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37 #ifndef GMX_MDLIB_NSGRID_H
38 #define GMX_MDLIB_NSGRID_H
42 #include "gromacs/math/vectypes.h"
43 #include "gromacs/utility/real.h"
46 struct gmx_domdec_zones_t;
50 /*! \brief Used when estimating the interaction density.
52 * GRID_STDDEV_FAC * stddev estimates the interaction density. The
53 * value sqrt(3) == 1.73205080757 gives a uniform load for a
54 * rectangular 3D block of charge groups. For a sphere, it is not a
55 * bad approximation for 4x1x1 up to 4x2x2.
57 * \todo It would be nicer to use sqrt(3) here, when all code that
58 * includes this file is in C++, which will let us cope with the
59 * std::sqrt<T> on Windows. */
60 static const real GRID_STDDEV_FAC = 1.73205080757;
62 /*! \brief The extent of the neighborsearch grid is a bit larger than sqrt(3)
63 * to account for less dense regions at the edges of the system.
65 static const real NSGRID_STDDEV_FAC = 2.0;
67 #define NSGRID_SIGNAL_MOVED_FAC 4
68 /* A cell index of NSGRID_SIGNAL_MOVED_FAC*ncells signals
69 * that a charge group moved to another DD domain.
72 void get_nsgrid_boundaries(int nboundeddim,
74 struct gmx_domdec_t* dd,
83 /* Return the ns grid boundaries grid_x0 and grid_x1
84 * and the estimate for the grid density.
85 * For non-bounded dimensions the boundaries are determined
86 * from the average and std.dev. of cgcm.
87 * The are determined from box, unless gr0!=NULL or gr1!=NULL,
88 * then they are taken from gr0 or gr1.
89 * With dd and unbounded dimensions, the proper grid borders for cells
90 * on the edges are determined from cgcm.