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38 /* The gmx_bools indicate whether a field was read from the trajectory.
39 * Do not try to use a pointer when its gmx_bool is FALSE, as memory might
42 #ifndef GMX_TRAJECTORY_TRX_H
43 #define GMX_TRAJECTORY_TRX_H
49 #include "gromacs/math/vectypes.h"
50 #include "gromacs/utility/arrayref.h"
51 #include "gromacs/utility/basedefinitions.h"
52 #include "gromacs/utility/real.h"
56 typedef struct t_trxframe // NOLINT (clang-analyzer-optin.performance.Padding)
58 int not_ok; /* integrity flags */
59 gmx_bool bDouble; /* Double precision? */
60 int natoms; /* number of atoms (atoms, x, v, f, index) */
62 int64_t step; /* MD step number */
64 real time; /* time of the frame */
66 gmx_bool bFepState; /* does it contain fep_state? */
67 real lambda; /* free energy perturbation lambda */
68 int fep_state; /* which fep state are we in? */
70 t_atoms* atoms; /* atoms struct (natoms) */
72 real prec; /* precision of x, fraction of 1 nm */
74 rvec* x; /* coordinates (natoms) */
76 rvec* v; /* velocities (natoms) */
78 rvec* f; /* forces (natoms) */
80 matrix box; /* the 3 box vectors */
82 int ePBC; /* the type of pbc */
84 int* index; /* atom indices of contained coordinates */
87 void comp_frame(FILE* fp, t_trxframe* fr1, t_trxframe* fr2, gmx_bool bRMSD, real ftol, real abstol);
89 void done_frame(t_trxframe* frame);
94 /*!\brief A 3x3 matrix data type useful for simulation boxes
96 * \todo Implement a full replacement for C-style real[DIM][DIM] */
97 using BoxMatrix = std::array<std::array<real, DIM>, DIM>;
100 * \brief Contains a valid trajectory frame.
102 * Valid frames have a step and time, but need not have any particular
105 * \todo Eventually t_trxframe should be replaced by a class such as
106 * this. Currently we need to introduce BoxMatrix so that we can have
107 * a normal C++ getter that returns the contents of a box matrix,
108 * since you cannot use a real[DIM][DIM] as a function return type.
110 * \todo Consider a std::optional work-alike type for expressing that
111 * a field may or may not have content. */
112 class TrajectoryFrame
115 /*! \brief Constructor
117 * \throws APIError If \c frame lacks either step or time.
119 explicit TrajectoryFrame(const t_trxframe& frame);
120 /*! \brief Return a string that helps users identify this frame, containing time and step number.
122 * \throws std::bad_alloc when out of memory */
123 std::string frameName() const;
124 //! Step number read from the trajectory file frame.
125 std::int64_t step() const;
126 //! Time read from the trajectory file frame.
128 //! The PBC characteristics of the box.
130 //! Get a view of position coordinates of the frame (which could be empty).
131 ArrayRef<const RVec> x() const;
132 //! Get a view of velocity coordinates of the frame (which could be empty).
133 ArrayRef<const RVec> v() const;
134 //! Get a view of force coordinates of the frame (which could be empty).
135 ArrayRef<const RVec> f() const;
136 //! Return whether the frame has a box.
138 //! Return a handle to the frame's box, which is all zero if the frame has no box.
139 const BoxMatrix& box() const;
142 //! Handle to trajectory data
143 const t_trxframe& frame_;
144 //! Box matrix data from the frame_.