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ewald_omp.cpp
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ewald_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 authors: Roy Pollock (LLNL), Paul Crozier (SNL)
------------------------------------------------------------------------- */
#include "mpi.h"
#include "ewald_omp.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "memory.h"
#include <math.h>
#include "math_const.h"
#include "suffix.h"
using namespace LAMMPS_NS;
using namespace MathConst;
#define SMALL 0.00001
/* ---------------------------------------------------------------------- */
EwaldOMP::EwaldOMP(LAMMPS *lmp, int narg, char **arg)
: Ewald(lmp, narg, arg), ThrOMP(lmp, THR_KSPACE)
{
suffix_flag |= Suffix::OMP;
}
/* ---------------------------------------------------------------------- */
void EwaldOMP::allocate()
{
Ewald::allocate();
// always re-allocate for simplicity.
delete[] sfacrl;
delete[] sfacim;
sfacrl = new double[kmax3d*comm->nthreads];
sfacim = new double[kmax3d*comm->nthreads];
}
/* ----------------------------------------------------------------------
compute the Ewald long-range force, energy, virial
------------------------------------------------------------------------- */
void EwaldOMP::compute(int eflag, int vflag)
{
// set energy/virial flags
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = evflag_atom = eflag_global = vflag_global =
eflag_atom = vflag_atom = 0;
// extend size of per-atom arrays if necessary
if (atom->nlocal > nmax) {
memory->destroy(ek);
memory->destroy3d_offset(cs,-kmax_created);
memory->destroy3d_offset(sn,-kmax_created);
nmax = atom->nmax;
memory->create(ek,nmax,3,"ewald:ek");
memory->create3d_offset(cs,-kmax,kmax,3,nmax,"ewald:cs");
memory->create3d_offset(sn,-kmax,kmax,3,nmax,"ewald:sn");
kmax_created = kmax;
}
// partial structure factors on each processor
// total structure factor by summing over procs
eik_dot_r();
MPI_Allreduce(sfacrl,sfacrl_all,kcount,MPI_DOUBLE,MPI_SUM,world);
MPI_Allreduce(sfacim,sfacim_all,kcount,MPI_DOUBLE,MPI_SUM,world);
// K-space portion of electric field
// double loop over K-vectors and local atoms
double * const * const f = atom->f;
const double * const q = atom->q;
const int nthreads = comm->nthreads;
const int nlocal = atom->nlocal;
const double qscale = force->qqrd2e * scale;
double eng_tmp = 0.0;
double v0,v1,v2,v3,v4,v5;
v0=v1=v2=v3=v4=v5=0.0;
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(eflag,vflag) reduction(+:eng_tmp,v0,v1,v2,v3,v4,v5)
#endif
{
int i,j,k,ifrom,ito,tid;
int kx,ky,kz;
double cypz,sypz,exprl,expim,partial;
loop_setup_thr(ifrom, ito, tid, nlocal, nthreads);
ThrData *thr = fix->get_thr(tid);
ev_setup_thr(eflag, vflag, 0, NULL, NULL, thr);
for (i = ifrom; i < ito; i++) {
ek[i][0] = 0.0;
ek[i][1] = 0.0;
ek[i][2] = 0.0;
}
for (k = 0; k < kcount; k++) {
kx = kxvecs[k];
ky = kyvecs[k];
kz = kzvecs[k];
for (i = ifrom; i < ito; i++) {
cypz = cs[ky][1][i]*cs[kz][2][i] - sn[ky][1][i]*sn[kz][2][i];
sypz = sn[ky][1][i]*cs[kz][2][i] + cs[ky][1][i]*sn[kz][2][i];
exprl = cs[kx][0][i]*cypz - sn[kx][0][i]*sypz;
expim = sn[kx][0][i]*cypz + cs[kx][0][i]*sypz;
partial = expim*sfacrl_all[k] - exprl*sfacim_all[k];
ek[i][0] += partial*eg[k][0];
ek[i][1] += partial*eg[k][1];
ek[i][2] += partial*eg[k][2];
if (evflag_atom) {
const double partial_peratom = exprl*sfacrl_all[k] + expim*sfacim_all[k];
if (eflag_atom) eatom[i] += q[i]*ug[k]*partial_peratom;
if (vflag_atom)
for (j = 0; j < 6; j++)
vatom[i][j] += ug[k]*vg[k][j]*partial_peratom;
}
}
}
// convert E-field to force
for (i = ifrom; i < ito; i++) {
const double fac = qscale*q[i];
f[i][0] += fac*ek[i][0];
f[i][1] += fac*ek[i][1];
f[i][2] += fac*ek[i][2];
}
// global energy
if (eflag_global) {
#if defined(_OPENMP)
#pragma omp for private(k)
#endif
for (k = 0; k < kcount; k++)
eng_tmp += ug[k] * (sfacrl_all[k]*sfacrl_all[k] +
sfacim_all[k]*sfacim_all[k]);
}
// global virial
if (vflag_global) {
#if defined(_OPENMP)
#pragma omp for private(k)
#endif
for (k = 0; k < kcount; k++) {
double uk = ug[k] * (sfacrl_all[k]*sfacrl_all[k] + sfacim_all[k]*sfacim_all[k]);
v0 += uk*vg[k][0];
v1 += uk*vg[k][1];
v2 += uk*vg[k][2];
v3 += uk*vg[k][3];
v4 += uk*vg[k][4];
v5 += uk*vg[k][5];
}
}
// per-atom energy/virial
// energy includes self-energy correction
if (evflag_atom) {
if (eflag_atom) {
for (i = ifrom; i < ito; i++) {
eatom[i] -= g_ewald*q[i]*q[i]/MY_PIS + MY_PI2*q[i]*qsum /
(g_ewald*g_ewald*volume);
eatom[i] *= qscale;
}
}
if (vflag_atom)
for (i = ifrom; i < ito; i++)
for (j = 0; j < 6; j++) vatom[i][j] *= q[i]*qscale;
}
reduce_thr(this, eflag,vflag,thr);
} // end of omp parallel region
if (eflag_global) {
eng_tmp -= g_ewald*qsqsum/MY_PIS +
MY_PI2*qsum*qsum / (g_ewald*g_ewald*volume);
energy = eng_tmp * qscale;
}
if (vflag_global) {
virial[0] = v0 * qscale;
virial[1] = v1 * qscale;
virial[2] = v2 * qscale;
virial[3] = v3 * qscale;
virial[4] = v4 * qscale;
virial[5] = v5 * qscale;
}
if (slabflag) slabcorr();
}
/* ---------------------------------------------------------------------- */
void EwaldOMP::eik_dot_r()
{
const double * const * const x = atom->x;
const double * const q = atom->q;
const int nlocal = atom->nlocal;
const int nthreads = comm->nthreads;
#if defined(_OPENMP)
#pragma omp parallel default(none)
#endif
{
int i,ifrom,ito,k,l,m,n,ic,tid;
double cstr1,sstr1,cstr2,sstr2,cstr3,sstr3,cstr4,sstr4;
double sqk,clpm,slpm;
loop_setup_thr(ifrom, ito, tid, nlocal, nthreads);
double * const sfacrl_thr = sfacrl + tid*kmax3d;
double * const sfacim_thr = sfacim + tid*kmax3d;
n = 0;
// (k,0,0), (0,l,0), (0,0,m)
for (ic = 0; ic < 3; ic++) {
sqk = unitk[ic]*unitk[ic];
if (sqk <= gsqmx) {
cstr1 = 0.0;
sstr1 = 0.0;
for (i = ifrom; i < ito; i++) {
cs[0][ic][i] = 1.0;
sn[0][ic][i] = 0.0;
cs[1][ic][i] = cos(unitk[ic]*x[i][ic]);
sn[1][ic][i] = sin(unitk[ic]*x[i][ic]);
cs[-1][ic][i] = cs[1][ic][i];
sn[-1][ic][i] = -sn[1][ic][i];
cstr1 += q[i]*cs[1][ic][i];
sstr1 += q[i]*sn[1][ic][i];
}
sfacrl_thr[n] = cstr1;
sfacim_thr[n++] = sstr1;
}
}
for (m = 2; m <= kmax; m++) {
for (ic = 0; ic < 3; ic++) {
sqk = m*unitk[ic] * m*unitk[ic];
if (sqk <= gsqmx) {
cstr1 = 0.0;
sstr1 = 0.0;
for (i = ifrom; i < ito; i++) {
cs[m][ic][i] = cs[m-1][ic][i]*cs[1][ic][i] -
sn[m-1][ic][i]*sn[1][ic][i];
sn[m][ic][i] = sn[m-1][ic][i]*cs[1][ic][i] +
cs[m-1][ic][i]*sn[1][ic][i];
cs[-m][ic][i] = cs[m][ic][i];
sn[-m][ic][i] = -sn[m][ic][i];
cstr1 += q[i]*cs[m][ic][i];
sstr1 += q[i]*sn[m][ic][i];
}
sfacrl_thr[n] = cstr1;
sfacim_thr[n++] = sstr1;
}
}
}
// 1 = (k,l,0), 2 = (k,-l,0)
for (k = 1; k <= kxmax; k++) {
for (l = 1; l <= kymax; l++) {
sqk = (k*unitk[0] * k*unitk[0]) + (l*unitk[1] * l*unitk[1]);
if (sqk <= gsqmx) {
cstr1 = 0.0;
sstr1 = 0.0;
cstr2 = 0.0;
sstr2 = 0.0;
for (i = ifrom; i < ito; i++) {
cstr1 += q[i]*(cs[k][0][i]*cs[l][1][i] - sn[k][0][i]*sn[l][1][i]);
sstr1 += q[i]*(sn[k][0][i]*cs[l][1][i] + cs[k][0][i]*sn[l][1][i]);
cstr2 += q[i]*(cs[k][0][i]*cs[l][1][i] + sn[k][0][i]*sn[l][1][i]);
sstr2 += q[i]*(sn[k][0][i]*cs[l][1][i] - cs[k][0][i]*sn[l][1][i]);
}
sfacrl_thr[n] = cstr1;
sfacim_thr[n++] = sstr1;
sfacrl_thr[n] = cstr2;
sfacim_thr[n++] = sstr2;
}
}
}
// 1 = (0,l,m), 2 = (0,l,-m)
for (l = 1; l <= kymax; l++) {
for (m = 1; m <= kzmax; m++) {
sqk = (l*unitk[1] * l*unitk[1]) + (m*unitk[2] * m*unitk[2]);
if (sqk <= gsqmx) {
cstr1 = 0.0;
sstr1 = 0.0;
cstr2 = 0.0;
sstr2 = 0.0;
for (i = ifrom; i < ito; i++) {
cstr1 += q[i]*(cs[l][1][i]*cs[m][2][i] - sn[l][1][i]*sn[m][2][i]);
sstr1 += q[i]*(sn[l][1][i]*cs[m][2][i] + cs[l][1][i]*sn[m][2][i]);
cstr2 += q[i]*(cs[l][1][i]*cs[m][2][i] + sn[l][1][i]*sn[m][2][i]);
sstr2 += q[i]*(sn[l][1][i]*cs[m][2][i] - cs[l][1][i]*sn[m][2][i]);
}
sfacrl_thr[n] = cstr1;
sfacim_thr[n++] = sstr1;
sfacrl_thr[n] = cstr2;
sfacim_thr[n++] = sstr2;
}
}
}
// 1 = (k,0,m), 2 = (k,0,-m)
for (k = 1; k <= kxmax; k++) {
for (m = 1; m <= kzmax; m++) {
sqk = (k*unitk[0] * k*unitk[0]) + (m*unitk[2] * m*unitk[2]);
if (sqk <= gsqmx) {
cstr1 = 0.0;
sstr1 = 0.0;
cstr2 = 0.0;
sstr2 = 0.0;
for (i = ifrom; i < ito; i++) {
cstr1 += q[i]*(cs[k][0][i]*cs[m][2][i] - sn[k][0][i]*sn[m][2][i]);
sstr1 += q[i]*(sn[k][0][i]*cs[m][2][i] + cs[k][0][i]*sn[m][2][i]);
cstr2 += q[i]*(cs[k][0][i]*cs[m][2][i] + sn[k][0][i]*sn[m][2][i]);
sstr2 += q[i]*(sn[k][0][i]*cs[m][2][i] - cs[k][0][i]*sn[m][2][i]);
}
sfacrl_thr[n] = cstr1;
sfacim_thr[n++] = sstr1;
sfacrl_thr[n] = cstr2;
sfacim_thr[n++] = sstr2;
}
}
}
// 1 = (k,l,m), 2 = (k,-l,m), 3 = (k,l,-m), 4 = (k,-l,-m)
for (k = 1; k <= kxmax; k++) {
for (l = 1; l <= kymax; l++) {
for (m = 1; m <= kzmax; m++) {
sqk = (k*unitk[0] * k*unitk[0]) + (l*unitk[1] * l*unitk[1]) +
(m*unitk[2] * m*unitk[2]);
if (sqk <= gsqmx) {
cstr1 = 0.0;
sstr1 = 0.0;
cstr2 = 0.0;
sstr2 = 0.0;
cstr3 = 0.0;
sstr3 = 0.0;
cstr4 = 0.0;
sstr4 = 0.0;
for (i = ifrom; i < ito; i++) {
clpm = cs[l][1][i]*cs[m][2][i] - sn[l][1][i]*sn[m][2][i];
slpm = sn[l][1][i]*cs[m][2][i] + cs[l][1][i]*sn[m][2][i];
cstr1 += q[i]*(cs[k][0][i]*clpm - sn[k][0][i]*slpm);
sstr1 += q[i]*(sn[k][0][i]*clpm + cs[k][0][i]*slpm);
clpm = cs[l][1][i]*cs[m][2][i] + sn[l][1][i]*sn[m][2][i];
slpm = -sn[l][1][i]*cs[m][2][i] + cs[l][1][i]*sn[m][2][i];
cstr2 += q[i]*(cs[k][0][i]*clpm - sn[k][0][i]*slpm);
sstr2 += q[i]*(sn[k][0][i]*clpm + cs[k][0][i]*slpm);
clpm = cs[l][1][i]*cs[m][2][i] + sn[l][1][i]*sn[m][2][i];
slpm = sn[l][1][i]*cs[m][2][i] - cs[l][1][i]*sn[m][2][i];
cstr3 += q[i]*(cs[k][0][i]*clpm - sn[k][0][i]*slpm);
sstr3 += q[i]*(sn[k][0][i]*clpm + cs[k][0][i]*slpm);
clpm = cs[l][1][i]*cs[m][2][i] - sn[l][1][i]*sn[m][2][i];
slpm = -sn[l][1][i]*cs[m][2][i] - cs[l][1][i]*sn[m][2][i];
cstr4 += q[i]*(cs[k][0][i]*clpm - sn[k][0][i]*slpm);
sstr4 += q[i]*(sn[k][0][i]*clpm + cs[k][0][i]*slpm);
}
sfacrl_thr[n] = cstr1;
sfacim_thr[n++] = sstr1;
sfacrl_thr[n] = cstr2;
sfacim_thr[n++] = sstr2;
sfacrl_thr[n] = cstr3;
sfacim_thr[n++] = sstr3;
sfacrl_thr[n] = cstr4;
sfacim_thr[n++] = sstr4;
}
}
}
}
sync_threads();
data_reduce_thr(sfacrl,kmax3d,nthreads,1,tid);
data_reduce_thr(sfacim,kmax3d,nthreads,1,tid);
} // end of parallel region
}

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