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Classes | Functions
#include "gromacs/math/vec.h"
#include "gromacs/mdtypes/inputrec.h"
#include "gromacs/pbcutil/pbc.h"
#include "gromacs/utility/gmxassert.h"
#include "gromacs/utility/real.h"
+ Include dependency graph for ewald_utils.h:

Description

Declares utility functions related to Ewald.

Author
Mark Abraham mark..nosp@m.j.ab.nosp@m.raham.nosp@m.@gma.nosp@m.il.co.nosp@m.m
Szilárd Páll pall..nosp@m.szil.nosp@m.ard@g.nosp@m.mail.nosp@m..com

Classes

class  EwaldBoxZScaler
 Class to handle box scaling for Ewald and PME. More...
 

Functions

real calc_ewaldcoeff_q (real rc, real rtol)
 Computes the Ewald splitting coefficient for Coulomb. More...
 
real calc_ewaldcoeff_lj (real rc, real rtol)
 Computes the Ewald splitting coefficient for LJ. More...
 

Function Documentation

real calc_ewaldcoeff_lj ( real  rc,
real  rtol 
)

Computes the Ewald splitting coefficient for LJ.

Returns a value of beta that satisfies dtol > erfc(beta * rc) * (1

  • beta^2 * rc^2 + 0.5 * beta^4 * rc^4) (and is very close to equality), which is used in LJ-PME.
Parameters
[in]rcCutoff radius
[in]rtolRequired maximum value of the short-ranged potential at the cutoff (ie. ewald-rtol-lj)
Returns
The value of the splitting coefficient that produces the required dtol at rc.
real calc_ewaldcoeff_q ( real  rc,
real  rtol 
)

Computes the Ewald splitting coefficient for Coulomb.

Returns a value of beta that satisfies rtol > erfc(beta * rc) (and is very close to equality). That value is used the same way in all Coulomb-based Ewald methods.

Parameters
[in]rcCutoff radius
[in]rtolRequired maximum value of the short-ranged potential at the cutoff (ie. ewald-rtol)
Returns
The value of the splitting coefficient that produces the required dtol at rc.