Files
lammps/src/OPENMP/reaxff_forces_omp.cpp
2022-02-13 19:39:15 -05:00

477 lines
16 KiB
C++

// clang-format off
/*----------------------------------------------------------------------
PuReMD - Purdue ReaxFF Molecular Dynamics Program
Website: https://www.cs.purdue.edu/puremd
Copyright (2010) Purdue University
Contributing authors:
H. M. Aktulga, J. Fogarty, S. Pandit, A. Grama
Corresponding author:
Hasan Metin Aktulga, Michigan State University, hma@cse.msu.edu
Please cite the related publication:
H. M. Aktulga, J. C. Fogarty, S. A. Pandit, A. Y. Grama,
"Parallel Reactive Molecular Dynamics: Numerical Methods and
Algorithmic Techniques", Parallel Computing, 38 (4-5), 245-259
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details:
<https://www.gnu.org/licenses/>.
----------------------------------------------------------------------*/
#include "reaxff_omp.h"
#include "error.h"
#include "pair_reaxff_omp.h"
#include "reaxff_api.h"
#include <cmath>
using namespace LAMMPS_NS;
namespace ReaxFF {
/* ---------------------------------------------------------------------- */
static void Compute_Bonded_ForcesOMP(reax_system *system, control_params *control,
simulation_data *data, storage *workspace,
reax_list **lists)
{
BOOMP(system, workspace, lists);
BondsOMP(system, data, workspace, lists);
Atom_EnergyOMP(system, data, workspace, lists);
Valence_AnglesOMP(system, control, data, workspace, lists);
Torsion_AnglesOMP(system, control, data, workspace, lists);
if (control->hbond_cut > 0)
Hydrogen_BondsOMP(system, control, data, workspace, lists);
}
static void Compute_NonBonded_ForcesOMP(reax_system *system, control_params *control,
simulation_data *data, storage *workspace,
reax_list **lists)
{
/* van der Waals and Coulomb interactions */
if (control->tabulate == 0)
vdW_Coulomb_Energy_OMP(system, control, data, workspace, lists);
else
Tabulated_vdW_Coulomb_Energy_OMP(system, control, data, workspace, lists);
}
/* ---------------------------------------------------------------------- */
/* this version of Compute_Total_Force computes forces from
coefficients accumulated by all interaction functions.
Saves enormous time & space! */
static void Compute_Total_ForceOMP(reax_system *system, control_params *control,
storage *workspace, reax_list **lists)
{
int natoms = system->N;
int nthreads = control->nthreads;
long totalReductionSize = (bigint)system->N * nthreads;
reax_list *bonds = (*lists) + BONDS;
#if defined(_OPENMP)
#pragma omp parallel default(shared) //LMP_DEFAULT_NONE
#endif
{
int i, j, k, pj, pk, start_j, end_j;
int tid = get_tid();
bond_order_data *bo_jk;
class PairReaxFFOMP *pair_reax_ptr;
pair_reax_ptr = static_cast<class PairReaxFFOMP*>(system->pair_ptr);
class ThrData *thr = pair_reax_ptr->getFixOMP()->get_thr(tid);
pair_reax_ptr->ev_setup_thr_proxy(0, 1, natoms, system->pair_ptr->eatom,
system->pair_ptr->vatom, nullptr, thr);
#if defined(_OPENMP)
#pragma omp for schedule(guided)
#endif
for (i = 0; i < system->N; ++i) {
for (j = 0; j < nthreads; ++j)
workspace->CdDelta[i] += workspace->CdDeltaReduction[system->N*j+i];
}
#if defined(_OPENMP)
#pragma omp for schedule(dynamic,50)
#endif
for (j = 0; j < system->N; ++j) {
start_j = Start_Index(j, bonds);
end_j = End_Index(j, bonds);
for (pk = start_j; pk < end_j; ++pk) {
bo_jk = &(bonds->select.bond_list[pk].bo_data);
for (k = 0; k < nthreads; ++k)
bo_jk->Cdbo += bo_jk->CdboReduction[k];
}
}
#if defined(_OPENMP)
#pragma omp for schedule(dynamic,50)
#endif
for (i = 0; i < system->N; ++i) {
const int startj = Start_Index(i, bonds);
const int endj = End_Index(i, bonds);
for (pj = startj; pj < endj; ++pj)
if (i < bonds->select.bond_list[pj].nbr)
Add_dBond_to_ForcesOMP(system, i, pj, workspace, lists);
}
pair_reax_ptr->reduce_thr_proxy(system->pair_ptr, 0, 1, thr);
#if defined(_OPENMP)
#pragma omp for schedule(guided)
#endif
for (i = 0; i < system->N; ++i) {
for (j = 0; j < nthreads; ++j)
rvec_Add(workspace->f[i], workspace->forceReduction[system->N*j+i]);
}
#if defined(_OPENMP)
#pragma omp for schedule(guided)
#endif
for (i = 0; i < totalReductionSize; i++) {
workspace->forceReduction[i][0] = 0;
workspace->forceReduction[i][1] = 0;
workspace->forceReduction[i][2] = 0;
workspace->CdDeltaReduction[i] = 0;
}
} // parallel region
}
/* ---------------------------------------------------------------------- */
static void Validate_ListsOMP(reax_system *system, reax_list **lists,
int step, int n, int N, int numH)
{
int comp, Hindex;
reax_list *bonds, *hbonds;
double saferzone = system->saferzone;
#if defined(_OPENMP)
#pragma omp parallel default(shared) private(comp,Hindex)
#endif
{
/* bond list */
if (N > 0) {
bonds = *lists + BONDS;
#if defined(_OPENMP)
#pragma omp for schedule(guided)
#endif
for (int i = 0; i < N; ++i) {
system->my_atoms[i].num_bonds = MAX(Num_Entries(i,bonds)*2, MIN_BONDS);
if (i < N-1)
comp = Start_Index(i+1, bonds);
else comp = bonds->num_intrs;
if (End_Index(i, bonds) > comp)
system->error_ptr->one(FLERR, fmt::format("step {}: bondchk failed: "
"i={} end(i)={} str(i+1)={}\n",
step,i,End_Index(i,bonds),comp));
}
}
/* hbonds list */
if (numH > 0) {
hbonds = *lists + HBONDS;
#if defined(_OPENMP)
#pragma omp for schedule(guided)
#endif
for (int i = 0; i < n; ++i) {
Hindex = system->my_atoms[i].Hindex;
if (Hindex > -1) {
system->my_atoms[i].num_hbonds =
(int)(MAX(Num_Entries(Hindex,hbonds)*saferzone,system->minhbonds));
if (Hindex < numH-1)
comp = Start_Index(Hindex+1, hbonds);
else comp = hbonds->num_intrs;
if (End_Index(Hindex, hbonds) > comp)
system->error_ptr->one(FLERR, fmt::format("step {}: hbondchk failed: "
"H={} end(H)={} str(H+1)={}\n",
step, Hindex,End_Index(Hindex,hbonds),comp));
}
}
}
} // omp parallel
}
void Init_Forces_noQEq_OMP(reax_system *system, control_params *control,
simulation_data *data, storage *workspace,
reax_list **lists) {
int j, pj;
int start_i, end_i;
int type_i, type_j;
int ihb, jhb, ihb_top, jhb_top;
double cutoff;
single_body_parameters *sbp_i, *sbp_j;
two_body_parameters *twbp;
far_neighbor_data *nbr_pj;
reax_atom *atom_i, *atom_j;
reax_list *far_nbrs = *lists + FAR_NBRS;
reax_list *bonds = *lists + BONDS;
reax_list *hbonds = *lists + HBONDS;
int num_bonds = 0;
int num_hbonds = 0;
int btop_i = 0;
// We will use CdDeltaReduction as a temporary (double) buffer to accumulate total_bond_order
// This is safe because CdDeltaReduction is currently zeroed and its accumulation doesn't start until BondsOMP()
double * tmp_bond_order = workspace->CdDeltaReduction;
// We do the same with forceReduction as a temporary (rvec) buffer to accumulate dDeltap_self
// This is safe because forceReduction is currently zeroed and its accumulation does start until Hydrogen_BondsOMP()
rvec * tmp_ddelta = workspace->forceReduction;
/* uncorrected bond orders */
cutoff = control->bond_cut;
#if defined(_OPENMP)
#pragma omp parallel default(shared) \
private(atom_i, type_i, start_i, end_i, sbp_i, btop_i, ihb, ihb_top, \
atom_j, type_j, pj, sbp_j, nbr_pj, jhb, twbp)
#endif
{
int nthreads = control->nthreads;
int tid = get_tid();
long reductionOffset = (bigint)system->N * tid;
long totalReductionSize = (bigint)system->N * nthreads;
#if defined(_OPENMP)
#pragma omp for schedule(dynamic,50) reduction(+:num_bonds)
#endif
for (int i = 0; i < system->N; ++i) {
atom_i = &(system->my_atoms[i]);
type_i = atom_i->type;
sbp_i = &(system->reax_param.sbp[type_i]);
start_i = Start_Index(i, far_nbrs);
end_i = End_Index(i, far_nbrs);
for (pj = start_i; pj < end_i; ++pj) {
nbr_pj = &(far_nbrs->select.far_nbr_list[pj]);
if (nbr_pj->d <= cutoff) {
int j = nbr_pj->nbr;
atom_j = &(system->my_atoms[j]);
type_j = atom_j->type;
sbp_j = &(system->reax_param.sbp[type_j]);
twbp = &(system->reax_param.tbp[type_i][type_j]);
// Trying to minimize time spent in critical section by moving initial part of BOp()
// outside of critical section.
// Start top portion of BOp()
double C12, C34, C56;
double BO, BO_s, BO_pi, BO_pi2;
double bo_cut = control->bo_cut;
if (sbp_i->r_s > 0.0 && sbp_j->r_s > 0.0) {
C12 = twbp->p_bo1 * pow(nbr_pj->d / twbp->r_s, twbp->p_bo2);
BO_s = (1.0 + bo_cut) * exp(C12);
}
else BO_s = C12 = 0.0;
if (sbp_i->r_pi > 0.0 && sbp_j->r_pi > 0.0) {
C34 = twbp->p_bo3 * pow(nbr_pj->d / twbp->r_p, twbp->p_bo4);
BO_pi = exp(C34);
}
else BO_pi = C34 = 0.0;
if (sbp_i->r_pi_pi > 0.0 && sbp_j->r_pi_pi > 0.0) {
C56 = twbp->p_bo5 * pow(nbr_pj->d / twbp->r_pp, twbp->p_bo6);
BO_pi2= exp(C56);
}
else BO_pi2 = C56 = 0.0;
/* Initially BO values are the uncorrected ones, page 1 */
BO = BO_s + BO_pi + BO_pi2;
// End top portion of BOp()
if (BO >= bo_cut) {
int btop_j;
// Update indices in critical section
#if defined(_OPENMP)
#pragma omp critical
#endif
{
btop_i = End_Index(i, bonds);
btop_j = End_Index(j, bonds);
Set_End_Index(j, btop_j+1, bonds);
Set_End_Index(i, btop_i+1, bonds);
} // omp critical
// Finish remaining BOp() work
BOp_OMP(workspace, bonds, bo_cut,
i , btop_i, nbr_pj, sbp_i, sbp_j, twbp, btop_j,
C12, C34, C56, BO, BO_s, BO_pi, BO_pi2);
bond_data * ibond = &(bonds->select.bond_list[btop_i]);
bond_order_data * bo_ij = &(ibond->bo_data);
bond_data * jbond = &(bonds->select.bond_list[btop_j]);
bond_order_data * bo_ji = &(jbond->bo_data);
workspace->total_bond_order[i] += bo_ij->BO;
tmp_bond_order[reductionOffset + j] += bo_ji->BO;
rvec_Add(workspace->dDeltap_self[i], bo_ij->dBOp);
rvec_Add(tmp_ddelta[reductionOffset + j], bo_ji->dBOp);
btop_i++;
num_bonds++;
} // if (BO>=bo_cut)
} // if (cutoff)
} // for (pj)
} // for (i)
// Need to wait for all indices and tmp arrays accumulated.
#if defined(_OPENMP)
#pragma omp barrier
#endif
#if defined(_OPENMP)
#pragma omp for schedule(dynamic,50)
#endif
for (int i=0; i<system->N; i++)
for (int t=0; t<nthreads; t++) {
const int indx = t*system->N + i;
workspace->dDeltap_self[i][0] += tmp_ddelta[indx][0];
workspace->dDeltap_self[i][1] += tmp_ddelta[indx][1];
workspace->dDeltap_self[i][2] += tmp_ddelta[indx][2];
workspace->total_bond_order[i] += tmp_bond_order[indx];
}
/* hydrogen bond list */
if (control->hbond_cut > 0) {
cutoff = control->hbond_cut;
#if defined(_OPENMP)
#pragma omp for schedule(dynamic,50) reduction(+ : num_hbonds)
#endif
for (int i = 0; i < system->n; ++i) {
atom_i = &(system->my_atoms[i]);
type_i = atom_i->type;
sbp_i = &(system->reax_param.sbp[type_i]);
ihb = sbp_i->p_hbond;
#if defined(_OPENMP)
#pragma omp critical
#endif
{
if (ihb == 1 || ihb == 2) {
start_i = Start_Index(i, far_nbrs);
end_i = End_Index(i, far_nbrs);
for (pj = start_i; pj < end_i; ++pj) {
nbr_pj = &(far_nbrs->select.far_nbr_list[pj]);
j = nbr_pj->nbr;
atom_j = &(system->my_atoms[j]);
type_j = atom_j->type;
if (type_j < 0) continue;
sbp_j = &(system->reax_param.sbp[type_j]);
jhb = sbp_j->p_hbond;
if (nbr_pj->d <= control->hbond_cut) {
int iflag = 0;
int jflag = 0;
if (ihb==1 && jhb==2) iflag = 1;
else if (j<system->n && ihb == 2 && jhb == 1) jflag = 1;
if (iflag || jflag) {
if (iflag) {
ihb_top = End_Index(atom_i->Hindex, hbonds);
Set_End_Index(atom_i->Hindex, ihb_top+1, hbonds);
} else if (jflag) {
jhb_top = End_Index(atom_j->Hindex, hbonds);
Set_End_Index(atom_j->Hindex, jhb_top+1, hbonds);
}
if (iflag) {
hbonds->select.hbond_list[ihb_top].nbr = j;
hbonds->select.hbond_list[ihb_top].scl = 1;
hbonds->select.hbond_list[ihb_top].ptr = nbr_pj;
} else if (jflag) {
hbonds->select.hbond_list[jhb_top].nbr = i;
hbonds->select.hbond_list[jhb_top].scl = -1;
hbonds->select.hbond_list[jhb_top].ptr = nbr_pj;
}
num_hbonds++;
} // if (iflag || jflag)
}
}
}
} // omp critical
}
} // if (control->hbond > 0)
// Zero buffers for others to use as intended.
#if defined(_OPENMP)
#pragma omp for schedule(guided)
#endif
for (int i=0; i<totalReductionSize; i++) {
tmp_ddelta[i][0] = 0.0;
tmp_ddelta[i][1] = 0.0;
tmp_ddelta[i][2] = 0.0;
tmp_bond_order[i] = 0.0;
}
} // omp
workspace->realloc.num_bonds = num_bonds;
workspace->realloc.num_hbonds = num_hbonds;
Validate_ListsOMP(system, lists, data->step,
system->n, system->N, system->numH);
}
/* ---------------------------------------------------------------------- */
void Compute_ForcesOMP(reax_system *system, control_params *control,
simulation_data *data, storage *workspace,
reax_list **lists)
{
// Init Forces
Init_Forces_noQEq_OMP(system, control, data, workspace, lists);
// Bonded Interactions
Compute_Bonded_ForcesOMP(system, control, data, workspace, lists);
// Nonbonded Interactions
Compute_NonBonded_ForcesOMP(system, control, data, workspace, lists);
// Total Force
Compute_Total_ForceOMP(system, control, workspace, lists);
}
}