/** calculate buck_capradius from force_cap */
void calc_buck_cap_radii()
{
/* do not compute cap radii if force capping is individual */
if( force_cap != -1.0 ) {
int i,j,cnt=0;
IA_parameters *params = NULL;
double force=0.0, frac2, frac6, frac8;
double r0,r1 = 0.0,diff,exp_term,C_R,D_R;
for(i=0; i<n_particle_types; i++) {
for(j=0; j<n_particle_types; j++) {
params = get_ia_param(i,j);
if(force_cap>0.0 ) {
force = -params->BUCK_F2;
if (force_cap<force)
{
/* Solving numerically using Newton Raphson Technique */
force = 0.0;
cnt = 0;
r1 = (params->BUCK_cut+params->BUCK_discont)/2.0; //First guess value
r0 = 0.0 ;
while(fabs(r1 - r0)>1.0e-10) {
r0 = r1;
exp_term = params->BUCK_A*params->BUCK_B*exp(-params->BUCK_B*r0);
frac2 = SQR(r0);
frac6 = frac2*frac2*frac2;
frac8 = frac6*frac2;
C_R = 6.0*params->BUCK_C/frac8;
D_R = 4.0*params->BUCK_D/frac6;
diff = (exp_term - C_R*r0 - D_R*r0 - force_cap)/(-params->BUCK_B*exp_term + 7.0*C_R + 5.0*D_R);
r1 = r0 - diff;
if(r1>params->BUCK_discont)
r1=0.5*(params->BUCK_discont+r0);
cnt++;
if(cnt>500)
{
fprintf(stderr,"%d: [email protected]: Failed to converge while determining Buckingham cap radius!!",this_node);
fprintf(stderr,"%d: tolerance = %f",this_node, diff);
errexit();
}
}
frac2 = SQR(r1);
frac6 = frac2*frac2*frac2;
force = params->BUCK_A*params->BUCK_B*exp(-params->BUCK_B*r1) - 6.0*params->BUCK_C/(r1*frac6) - 4.0*params->BUCK_D*r1/(frac6);
params->BUCK_capradius = r1;
}
else
params->BUCK_capradius = params->BUCK_discont;
}
else
params->BUCK_capradius = 0.0;
FORCE_TRACE(fprintf(stderr,"%d: Ptypes %d-%d have cap_radius %f and cap_force %f (iterations: %d)\n",
this_node,i,j,r1,force,cnt));
}
}
BUCK_TRACE(fprintf(stderr,"%d: BUCK: Buckingham force cap imposed %f, Calculated force %f and Cap radius %f after %d iterations\n",this_node,force_cap,force,params->BUCK_capradius,cnt);
);
/** calculate ljcos2_capradius from force_cap */
void calc_ljcos2_cap_radii()
{
/* do not compute cap radii if force capping is "individual" */
if( force_cap != -1.0){
int i,j,cnt=0;
IA_parameters *params;
double force=0.0, rad=0.0, step, frac2, frac6;
for(i=0; i<n_particle_types; i++) {
for(j=0; j<n_particle_types; j++) {
params = get_ia_param(i,j);
if(force_cap > 0.0 && params->LJCOS2_eps > 0.0) {
/* I think we have to solve this numerically... and very crude as well */
cnt=0;
rad = params->LJCOS2_sig;
step = -0.1 * params->LJCOS2_sig;
force=0.0;
while(step != 0) {
frac2 = SQR(params->LJCOS2_sig/rad);
frac6 = frac2*frac2*frac2;
if (rad < params->LJCOS2_rchange) {
force = 48.0 * params->LJCOS2_eps * frac6*(frac6 - 0.5)/rad;
}
else {
force = 0;
}
if((step < 0 && force_cap < force) || (step > 0 && force_cap > force)) {
step = - (step/2.0);
}
if(fabs(force-force_cap) < 1.0e-6) step=0;
rad += step; cnt++;
}
params->LJCOS2_capradius = rad;
}
else {
params->LJCOS2_capradius = 0.0;
}
FORCE_TRACE(fprintf(stderr,"%d: Ptypes %d-%d have cap_radius %f and cap_force %f (iterations: %d)\n",
this_node,i,j,rad,force,cnt));
}
}
}
}
/** calculate lj_capradius from force_cap */
void calc_ljgen_cap_radii()
{
/* do not compute cap radii if force capping is "individual" */
if( force_cap != -1.0){
int i,j,cnt=0;
IA_parameters *params;
double force=0.0, rad=0.0, step, frac;
for(i=0; i<n_particle_types; i++) {
for(j=0; j<n_particle_types; j++) {
params = get_ia_param(i,j);
if(force_cap > 0.0 && params->LJGEN_eps > 0.0) {
/* I think we have to solve this numerically... and very crude as well */
cnt=0;
rad = params->LJGEN_sig;
step = -0.1 * params->LJGEN_sig;
force=0.0;
while(step != 0) {
frac = params->LJGEN_sig/rad;
force = params->LJGEN_eps
#ifdef LJGEN_SOFTCORE
* params->LJGEN_lambda
#endif
* (params->LJGEN_b1 * params->LJGEN_a1 * pow(frac, params->LJGEN_a1)
- params->LJGEN_b2 * params->LJGEN_a2 * pow(frac, params->LJGEN_a2))/rad;
if((step < 0 && force_cap < force) || (step > 0 && force_cap > force)) {
step = - (step/2.0);
}
if(fabs(force-force_cap) < 1.0e-6) step=0;
rad += step; cnt++;
}
params->LJGEN_capradius = rad;
}
else {
params->LJGEN_capradius = 0.0;
}
FORCE_TRACE(fprintf(stderr,"%d: Ptypes %d-%d have cap_radius %f and cap_force %f (iterations: %d)\n",
this_node,i,j,rad,force,cnt));
}
}
}
}
void calc_morse_cap_radii()
{
/* do not compute cap radii if force capping is "individual" */
if( force_cap != -1.0){
int i,j,cnt=0;
IA_parameters *params;
double force=0.0, rad=0.0, step, add1, add2;
for(i=0; i<n_particle_types; i++) {
for(j=0; j<n_particle_types; j++) {
params = get_ia_param(i,j);
if(force_cap > 0.0 && params->MORSE_eps > 0.0) {
/* I think we have to solve this numerically... and very crude as well */
cnt=0;
rad = params->MORSE_rmin - 0.69314719 / params->MORSE_alpha;
step = -0.1 * rad;
force=0.0;
while(step != 0) {
add1 = exp(-2.0 * params->MORSE_alpha * (rad - params->MORSE_rmin));
add2 = exp( -params->MORSE_alpha * (rad - params->MORSE_rmin));
force = -params->MORSE_eps * 2.0 * params->MORSE_alpha * (add2 - add1) / rad;
if((step < 0 && force_cap < force) || (step > 0 && force_cap > force)) {
step = - (step/2.0);
}
if(fabs(force-force_cap) < 1.0e-6) step=0;
rad += step; cnt++;
}
params->MORSE_capradius = rad;
}
else {
params->MORSE_capradius = 0.0;
}
FORCE_TRACE(fprintf(stderr,"%d: Ptypes %d-%d have cap_radius %f and cap_force %f (iterations: %d)\n",
this_node,i,j,rad,force,cnt));
}
}
}
}
/* This routine does not take the optional 2nd environment into account. */
void calc_ljangle_cap_radii()
{
if( force_cap != -1.0){
int i,j,cnt=0;
IA_parameters *params;
double force=0.0, rad=0.0, step, frac2, frac10;
for(i=0; i<n_particle_types; i++) {
for(j=0; j<n_particle_types; j++) {
params = get_ia_param(i,j);
if(force_cap > 0.0 && params->LJANGLE_eps > 0.0) {
/* I think we have to solve this numerically... and very crude as well */
cnt=0;
rad = params->LJANGLE_sig;
step = -0.1 * params->LJANGLE_sig;
force=0.0;
while(step != 0) {
frac2 = SQR(params->LJANGLE_sig/rad);
frac10 = frac2*frac2*frac2*frac2*frac2;
force = 60.0 * params->LJANGLE_eps * frac10*(frac2 - 1.0) / rad;
if((step < 0 && force_cap < force) || (step > 0 && force_cap > force)) {
step = - (step/2.0);
}
if(fabs(force-force_cap) < 1.0e-6) step=0;
rad += step; cnt++;
}
params->LJANGLE_capradius = rad;
}
else {
params->LJANGLE_capradius = 0.0;
}
FORCE_TRACE(fprintf(stderr,"%d: LJANGLE Ptypes %d-%d have cap_radius %f and cap_force %f (iterations: %d)\n",
this_node,i,j,rad,force,cnt));
}
}
}
}
/** Calculate non bonded forces between a pair of particles.
@param p1 pointer to particle 1.
@param p2 pointer to particle 2.
@param d vector between p1 and p2.
@param dist distance between p1 and p2.
@param dist2 distance squared between p1 and p2. */
inline void add_non_bonded_pair_force(Particle *p1, Particle *p2,
double d[3], double dist, double dist2)
{
IA_parameters *ia_params = get_ia_param(p1->p.type,p2->p.type);
double force[3] = { 0., 0., 0. };
double torque1[3] = { 0., 0., 0. };
double torque2[3] = { 0., 0., 0. };
int j;
/***********************************************/
/* bond creation and breaking */
/***********************************************/
#ifdef COLLISION_DETECTION
if (collision_params.mode > 0)
detect_collision(p1,p2);
#endif
/*affinity potential*/
#ifdef AFFINITY
add_affinity_pair_force(p1,p2,ia_params,d,dist,force);
#endif
FORCE_TRACE(fprintf(stderr, "%d: interaction %d<->%d dist %f\n", this_node, p1->p.identity, p2->p.identity, dist));
/***********************************************/
/* thermostat */
/***********************************************/
#ifdef DPD
/* DPD thermostat forces */
if ( thermo_switch & THERMO_DPD ) add_dpd_thermo_pair_force(p1,p2,d,dist,dist2);
#endif
/** The inter dpd force should not be part of the virial
#ifdef INTER_DPD
add_inter_dpd_pair_force(p1,p2,ia_params,d,dist,dist2);
#endif
/***********************************************/
/* non bonded pair potentials */
/***********************************************/
calc_non_bonded_pair_force(p1,p2,ia_params,d,dist,dist2,force,torque1,torque2);
/***********************************************/
/* short range electrostatics */
/***********************************************/
#ifdef ELECTROSTATICS
if (coulomb.method == COULOMB_DH)
add_dh_coulomb_pair_force(p1,p2,d,dist,force);
if (coulomb.method == COULOMB_RF)
add_rf_coulomb_pair_force(p1,p2,d,dist,force);
#endif
/*********************************************************************/
/* everything before this contributes to the virial pressure in NpT, */
/* but nothing afterwards */
/*********************************************************************/
#ifdef NPT
for (j = 0; j < 3; j++)
if(integ_switch == INTEG_METHOD_NPT_ISO)
nptiso.p_vir[j] += force[j] * d[j];
#endif
/***********************************************/
/* semi-bonded multi-body potentials */
/***********************************************/
/* Directional LJ */
#ifdef LJ_ANGLE
/* This is a multi-body forces that changes the forces of 6 particles */
add_ljangle_force(p1, p2, ia_params, d, dist);
#endif
/***********************************************/
/* long range electrostatics */
/***********************************************/
#ifdef ELECTROSTATICS
/* real space coulomb */
double q1q2 = p1->p.q*p2->p.q;
switch (coulomb.method) {
#ifdef P3M
case COULOMB_ELC_P3M: {
if (q1q2) {
p3m_add_pair_force(q1q2,d,dist2,dist,force);
// forces from the virtual charges
// they go directly onto the particles, since they are not pairwise forces
if (elc_params.dielectric_contrast_on)
ELC_P3M_dielectric_layers_force_contribution(p1, p2, p1->f.f, p2->f.f);
}
break;
}
case COULOMB_P3M_GPU:
case COULOMB_P3M: {
#ifdef NPT
if (q1q2) {
double eng = p3m_add_pair_force(q1q2,d,dist2,dist,force);
if(integ_switch == INTEG_METHOD_NPT_ISO)
nptiso.p_vir[0] += eng;
}
#else
if (q1q2) p3m_add_pair_force(q1q2,d,dist2,dist,force);
#endif
break;
}
#endif
case COULOMB_MMM1D:
if (q1q2) add_mmm1d_coulomb_pair_force(q1q2,d,dist2,dist,force);
break;
case COULOMB_MMM2D:
if (q1q2) add_mmm2d_coulomb_pair_force(q1q2,d,dist2,dist,force);
break;
#ifdef EWALD_GPU
case COULOMB_EWALD_GPU:
if (q1q2) add_ewald_gpu_coulomb_pair_force(p1,p2,d,dist,force);
break;
#endif
default:
break;
}
#endif /*ifdef ELECTROSTATICS */
/***********************************************/
/* long range magnetostatics */
/***********************************************/
#ifdef DIPOLES
/* real space magnetic dipole-dipole */
switch (coulomb.Dmethod) {
#ifdef DP3M
case DIPOLAR_MDLC_P3M:
//fall trough
case DIPOLAR_P3M: {
#ifdef NPT
double eng = dp3m_add_pair_force(p1,p2,d,dist2,dist,force);
if(integ_switch == INTEG_METHOD_NPT_ISO)
nptiso.p_vir[0] += eng;
#else
dp3m_add_pair_force(p1,p2,d,dist2,dist,force);
#endif
break;
}
#endif /*ifdef DP3M */
default:
break;
}
#endif /* ifdef DIPOLES */
/***********************************************/
/* add total nonbonded forces to particle */
/***********************************************/
for (j = 0; j < 3; j++) {
p1->f.f[j] += force[j];
p2->f.f[j] -= force[j];
#ifdef ROTATION
p1->f.torque[j] += torque1[j];
p2->f.torque[j] += torque2[j];
#endif
}
}
void calc_long_range_forces()
{
#ifdef ELECTROSTATICS
/* calculate k-space part of electrostatic interaction. */
switch (coulomb.method) {
#ifdef P3M
case COULOMB_ELC_P3M:
if (elc_params.dielectric_contrast_on) {
ELC_P3M_modify_p3m_sums_both();
ELC_p3m_charge_assign_both();
ELC_P3M_self_forces();
}
else
p3m_charge_assign();
p3m_calc_kspace_forces(1,0);
if (elc_params.dielectric_contrast_on)
ELC_P3M_restore_p3m_sums();
ELC_add_force();
break;
#endif
#ifdef CUDA
case COULOMB_P3M_GPU:
if (this_node == 0) {
FORCE_TRACE(printf("Computing GPU P3M forces.\n"));
p3m_gpu_add_farfield_force();
}
/* there is no NPT handling here as long as we cannot compute energies.
This is checked in integrator_npt_sanity_checks() when integration starts. */
break;
#endif
#ifdef P3M
case COULOMB_P3M:
FORCE_TRACE(printf("%d: Computing P3M forces.\n", this_node));
p3m_charge_assign();
#ifdef NPT
if (integ_switch == INTEG_METHOD_NPT_ISO)
nptiso.p_vir[0] += p3m_calc_kspace_forces(1,1);
else
#endif
p3m_calc_kspace_forces(1, 0);
break;
#endif
case COULOMB_MAGGS:
maggs_calc_forces();
break;
case COULOMB_MMM2D:
MMM2D_add_far_force();
MMM2D_dielectric_layers_force_contribution();
break;
#ifdef SCAFACOS
case COULOMB_SCAFACOS:
Electrostatics::Scafacos::add_long_range_force();
break;
#endif
default:
break;
}
/* If enabled, calculate electrostatics contribution from electrokinetics species. */
#ifdef EK_ELECTROSTATIC_COUPLING
ek_calculate_electrostatic_coupling();
#endif
#endif /*ifdef ELECTROSTATICS */
#ifdef DIPOLES
/* calculate k-space part of the magnetostatic interaction. */
switch (coulomb.Dmethod) {
#ifdef DP3M
case DIPOLAR_MDLC_P3M:
add_mdlc_force_corrections();
//fall through
case DIPOLAR_P3M:
dp3m_dipole_assign();
#ifdef NPT
if(integ_switch == INTEG_METHOD_NPT_ISO) {
nptiso.p_vir[0] += dp3m_calc_kspace_forces(1,1);
fprintf(stderr,"dipolar_P3M at this moment is added to p_vir[0]\n");
} else
#endif
dp3m_calc_kspace_forces(1,0);
break;
#endif
case DIPOLAR_ALL_WITH_ALL_AND_NO_REPLICA:
dawaanr_calculations(1,0);
break;
case DIPOLAR_MDLC_DS:
add_mdlc_force_corrections();
//fall through
case DIPOLAR_DS:
magnetic_dipolar_direct_sum_calculations(1,0);
break;
case DIPOLAR_DS_GPU:
// Do nothing. It's an actor
break;
case DIPOLAR_NONE:
break;
default:
runtimeErrorMsg() <<"unknown dipolar method";
break;
}
#endif /*ifdef DIPOLES */
}
