal index 1
 104     int level2Factor = 0;
 105 };
 106
 107 /*! \brief Sets up and returns the MTS levels and checks requirements of MTS
 108  *
 109  * Appends errors about allowed input values ir to errorMessages, when not nullptr.
 110  *
 111  * \param[in]     mtsOpts        Options for setting the MTS levels
 112  * \param[in,out] errorMessages  List of error messages, can be nullptr
 113  */
 114 std::vector<MtsLevel> setupMtsLevels(const GromppMtsOpts& mtsOpts, std::vector<std::string>* errorMessages);
 115
 116 /*! \brief Returns whether we use MTS and the MTS setup is internally valid
 117  *
 118  * Note that setupMtsLevels would have returned at least one error message
 119  * when this function returns false
 120  */
 121 bool haveValidMtsSetup(const t_inputrec& ir);
 122
 123 /*! \brief Checks whether the MTS requirements on other algorithms and output frequencies are met
 124  *
 125  * Note: exits with an assertion failure when
 126  * ir.useMts == true && haveValidMtsSetup(ir) == false
 127  *
 128  * \param[in] ir  Complete input record
 129  * \returns list of error messages, empty when all MTS requirements are met
 130  */
 131 std::vector<std::string> checkMtsRequirements(const t_inputrec& ir);
 132
 133 } // namespace gmx
 134
 135 #endif /* GMX_MULTIPLETIMESTEPPING_H */