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lammps/src/REAXFF/reaxff_valence_angles.cpp

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// clang-format off
/*----------------------------------------------------------------------
PuReMD - Purdue ReaxFF Molecular Dynamics Program
Copyright (2010) Purdue University
Hasan Metin Aktulga, hmaktulga@lbl.gov
Joseph Fogarty, jcfogart@mail.usf.edu
Sagar Pandit, pandit@usf.edu
Ananth Y Grama, ayg@cs.purdue.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, in press.
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_api.h"
#include <cmath>
#include "pair.h"
#include "error.h"
namespace ReaxFF {
void Calculate_Theta(rvec dvec_ji, double d_ji, rvec dvec_jk, double d_jk,
double *theta, double *cos_theta)
{
(*cos_theta) = rvec_Dot(dvec_ji,dvec_jk) / (d_ji * d_jk);
if (*cos_theta > 1.) *cos_theta = 1.0;
if (*cos_theta < -1.) *cos_theta = -1.0;
(*theta) = acos(*cos_theta);
}
void Calculate_dCos_Theta(rvec dvec_ji, double d_ji, rvec dvec_jk, double d_jk,
rvec* dcos_theta_di,
rvec* dcos_theta_dj,
rvec* dcos_theta_dk)
{
int t;
double sqr_d_ji = SQR(d_ji);
double sqr_d_jk = SQR(d_jk);
double inv_dists = 1.0 / (d_ji * d_jk);
double inv_dists3 = CUBE(inv_dists);
double dot_dvecs = rvec_Dot(dvec_ji,dvec_jk);
double Cdot_inv3 = dot_dvecs * inv_dists3;
for (t = 0; t < 3; ++t) {
(*dcos_theta_di)[t] = dvec_jk[t] * inv_dists -
Cdot_inv3 * sqr_d_jk * dvec_ji[t];
(*dcos_theta_dj)[t] = -(dvec_jk[t] + dvec_ji[t]) * inv_dists +
Cdot_inv3 * (sqr_d_jk * dvec_ji[t] + sqr_d_ji * dvec_jk[t]);
(*dcos_theta_dk)[t] = dvec_ji[t] * inv_dists -
Cdot_inv3 * sqr_d_ji * dvec_jk[t];
}
}
void Valence_Angles(reax_system *system, control_params *control, simulation_data *data,
storage *workspace, reax_list **lists)
{
int i, j, pi, k, pk, t;
int type_i, type_j, type_k;
int start_j, end_j, start_pk, end_pk;
int cnt, num_thb_intrs;
double temp, temp_bo_jt, pBOjt7;
double p_val1, p_val2, p_val3, p_val4, p_val5;
double p_val6, p_val7, p_val8, p_val9, p_val10;
double p_pen1, p_pen2, p_pen3, p_pen4;
double p_coa1, p_coa2, p_coa3, p_coa4;
double trm8, expval6, expval7, expval2theta, expval12theta, exp3ij, exp3jk;
double exp_pen2ij, exp_pen2jk, exp_pen3, exp_pen4, trm_pen34, exp_coa2;
double dSBO1, dSBO2, SBO, SBO2, CSBO2, SBOp, prod_SBO, vlpadj;
double CEval1, CEval2, CEval3, CEval4, CEval5, CEval6, CEval7, CEval8;
double CEpen1, CEpen2, CEpen3;
double e_ang, e_coa, e_pen;
double CEcoa1, CEcoa2, CEcoa3, CEcoa4, CEcoa5;
double Cf7ij, Cf7jk, Cf8j, Cf9j;
double f7_ij, f7_jk, f8_Dj, f9_Dj;
double Ctheta_0, theta_0, theta_00, theta, cos_theta, sin_theta;
double BOA_ij, BOA_jk;
// Tallying variables
double eng_tmp, fi_tmp[3], fj_tmp[3], fk_tmp[3];
double delij[3], delkj[3];
three_body_header *thbh;
three_body_parameters *thbp;
three_body_interaction_data *p_ijk, *p_kji;
bond_data *pbond_ij, *pbond_jk, *pbond_jt;
bond_order_data *bo_ij, *bo_jk, *bo_jt;
reax_list *bonds = (*lists) + BONDS;
reax_list *thb_intrs = (*lists) + THREE_BODIES;
/* global parameters used in these calculations */
p_val6 = system->reax_param.gp.l[14];
p_val8 = system->reax_param.gp.l[33];
p_val9 = system->reax_param.gp.l[16];
p_val10 = system->reax_param.gp.l[17];
num_thb_intrs = 0;
for (j = 0; j < system->N; ++j) {
type_j = system->my_atoms[j].type;
if (type_j < 0) continue;
start_j = Start_Index(j, bonds);
end_j = End_Index(j, bonds);
p_val3 = system->reax_param.sbp[type_j].p_val3;
p_val5 = system->reax_param.sbp[type_j].p_val5;
SBOp = 0, prod_SBO = 1;
for (t = start_j; t < end_j; ++t) {
bo_jt = &(bonds->select.bond_list[t].bo_data);
SBOp += (bo_jt->BO_pi + bo_jt->BO_pi2);
temp = SQR(bo_jt->BO);
temp *= temp;
temp *= temp;
prod_SBO *= exp(-temp);
}
if (workspace->vlpex[j] >= 0) {
vlpadj = 0;
dSBO2 = prod_SBO - 1;
} else {
vlpadj = workspace->nlp[j];
dSBO2 = (prod_SBO - 1) * (1 - p_val8 * workspace->dDelta_lp[j]);
}
SBO = SBOp + (1 - prod_SBO) * (-workspace->Delta_boc[j] - p_val8 * vlpadj);
dSBO1 = -8 * prod_SBO * (workspace->Delta_boc[j] + p_val8 * vlpadj);
if (SBO <= 0)
SBO2 = 0, CSBO2 = 0;
else if (SBO > 0 && SBO <= 1) {
SBO2 = pow(SBO, p_val9);
CSBO2 = p_val9 * pow(SBO, p_val9 - 1);
}
else if (SBO > 1 && SBO < 2) {
SBO2 = 2 - pow(2-SBO, p_val9);
CSBO2 = p_val9 * pow(2 - SBO, p_val9 - 1);
}
else
SBO2 = 2, CSBO2 = 0;
expval6 = exp(p_val6 * workspace->Delta_boc[j]);
for (pi = start_j; pi < end_j; ++pi) {
Set_Start_Index(pi, num_thb_intrs, thb_intrs);
pbond_ij = &(bonds->select.bond_list[pi]);
bo_ij = &(pbond_ij->bo_data);
BOA_ij = bo_ij->BO - control->thb_cut;
if (BOA_ij/*bo_ij->BO*/ > 0.0 &&
(j < system->n || pbond_ij->nbr < system->n)) {
i = pbond_ij->nbr;
type_i = system->my_atoms[i].type;
for (pk = start_j; pk < pi; ++pk) {
start_pk = Start_Index(pk, thb_intrs);
end_pk = End_Index(pk, thb_intrs);
for (t = start_pk; t < end_pk; ++t)
if (thb_intrs->select.three_body_list[t].thb == i) {
p_ijk = &(thb_intrs->select.three_body_list[num_thb_intrs]);
p_kji = &(thb_intrs->select.three_body_list[t]);
p_ijk->thb = bonds->select.bond_list[pk].nbr;
p_ijk->pthb = pk;
p_ijk->theta = p_kji->theta;
rvec_Copy(p_ijk->dcos_di, p_kji->dcos_dk);
rvec_Copy(p_ijk->dcos_dj, p_kji->dcos_dj);
rvec_Copy(p_ijk->dcos_dk, p_kji->dcos_di);
++num_thb_intrs;
break;
}
}
for (pk = pi+1; pk < end_j; ++pk) {
pbond_jk = &(bonds->select.bond_list[pk]);
bo_jk = &(pbond_jk->bo_data);
BOA_jk = bo_jk->BO - control->thb_cut;
k = pbond_jk->nbr;
type_k = system->my_atoms[k].type;
p_ijk = &(thb_intrs->select.three_body_list[num_thb_intrs]);
Calculate_Theta(pbond_ij->dvec, pbond_ij->d,
pbond_jk->dvec, pbond_jk->d,
&theta, &cos_theta);
Calculate_dCos_Theta(pbond_ij->dvec, pbond_ij->d,
pbond_jk->dvec, pbond_jk->d,
&(p_ijk->dcos_di), &(p_ijk->dcos_dj),
&(p_ijk->dcos_dk));
p_ijk->thb = k;
p_ijk->pthb = pk;
p_ijk->theta = theta;
sin_theta = sin(theta);
if (sin_theta < 1.0e-5)
sin_theta = 1.0e-5;
++num_thb_intrs;
if ((j < system->n) && (BOA_jk > 0.0) &&
(bo_ij->BO > control->thb_cut) &&
(bo_jk->BO > control->thb_cut) &&
(bo_ij->BO * bo_jk->BO > control->thb_cutsq)) {
thbh = &(system->reax_param.thbp[type_i][type_j][type_k]);
for (cnt = 0; cnt < thbh->cnt; ++cnt) {
if (fabs(thbh->prm[cnt].p_val1) > 0.001) {
thbp = &(thbh->prm[cnt]);
/* ANGLE ENERGY */
p_val1 = thbp->p_val1;
p_val2 = thbp->p_val2;
p_val4 = thbp->p_val4;
p_val7 = thbp->p_val7;
theta_00 = thbp->theta_00;
exp3ij = exp(-p_val3 * pow(BOA_ij, p_val4));
f7_ij = 1.0 - exp3ij;
Cf7ij = p_val3 * p_val4 * pow(BOA_ij, p_val4 - 1.0) * exp3ij;
exp3jk = exp(-p_val3 * pow(BOA_jk, p_val4));
f7_jk = 1.0 - exp3jk;
Cf7jk = p_val3 * p_val4 * pow(BOA_jk, p_val4 - 1.0) * exp3jk;
expval7 = exp(-p_val7 * workspace->Delta_boc[j]);
trm8 = 1.0 + expval6 + expval7;
f8_Dj = p_val5 - ((p_val5 - 1.0) * (2.0 + expval6) / trm8);
Cf8j = ((1.0 - p_val5) / SQR(trm8)) *
(p_val6 * expval6 * trm8 -
(2.0 + expval6) * (p_val6*expval6 - p_val7*expval7));
theta_0 = 180.0 - theta_00 * (1.0 -
exp(-p_val10 * (2.0 - SBO2)));
theta_0 = DEG2RAD(theta_0);
expval2theta = exp(-p_val2 * SQR(theta_0 - theta));
if (p_val1 >= 0)
expval12theta = p_val1 * (1.0 - expval2theta);
else // To avoid linear Me-H-Me angles (6/6/06)
expval12theta = p_val1 * -expval2theta;
CEval1 = Cf7ij * f7_jk * f8_Dj * expval12theta;
CEval2 = Cf7jk * f7_ij * f8_Dj * expval12theta;
CEval3 = Cf8j * f7_ij * f7_jk * expval12theta;
CEval4 = -2.0 * p_val1 * p_val2 * f7_ij * f7_jk * f8_Dj *
expval2theta * (theta_0 - theta);
Ctheta_0 = p_val10 * DEG2RAD(theta_00) *
exp(-p_val10 * (2.0 - SBO2));
CEval5 = -CEval4 * Ctheta_0 * CSBO2;
CEval6 = CEval5 * dSBO1;
CEval7 = CEval5 * dSBO2;
CEval8 = -CEval4 / sin_theta;
data->my_en.e_ang += e_ang =
f7_ij * f7_jk * f8_Dj * expval12theta;
/* END ANGLE ENERGY*/
/* PENALTY ENERGY */
p_pen1 = thbp->p_pen1;
p_pen2 = system->reax_param.gp.l[19];
p_pen3 = system->reax_param.gp.l[20];
p_pen4 = system->reax_param.gp.l[21];
exp_pen2ij = exp(-p_pen2 * SQR(BOA_ij - 2.0));
exp_pen2jk = exp(-p_pen2 * SQR(BOA_jk - 2.0));
exp_pen3 = exp(-p_pen3 * workspace->Delta[j]);
exp_pen4 = exp( p_pen4 * workspace->Delta[j]);
trm_pen34 = 1.0 + exp_pen3 + exp_pen4;
f9_Dj = (2.0 + exp_pen3) / trm_pen34;
Cf9j = (-p_pen3 * exp_pen3 * trm_pen34 -
(2.0 + exp_pen3) * (-p_pen3 * exp_pen3 +
p_pen4 * exp_pen4)) /
SQR(trm_pen34);
data->my_en.e_pen += e_pen =
p_pen1 * f9_Dj * exp_pen2ij * exp_pen2jk;
CEpen1 = e_pen * Cf9j / f9_Dj;
temp = -2.0 * p_pen2 * e_pen;
CEpen2 = temp * (BOA_ij - 2.0);
CEpen3 = temp * (BOA_jk - 2.0);
/* END PENALTY ENERGY */
/* COALITION ENERGY */
p_coa1 = thbp->p_coa1;
p_coa2 = system->reax_param.gp.l[2];
p_coa3 = system->reax_param.gp.l[38];
p_coa4 = system->reax_param.gp.l[30];
exp_coa2 = exp(p_coa2 * workspace->Delta_val[j]);
data->my_en.e_coa += e_coa =
p_coa1 / (1. + exp_coa2) *
exp(-p_coa3 * SQR(workspace->total_bond_order[i]-BOA_ij)) *
exp(-p_coa3 * SQR(workspace->total_bond_order[k]-BOA_jk)) *
exp(-p_coa4 * SQR(BOA_ij - 1.5)) *
exp(-p_coa4 * SQR(BOA_jk - 1.5));
CEcoa1 = -2 * p_coa4 * (BOA_ij - 1.5) * e_coa;
CEcoa2 = -2 * p_coa4 * (BOA_jk - 1.5) * e_coa;
CEcoa3 = -p_coa2 * exp_coa2 * e_coa / (1 + exp_coa2);
CEcoa4 = -2 * p_coa3 *
(workspace->total_bond_order[i]-BOA_ij) * e_coa;
CEcoa5 = -2 * p_coa3 *
(workspace->total_bond_order[k]-BOA_jk) * e_coa;
/* END COALITION ENERGY */
/* FORCES */
bo_ij->Cdbo += (CEval1 + CEpen2 + (CEcoa1 - CEcoa4));
bo_jk->Cdbo += (CEval2 + CEpen3 + (CEcoa2 - CEcoa5));
workspace->CdDelta[j] += ((CEval3 + CEval7) + CEpen1 + CEcoa3);
workspace->CdDelta[i] += CEcoa4;
workspace->CdDelta[k] += CEcoa5;
for (t = start_j; t < end_j; ++t) {
pbond_jt = &(bonds->select.bond_list[t]);
bo_jt = &(pbond_jt->bo_data);
temp_bo_jt = bo_jt->BO;
temp = CUBE(temp_bo_jt);
pBOjt7 = temp * temp * temp_bo_jt;
bo_jt->Cdbo += (CEval6 * pBOjt7);
bo_jt->Cdbopi += CEval5;
bo_jt->Cdbopi2 += CEval5;
}
rvec_ScaledAdd(workspace->f[i], CEval8, p_ijk->dcos_di);
rvec_ScaledAdd(workspace->f[j], CEval8, p_ijk->dcos_dj);
rvec_ScaledAdd(workspace->f[k], CEval8, p_ijk->dcos_dk);
/* tally energy */
if (system->pair_ptr->eflag_either) {
eng_tmp = e_ang + e_pen + e_coa;
system->pair_ptr->ev_tally(j,j,system->N,1,eng_tmp,0.0,0.0,0.0,0.0,0.0);
}
/* tally virial */
if (system->pair_ptr->vflag_either) {
/* Acquire vectors */
rvec_ScaledSum(delij, 1., system->my_atoms[i].x, -1., system->my_atoms[j].x);
rvec_ScaledSum(delkj, 1., system->my_atoms[k].x, -1., system->my_atoms[j].x);
rvec_Scale(fi_tmp, -CEval8, p_ijk->dcos_di);
rvec_Scale(fj_tmp, -CEval8, p_ijk->dcos_dj);
rvec_Scale(fk_tmp, -CEval8, p_ijk->dcos_dk);
system->pair_ptr->v_tally3(i,j,k,fi_tmp,fk_tmp,delij,delkj);
}
}
}
}
}
}
Set_End_Index(pi, num_thb_intrs, thb_intrs);
}
}
if (num_thb_intrs >= thb_intrs->num_intrs * DANGER_ZONE) {
workspace->realloc.num_3body = num_thb_intrs;
if (num_thb_intrs > thb_intrs->num_intrs)
control->error_ptr->one(FLERR, fmt::format("step {}: ran out of space on "
"angle_list: top={}, max={}",
data->step, num_thb_intrs,
thb_intrs->num_intrs));
}
}
}