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36 #ifndef GMX_MDTYPES_INTERACTION_CONST_H
37 #define GMX_MDTYPES_INTERACTION_CONST_H
42 #include "gromacs/mdtypes/md_enums.h"
43 #include "gromacs/utility/alignedallocator.h"
44 #include "gromacs/utility/basedefinitions.h"
45 #include "gromacs/utility/real.h"
47 /* Used with force switching or a constant potential shift:
48 * rsw = max(r - r_switch, 0)
49 * force/p = r^-(p+1) + c2*rsw^2 + c3*rsw^3
50 * potential = r^-p + c2/3*rsw^3 + c3/4*rsw^4 + cpot
51 * With a constant potential shift c2 and c3 are both 0.
60 /* Used with potential switching:
61 * rsw = max(r - r_switch, 0)
62 * sw = 1 + c3*rsw^3 + c4*rsw^4 + c5*rsw^5
63 * dsw = 3*c3*rsw^2 + 4*c4*rsw^3 + 5*c5*rsw^4
64 * force = force*dsw - potential*sw
67 struct switch_consts_t
74 /* Convenience type for vector with aligned memory */
76 using AlignedVector
= std::vector
<T
, gmx::AlignedAllocator
<T
>>;
78 /* Force/energy interpolation tables for Ewald long-range corrections
80 * Interpolation is linear for the force, quadratic for the potential.
82 struct EwaldCorrectionTables
84 // 1/table_spacing, units 1/nm
87 AlignedVector
<real
> tableF
;
89 AlignedVector
<real
> tableV
;
90 // Coulomb force+energy table, size of array is tabq_size*4,
91 // entry quadruplets are: F[i], F[i+1]-F[i], V[i], 0,
92 // this is used with 4-wide SIMD for aligned loads
93 AlignedVector
<real
> tableFDV0
;
96 /* The physical interaction parameters for non-bonded interaction calculations
98 * This struct contains copies of the physical interaction parameters
99 * from the user input as well as processed values that are need in
100 * non-bonded interaction kernels.
102 * The default constructor gives plain Coulomb and LJ interactions cut off
103 * a 1 nm without potential shifting and a Coulomb pre-factor of 1.
105 struct interaction_const_t
107 int cutoff_scheme
= ecutsVERLET
;
110 int vdwtype
= evdwCUT
;
111 int vdw_modifier
= eintmodNONE
;
114 real rvdw_switch
= 0;
115 struct shift_consts_t dispersion_shift
= { 0, 0, 0 };
116 struct shift_consts_t repulsion_shift
= { 0, 0, 0 };
117 struct switch_consts_t vdw_switch
= { 0, 0, 0 };
118 gmx_bool useBuckingham
= false;
119 real buckinghamBMax
= 0;
121 /* type of electrostatics */
122 int eeltype
= eelCUT
;
123 int coulomb_modifier
= eintmodNONE
;
127 real rcoulomb_switch
= 0;
130 real ewaldcoeff_q
= 0;
131 real ewaldcoeff_lj
= 0;
132 int ljpme_comb_rule
= eljpmeGEOM
; /* LJ combination rule for the LJ PME mesh part */
133 real sh_ewald
= 0; /* -sh_ewald is added to the direct space potential */
134 real sh_lj_ewald
= 0; /* sh_lj_ewald is added to the correction potential */
136 /* Dielectric constant resp. multiplication factor for charges */
140 /* Constants for reaction-field or plain cut-off */
145 // Coulomb Ewald correction table
146 std::unique_ptr
<EwaldCorrectionTables
> coulombEwaldTables
;
147 /* Note that a Van der Waals Ewald correction table
148 * of type EwaldCorrectionTables can be added here if wanted.