MD-Bench/gromacs/force_eam.c

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/*
* Copyright (C) 2022 NHR@FAU, University Erlangen-Nuremberg.
* All rights reserved. This file is part of MD-Bench.
* Use of this source code is governed by a LGPL-3.0
* license that can be found in the LICENSE file.
*/
#include <likwid-marker.h>
#include <math.h>
#include <allocate.h>
#include <timing.h>
#include <neighbor.h>
#include <parameter.h>
#include <atom.h>
#include <stats.h>
#include <eam.h>
#include <util.h>
double computeForceEam(Eam* eam, Parameter* param, Atom *atom, Neighbor *neighbor, Stats *stats) {
/*
if(eam->nmax < atom->Nmax) {
eam->nmax = atom->Nmax;
if(eam->fp != NULL) { free(eam->fp); }
eam->fp = (MD_FLOAT *) allocate(ALIGNMENT, atom->Nmax * sizeof(MD_FLOAT));
}
int Nlocal = atom->Nlocal;
int* neighs;
MD_FLOAT* fx = atom->fx; MD_FLOAT* fy = atom->fy; MD_FLOAT* fz = atom->fz; int ntypes = atom->ntypes; MD_FLOAT* fp = eam->fp;
MD_FLOAT* rhor_spline = eam->rhor_spline; MD_FLOAT* frho_spline = eam->frho_spline; MD_FLOAT* z2r_spline = eam->z2r_spline;
MD_FLOAT rdr = eam->rdr; int nr = eam->nr; int nr_tot = eam->nr_tot; MD_FLOAT rdrho = eam->rdrho;
int nrho = eam->nrho; int nrho_tot = eam->nrho_tot;
*/
double S = getTimeStamp();
LIKWID_MARKER_START("force_eam_fp");
/*
#pragma omp parallel for
for(int i = 0; i < Nlocal; i++) {
neighs = &neighbor->neighbors[i * neighbor->maxneighs];
int numneighs = neighbor->numneigh[i];
MD_FLOAT xtmp = atom_x(i);
MD_FLOAT ytmp = atom_y(i);
MD_FLOAT ztmp = atom_z(i);
MD_FLOAT rhoi = 0;
#ifdef EXPLICIT_TYPES
const int type_i = atom->type[i];
#endif
#pragma ivdep
for(int k = 0; k < numneighs; k++) {
int j = neighs[k];
MD_FLOAT delx = xtmp - atom_x(j);
MD_FLOAT dely = ytmp - atom_y(j);
MD_FLOAT delz = ztmp - atom_z(j);
MD_FLOAT rsq = delx * delx + dely * dely + delz * delz;
#ifdef EXPLICIT_TYPES
const int type_j = atom->type[j];
const int type_ij = type_i * ntypes + type_j;
const MD_FLOAT cutforcesq = atom->cutforcesq[type_ij];
#else
const MD_FLOAT cutforcesq = param->cutforce * param->cutforce;
#endif
if(rsq < cutforcesq) {
MD_FLOAT p = sqrt(rsq) * rdr + 1.0;
int m = (int)(p);
m = m < nr - 1 ? m : nr - 1;
p -= m;
p = p < 1.0 ? p : 1.0;
#ifdef EXPLICIT_TYPES
rhoi += ((rhor_spline[type_ij * nr_tot + m * 7 + 3] * p +
rhor_spline[type_ij * nr_tot + m * 7 + 4]) * p +
rhor_spline[type_ij * nr_tot + m * 7 + 5]) * p +
rhor_spline[type_ij * nr_tot + m * 7 + 6];
#else
rhoi += ((rhor_spline[m * 7 + 3] * p +
rhor_spline[m * 7 + 4]) * p +
rhor_spline[m * 7 + 5]) * p +
rhor_spline[m * 7 + 6];
#endif
}
}
#ifdef EXPLICIT_TYPES
const int type_ii = type_i * type_i;
#endif
MD_FLOAT p = 1.0 * rhoi * rdrho + 1.0;
int m = (int)(p);
m = MAX(1, MIN(m, nrho - 1));
p -= m;
p = MIN(p, 1.0);
#ifdef EXPLICIT_TYPES
fp[i] = (frho_spline[type_ii * nrho_tot + m * 7 + 0] * p +
frho_spline[type_ii * nrho_tot + m * 7 + 1]) * p +
frho_spline[type_ii * nrho_tot + m * 7 + 2];
#else
fp[i] = (frho_spline[m * 7 + 0] * p + frho_spline[m * 7 + 1]) * p + frho_spline[m * 7 + 2];
#endif
}
LIKWID_MARKER_STOP("force_eam_fp");
// We still need to update fp for PBC atoms
for(int i = 0; i < atom->Nghost; i++) {
fp[Nlocal + i] = fp[atom->border_map[i]];
}
LIKWID_MARKER_START("force_eam");
for(int i = 0; i < Nlocal; i++) {
neighs = &neighbor->neighbors[i * neighbor->maxneighs];
int numneighs = neighbor->numneigh[i];
MD_FLOAT xtmp = atom_x(i);
MD_FLOAT ytmp = atom_y(i);
MD_FLOAT ztmp = atom_z(i);
MD_FLOAT fix = 0;
MD_FLOAT fiy = 0;
MD_FLOAT fiz = 0;
#ifdef EXPLICIT_TYPES
const int type_i = atom->type[i];
#endif
#pragma ivdep
for(int k = 0; k < numneighs; k++) {
int j = neighs[k];
MD_FLOAT delx = xtmp - atom_x(j);
MD_FLOAT dely = ytmp - atom_y(j);
MD_FLOAT delz = ztmp - atom_z(j);
MD_FLOAT rsq = delx * delx + dely * dely + delz * delz;
#ifdef EXPLICIT_TYPES
const int type_j = atom->type[j];
const int type_ij = type_i * ntypes + type_j;
const MD_FLOAT cutforcesq = atom->cutforcesq[type_ij];
#else
const MD_FLOAT cutforcesq = param->cutforce * param->cutforce;
#endif
if(rsq < cutforcesq) {
MD_FLOAT r = sqrt(rsq);
MD_FLOAT p = r * rdr + 1.0;
int m = (int)(p);
m = m < nr - 1 ? m : nr - 1;
p -= m;
p = p < 1.0 ? p : 1.0;
// rhoip = derivative of (density at atom j due to atom i)
// rhojp = derivative of (density at atom i due to atom j)
// phi = pair potential energy
// phip = phi'
// z2 = phi * r
// z2p = (phi * r)' = (phi' r) + phi
// psip needs both fp[i] and fp[j] terms since r_ij appears in two
// terms of embed eng: Fi(sum rho_ij) and Fj(sum rho_ji)
// hence embed' = Fi(sum rho_ij) rhojp + Fj(sum rho_ji) rhoip
#ifdef EXPLICIT_TYPES
MD_FLOAT rhoip = (rhor_spline[type_ij * nr_tot + m * 7 + 0] * p +
rhor_spline[type_ij * nr_tot + m * 7 + 1]) * p +
rhor_spline[type_ij * nr_tot + m * 7 + 2];
MD_FLOAT z2p = (z2r_spline[type_ij * nr_tot + m * 7 + 0] * p +
z2r_spline[type_ij * nr_tot + m * 7 + 1]) * p +
z2r_spline[type_ij * nr_tot + m * 7 + 2];
MD_FLOAT z2 = ((z2r_spline[type_ij * nr_tot + m * 7 + 3] * p +
z2r_spline[type_ij * nr_tot + m * 7 + 4]) * p +
z2r_spline[type_ij * nr_tot + m * 7 + 5]) * p +
z2r_spline[type_ij * nr_tot + m * 7 + 6];
#else
MD_FLOAT rhoip = (rhor_spline[m * 7 + 0] * p + rhor_spline[m * 7 + 1]) * p + rhor_spline[m * 7 + 2];
MD_FLOAT z2p = (z2r_spline[m * 7 + 0] * p + z2r_spline[m * 7 + 1]) * p + z2r_spline[m * 7 + 2];
MD_FLOAT z2 = ((z2r_spline[m * 7 + 3] * p +
z2r_spline[m * 7 + 4]) * p +
z2r_spline[m * 7 + 5]) * p +
z2r_spline[m * 7 + 6];
#endif
MD_FLOAT recip = 1.0 / r;
MD_FLOAT phi = z2 * recip;
MD_FLOAT phip = z2p * recip - phi * recip;
MD_FLOAT psip = fp[i] * rhoip + fp[j] * rhoip + phip;
MD_FLOAT fpair = -psip * recip;
fix += delx * fpair;
fiy += dely * fpair;
fiz += delz * fpair;
//fpair *= 0.5;
}
}
fx[i] = fix;
fy[i] = fiy;
fz[i] = fiz;
addStat(stats->total_force_neighs, numneighs);
addStat(stats->total_force_iters, (numneighs + VECTOR_WIDTH - 1) / VECTOR_WIDTH);
}
*/
LIKWID_MARKER_STOP("force_eam");
double E = getTimeStamp();
return E-S;
}