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Adding a method for estimating coulomb table precision and factoring that into overall kspace precision estimate.

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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@8453 f3b2605a-c512-4ea7-a41b-209d697bcdaa
This commit is contained in:
pscrozi
2012-06-29 22:49:51 +00:00
parent 0c9ab4551e
commit 71f4cdf3f1
5 changed files with 52 additions and 9 deletions
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32
src/kspace.cpp
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@ -17,6 +17,7 @@
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "pair.h"
#include "memory.h"
#include "error.h"
#include "suffix.h"
@ -124,6 +125,37 @@ void KSpace::ev_setup(int eflag, int vflag)
}
}
/* ----------------------------------------------------------------------
estimate the accuracy of the short-range coulomb tables
------------------------------------------------------------------------- */
double KSpace::estimate_table_accuracy(double spr)
{
double table_accuracy = 0.0;
int nctb = force->pair->ncoultablebits;
if (nctb) {
double empirical_precision[17];
empirical_precision[6] = 2.12E-04;
empirical_precision[7] = 4.97E-05;
empirical_precision[8] = 1.24E-05;
empirical_precision[9] = 3.04E-06;
empirical_precision[10] = 8.51E-07;
empirical_precision[11] = 1.85E-07;
empirical_precision[12] = 5.87E-08;
empirical_precision[13] = 2.81E-08;
empirical_precision[14] = 2.20E-08;
empirical_precision[15] = 2.13E-08;
empirical_precision[16] = 2.11E-08;
if (nctb <= 6) table_accuracy = empirical_precision[6];
else if (nctb <= 16) table_accuracy = empirical_precision[nctb];
else table_accuracy = empirical_precision[16];
table_accuracy *= two_charge_force;
if (table_accuracy > spr)
error->warning(FLERR,"For better accuracy use 'pair_modify table 0'");
}
return table_accuracy;
}
/* ----------------------------------------------------------------------
modify parameters of the KSpace style
------------------------------------------------------------------------- */