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 1 body part */
47 int albe_mult_1bp(t_moldyn *moldyn,t_atom *ai) {
50 t_albe_mult_params *params;
51 t_albe_exchange *exchange;
54 params=moldyn->pot_params;
55 exchange=&(params->exchange);
58 * simple: point constant parameters only depending on atom i to
62 exchange->gamma_i=&(params->gamma[brand]);
63 exchange->c_i=&(params->c[brand]);
64 exchange->d_i=&(params->d[brand]);
65 exchange->h_i=&(params->h[brand]);
67 exchange->ci2=params->c[brand]*params->c[brand];
68 exchange->di2=params->d[brand]*params->d[brand];
69 exchange->ci2di2=exchange->ci2/exchange->di2;
74 /* albe 3 body potential function (first ij loop) */
75 int albe_mult_3bp_j1(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
77 t_albe_mult_params *params;
78 t_albe_exchange *exchange;
84 params=moldyn->pot_params;
85 exchange=&(params->exchange);
88 exchange->zeta_ij=0.0;
91 * set ij depending values
102 v3_sub(&dist_ij,&(aj->r),&(ai->r));
103 if(bc) check_per_bound(moldyn,&dist_ij);
104 d_ij2=v3_absolute_square(&dist_ij);
106 /* if d_ij2 > S2 => no force & potential energy contribution */
116 exchange->dist_ij=dist_ij;
117 exchange->d_ij2=d_ij2;
120 /* reset k counter for first k loop */
126 /* albe 3 body potential function (first k loop) */
127 int albe_mult_3bp_k1(t_moldyn *moldyn,
128 t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
130 t_albe_mult_params *params;
131 t_albe_exchange *exchange;
134 t_3dvec dist_ij,dist_ik;
135 double d_ik2,d_ik,d_ij;
136 double cos_theta,h_cos,d2_h_cos2,frac,g,dg,s_r,arg;
137 double f_c_ik,df_c_ik;
140 params=moldyn->pot_params;
141 exchange=&(params->exchange);
142 kcount=exchange->kcount;
144 if(kcount>ALBE_MAXN) {
145 printf("FATAL: neighbours = %d\n",kcount);
146 printf(" -> %d %d %d\n",ai->tag,aj->tag,ak->tag);
151 if(brand==ak->brand) {
154 S2=params->S2[brand];
163 v3_sub(&dist_ik,&(ak->r),&(ai->r));
164 if(bc) check_per_bound(moldyn,&dist_ik);
165 d_ik2=v3_absolute_square(&dist_ik);
167 /* store data for second k loop */
168 exchange->dist_ik[kcount]=dist_ik;
169 exchange->d_ik2[kcount]=d_ik2;
171 /* return if not within cutoff */
181 dist_ij=exchange->dist_ij;
185 cos_theta=v3_scalar_product(&dist_ij,&dist_ik)/(d_ij*d_ik);
188 h_cos=*(exchange->h_i)-cos_theta;
189 d2_h_cos2=exchange->di2+(h_cos*h_cos);
190 frac=exchange->ci2/d2_h_cos2;
191 g=*(exchange->gamma_i)*(1.0+exchange->ci2di2-frac);
192 dg=-2.0*frac**(exchange->gamma_i)*h_cos/d2_h_cos2;
194 /* zeta sum += f_c_ik * g_ijk */
196 exchange->zeta_ij+=g;
202 arg=M_PI*(d_ik-R)/s_r;
203 f_c_ik=0.5+0.5*cos(arg);
204 df_c_ik=0.5*sin(arg)*(M_PI/(s_r*d_ik));
205 exchange->zeta_ij+=f_c_ik*g;
208 /* store even more data for second k loop */
209 exchange->g[kcount]=g;
210 exchange->dg[kcount]=dg;
211 exchange->d_ik[kcount]=d_ik;
212 exchange->cos_theta[kcount]=cos_theta;
213 exchange->f_c_ik[kcount]=f_c_ik;
214 exchange->df_c_ik[kcount]=df_c_ik;
216 /* increase k counter */
222 int albe_mult_3bp_j2(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
224 t_albe_mult_params *params;
225 t_albe_exchange *exchange;
227 double f_a,df_a,b,db,f_c,df_c;
236 params=moldyn->pot_params;
237 exchange=&(params->exchange);
240 if(brand==ai->brand) {
245 r0=params->r0[brand];
246 mu=params->mu[brand];
247 lambda=params->lambda[brand];
256 lambda=params->lambda_m;
268 arg=M_PI*(d_ij-R)/s_r;
269 f_c=0.5+0.5*cos(arg);
270 df_c=0.5*sin(arg)*(M_PI/(s_r*d_ij));
274 f_a=-B*exp(-mu*(d_ij-r0));
278 f_r=A*exp(-lambda*(d_ij-r0));
279 df_r=lambda*f_r/d_ij;
282 if(exchange->zeta_ij==0.0) {
287 b=1.0/sqrt(1.0+exchange->zeta_ij);
288 db=-0.5*b/(1.0+exchange->zeta_ij);
291 /* force contribution */
292 scale=-0.5*(f_c*(df_r+b*df_a)+df_c*(f_r+b*df_a));
293 v3_scale(&force,&(exchange->dist_ij),scale);
294 v3_add(&(ai->f),&(ai->f),&force);
295 v3_sub(&(aj->f),&(aj->f),&force); // dri rij = - drj rij
298 if((ai==&(moldyn->atom[0]))|(aj==&(moldyn->atom[0]))) {
299 printf("force 3bp (j2): [%d %d sum]\n",ai->tag,aj->tag);
300 printf("adding %f %f %f\n",force.x,force.y,force.z);
301 if(ai==&(moldyn->atom[0]))
302 printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
303 if(aj==&(moldyn->atom[0]))
304 printf("total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
305 printf("energy: %f = %f %f %f %f\n",0.5*f_c*(b*f_a+f_r),
312 virial_calc(ai,&force,&(exchange->dist_ij));
314 /* dzeta prefactor = - 0.5 f_c f_a db */
315 exchange->pre_dzeta=-0.5*f_a*f_c*db;
317 /* energy contribution */
318 moldyn->energy+=0.5*f_c*(f_r+b*f_a);
320 /* reset k counter for second k loop */
326 /* albe 3 body potential function (second k loop) */
327 int albe_mult_3bp_k2(t_moldyn *moldyn,
328 t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
330 t_albe_mult_params *params;
331 t_albe_exchange *exchange;
333 t_3dvec dist_ik,dist_ij;
334 double d_ik2,d_ik,d_ij2,d_ij;
337 double g,dg,cos_theta;
339 double f_c_ik,df_c_ik;
340 double dijdik_inv,fcdg,dfcg;
341 t_3dvec dcosdri,dcosdrj,dcosdrk;
344 params=moldyn->pot_params;
345 exchange=&(params->exchange);
346 kcount=exchange->kcount;
349 printf("FATAL: neighbours!\n");
352 d_ik2=exchange->d_ik2[kcount];
356 S2=params->S2[brand];
360 /* return if d_ik > S */
366 /* prefactor dzeta */
367 pre_dzeta=exchange->pre_dzeta;
370 dist_ik=exchange->dist_ik[kcount];
371 d_ik=exchange->d_ik[kcount];
373 /* f_c_ik, df_c_ik */
374 f_c_ik=exchange->f_c_ik[kcount];
375 df_c_ik=exchange->df_c_ik[kcount];
377 /* dist_ij, d_ij2, d_ij */
378 dist_ij=exchange->dist_ij;
379 d_ij2=exchange->d_ij2;
382 /* g, dg, cos_theta */
383 g=exchange->g[kcount];
384 dg=exchange->dg[kcount];
385 cos_theta=exchange->cos_theta[kcount];
387 /* cos_theta derivatives wrt i,j,k */
388 dijdik_inv=1.0/(d_ij*d_ik);
389 v3_scale(&dcosdrj,&dist_ik,dijdik_inv);
390 v3_scale(&tmp,&dist_ij,-cos_theta/d_ij2);
391 v3_add(&dcosdrj,&dcosdrj,&tmp);
392 v3_scale(&dcosdrk,&dist_ij,dijdik_inv);
393 v3_scale(&tmp,&dist_ik,-cos_theta/d_ik2);
394 v3_add(&dcosdrk,&dcosdrk,&tmp);
395 v3_add(&dcosdri,&dcosdrj,&dcosdrk);
396 v3_scale(&dcosdri,&dcosdri,-1.0);
398 /* f_c_ik * dg, df_c_ik * g */
402 /* derivative wrt i */
403 v3_scale(&force,&dist_ik,dfcg);
404 v3_scale(&tmp,&dcosdri,fcdg);
405 v3_add(&force,&force,&tmp);
406 v3_scale(&force,&force,pre_dzeta);
408 /* force contribution */
409 v3_add(&(ai->f),&(ai->f),&force);
412 if(ai==&(moldyn->atom[0])) {
413 printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
414 printf("adding %f %f %f\n",force.x,force.y,force.z);
415 printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
420 //virial_calc(ai,&force,&dist_ij);
422 /* derivative wrt j */
423 v3_scale(&force,&dcosdrj,fcdg*pre_dzeta);
425 /* force contribution */
426 v3_add(&(aj->f),&(aj->f),&force);
429 if(aj==&(moldyn->atom[0])) {
430 printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
431 printf("adding %f %f %f\n",force.x,force.y,force.z);
432 printf("total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
437 //v3_scale(&force,&force,-1.0);
439 virial_calc(ai,&force,&dist_ij);
441 /* derivative wrt k */
442 v3_scale(&force,&dist_ik,-1.0*dfcg); // dri rik = - drk rik
443 v3_scale(&tmp,&dcosdrk,fcdg);
444 v3_add(&force,&force,&tmp);
445 v3_scale(&force,&force,pre_dzeta);
447 /* force contribution */
448 v3_add(&(ak->f),&(ak->f),&force);
451 if(ak==&(moldyn->atom[0])) {
452 printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
453 printf("adding %f %f %f\n",force.x,force.y,force.z);
454 printf("total k: %f %f %f\n",ak->f.x,ak->f.y,ak->f.z);
459 //v3_scale(&force,&force,-1.0);
461 virial_calc(ai,&force,&dist_ik);
463 /* increase k counter */