341 lines
12 KiB
C++
341 lines
12 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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https://www.lammps.org/, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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/* ----------------------------------------------------------------------
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Contributing author: Mike Brown (SNL)
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------------------------------------------------------------------------- */
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#include "pair_lj_spica_coul_long_gpu.h"
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#include "atom.h"
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#include "domain.h"
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#include "error.h"
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#include "force.h"
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#include "gpu_extra.h"
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#include "kspace.h"
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#include "neigh_list.h"
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#include "neighbor.h"
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#include "suffix.h"
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#include <cmath>
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#define EWALD_F 1.12837917
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#define EWALD_P 0.3275911
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#define A1 0.254829592
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#define A2 -0.284496736
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#define A3 1.421413741
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#define A4 -1.453152027
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#define A5 1.061405429
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using namespace LAMMPS_NS;
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// External functions from cuda library for atom decomposition
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int spical_gpu_init(const int ntypes, double **cutsq, int **lj_type, double **host_lj1,
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double **host_lj2, double **host_lj3, double **host_lj4, double **offset,
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double *special_lj, const int nlocal, const int nall, const int max_nbors,
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const int maxspecial, const double cell_size, int &gpu_mode, FILE *screen,
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double **host_cut_ljsq, double host_cut_coulsq, double *host_special_coul,
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const double qqrd2e, const double g_ewald);
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void spical_gpu_clear();
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int **spical_gpu_compute_n(const int ago, const int inum, const int nall, double **host_x,
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int *host_type, double *sublo, double *subhi, tagint *tag, int **nspecial,
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tagint **special, const bool eflag, const bool vflag, const bool eatom,
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const bool vatom, int &host_start, int **ilist, int **jnum,
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const double cpu_time, bool &success, double *host_q, double *boxlo,
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double *prd);
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void spical_gpu_compute(const int ago, const int inum, const int nall, double **host_x,
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int *host_type, int *ilist, int *numj, int **firstneigh, const bool eflag,
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const bool vflag, const bool eatom, const bool vatom, int &host_start,
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const double cpu_time, bool &success, double *host_q, const int nlocal,
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double *boxlo, double *prd);
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double spical_gpu_bytes();
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#include "lj_spica_common.h"
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using namespace LJSPICAParms;
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/* ---------------------------------------------------------------------- */
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PairLJSPICACoulLongGPU::PairLJSPICACoulLongGPU(LAMMPS *lmp) :
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PairLJSPICACoulLong(lmp), gpu_mode(GPU_FORCE)
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{
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respa_enable = 0;
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reinitflag = 0;
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cpu_time = 0.0;
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suffix_flag |= Suffix::GPU;
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GPU_EXTRA::gpu_ready(lmp->modify, lmp->error);
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}
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/* ----------------------------------------------------------------------
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free all arrays
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------------------------------------------------------------------------- */
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PairLJSPICACoulLongGPU::~PairLJSPICACoulLongGPU()
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{
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spical_gpu_clear();
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}
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/* ---------------------------------------------------------------------- */
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void PairLJSPICACoulLongGPU::compute(int eflag, int vflag)
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{
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ev_init(eflag, vflag);
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int nall = atom->nlocal + atom->nghost;
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int inum, host_start;
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bool success = true;
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int *ilist, *numneigh, **firstneigh;
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if (gpu_mode != GPU_FORCE) {
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double sublo[3], subhi[3];
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if (domain->triclinic == 0) {
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sublo[0] = domain->sublo[0];
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sublo[1] = domain->sublo[1];
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sublo[2] = domain->sublo[2];
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subhi[0] = domain->subhi[0];
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subhi[1] = domain->subhi[1];
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subhi[2] = domain->subhi[2];
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} else {
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domain->bbox(domain->sublo_lamda, domain->subhi_lamda, sublo, subhi);
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}
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inum = atom->nlocal;
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firstneigh = spical_gpu_compute_n(neighbor->ago, inum, nall, atom->x, atom->type, sublo, subhi,
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atom->tag, atom->nspecial, atom->special, eflag, vflag,
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eflag_atom, vflag_atom, host_start, &ilist, &numneigh, cpu_time,
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success, atom->q, domain->boxlo, domain->prd);
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} else {
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inum = list->inum;
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ilist = list->ilist;
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numneigh = list->numneigh;
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firstneigh = list->firstneigh;
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spical_gpu_compute(neighbor->ago, inum, nall, atom->x, atom->type, ilist, numneigh, firstneigh,
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eflag, vflag, eflag_atom, vflag_atom, host_start, cpu_time, success, atom->q,
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atom->nlocal, domain->boxlo, domain->prd);
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}
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if (!success) error->one(FLERR, "Insufficient memory on accelerator");
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if (host_start < inum) {
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cpu_time = platform::walltime();
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if (evflag) {
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if (eflag)
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cpu_compute<1, 1>(host_start, inum, ilist, numneigh, firstneigh);
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else
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cpu_compute<1, 0>(host_start, inum, ilist, numneigh, firstneigh);
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} else
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cpu_compute<0, 0>(host_start, inum, ilist, numneigh, firstneigh);
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cpu_time = platform::walltime() - cpu_time;
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}
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}
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/* ----------------------------------------------------------------------
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init specific to this pair style
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------------------------------------------------------------------------- */
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void PairLJSPICACoulLongGPU::init_style()
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{
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if (!atom->q_flag) error->all(FLERR, "Pair style lj/spica/coul/long/gpu requires atom attribute q");
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// Repeat cutsq calculation because done after call to init_style
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double maxcut = -1.0;
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double cut;
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for (int i = 1; i <= atom->ntypes; i++) {
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for (int j = i; j <= atom->ntypes; j++) {
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if (setflag[i][j] != 0 || (setflag[i][i] != 0 && setflag[j][j] != 0)) {
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cut = init_one(i, j);
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cut *= cut;
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if (cut > maxcut) maxcut = cut;
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cutsq[i][j] = cutsq[j][i] = cut;
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} else
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cutsq[i][j] = cutsq[j][i] = 0.0;
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}
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}
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double cell_size = sqrt(maxcut) + neighbor->skin;
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cut_coulsq = cut_coul * cut_coul;
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// insure use of KSpace long-range solver, set g_ewald
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if (force->kspace == nullptr) error->all(FLERR, "Pair style is incompatible with KSpace style");
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g_ewald = force->kspace->g_ewald;
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// setup force tables
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if (ncoultablebits) init_tables(cut_coul, nullptr);
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int maxspecial = 0;
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if (atom->molecular != Atom::ATOMIC) maxspecial = atom->maxspecial;
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int mnf = 5e-2 * neighbor->oneatom;
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int success =
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spical_gpu_init(atom->ntypes + 1, cutsq, lj_type, lj1, lj2, lj3, lj4, offset, force->special_lj,
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atom->nlocal, atom->nlocal + atom->nghost, mnf, maxspecial, cell_size, gpu_mode,
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screen, cut_ljsq, cut_coulsq, force->special_coul, force->qqrd2e, g_ewald);
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GPU_EXTRA::check_flag(success, error, world);
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if (gpu_mode == GPU_FORCE) neighbor->add_request(this, NeighConst::REQ_FULL);
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}
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/* ---------------------------------------------------------------------- */
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double PairLJSPICACoulLongGPU::memory_usage()
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{
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double bytes = Pair::memory_usage();
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return bytes + spical_gpu_bytes();
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}
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/* ---------------------------------------------------------------------- */
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template <int EVFLAG, int EFLAG>
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void PairLJSPICACoulLongGPU::cpu_compute(int start, int inum, int *ilist, int *numneigh,
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int **firstneigh)
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{
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int i, j, ii, jj;
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double qtmp, xtmp, ytmp, ztmp;
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double r2inv, forcecoul, forcelj, factor_coul, factor_lj;
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const double *const *const x = atom->x;
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double *const *const f = atom->f;
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const double *const q = atom->q;
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const int *const type = atom->type;
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const double *const special_coul = force->special_coul;
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const double *const special_lj = force->special_lj;
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const double qqrd2e = force->qqrd2e;
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double fxtmp, fytmp, fztmp;
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// loop over neighbors of my atoms
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for (ii = start; ii < inum; ii++) {
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i = ilist[ii];
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qtmp = q[i];
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xtmp = x[i][0];
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ytmp = x[i][1];
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ztmp = x[i][2];
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fxtmp = fytmp = fztmp = 0.0;
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const int itype = type[i];
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const int *const jlist = firstneigh[i];
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const int jnum = numneigh[i];
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for (jj = 0; jj < jnum; jj++) {
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j = jlist[jj];
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factor_lj = special_lj[sbmask(j)];
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factor_coul = special_coul[sbmask(j)];
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j &= NEIGHMASK;
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const double delx = xtmp - x[j][0];
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const double dely = ytmp - x[j][1];
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const double delz = ztmp - x[j][2];
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const double rsq = delx * delx + dely * dely + delz * delz;
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const int jtype = type[j];
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double evdwl = 0.0;
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double ecoul = 0.0;
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double fpair = 0.0;
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if (rsq < cutsq[itype][jtype]) {
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r2inv = 1.0 / rsq;
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const int ljt = lj_type[itype][jtype];
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if (rsq < cut_coulsq) {
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if (!ncoultablebits || rsq <= tabinnersq) {
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const double r = sqrt(rsq);
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const double grij = g_ewald * r;
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const double expm2 = exp(-grij * grij);
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const double t = 1.0 / (1.0 + EWALD_P * grij);
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const double erfc = t * (A1 + t * (A2 + t * (A3 + t * (A4 + t * A5)))) * expm2;
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const double prefactor = qqrd2e * qtmp * q[j] / r;
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forcecoul = prefactor * (erfc + EWALD_F * grij * expm2);
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if (EFLAG) ecoul = prefactor * erfc;
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if (factor_coul < 1.0) {
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forcecoul -= (1.0 - factor_coul) * prefactor;
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if (EFLAG) ecoul -= (1.0 - factor_coul) * prefactor;
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}
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} else {
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union_int_float_t rsq_lookup;
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rsq_lookup.f = rsq;
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int itable = rsq_lookup.i & ncoulmask;
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itable >>= ncoulshiftbits;
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const double fraction = (rsq_lookup.f - rtable[itable]) * drtable[itable];
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const double table = ftable[itable] + fraction * dftable[itable];
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forcecoul = qtmp * q[j] * table;
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if (EFLAG) {
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const double table2 = etable[itable] + fraction * detable[itable];
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ecoul = qtmp * q[j] * table2;
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}
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if (factor_coul < 1.0) {
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const double table2 = ctable[itable] + fraction * dctable[itable];
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const double prefactor = qtmp * q[j] * table2;
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forcecoul -= (1.0 - factor_coul) * prefactor;
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if (EFLAG) ecoul -= (1.0 - factor_coul) * prefactor;
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}
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}
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} else {
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forcecoul = 0.0;
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ecoul = 0.0;
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}
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if (rsq < cut_ljsq[itype][jtype]) {
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if (ljt == LJ12_4) {
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const double r4inv = r2inv * r2inv;
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forcelj = r4inv * (lj1[itype][jtype] * r4inv * r4inv - lj2[itype][jtype]);
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if (EFLAG)
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evdwl = r4inv * (lj3[itype][jtype] * r4inv * r4inv - lj4[itype][jtype]) -
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offset[itype][jtype];
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} else if (ljt == LJ9_6) {
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const double r3inv = r2inv * sqrt(r2inv);
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const double r6inv = r3inv * r3inv;
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forcelj = r6inv * (lj1[itype][jtype] * r3inv - lj2[itype][jtype]);
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if (EFLAG)
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evdwl =
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r6inv * (lj3[itype][jtype] * r3inv - lj4[itype][jtype]) - offset[itype][jtype];
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} else if (ljt == LJ12_6) {
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const double r6inv = r2inv * r2inv * r2inv;
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forcelj = r6inv * (lj1[itype][jtype] * r6inv - lj2[itype][jtype]);
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if (EFLAG)
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evdwl =
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r6inv * (lj3[itype][jtype] * r6inv - lj4[itype][jtype]) - offset[itype][jtype];
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} else if (ljt == LJ12_5) {
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const double r5inv = r2inv * r2inv * sqrt(r2inv);
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const double r7inv = r5inv * r2inv;
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forcelj = r5inv * (lj1[itype][jtype] * r7inv - lj2[itype][jtype]);
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if (EFLAG)
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evdwl =
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r5inv * (lj3[itype][jtype] * r7inv - lj4[itype][jtype]) - offset[itype][jtype];
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}
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if (EFLAG) evdwl *= factor_lj;
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} else {
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forcelj = 0.0;
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evdwl = 0.0;
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}
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fpair = (forcecoul + factor_lj * forcelj) * r2inv;
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fxtmp += delx * fpair;
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fytmp += dely * fpair;
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fztmp += delz * fpair;
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if (EVFLAG) ev_tally_full(i, evdwl, ecoul, fpair, delx, dely, delz);
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}
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}
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f[i][0] += fxtmp;
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f[i][1] += fytmp;
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f[i][2] += fztmp;
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}
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}
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