void Hydrogen_Bonds( reax_system *system, control_params *control,
simulation_data *data, storage *workspace,
reax_list **lists, output_controls *out_control )
{
int i, j, k, pi, pk;
int type_i, type_j, type_k;
int start_j, end_j, hb_start_j, hb_end_j;
int hblist[MAX_BONDS];
int itr, top;
int num_hb_intrs = 0;
ivec rel_jk;
real r_ij, r_jk, theta, cos_theta, sin_xhz4, cos_xhz1, sin_theta2;
real e_hb, exp_hb2, exp_hb3, CEhb1, CEhb2, CEhb3;
rvec dcos_theta_di, dcos_theta_dj, dcos_theta_dk;
rvec dvec_jk, force, ext_press;
// rtensor temp_rtensor, total_rtensor;
hbond_parameters *hbp;
bond_order_data *bo_ij;
bond_data *pbond_ij;
far_neighbor_data *nbr_jk;
reax_list *bonds, *hbonds;
bond_data *bond_list;
hbond_data *hbond_list;
// tally variables
real fi_tmp[3], fk_tmp[3], delij[3], delkj[3];
bonds = (*lists) + BONDS;
bond_list = bonds->select.bond_list;
hbonds = (*lists) + HBONDS;
hbond_list = hbonds->select.hbond_list;
/* loops below discover the Hydrogen bonds between i-j-k triplets.
here j is H atom and there has to be some bond between i and j.
Hydrogen bond is between j and k.
so in this function i->X, j->H, k->Z when we map
variables onto the ones in the handout.*/
for( j = 0; j < system->n; ++j )
/* j has to be of type H */
if( system->reax_param.sbp[system->my_atoms[j].type].p_hbond == 1 ) {
/*set j's variables */
type_j = system->my_atoms[j].type;
start_j = Start_Index(j, bonds);
end_j = End_Index(j, bonds);
hb_start_j = Start_Index( system->my_atoms[j].Hindex, hbonds );
hb_end_j = End_Index( system->my_atoms[j].Hindex, hbonds );
top = 0;
for( pi = start_j; pi < end_j; ++pi ) {
pbond_ij = &( bond_list[pi] );
i = pbond_ij->nbr;
bo_ij = &(pbond_ij->bo_data);
type_i = system->my_atoms[i].type;
if( system->reax_param.sbp[type_i].p_hbond == 2 &&
bo_ij->BO >= HB_THRESHOLD )
hblist[top++] = pi;
}
// fprintf( stderr, "j: %d, top: %d, hb_start_j: %d, hb_end_j:%d\n",
// j, top, hb_start_j, hb_end_j );
for( pk = hb_start_j; pk < hb_end_j; ++pk ) {
/* set k's varibles */
k = hbond_list[pk].nbr;
type_k = system->my_atoms[k].type;
nbr_jk = hbond_list[pk].ptr;
r_jk = nbr_jk->d;
rvec_Scale( dvec_jk, hbond_list[pk].scl, nbr_jk->dvec );
for( itr = 0; itr < top; ++itr ) {
pi = hblist[itr];
pbond_ij = &( bonds->select.bond_list[pi] );
i = pbond_ij->nbr;
if( system->my_atoms[i].orig_id != system->my_atoms[k].orig_id ) {
bo_ij = &(pbond_ij->bo_data);
type_i = system->my_atoms[i].type;
r_ij = pbond_ij->d;
hbp = &(system->reax_param.hbp[ type_i ][ type_j ][ type_k ]);
++num_hb_intrs;
Calculate_Theta( pbond_ij->dvec, pbond_ij->d, dvec_jk, r_jk,
&theta, &cos_theta );
/* the derivative of cos(theta) */
Calculate_dCos_Theta( pbond_ij->dvec, pbond_ij->d, dvec_jk, r_jk,
&dcos_theta_di, &dcos_theta_dj,
&dcos_theta_dk );
/* hyrogen bond energy*/
sin_theta2 = sin( theta/2.0 );
sin_xhz4 = SQR(sin_theta2);
sin_xhz4 *= sin_xhz4;
cos_xhz1 = ( 1.0 - cos_theta );
exp_hb2 = exp( -hbp->p_hb2 * bo_ij->BO );
exp_hb3 = exp( -hbp->p_hb3 * ( hbp->r0_hb / r_jk +
r_jk / hbp->r0_hb - 2.0 ) );
data->my_en.e_hb += e_hb =
hbp->p_hb1 * (1.0 - exp_hb2) * exp_hb3 * sin_xhz4;
CEhb1 = hbp->p_hb1 * hbp->p_hb2 * exp_hb2 * exp_hb3 * sin_xhz4;
CEhb2 = -hbp->p_hb1/2.0 * (1.0 - exp_hb2) * exp_hb3 * cos_xhz1;
CEhb3 = -hbp->p_hb3 *
(-hbp->r0_hb / SQR(r_jk) + 1.0 / hbp->r0_hb) * e_hb;
/*fprintf( stdout,
"%6d%6d%6d%12.6f%12.6f%12.6f%12.6f%12.6f%12.6f%12.6f%12.6f%12.6f\n",
system->my_atoms[i].orig_id, system->my_atoms[j].orig_id,
system->my_atoms[k].orig_id,
r_jk, theta, hbp->p_hb1, exp_hb2, hbp->p_hb3, hbp->r0_hb,
exp_hb3, sin_xhz4, e_hb ); */
/* hydrogen bond forces */
bo_ij->Cdbo += CEhb1; // dbo term
if( control->virial == 0 ) {
// dcos terms
rvec_ScaledAdd( workspace->f[i], +CEhb2, dcos_theta_di );
rvec_ScaledAdd( workspace->f[j], +CEhb2, dcos_theta_dj );
rvec_ScaledAdd( workspace->f[k], +CEhb2, dcos_theta_dk );
// dr terms
rvec_ScaledAdd( workspace->f[j], -CEhb3/r_jk, dvec_jk );
rvec_ScaledAdd( workspace->f[k], +CEhb3/r_jk, dvec_jk );
}
else {
/* for pressure coupling, terms that are not related to bond order
derivatives are added directly into pressure vector/tensor */
rvec_Scale( force, +CEhb2, dcos_theta_di ); // dcos terms
rvec_Add( workspace->f[i], force );
rvec_iMultiply( ext_press, pbond_ij->rel_box, force );
rvec_ScaledAdd( data->my_ext_press, 1.0, ext_press );
rvec_ScaledAdd( workspace->f[j], +CEhb2, dcos_theta_dj );
ivec_Scale( rel_jk, hbond_list[pk].scl, nbr_jk->rel_box );
rvec_Scale( force, +CEhb2, dcos_theta_dk );
rvec_Add( workspace->f[k], force );
rvec_iMultiply( ext_press, rel_jk, force );
rvec_ScaledAdd( data->my_ext_press, 1.0, ext_press );
// dr terms
rvec_ScaledAdd( workspace->f[j], -CEhb3/r_jk, dvec_jk );
rvec_Scale( force, CEhb3/r_jk, dvec_jk );
rvec_Add( workspace->f[k], force );
rvec_iMultiply( ext_press, rel_jk, force );
rvec_ScaledAdd( data->my_ext_press, 1.0, ext_press );
}
/* tally into per-atom virials */
if (system->pair_ptr->vflag_atom || system->pair_ptr->evflag) {
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, CEhb2, dcos_theta_di);
rvec_Scale(fk_tmp, CEhb2, dcos_theta_dk);
rvec_ScaledAdd(fk_tmp, CEhb3/r_jk, dvec_jk);
system->pair_ptr->ev_tally3(i,j,k,e_hb,0.0,fi_tmp,fk_tmp,delij,delkj);
}
#ifdef TEST_ENERGY
/* fprintf( out_control->ehb,
"%24.15e%24.15e%24.15e\n%24.15e%24.15e%24.15e\n%24.15e%24.15e%24.15e\n",
dcos_theta_di[0], dcos_theta_di[1], dcos_theta_di[2],
dcos_theta_dj[0], dcos_theta_dj[1], dcos_theta_dj[2],
dcos_theta_dk[0], dcos_theta_dk[1], dcos_theta_dk[2]);
fprintf( out_control->ehb, "%24.15e%24.15e%24.15e\n",
CEhb1, CEhb2, CEhb3 ); */
fprintf( out_control->ehb,
//"%6d%6d%6d%24.15e%24.15e%24.15e%24.15e%24.15e\n",
"%6d%6d%6d%12.4f%12.4f%12.4f%12.4f%12.4f\n",
system->my_atoms[i].orig_id, system->my_atoms[j].orig_id,
system->my_atoms[k].orig_id,
r_jk, theta, bo_ij->BO, e_hb, data->my_en.e_hb );
#endif
#ifdef TEST_FORCES
Add_dBO( system, lists, j, pi, +CEhb1, workspace->f_hb ); //dbo term
// dcos terms
rvec_ScaledAdd( workspace->f_hb[i], +CEhb2, dcos_theta_di );
rvec_ScaledAdd( workspace->f_hb[j], +CEhb2, dcos_theta_dj );
rvec_ScaledAdd( workspace->f_hb[k], +CEhb2, dcos_theta_dk );
// dr terms
rvec_ScaledAdd( workspace->f_hb[j], -CEhb3/r_jk, dvec_jk );
rvec_ScaledAdd( workspace->f_hb[k], +CEhb3/r_jk, dvec_jk );
#endif
}
}
}
}
#if defined(DEBUG)
fprintf( stderr, "Number of hydrogen bonds: %d\n", num_hb_intrs );
fprintf( stderr, "Hydrogen Bond Energy: %g\n", data->my_en.e_hb );
fprintf( stderr, "hydbonds: ext_press (%24.15e %24.15e %24.15e)\n",
data->ext_press[0], data->ext_press[1], data->ext_press[2] );
#endif
}
void Init_Forces(reax_system *system, control_params *control,
simulation_data *data, static_storage *workspace, list **lists,
output_controls *out_control) {
int i, j, pj;
int start_i, end_i;
int type_i, type_j;
int Htop, btop_i, btop_j, num_bonds, num_hbonds;
int ihb, jhb, ihb_top, jhb_top;
int flag;
real r_ij, r2, self_coef;
real dr3gamij_1, dr3gamij_3, Tap;
//real val, dif, base;
real C12, C34, C56;
real Cln_BOp_s, Cln_BOp_pi, Cln_BOp_pi2;
real BO, BO_s, BO_pi, BO_pi2;
real p_boc1, p_boc2;
sparse_matrix *H;
list *far_nbrs, *bonds, *hbonds;
single_body_parameters *sbp_i, *sbp_j;
two_body_parameters *twbp;
far_neighbor_data *nbr_pj;
//LR_lookup_table *t;
reax_atom *atom_i, *atom_j;
bond_data *ibond, *jbond;
bond_order_data *bo_ij, *bo_ji;
far_nbrs = *lists + FAR_NBRS;
bonds = *lists + BONDS;
hbonds = *lists + HBONDS;
H = workspace->H;
Htop = 0;
num_bonds = 0;
num_hbonds = 0;
btop_i = btop_j = 0;
p_boc1 = system->reaxprm.gp.l[0];
p_boc2 = system->reaxprm.gp.l[1];
for (i = 0; i < system->N; ++i) {
atom_i = &(system->atoms[i]);
type_i = atom_i->type;
start_i = Start_Index(i, far_nbrs);
end_i = End_Index(i, far_nbrs);
H->start[i] = Htop;
btop_i = End_Index(i, bonds);
sbp_i = &(system->reaxprm.sbp[type_i]);
ihb = ihb_top = -1;
if (control->hb_cut > 0 && (ihb = sbp_i->p_hbond) == 1)
ihb_top = End_Index(workspace->hbond_index[i], hbonds);
for (pj = start_i; pj < end_i; ++pj) {
nbr_pj = &(far_nbrs->select.far_nbr_list[pj]);
j = nbr_pj->nbr;
atom_j = &(system->atoms[j]);
flag = 0;
if ((data->step - data->prev_steps) % control->reneighbor == 0) {
if (nbr_pj->d <= control->r_cut)
flag = 1;
else
flag = 0;
} else if ((nbr_pj->d = Sq_Distance_on_T3(atom_i->x, atom_j->x,
&(system->box), nbr_pj->dvec)) <= SQR(control->r_cut)) {
nbr_pj->d = sqrt(nbr_pj->d);
flag = 1;
}
if (flag) {
type_j = system->atoms[j].type;
r_ij = nbr_pj->d;
sbp_j = &(system->reaxprm.sbp[type_j]);
twbp = &(system->reaxprm.tbp[type_i][type_j]);
self_coef = (i == j) ? 0.5 : 1.0;
/* H matrix entry */
Tap = control->Tap7 * r_ij + control->Tap6;
Tap = Tap * r_ij + control->Tap5;
Tap = Tap * r_ij + control->Tap4;
Tap = Tap * r_ij + control->Tap3;
Tap = Tap * r_ij + control->Tap2;
Tap = Tap * r_ij + control->Tap1;
Tap = Tap * r_ij + control->Tap0;
dr3gamij_1 = (r_ij * r_ij * r_ij + twbp->gamma);
dr3gamij_3 = POW(dr3gamij_1, 0.33333333333333);
H->entries[Htop].j = j;
H->entries[Htop].val = self_coef * Tap * EV_to_KCALpMOL
/ dr3gamij_3;
++Htop;
/* hydrogen bond lists */
if (control->hb_cut > 0 && (ihb == 1 || ihb == 2) && nbr_pj->d
<= control->hb_cut) {
// fprintf( stderr, "%d %d\n", atom1, atom2 );
jhb = sbp_j->p_hbond;
if (ihb == 1 && jhb == 2) {
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;
++ihb_top;
++num_hbonds;
} else if (ihb == 2 && jhb == 1) {
jhb_top = End_Index(workspace->hbond_index[j], hbonds);
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;
Set_End_Index(workspace->hbond_index[j], jhb_top + 1,
hbonds);
++num_hbonds;
}
}
/* uncorrected bond orders */
if (far_nbrs->select.far_nbr_list[pj].d <= control->nbr_cut) {
r2 = SQR(r_ij);
if (sbp_i->r_s > 0.0 && sbp_j->r_s > 0.0) {
C12 = twbp->p_bo1 * POW(r_ij / twbp->r_s, twbp->p_bo2);
BO_s = (1.0 + control->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(r_ij / 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(r_ij / 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;
if (BO >= control->bo_cut) {
num_bonds += 2;
/****** bonds i-j and j-i ******/
ibond = &(bonds->select.bond_list[btop_i]);
btop_j = End_Index(j, bonds);
jbond = &(bonds->select.bond_list[btop_j]);
ibond->nbr = j;
jbond->nbr = i;
ibond->d = r_ij;
jbond->d = r_ij;
rvec_Copy(ibond->dvec, nbr_pj->dvec);
rvec_Scale(jbond->dvec, -1, nbr_pj->dvec);
ivec_Copy(ibond->rel_box, nbr_pj->rel_box);
ivec_Scale(jbond->rel_box, -1, nbr_pj->rel_box);
ibond->dbond_index = btop_i;
jbond->dbond_index = btop_i;
ibond->sym_index = btop_j;
jbond->sym_index = btop_i;
++btop_i;
Set_End_Index(j, btop_j + 1, bonds);
bo_ij = &(ibond->bo_data);
bo_ji = &(jbond->bo_data);
bo_ji->BO = bo_ij->BO = BO;
bo_ji->BO_s = bo_ij->BO_s = BO_s;
bo_ji->BO_pi = bo_ij->BO_pi = BO_pi;
bo_ji->BO_pi2 = bo_ij->BO_pi2 = BO_pi2;
/* Bond Order page2-3, derivative of total bond order prime */
Cln_BOp_s = twbp->p_bo2 * C12 / r2;
Cln_BOp_pi = twbp->p_bo4 * C34 / r2;
Cln_BOp_pi2 = twbp->p_bo6 * C56 / r2;
/* Only dln_BOp_xx wrt. dr_i is stored here, note that
dln_BOp_xx/dr_i = -dln_BOp_xx/dr_j and all others are 0 */
rvec_Scale(bo_ij->dln_BOp_s, -bo_ij->BO_s * Cln_BOp_s,
ibond->dvec);
rvec_Scale(bo_ij->dln_BOp_pi, -bo_ij->BO_pi
* Cln_BOp_pi, ibond->dvec);
rvec_Scale(bo_ij->dln_BOp_pi2, -bo_ij->BO_pi2
* Cln_BOp_pi2, ibond->dvec);
rvec_Scale(bo_ji->dln_BOp_s, -1., bo_ij->dln_BOp_s);
rvec_Scale(bo_ji->dln_BOp_pi, -1., bo_ij->dln_BOp_pi);
rvec_Scale(bo_ji->dln_BOp_pi2, -1., bo_ij->dln_BOp_pi2);
/* Only dBOp wrt. dr_i is stored here, note that
dBOp/dr_i = -dBOp/dr_j and all others are 0 */
rvec_Scale(bo_ij->dBOp, -(bo_ij->BO_s * Cln_BOp_s
+ bo_ij->BO_pi * Cln_BOp_pi + bo_ij->BO_pi2
* Cln_BOp_pi2), ibond->dvec);
rvec_Scale(bo_ji->dBOp, -1., bo_ij->dBOp);
rvec_Add(workspace->dDeltap_self[i], bo_ij->dBOp);
rvec_Add(workspace->dDeltap_self[j], bo_ji->dBOp);
bo_ij->BO_s -= control->bo_cut;
bo_ij->BO -= control->bo_cut;
bo_ji->BO_s -= control->bo_cut;
bo_ji->BO -= control->bo_cut;
workspace->total_bond_order[i] += bo_ij->BO; //currently total_BOp
workspace->total_bond_order[j] += bo_ji->BO; //currently total_BOp
bo_ij->Cdbo = bo_ij->Cdbopi = bo_ij->Cdbopi2 = 0.0;
bo_ji->Cdbo = bo_ji->Cdbopi = bo_ji->Cdbopi2 = 0.0;
/*fprintf( stderr, "%d %d %g %g %g\n",
i+1, j+1, bo_ij->BO, bo_ij->BO_pi, bo_ij->BO_pi2 );*/
/*fprintf( stderr, "Cln_BOp_s: %f, pbo2: %f, C12:%f\n",
Cln_BOp_s, twbp->p_bo2, C12 );
fprintf( stderr, "Cln_BOp_pi: %f, pbo4: %f, C34:%f\n",
Cln_BOp_pi, twbp->p_bo4, C34 );
fprintf( stderr, "Cln_BOp_pi2: %f, pbo6: %f, C56:%f\n",
Cln_BOp_pi2, twbp->p_bo6, C56 );*/
/*fprintf(stderr, "pbo1: %f, pbo2:%f\n", twbp->p_bo1, twbp->p_bo2);
fprintf(stderr, "pbo3: %f, pbo4:%f\n", twbp->p_bo3, twbp->p_bo4);
fprintf(stderr, "pbo5: %f, pbo6:%f\n", twbp->p_bo5, twbp->p_bo6);
fprintf( stderr, "r_s: %f, r_p: %f, r_pp: %f\n",
twbp->r_s, twbp->r_p, twbp->r_pp );
fprintf( stderr, "C12: %g, C34:%g, C56:%g\n", C12, C34, C56 );*/
/*fprintf( stderr, "\tfactors: %g %g %g\n",
-(bo_ij->BO_s * Cln_BOp_s + bo_ij->BO_pi * Cln_BOp_pi +
bo_ij->BO_pi2 * Cln_BOp_pp),
-bo_ij->BO_pi * Cln_BOp_pi, -bo_ij->BO_pi2 * Cln_BOp_pi2 );*/
/*fprintf( stderr, "dBOpi:\t[%g, %g, %g]\n",
bo_ij->dBOp[0], bo_ij->dBOp[1], bo_ij->dBOp[2] );
fprintf( stderr, "dBOpi:\t[%g, %g, %g]\n",
bo_ij->dln_BOp_pi[0], bo_ij->dln_BOp_pi[1],
bo_ij->dln_BOp_pi[2] );
fprintf( stderr, "dBOpi2:\t[%g, %g, %g]\n\n",
bo_ij->dln_BOp_pi2[0], bo_ij->dln_BOp_pi2[1],
bo_ij->dln_BOp_pi2[2] );*/
Set_End_Index(j, btop_j + 1, bonds);
}
}
}
}
H->entries[Htop].j = i;
H->entries[Htop].val = system->reaxprm.sbp[type_i].eta;
++Htop;
Set_End_Index(i, btop_i, bonds);
if (ihb == 1)
Set_End_Index(workspace->hbond_index[i], ihb_top, hbonds);
//fprintf( stderr, "%d bonds start: %d, end: %d\n",
// i, Start_Index( i, bonds ), End_Index( i, bonds ) );
}
// mark the end of j list
H->start[i] = Htop;
/* validate lists - decide if reallocation is required! */
Validate_Lists(workspace, lists, data->step, system->N, H->m, Htop,
num_bonds, num_hbonds);
#if defined(DEBUG_FOCUS)
fprintf( stderr, "step%d: Htop = %d, num_bonds = %d, num_hbonds = %d\n",
data->step, Htop, num_bonds, num_hbonds );
#endif
}
int BOp( storage *workspace, reax_list *bonds, double bo_cut,
int i, int btop_i, far_neighbor_data *nbr_pj,
single_body_parameters *sbp_i, single_body_parameters *sbp_j,
two_body_parameters *twbp ) {
int j, btop_j;
double r2, C12, C34, C56;
double Cln_BOp_s, Cln_BOp_pi, Cln_BOp_pi2;
double BO, BO_s, BO_pi, BO_pi2;
bond_data *ibond, *jbond;
bond_order_data *bo_ij, *bo_ji;
j = nbr_pj->nbr;
r2 = SQR(nbr_pj->d);
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;
if( BO >= bo_cut ) {
/****** bonds i-j and j-i ******/
ibond = &( bonds->select.bond_list[btop_i] );
btop_j = End_Index( j, bonds );
jbond = &(bonds->select.bond_list[btop_j]);
ibond->nbr = j;
jbond->nbr = i;
ibond->d = nbr_pj->d;
jbond->d = nbr_pj->d;
rvec_Copy( ibond->dvec, nbr_pj->dvec );
rvec_Scale( jbond->dvec, -1, nbr_pj->dvec );
ivec_Copy( ibond->rel_box, nbr_pj->rel_box );
ivec_Scale( jbond->rel_box, -1, nbr_pj->rel_box );
ibond->dbond_index = btop_i;
jbond->dbond_index = btop_i;
ibond->sym_index = btop_j;
jbond->sym_index = btop_i;
Set_End_Index( j, btop_j+1, bonds );
bo_ij = &( ibond->bo_data );
bo_ji = &( jbond->bo_data );
bo_ji->BO = bo_ij->BO = BO;
bo_ji->BO_s = bo_ij->BO_s = BO_s;
bo_ji->BO_pi = bo_ij->BO_pi = BO_pi;
bo_ji->BO_pi2 = bo_ij->BO_pi2 = BO_pi2;
/* Bond Order page2-3, derivative of total bond order prime */
Cln_BOp_s = twbp->p_bo2 * C12 / r2;
Cln_BOp_pi = twbp->p_bo4 * C34 / r2;
Cln_BOp_pi2 = twbp->p_bo6 * C56 / r2;
/* Only dln_BOp_xx wrt. dr_i is stored here, note that
dln_BOp_xx/dr_i = -dln_BOp_xx/dr_j and all others are 0 */
rvec_Scale(bo_ij->dln_BOp_s,-bo_ij->BO_s*Cln_BOp_s,ibond->dvec);
rvec_Scale(bo_ij->dln_BOp_pi,-bo_ij->BO_pi*Cln_BOp_pi,ibond->dvec);
rvec_Scale(bo_ij->dln_BOp_pi2,
-bo_ij->BO_pi2*Cln_BOp_pi2,ibond->dvec);
rvec_Scale(bo_ji->dln_BOp_s, -1., bo_ij->dln_BOp_s);
rvec_Scale(bo_ji->dln_BOp_pi, -1., bo_ij->dln_BOp_pi );
rvec_Scale(bo_ji->dln_BOp_pi2, -1., bo_ij->dln_BOp_pi2 );
rvec_Scale( bo_ij->dBOp,
-(bo_ij->BO_s * Cln_BOp_s +
bo_ij->BO_pi * Cln_BOp_pi +
bo_ij->BO_pi2 * Cln_BOp_pi2), ibond->dvec );
rvec_Scale( bo_ji->dBOp, -1., bo_ij->dBOp );
rvec_Add( workspace->dDeltap_self[i], bo_ij->dBOp );
rvec_Add( workspace->dDeltap_self[j], bo_ji->dBOp );
bo_ij->BO_s -= bo_cut;
bo_ij->BO -= bo_cut;
bo_ji->BO_s -= bo_cut;
bo_ji->BO -= bo_cut;
workspace->total_bond_order[i] += bo_ij->BO; //currently total_BOp
workspace->total_bond_order[j] += bo_ji->BO; //currently total_BOp
bo_ij->Cdbo = bo_ij->Cdbopi = bo_ij->Cdbopi2 = 0.0;
bo_ji->Cdbo = bo_ji->Cdbopi = bo_ji->Cdbopi2 = 0.0;
return 1;
}
return 0;
}
void Init_Forces_Tab(reax_system *system, control_params *control,
simulation_data *data, static_storage *workspace, list **lists,
output_controls *out_control) {
int i, j, pj;
int start_i, end_i;
int type_i, type_j;
int Htop, btop_i, btop_j, num_bonds, num_hbonds;
int tmin, tmax, r;
int ihb, jhb, ihb_top, jhb_top;
int flag;
real r_ij, r2, self_coef;
real val, dif, base;
real C12, C34, C56;
real Cln_BOp_s, Cln_BOp_pi, Cln_BOp_pi2;
real BO, BO_s, BO_pi, BO_pi2;
real p_boc1, p_boc2;
sparse_matrix *H;
list *far_nbrs, *bonds, *hbonds;
single_body_parameters *sbp_i, *sbp_j;
two_body_parameters *twbp;
far_neighbor_data *nbr_pj;
LR_lookup_table *t;
reax_atom *atom_i, *atom_j;
bond_data *ibond, *jbond;
bond_order_data *bo_ij, *bo_ji;
far_nbrs = *lists + FAR_NBRS;
bonds = *lists + BONDS;
hbonds = *lists + HBONDS;
H = workspace->H;
Htop = 0;
num_bonds = 0;
num_hbonds = 0;
btop_i = btop_j = 0;
p_boc1 = system->reaxprm.gp.l[0];
p_boc2 = system->reaxprm.gp.l[1];
for (i = 0; i < system->N; ++i) {
atom_i = &(system->atoms[i]);
type_i = atom_i->type;
start_i = Start_Index(i, far_nbrs);
end_i = End_Index(i, far_nbrs);
H->start[i] = Htop;
btop_i = End_Index(i, bonds);
sbp_i = &(system->reaxprm.sbp[type_i]);
ihb = ihb_top = -1;
if (control->hb_cut > 0 && (ihb = sbp_i->p_hbond) == 1)
ihb_top = End_Index(workspace->hbond_index[i], hbonds);
for (pj = start_i; pj < end_i; ++pj) {
nbr_pj = &(far_nbrs->select.far_nbr_list[pj]);
j = nbr_pj->nbr;
atom_j = &(system->atoms[j]);
flag = 0;
if ((data->step - data->prev_steps) % control->reneighbor == 0) {
if (nbr_pj->d <= control->r_cut)
flag = 1;
else
flag = 0;
} else if ((nbr_pj->d = Sq_Distance_on_T3(atom_i->x, atom_j->x,
&(system->box), nbr_pj->dvec)) <= SQR(control->r_cut)) {
nbr_pj->d = sqrt(nbr_pj->d);
flag = 1;
}
if (flag) {
type_j = system->atoms[j].type;
r_ij = nbr_pj->d;
sbp_j = &(system->reaxprm.sbp[type_j]);
twbp = &(system->reaxprm.tbp[type_i][type_j]);
self_coef = (i == j) ? 0.5 : 1.0;
tmin = MIN( type_i, type_j );
tmax = MAX( type_i, type_j );
t = &(LR[tmin][tmax]);
/* cubic spline interpolation */
r = (int) (r_ij * t->inv_dx);
if (r == 0)
++r;
base = (real) (r + 1) * t->dx;
dif = r_ij - base;
val = ((t->ele[r].d * dif + t->ele[r].c) * dif + t->ele[r].b)
* dif + t->ele[r].a;
val *= EV_to_KCALpMOL / C_ele;
H->entries[Htop].j = j;
H->entries[Htop].val = self_coef * val;
++Htop;
/* hydrogen bond lists */
if (control->hb_cut > 0 && (ihb == 1 || ihb == 2) && nbr_pj->d
<= control->hb_cut) {
// fprintf( stderr, "%d %d\n", atom1, atom2 );
jhb = sbp_j->p_hbond;
if (ihb == 1 && jhb == 2) {
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;
++ihb_top;
++num_hbonds;
} else if (ihb == 2 && jhb == 1) {
jhb_top = End_Index(workspace->hbond_index[j], hbonds);
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;
Set_End_Index(workspace->hbond_index[j], jhb_top + 1,
hbonds);
++num_hbonds;
}
}
/* uncorrected bond orders */
if (far_nbrs->select.far_nbr_list[pj].d <= control->nbr_cut) {
r2 = SQR(r_ij);
if (sbp_i->r_s > 0.0 && sbp_j->r_s > 0.0) {
C12 = twbp->p_bo1 * POW(r_ij / twbp->r_s, twbp->p_bo2);
BO_s = (1.0 + control->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(r_ij / 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(r_ij / 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;
if (BO >= control->bo_cut) {
num_bonds += 2;
/****** bonds i-j and j-i ******/
ibond = &(bonds->select.bond_list[btop_i]);
btop_j = End_Index(j, bonds);
jbond = &(bonds->select.bond_list[btop_j]);
ibond->nbr = j;
jbond->nbr = i;
ibond->d = r_ij;
jbond->d = r_ij;
rvec_Copy(ibond->dvec, nbr_pj->dvec);
rvec_Scale(jbond->dvec, -1, nbr_pj->dvec);
ivec_Copy(ibond->rel_box, nbr_pj->rel_box);
ivec_Scale(jbond->rel_box, -1, nbr_pj->rel_box);
ibond->dbond_index = btop_i;
jbond->dbond_index = btop_i;
ibond->sym_index = btop_j;
jbond->sym_index = btop_i;
++btop_i;
Set_End_Index(j, btop_j + 1, bonds);
bo_ij = &(ibond->bo_data);
bo_ji = &(jbond->bo_data);
bo_ji->BO = bo_ij->BO = BO;
bo_ji->BO_s = bo_ij->BO_s = BO_s;
bo_ji->BO_pi = bo_ij->BO_pi = BO_pi;
bo_ji->BO_pi2 = bo_ij->BO_pi2 = BO_pi2;
/* Bond Order page2-3, derivative of total bond order prime */
Cln_BOp_s = twbp->p_bo2 * C12 / r2;
Cln_BOp_pi = twbp->p_bo4 * C34 / r2;
Cln_BOp_pi2 = twbp->p_bo6 * C56 / r2;
/* Only dln_BOp_xx wrt. dr_i is stored here, note that
dln_BOp_xx/dr_i = -dln_BOp_xx/dr_j and all others are 0 */
rvec_Scale(bo_ij->dln_BOp_s, -bo_ij->BO_s * Cln_BOp_s,
ibond->dvec);
rvec_Scale(bo_ij->dln_BOp_pi, -bo_ij->BO_pi
* Cln_BOp_pi, ibond->dvec);
rvec_Scale(bo_ij->dln_BOp_pi2, -bo_ij->BO_pi2
* Cln_BOp_pi2, ibond->dvec);
rvec_Scale(bo_ji->dln_BOp_s, -1., bo_ij->dln_BOp_s);
rvec_Scale(bo_ji->dln_BOp_pi, -1., bo_ij->dln_BOp_pi);
rvec_Scale(bo_ji->dln_BOp_pi2, -1., bo_ij->dln_BOp_pi2);
/* Only dBOp wrt. dr_i is stored here, note that
dBOp/dr_i = -dBOp/dr_j and all others are 0 */
rvec_Scale(bo_ij->dBOp, -(bo_ij->BO_s * Cln_BOp_s
+ bo_ij->BO_pi * Cln_BOp_pi + bo_ij->BO_pi2
* Cln_BOp_pi2), ibond->dvec);
rvec_Scale(bo_ji->dBOp, -1., bo_ij->dBOp);
rvec_Add(workspace->dDeltap_self[i], bo_ij->dBOp);
rvec_Add(workspace->dDeltap_self[j], bo_ji->dBOp);
bo_ij->BO_s -= control->bo_cut;
bo_ij->BO -= control->bo_cut;
bo_ji->BO_s -= control->bo_cut;
bo_ji->BO -= control->bo_cut;
workspace->total_bond_order[i] += bo_ij->BO; //currently total_BOp
workspace->total_bond_order[j] += bo_ji->BO; //currently total_BOp
bo_ij->Cdbo = bo_ij->Cdbopi = bo_ij->Cdbopi2 = 0.0;
bo_ji->Cdbo = bo_ji->Cdbopi = bo_ji->Cdbopi2 = 0.0;
Set_End_Index(j, btop_j + 1, bonds);
}
}
}
}
H->entries[Htop].j = i;
H->entries[Htop].val = system->reaxprm.sbp[type_i].eta;
++Htop;
Set_End_Index(i, btop_i, bonds);
if (ihb == 1)
Set_End_Index(workspace->hbond_index[i], ihb_top, hbonds);
}
// mark the end of j list
H->start[i] = Htop;
/* validate lists - decide if reallocation is required! */
Validate_Lists(workspace, lists, data->step, system->N, H->m, Htop,
num_bonds, num_hbonds);
#if defined(DEBUG_FOCUS)
fprintf( stderr, "step%d: Htop = %d, num_bonds = %d, num_hbonds = %d\n",
data->step, Htop, num_bonds, num_hbonds );
//Print_Bonds( system, bonds, "sbonds.out" );
//Print_Bond_List2( system, bonds, "sbonds.out" );
//Print_Sparse_Matrix2( H, "H.out" );
#endif
}
void Hydrogen_Bonds( reax_system *system, control_params *control,
simulation_data *data, storage *workspace,
reax_list **lists, output_controls *out_control )
{
int i, j, k, pi, pk;
int type_i, type_j, type_k;
int start_j, end_j, hb_start_j, hb_end_j;
int hblist[MAX_BONDS];
int itr, top;
int num_hb_intrs = 0;
ivec rel_jk;
real r_jk, theta, cos_theta, sin_xhz4, cos_xhz1, sin_theta2;
real e_hb, exp_hb2, exp_hb3, CEhb1, CEhb2, CEhb3;
rvec dcos_theta_di, dcos_theta_dj, dcos_theta_dk;
rvec dvec_jk, force, ext_press;
hbond_parameters *hbp;
bond_order_data *bo_ij;
bond_data *pbond_ij;
far_neighbor_data *nbr_jk;
reax_list *bonds, *hbonds;
bond_data *bond_list;
hbond_data *hbond_list;
// tally variables
real fi_tmp[3], fk_tmp[3], delij[3], delkj[3];
bonds = (*lists) + BONDS;
bond_list = bonds->select.bond_list;
hbonds = (*lists) + HBONDS;
hbond_list = hbonds->select.hbond_list;
for( j = 0; j < system->n; ++j )
if( system->reax_param.sbp[system->my_atoms[j].type].p_hbond == 1 ) {
type_j = system->my_atoms[j].type;
start_j = Start_Index(j, bonds);
end_j = End_Index(j, bonds);
hb_start_j = Start_Index( system->my_atoms[j].Hindex, hbonds );
hb_end_j = End_Index( system->my_atoms[j].Hindex, hbonds );
if (type_j < 0) continue;
top = 0;
for( pi = start_j; pi < end_j; ++pi ) {
pbond_ij = &( bond_list[pi] );
i = pbond_ij->nbr;
type_i = system->my_atoms[i].type;
if (type_i < 0) continue;
bo_ij = &(pbond_ij->bo_data);
if( system->reax_param.sbp[type_i].p_hbond == 2 &&
bo_ij->BO >= HB_THRESHOLD )
hblist[top++] = pi;
}
for( pk = hb_start_j; pk < hb_end_j; ++pk ) {
/* set k's varibles */
k = hbond_list[pk].nbr;
type_k = system->my_atoms[k].type;
if (type_k < 0) continue;
nbr_jk = hbond_list[pk].ptr;
r_jk = nbr_jk->d;
rvec_Scale( dvec_jk, hbond_list[pk].scl, nbr_jk->dvec );
for( itr = 0; itr < top; ++itr ) {
pi = hblist[itr];
pbond_ij = &( bonds->select.bond_list[pi] );
i = pbond_ij->nbr;
if( system->my_atoms[i].orig_id != system->my_atoms[k].orig_id ) {
bo_ij = &(pbond_ij->bo_data);
type_i = system->my_atoms[i].type;
if (type_i < 0) continue;
hbp = &(system->reax_param.hbp[ type_i ][ type_j ][ type_k ]);
++num_hb_intrs;
Calculate_Theta( pbond_ij->dvec, pbond_ij->d, dvec_jk, r_jk,
&theta, &cos_theta );
/* the derivative of cos(theta) */
Calculate_dCos_Theta( pbond_ij->dvec, pbond_ij->d, dvec_jk, r_jk,
&dcos_theta_di, &dcos_theta_dj,
&dcos_theta_dk );
/* hyrogen bond energy*/
sin_theta2 = sin( theta/2.0 );
sin_xhz4 = SQR(sin_theta2);
sin_xhz4 *= sin_xhz4;
cos_xhz1 = ( 1.0 - cos_theta );
exp_hb2 = exp( -hbp->p_hb2 * bo_ij->BO );
exp_hb3 = exp( -hbp->p_hb3 * ( hbp->r0_hb / r_jk +
r_jk / hbp->r0_hb - 2.0 ) );
data->my_en.e_hb += e_hb =
hbp->p_hb1 * (1.0 - exp_hb2) * exp_hb3 * sin_xhz4;
CEhb1 = hbp->p_hb1 * hbp->p_hb2 * exp_hb2 * exp_hb3 * sin_xhz4;
CEhb2 = -hbp->p_hb1/2.0 * (1.0 - exp_hb2) * exp_hb3 * cos_xhz1;
CEhb3 = -hbp->p_hb3 *
(-hbp->r0_hb / SQR(r_jk) + 1.0 / hbp->r0_hb) * e_hb;
/* hydrogen bond forces */
bo_ij->Cdbo += CEhb1; // dbo term
if( control->virial == 0 ) {
// dcos terms
rvec_ScaledAdd( workspace->f[i], +CEhb2, dcos_theta_di );
rvec_ScaledAdd( workspace->f[j], +CEhb2, dcos_theta_dj );
rvec_ScaledAdd( workspace->f[k], +CEhb2, dcos_theta_dk );
// dr terms
rvec_ScaledAdd( workspace->f[j], -CEhb3/r_jk, dvec_jk );
rvec_ScaledAdd( workspace->f[k], +CEhb3/r_jk, dvec_jk );
}
else {
rvec_Scale( force, +CEhb2, dcos_theta_di ); // dcos terms
rvec_Add( workspace->f[i], force );
rvec_iMultiply( ext_press, pbond_ij->rel_box, force );
rvec_ScaledAdd( data->my_ext_press, 1.0, ext_press );
rvec_ScaledAdd( workspace->f[j], +CEhb2, dcos_theta_dj );
ivec_Scale( rel_jk, hbond_list[pk].scl, nbr_jk->rel_box );
rvec_Scale( force, +CEhb2, dcos_theta_dk );
rvec_Add( workspace->f[k], force );
rvec_iMultiply( ext_press, rel_jk, force );
rvec_ScaledAdd( data->my_ext_press, 1.0, ext_press );
// dr terms
rvec_ScaledAdd( workspace->f[j], -CEhb3/r_jk, dvec_jk );
rvec_Scale( force, CEhb3/r_jk, dvec_jk );
rvec_Add( workspace->f[k], force );
rvec_iMultiply( ext_press, rel_jk, force );
rvec_ScaledAdd( data->my_ext_press, 1.0, ext_press );
}
/* tally into per-atom virials */
if (system->pair_ptr->vflag_atom || system->pair_ptr->evflag) {
rvec_ScaledSum( delij, 1., system->my_atoms[j].x,
-1., system->my_atoms[i].x );
rvec_ScaledSum( delkj, 1., system->my_atoms[j].x,
-1., system->my_atoms[k].x );
rvec_Scale(fi_tmp, CEhb2, dcos_theta_di);
rvec_Scale(fk_tmp, CEhb2, dcos_theta_dk);
rvec_ScaledAdd(fk_tmp, CEhb3/r_jk, dvec_jk);
system->pair_ptr->ev_tally3(i,j,k,e_hb,0.0,fi_tmp,fk_tmp,delij,delkj);
}
}
}
}
}
}
