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angle_class2_omp.cpp
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Wed, Nov 6, 01:28

angle_class2_omp.cpp
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/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing author: Axel Kohlmeyer (Temple U)
------------------------------------------------------------------------- */
#include "lmptype.h"
#include "angle_class2_omp.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "neighbor.h"
#include "domain.h"
#include "math_const.h"
#include <math.h>
using namespace LAMMPS_NS;
using namespace MathConst;
#define SMALL 0.001
/* ---------------------------------------------------------------------- */
void AngleClass2OMP::compute(int eflag, int vflag)
{
if (eflag || vflag) {
ev_setup(eflag,vflag);
} else evflag = 0;
const int nall = atom->nlocal + atom->nghost;
const int nthreads = comm->nthreads;
const int inum = neighbor->nanglelist;
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(eflag,vflag)
#endif
{
int ifrom, ito, tid;
loop_setup_thr(ifrom, ito, tid, inum, nthreads);
ThrData *thr = fix->get_thr(tid);
ev_setup_thr(eflag, vflag, nall, eatom, vatom, thr);
if (evflag) {
if (eflag) {
if (force->newton_bond) eval<1,1,1>(ifrom, ito, thr);
else eval<1,1,0>(ifrom, ito, thr);
} else {
if (force->newton_bond) eval<1,0,1>(ifrom, ito, thr);
else eval<1,0,0>(ifrom, ito, thr);
}
} else {
if (force->newton_bond) eval<0,0,1>(ifrom, ito, thr);
else eval<0,0,0>(ifrom, ito, thr);
}
reduce_thr(this, eflag, vflag, thr);
} // end of omp parallel region
}
template <int EVFLAG, int EFLAG, int NEWTON_BOND>
void AngleClass2OMP::eval(int nfrom, int nto, ThrData * const thr)
{
int i1,i2,i3,n,type;
double delx1,dely1,delz1,delx2,dely2,delz2;
double eangle,f1[3],f3[3];
double dtheta,dtheta2,dtheta3,dtheta4,de_angle;
double dr1,dr2,tk1,tk2,aa1,aa2,aa11,aa12,aa21,aa22;
double rsq1,rsq2,r1,r2,c,s,a,a11,a12,a22,b1,b2;
double vx11,vx12,vy11,vy12,vz11,vz12,vx21,vx22,vy21,vy22,vz21,vz22;
const double * const * const x = atom->x;
double * const * const f = thr->get_f();
const int * const * const anglelist = neighbor->anglelist;
const int nlocal = atom->nlocal;
for (n = nfrom; n < nto; n++) {
i1 = anglelist[n][0];
i2 = anglelist[n][1];
i3 = anglelist[n][2];
type = anglelist[n][3];
// 1st bond
delx1 = x[i1][0] - x[i2][0];
dely1 = x[i1][1] - x[i2][1];
delz1 = x[i1][2] - x[i2][2];
domain->minimum_image(delx1,dely1,delz1);
rsq1 = delx1*delx1 + dely1*dely1 + delz1*delz1;
r1 = sqrt(rsq1);
// 2nd bond
delx2 = x[i3][0] - x[i2][0];
dely2 = x[i3][1] - x[i2][1];
delz2 = x[i3][2] - x[i2][2];
domain->minimum_image(delx2,dely2,delz2);
rsq2 = delx2*delx2 + dely2*dely2 + delz2*delz2;
r2 = sqrt(rsq2);
// angle (cos and sin)
c = delx1*delx2 + dely1*dely2 + delz1*delz2;
c /= r1*r2;
if (c > 1.0) c = 1.0;
if (c < -1.0) c = -1.0;
s = sqrt(1.0 - c*c);
if (s < SMALL) s = SMALL;
s = 1.0/s;
// force & energy for angle term
dtheta = acos(c) - theta0[type];
dtheta2 = dtheta*dtheta;
dtheta3 = dtheta2*dtheta;
dtheta4 = dtheta3*dtheta;
de_angle = 2.0*k2[type]*dtheta + 3.0*k3[type]*dtheta2 +
4.0*k4[type]*dtheta3;
a = -de_angle*s;
a11 = a*c / rsq1;
a12 = -a / (r1*r2);
a22 = a*c / rsq2;
f1[0] = a11*delx1 + a12*delx2;
f1[1] = a11*dely1 + a12*dely2;
f1[2] = a11*delz1 + a12*delz2;
f3[0] = a22*delx2 + a12*delx1;
f3[1] = a22*dely2 + a12*dely1;
f3[2] = a22*delz2 + a12*delz1;
if (EFLAG) eangle = k2[type]*dtheta2 + k3[type]*dtheta3 + k4[type]*dtheta4;
// force & energy for bond-bond term
dr1 = r1 - bb_r1[type];
dr2 = r2 - bb_r2[type];
tk1 = bb_k[type] * dr1;
tk2 = bb_k[type] * dr2;
f1[0] -= delx1*tk2/r1;
f1[1] -= dely1*tk2/r1;
f1[2] -= delz1*tk2/r1;
f3[0] -= delx2*tk1/r2;
f3[1] -= dely2*tk1/r2;
f3[2] -= delz2*tk1/r2;
if (EFLAG) eangle += bb_k[type]*dr1*dr2;
// force & energy for bond-angle term
aa1 = s * dr1 * ba_k1[type];
aa2 = s * dr2 * ba_k2[type];
aa11 = aa1 * c / rsq1;
aa12 = -aa1 / (r1 * r2);
aa21 = aa2 * c / rsq1;
aa22 = -aa2 / (r1 * r2);
vx11 = (aa11 * delx1) + (aa12 * delx2);
vx12 = (aa21 * delx1) + (aa22 * delx2);
vy11 = (aa11 * dely1) + (aa12 * dely2);
vy12 = (aa21 * dely1) + (aa22 * dely2);
vz11 = (aa11 * delz1) + (aa12 * delz2);
vz12 = (aa21 * delz1) + (aa22 * delz2);
aa11 = aa1 * c / rsq2;
aa21 = aa2 * c / rsq2;
vx21 = (aa11 * delx2) + (aa12 * delx1);
vx22 = (aa21 * delx2) + (aa22 * delx1);
vy21 = (aa11 * dely2) + (aa12 * dely1);
vy22 = (aa21 * dely2) + (aa22 * dely1);
vz21 = (aa11 * delz2) + (aa12 * delz1);
vz22 = (aa21 * delz2) + (aa22 * delz1);
b1 = ba_k1[type] * dtheta / r1;
b2 = ba_k2[type] * dtheta / r2;
f1[0] -= vx11 + b1*delx1 + vx12;
f1[1] -= vy11 + b1*dely1 + vy12;
f1[2] -= vz11 + b1*delz1 + vz12;
f3[0] -= vx21 + b2*delx2 + vx22;
f3[1] -= vy21 + b2*dely2 + vy22;
f3[2] -= vz21 + b2*delz2 + vz22;
if (EFLAG) eangle += ba_k1[type]*dr1*dtheta + ba_k2[type]*dr2*dtheta;
// apply force to each of 3 atoms
if (NEWTON_BOND || i1 < nlocal) {
f[i1][0] += f1[0];
f[i1][1] += f1[1];
f[i1][2] += f1[2];
}
if (NEWTON_BOND || i2 < nlocal) {
f[i2][0] -= f1[0] + f3[0];
f[i2][1] -= f1[1] + f3[1];
f[i2][2] -= f1[2] + f3[2];
}
if (NEWTON_BOND || i3 < nlocal) {
f[i3][0] += f3[0];
f[i3][1] += f3[1];
f[i3][2] += f3[2];
}
if (EVFLAG) ev_tally_thr(this,i1,i2,i3,nlocal,NEWTON_BOND,eangle,f1,f3,
delx1,dely1,delz1,delx2,dely2,delz2,thr);
}
}

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