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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@6499 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2011-07-01 15:38:33 +00:00
parent 32a2028114
commit f19afbe481
3 changed files with 123 additions and 99 deletions
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35
src/KSPACE/pppm_tip4p.cpp
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@ -149,6 +149,7 @@ void PPPMTIP4P::fieldforce()
int iH1,iH2;
double xM[3];
double fx,fy,fz;
double ddotf, rOM[3], f1[3];
// loop over my charges, interpolate electric field from nearby grid points
// (nx,ny,nz) = global coords of grid pt to "lower left" of charge
@ -207,17 +208,27 @@ void PPPMTIP4P::fieldforce()
fz = qqrd2e * q[i] * ek[2];
find_M(i,iH1,iH2,xM);
f[i][0] += fx*(1.0-2.0*alpha);
f[i][1] += fy*(1.0-2.0*alpha);
f[i][2] += fz*(1.0-2.0*alpha);
rOM[0] = xM[0] - x[i][0];
rOM[1] = xM[1] - x[i][1];
rOM[2] = xM[2] - x[i][2];
ddotf = (rOM[0] * fx + rOM[1] * fy + rOM[2] * fz) / (qdist * qdist);
f[iH1][0] += alpha*(fx);
f[iH1][1] += alpha*(fy);
f[iH1][2] += alpha*(fz);
f1[0] = ddotf * rOM[0];
f1[1] = ddotf * rOM[1];
f1[2] = ddotf * rOM[2];
f[iH2][0] += alpha*(fx);
f[iH2][1] += alpha*(fy);
f[iH2][2] += alpha*(fz);
f[i][0] += fx - alpha * (fx - f1[0]);
f[i][1] += fy - alpha * (fy - f1[1]);
f[i][2] += fz - alpha * (fz - f1[2]);
f[iH1][0] += 0.5*alpha*(fx - f1[0]);
f[iH1][1] += 0.5*alpha*(fy - f1[1]);
f[iH1][2] += 0.5*alpha*(fz - f1[2]);
f[iH2][0] += 0.5*alpha*(fx - f1[0]);
f[iH2][1] += 0.5*alpha*(fy - f1[1]);
f[iH2][2] += 0.5*alpha*(fz - f1[2]);
}
}
}
@ -249,7 +260,7 @@ void PPPMTIP4P::find_M(int i, int &iH1, int &iH2, double *xM)
double delz2 = x[iH2][2] - x[i][2];
domain->minimum_image(delx2,dely2,delz2);
xM[0] = x[i][0] + alpha * (delx1 + delx2);
xM[1] = x[i][1] + alpha * (dely1 + dely2);
xM[2] = x[i][2] + alpha * (delz1 + delz2);
xM[0] = x[i][0] + alpha * 0.5 * (delx1 + delx2);
xM[1] = x[i][1] + alpha * 0.5 * (dely1 + dely2);
xM[2] = x[i][2] + alpha * 0.5 * (delz1 + delz2);
}