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Making initial estimate for g_ewald more robust and better documented. 

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@8448 f3b2605a-c512-4ea7-a41b-209d697bcdaa
This commit is contained in:
pscrozi 2012-06-29 22:25:31 +00:00
parent a8338a0263
commit 4323d1522a
4 changed files with 12 additions and 10 deletions
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7
src/KSPACE/ewald.cpp
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@ -157,10 +157,11 @@ void Ewald::init()
// zprd used rather than zprd_slab // zprd used rather than zprd_slab
if (!gewaldflag) { if (!gewaldflag) {
if (accuracy <= 0.0)
error->all(FLERR,"KSpace accuracy must be > 0");
g_ewald = accuracy*sqrt(natoms*cutoff*xprd*yprd*zprd) / (2.0*q2); g_ewald = accuracy*sqrt(natoms*cutoff*xprd*yprd*zprd) / (2.0*q2);
if (g_ewald >= 1.0) if (g_ewald >= 1.0) g_ewald = (1.35 - 0.15*log(accuracy))/cutoff;
error->all(FLERR,"KSpace accuracy too large to estimate G vector"); else g_ewald = sqrt(-log(g_ewald)) / cutoff;
g_ewald = sqrt(-log(g_ewald)) / cutoff;
} }
// setup Ewald coefficients so can print stats // setup Ewald coefficients so can print stats

4
src/KSPACE/ewald.h
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@ -119,9 +119,9 @@ W: System is not charge neutral, net charge = %g
The total charge on all atoms on the system is not 0.0, which The total charge on all atoms on the system is not 0.0, which
is not valid for Ewald or PPPM. is not valid for Ewald or PPPM.
E: KSpace accuracy too large to estimate G vector E: KSpace accuracy must be > 0
UNDOCUMENTED The kspace accuracy designated in the input must be greater than zero.
E: Cannot (yet) use Kspace slab correction with compute group/group E: Cannot (yet) use Kspace slab correction with compute group/group

7
src/KSPACE/pppm.cpp
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@ -1003,10 +1003,11 @@ void PPPM::set_grid()
bigint natoms = atom->natoms; bigint natoms = atom->natoms;
if (!gewaldflag) { if (!gewaldflag) {
if (accuracy <= 0.0)
error->all(FLERR,"KSpace accuracy must be > 0");
g_ewald = accuracy*sqrt(natoms*cutoff*xprd*yprd*zprd) / (2.0*q2); g_ewald = accuracy*sqrt(natoms*cutoff*xprd*yprd*zprd) / (2.0*q2);
if (g_ewald >= 1.0) if (g_ewald >= 1.0) g_ewald = (1.35 - 0.15*log(accuracy))/cutoff;
error->all(FLERR,"KSpace accuracy too large to estimate G vector"); else g_ewald = sqrt(-log(g_ewald)) / cutoff;
g_ewald = sqrt(-log(g_ewald)) / cutoff;
} }
// set optimal nx_pppm,ny_pppm,nz_pppm based on order and accuracy // set optimal nx_pppm,ny_pppm,nz_pppm based on order and accuracy

4
src/KSPACE/pppm.h
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@ -245,9 +245,9 @@ to run, but can reduce the order no further. Try increasing the
accuracy of PPPM by reducing the tolerance size, thus inducing a accuracy of PPPM by reducing the tolerance size, thus inducing a
larger PPPM grid. larger PPPM grid.
E: KSpace accuracy too large to estimate G vector E: KSpace accuracy must be > 0
UNDOCUMENTED The kspace accuracy designated in the input must be greater than zero.
E: Cannot compute PPPM G E: Cannot compute PPPM G