2 * albe.c - albe potential
4 * author: Frank Zirkelbach <frank.zirkelbach@physik.uni-augsburg.de>
12 #include <sys/types.h>
18 #include "../moldyn.h"
19 #include "../math/math.h"
22 /* create mixed terms from parameters and set them */
23 int albe_mult_complete_params(t_albe_mult_params *p) {
25 printf("[moldyn] albe parameter completion\n");
26 p->S2[0]=p->S[0]*p->S[0];
27 p->S2[1]=p->S[1]*p->S[1];
28 p->S2mixed=p->Smixed*p->Smixed;
30 printf("[moldyn] albe mult parameter info:\n");
31 printf(" S (A) | %f | %f | %f\n",p->S[0],p->S[1],p->Smixed);
32 printf(" R (A) | %f | %f | %f\n",p->R[0],p->R[1],p->Rmixed);
33 printf(" A (eV) | %f | %f | %f\n",p->A[0]/EV,p->A[1]/EV,p->Amixed/EV);
34 printf(" B (eV) | %f | %f | %f\n",p->B[0]/EV,p->B[1]/EV,p->Bmixed/EV);
35 printf(" lambda | %f | %f | %f\n",p->lambda[0],p->lambda[1],
37 printf(" mu | %f | %f | %f\n",p->mu[0],p->mu[1],p->mu_m);
38 printf(" gamma | %f | %f\n",p->gamma[0],p->gamma[1]);
39 printf(" c | %f | %f\n",p->c[0],p->c[1]);
40 printf(" d | %f | %f\n",p->d[0],p->d[1]);
41 printf(" h | %f | %f\n",p->h[0],p->h[1]);
46 /* albe 3 body potential function (first ij loop) */
47 int albe_mult_3bp_j1(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
49 t_albe_mult_params *params;
50 t_albe_exchange *exchange;
56 params=moldyn->pot_params;
57 exchange=&(params->exchange);
60 exchange->zeta_ij=0.0;
63 * set ij depending values
67 if(brand==aj->brand) {
75 v3_sub(&dist_ij,&(aj->r),&(ai->r));
76 if(bc) check_per_bound(moldyn,&dist_ij);
77 d_ij2=v3_absolute_square(&dist_ij);
79 /* if d_ij2 > S2 => no force & potential energy contribution */
89 exchange->dist_ij=dist_ij;
90 exchange->d_ij2=d_ij2;
93 /* reset k counter for first k loop */
99 /* albe 3 body potential function (first k loop) */
100 int albe_mult_3bp_k1(t_moldyn *moldyn,
101 t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
103 t_albe_mult_params *params;
104 t_albe_exchange *exchange;
107 t_3dvec dist_ij,dist_ik;
108 double d_ik2,d_ik,d_ij;
109 double cos_theta,h_cos,d2_h_cos2,frac,g,dg,s_r,arg;
110 double f_c_ik,df_c_ik;
113 params=moldyn->pot_params;
114 exchange=&(params->exchange);
115 kcount=exchange->kcount;
117 if(kcount>ALBE_MAXN) {
118 printf("FATAL: neighbours = %d\n",kcount);
119 printf(" -> %d %d %d\n",ai->tag,aj->tag,ak->tag);
124 if(brand==ak->brand) {
127 S2=params->S2[brand];
128 /* albe needs i,k depending c,d,h and gamma values */
129 exchange->gamma_i=&(params->gamma[brand]);
130 exchange->c_i=&(params->c[brand]);
131 exchange->d_i=&(params->d[brand]);
132 exchange->h_i=&(params->h[brand]);
138 /* albe needs i,k depending c,d,h and gamma values */
139 exchange->gamma_i=&(params->gamma_m);
140 exchange->c_i=&(params->c_mixed);
141 exchange->d_i=&(params->d_mixed);
142 exchange->h_i=&(params->h_mixed);
144 exchange->ci2=*(exchange->c_i)**(exchange->c_i);
145 exchange->di2=*(exchange->d_i)**(exchange->d_i);
146 exchange->ci2di2=exchange->ci2/exchange->di2;
149 v3_sub(&dist_ik,&(ak->r),&(ai->r));
150 if(bc) check_per_bound(moldyn,&dist_ik);
151 d_ik2=v3_absolute_square(&dist_ik);
153 /* store data for second k loop */
154 exchange->dist_ik[kcount]=dist_ik;
155 exchange->d_ik2[kcount]=d_ik2;
157 /* return if not within cutoff */
167 dist_ij=exchange->dist_ij;
171 cos_theta=v3_scalar_product(&dist_ij,&dist_ik)/(d_ij*d_ik);
174 h_cos=*(exchange->h_i)+cos_theta; // + in albe formalism
175 d2_h_cos2=exchange->di2+(h_cos*h_cos);
176 frac=exchange->ci2/d2_h_cos2;
177 g=*(exchange->gamma_i)*(1.0+exchange->ci2di2-frac);
178 dg=2.0*frac**(exchange->gamma_i)*h_cos/d2_h_cos2; // + in albe f..
180 /* zeta sum += f_c_ik * g_ijk */
182 exchange->zeta_ij+=g;
188 arg=M_PI*(d_ik-R)/s_r;
189 f_c_ik=0.5+0.5*cos(arg);
190 df_c_ik=0.5*sin(arg)*(M_PI/(s_r*d_ik));
191 exchange->zeta_ij+=f_c_ik*g;
194 /* store even more data for second k loop */
195 exchange->g[kcount]=g;
196 exchange->dg[kcount]=dg;
197 exchange->d_ik[kcount]=d_ik;
198 exchange->cos_theta[kcount]=cos_theta;
199 exchange->f_c_ik[kcount]=f_c_ik;
200 exchange->df_c_ik[kcount]=df_c_ik;
202 /* increase k counter */
208 int albe_mult_3bp_j2(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
210 t_albe_mult_params *params;
211 t_albe_exchange *exchange;
213 double f_a,df_a,b,db,f_c,df_c;
223 params=moldyn->pot_params;
224 exchange=&(params->exchange);
227 if(brand==ai->brand) {
232 r0=params->r0[brand];
233 mu=params->mu[brand];
234 lambda=params->lambda[brand];
243 lambda=params->lambda_m;
255 arg=M_PI*(d_ij-R)/s_r;
256 f_c=0.5+0.5*cos(arg);
257 df_c=0.5*sin(arg)*(M_PI/(s_r*d_ij));
261 f_a=-B*exp(-mu*(d_ij-r0));
265 f_r=A*exp(-lambda*(d_ij-r0));
266 df_r=lambda*f_r/d_ij;
269 if(exchange->zeta_ij==0.0) {
274 b=1.0/sqrt(1.0+exchange->zeta_ij);
275 db=-0.5*b/(1.0+exchange->zeta_ij);
278 /* force contribution */
279 scale=-0.5*(f_c*(df_r-b*df_a)+df_c*(f_r-b*f_a));
280 v3_scale(&force,&(exchange->dist_ij),scale);
281 v3_add(&(ai->f),&(ai->f),&force);
282 v3_sub(&(aj->f),&(aj->f),&force); // dri rij = - drj rij
285 if(moldyn->time>DSTART&&moldyn->time<DEND) {
286 if((ai==&(moldyn->atom[DATOM]))|(aj==&(moldyn->atom[DATOM]))) {
287 printf("force 3bp (j2): [%d %d sum]\n",ai->tag,aj->tag);
288 printf(" adding %f %f %f\n",force.x,force.y,force.z);
289 if(ai==&(moldyn->atom[0]))
290 printf(" total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
291 if(aj==&(moldyn->atom[0]))
292 printf(" total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
293 printf(" energy: %f = %f %f %f %f\n",0.5*f_c*(b*f_a+f_r),
295 printf(" %f %f %f\n",exchange->zeta_ij,.0,.0);
301 virial_calc(ai,&force,&(exchange->dist_ij));
303 /* dzeta prefactor = - f_c f_a db, (* -0.5 due to force calc) */
304 exchange->pre_dzeta=0.5*f_a*f_c*db;
306 /* energy contribution */
307 energy=0.5*f_c*(f_r-b*f_a);
308 moldyn->energy+=energy;
311 /* reset k counter for second k loop */
317 /* albe 3 body potential function (second k loop) */
318 int albe_mult_3bp_k2(t_moldyn *moldyn,
319 t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
321 t_albe_mult_params *params;
322 t_albe_exchange *exchange;
324 t_3dvec dist_ik,dist_ij;
325 double d_ik2,d_ik,d_ij2,d_ij;
328 double g,dg,cos_theta;
330 double f_c_ik,df_c_ik;
331 double dijdik_inv,fcdg,dfcg;
332 t_3dvec dcosdri,dcosdrj,dcosdrk;
335 params=moldyn->pot_params;
336 exchange=&(params->exchange);
337 kcount=exchange->kcount;
340 printf("FATAL: neighbours!\n");
343 d_ik2=exchange->d_ik2[kcount];
347 S2=params->S2[brand];
351 /* return if d_ik > S */
357 /* prefactor dzeta */
358 pre_dzeta=exchange->pre_dzeta;
361 dist_ik=exchange->dist_ik[kcount];
362 d_ik=exchange->d_ik[kcount];
364 /* f_c_ik, df_c_ik */
365 f_c_ik=exchange->f_c_ik[kcount];
366 df_c_ik=exchange->df_c_ik[kcount];
368 /* dist_ij, d_ij2, d_ij */
369 dist_ij=exchange->dist_ij;
370 d_ij2=exchange->d_ij2;
373 /* g, dg, cos_theta */
374 g=exchange->g[kcount];
375 dg=exchange->dg[kcount];
376 cos_theta=exchange->cos_theta[kcount];
378 /* cos_theta derivatives wrt i,j,k */
379 dijdik_inv=1.0/(d_ij*d_ik);
380 v3_scale(&dcosdrj,&dist_ik,dijdik_inv); // j
381 v3_scale(&tmp,&dist_ij,-cos_theta/d_ij2);
382 v3_add(&dcosdrj,&dcosdrj,&tmp);
383 v3_scale(&dcosdrk,&dist_ij,dijdik_inv); // k
384 v3_scale(&tmp,&dist_ik,-cos_theta/d_ik2);
385 v3_add(&dcosdrk,&dcosdrk,&tmp);
386 v3_add(&dcosdri,&dcosdrj,&dcosdrk); // i
387 v3_scale(&dcosdri,&dcosdri,-1.0);
389 /* f_c_ik * dg, df_c_ik * g */
393 /* derivative wrt i */
394 v3_scale(&force,&dist_ik,dfcg);
395 v3_scale(&tmp,&dcosdri,fcdg);
396 v3_add(&force,&force,&tmp);
397 v3_scale(&force,&force,pre_dzeta);
399 /* force contribution */
400 v3_add(&(ai->f),&(ai->f),&force);
403 if(moldyn->time>DSTART&&moldyn->time<DEND) {
404 if(ai==&(moldyn->atom[DATOM])) {
405 printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
406 printf(" adding %f %f %f\n",force.x,force.y,force.z);
407 printf(" total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
408 printf(" angle: %f\n",acos(cos_theta)*360.0/(2*M_PI));
409 printf(" d ij ik = %f %f\n",d_ij,d_ik);
415 //virial_calc(ai,&force,&dist_ij);
417 /* derivative wrt j */
418 v3_scale(&force,&dcosdrj,fcdg*pre_dzeta);
420 /* force contribution */
421 v3_add(&(aj->f),&(aj->f),&force);
424 if(moldyn->time>DSTART&&moldyn->time<DEND) {
425 if(aj==&(moldyn->atom[DATOM])) {
426 printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
427 printf(" adding %f %f %f\n",force.x,force.y,force.z);
428 printf(" total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
429 printf(" angle: %f\n",acos(cos_theta)*360.0/(2*M_PI));
430 printf(" d ij ik = %f %f\n",d_ij,d_ik);
436 v3_scale(&force,&force,-1.0);
437 virial_calc(ai,&force,&dist_ij);
439 /* derivative wrt k */
440 v3_scale(&force,&dist_ik,-1.0*dfcg); // dri rik = - drk rik
441 v3_scale(&tmp,&dcosdrk,fcdg);
442 v3_add(&force,&force,&tmp);
443 v3_scale(&force,&force,pre_dzeta);
445 /* force contribution */
446 v3_add(&(ak->f),&(ak->f),&force);
449 if(moldyn->time>DSTART&&moldyn->time<DEND) {
450 if(ak==&(moldyn->atom[DATOM])) {
451 printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
452 printf(" adding %f %f %f\n",force.x,force.y,force.z);
453 printf(" total k: %f %f %f\n",ak->f.x,ak->f.y,ak->f.z);
454 printf(" angle: %f\n",acos(cos_theta)*360.0/(2*M_PI));
455 printf(" d ij ik = %f %f\n",d_ij,d_ik);
461 v3_scale(&force,&force,-1.0);
462 virial_calc(ai,&force,&dist_ik);
464 /* increase k counter */