]> hackdaworld.org Git - physik/posic.git/commitdiff
nearly finished 3bp tersoff routine (2bp post needs to be done after
authorhackbard <hackbard>
Sun, 10 Dec 2006 04:06:24 +0000 (04:06 +0000)
committerhackbard <hackbard>
Sun, 10 Dec 2006 04:06:24 +0000 (04:06 +0000)
that!)

moldyn.c
moldyn.h

index 880e56c1cdfa5809741bfe3a9d07792a907b3616..8d1cb2334395528873284387debca19a6e210d2a 100644 (file)
--- a/moldyn.c
+++ b/moldyn.c
@@ -1084,17 +1084,16 @@ int tersoff_mult_1bp(t_moldyn *moldyn,t_atom *ai) {
         *         their right values
         */
 
-       exchange->beta=&(params->beta[num]);
-       exchange->n=&(params->n[num]);
-       exchange->c=&(params->c[num]);
-       exchange->d=&(params->d[num]);
-       exchange->h=&(params->h[num]);
-
-       exchange->betan=pow(*(exchange->beta),*(exchange->n));
-       exchange->n_betan=*(exchange->n)*exchange->betan;
-       exchange->c2=params->c[num]*params->c[num];
-       exchange->d2=params->d[num]*params->d[num];
-       exchange->c2d2=exchange->c2/exchange->d2;
+       exchange->beta_i=&(params->beta[num]);
+       exchange->n_i=&(params->n[num]);
+       exchange->c_i=&(params->c[num]);
+       exchange->d_i=&(params->d[num]);
+       exchange->h_i=&(params->h[num]);
+
+       exchange->betaini=pow(*(exchange->beta_i),*(exchange->n_i));
+       exchange->ci2=params->c[num]*params->c[num];
+       exchange->di2=params->d[num]*params->d[num];
+       exchange->ci2di2=exchange->ci2/exchange->di2;
 
        return 0;
 }
@@ -1115,22 +1114,33 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        double scale;
 
        params=moldyn->pot2b_params;
-       num=ai->bnum;
+       num=aj->bnum;
        exchange=&(params->exchange);
 
-       exchange->run3bp=0;
-       exchange->run2bp_post=0;
+       /* clear 3bp and 2bp post run */
+       exchange->run3bp_ij=0;
+       exchange->run3bp_ji=0;
+       exchange->run3bp_jk=0;
+       exchange->run2bp_post_ij=0;
+       exchange->run2bp_post_ji=0;
+       exchange->run2bp_post_jk=0;
        
        /*
-        * we need: f_c, df_c, f_r, df_r
+        * calc of 2bp contribution of V_ij and dV_ij/ji
+        *
+        * for Vij and dV_ij we need:
+        * - f_c_ij, df_c_ij
+        * - f_r_ij, df_r_ij
+        *
+        * for dV_ji we need:
+        * - f_c_ji = f_c_ij, df_c_ji = df_c_ij
+        * - f_r_ji = f_r_ij; df_r_ji = df_r_ij
         *
-        * therefore we need: R, S, A, lambda
         */
 
+       /* dist_ij, d_ij */
        v3_sub(&dist_ij,&(aj->r),&(ai->r));
-
        if(bc) check_per_bound(moldyn,&dist_ij);
-
        d_ij=v3_norm(&dist_ij);
 
        /* save for use in 3bp */
@@ -1138,14 +1148,14 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        exchange->dist_ij=dist_ij;
 
        /* constants */
-       if(num==aj->bnum) {
+       if(num==ai->bnum) {
                S=params->S[num];
                R=params->R[num];
                A=params->A[num];
                B=params->B[num];
                lambda=params->lambda[num];
                mu=params->mu[num];
-               params->exchange.chi=1.0;
+               exchange->chi=1.0;
        }
        else {
                S=params->Smixed;
@@ -1156,34 +1166,60 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
                mu=params->mu_m;
                params->exchange.chi=params->chi;
        }
+
+       /* if d_ij > S => no force & potential energy contribution */
        if(d_ij>S)
                return 0;
 
+       /* more constants */
+       exchange->beta_j=&(params->beta[num]);
+       exchange->n_j=&(params->n[num]);
+       exchange->c_j=&(params->c[num]);
+       exchange->d_j=&(params->d[num]);
+       exchange->h_j=&(params->h[num]);
+       if(num==ai->bnum) {
+               exchange->betajnj=exchange->betaini;
+               exchange->cj2=exchange->ci2;
+               exchange->dj2=exchange->di2;
+               exchange->cj2dj2=exchange->ci2di2;
+       }
+       else {
+               exchange->betajnj=pow(*(exchange->beta_j),*(exchange->n_j));
+               exchange->cj2=params->c[num]*params->c[num];
+               exchange->dj2=params->d[num]*params->d[num];
+               exchange->cj2dj2=exchange->cj2/exchange->dj2;
+       }
+
+       /* f_r_ij = f_r_ji, df_r_ij = df_r_ji */
        f_r=A*exp(-lambda*d_ij);
        df_r=-lambda*f_r/d_ij;
 
-       /* f_a, df_a calc + save for later use */
+       /* f_a, df_a calc (again, same for ij and ji) | save for later use! */
        exchange->f_a=-B*exp(-mu*d_ij);
        exchange->df_a=-mu*exchange->f_a/d_ij;
 
+       /* f_c, df_c calc (again, same for ij and ji) */
        if(d_ij<R) {
                /* f_c = 1, df_c = 0 */
                f_c=1.0;
                df_c=0.0;
-               v3_scale(&force,&dist_ij,df_r);
+               /* two body contribution (ij, ji) */
+               v3_scale(&force,&dist_ij,-df_r);
        }
        else {
                s_r=S-R;
                arg=M_PI*(d_ij-R)/s_r;
                f_c=0.5+0.5*cos(arg);
                df_c=-0.5*sin(arg)*(M_PI/(s_r*d_ij));
-               scale=df_c*f_r+df_r*f_c;
-               v3_scale(&force,&dist_ij,scale);
+               /* two body contribution (ij, ji) */
+               v3_scale(&force,&dist_ij,-df_c*f_r-df_r*f_c);
        }
 
-       /* add forces */
+       /* add forces of 2bp (ij, ji) contribution
+        * dVij = dVji and we sum up both: no 1/2) */
        v3_add(&(ai->f),&(ai->f),&force);
-       /* energy is 0.5 f_r f_c ... */
+
+       /* energy 2bp contribution (ij, ji) is 0.5 f_r f_c ... */
        moldyn->energy+=(0.5*f_r*f_c);
 
        /* save for use in 3bp */
@@ -1195,8 +1231,12 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        exchange->run2bp_post=1;
 
        /* reset 3bp sums */
-       exchange->zeta=0.0;
+       exchange->zeta_ij=0.0;
+       exchange->zeta_ji=0.0;
+       exchange->zeta_kl=0.0;
        v3_zero(&(exchange->db_ij));
+       v3_zero(&(exchange->db_ji));
+       v3_zero(&(exchange->db_jk));
 
        return 0;
 }
@@ -1272,11 +1312,11 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 
        t_tersoff_mult_params *params;
        t_tersoff_exchange *exchange;
-       t_3dvec dist_ij,dist_ik;
-       t_3dvec temp,force;
+       t_3dvec dist_ij,dist_ik,dist_jk;
+       t_3dvec temp1,temp2;
        double R,S,s_r;
-       double d_ij,d_ik;
-       double rijrik,dijdik;
+       double d_ij,d_ik,d_jk;
+       double rxxryy,dxxdyy;
        double f_c,df_c,f_a,df_a;
        double f_c_ik,df_c_ik,arg;
        double n,c,d,h;
@@ -1288,43 +1328,56 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
        int num;
 
        params=moldyn->pot3b_params;
-       num=ai->bnum;
        exchange=&(params->exchange);
 
        if(!(exchange->run3bp))
                return 0;
 
        /*
-        * we need: f_c, d_fc, b_ij, db_ij, f_a, df_a
+        * calc of 3bp contribution of V_ij and dV_ij/ji/jk &
+        * 2bp contribution of dV_jk
+        *
+        * for Vij and dV_ij we still need:
+        * - b_ij, db_ij (zeta_ij)
+        *   - f_c_ik, df_c_ik, constants_i, cos_theta_ijk, d_costheta_ijk
+        *
+        * for dV_ji we still need:
+        * - b_ji, db_ji (zeta_ji)
+        *   - f_c_jk, d_c_jk, constants_j, cos_theta_jik, d_costheta_jik
+        *
+        * for dV_jk we need:
+        * - f_c_jk
+        * - f_a_jk
+        * - db_jk (zeta_jk)
+        *   - f_c_ji, df_c_ji, constants_j, cos_theta_jki, d_costheta_jki
         *
-        * we got f_c, df_c, f_a, df_a from 2bp calculation
         */
 
-       d_ij=exchange->d_ij;
-       dist_ij=exchange->dist_ij;
+       /*
+        * get exchange data 
+        */
 
-       f_a=params->exchange.f_a;
-       df_a=params->exchange.df_a;
+       /* dist_ij, d_ij - this is < S_ij ! */
+       dist_ij=exchange->dist_ij;
+       d_ij=exchange->d_ij;
 
+       /* f_c_ij, df_c_ij (same for ji) */
        f_c=exchange->f_c;
        df_c=exchange->df_c;
-       
-       /* d_ij is <= S, as we didn't return so far! */
 
        /*
-        * calc of b_ij (scalar) and db_ij (vector)
-        *
-        * - for b_ij: chi, beta, f_c_ik, w(=1), c, d, h, n, cos_theta
-        *
-        * - for db_ij: d_costheta, cos_theta, f_c_ik, df_c_ik, w_ik
-        *
+        * calculate unknown values now ...
         */
 
+       /* V_ij and dV_ij stuff (in b_ij there is f_c_ik) */
+
+       /* dist_ik, d_ik */
        v3_sub(&dist_ik,&(ak->r),&(ai->r));
        if(bc) check_per_bound(moldyn,&dist_ik);
        d_ik=v3_norm(&dist_ik);
 
-       /* constants */
+       /* ik constants */
+       num=ai->bnum;
        if(num==ak->bnum) {
                R=params->R[num];
                S=params->S[num];
@@ -1334,84 +1387,166 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
                S=params->Smixed;
        }
 
-       /* there is no contribution if f_c_ik = 0 */
-       if(d_ik>S)
-               return 0;
-
-       /* get exchange data */
-       n=*(exchange->n);
-       c=*(exchange->c);
-       d=*(exchange->d);
-       h=*(exchange->h);
-       c2=exchange->c2;
-       d2=exchange->d2;
-       c2d2=exchange->c2d2;
-
-       /* cosine of theta by scalaproduct */
-       rijrik=v3_scalar_product(&dist_ij,&dist_ik);
-       dijdik=d_ij*d_ik;
-       cos_theta=rijrik/dijdik;
-
-       /* hack - cos theta machine accuracy problems! */
-       if(cos_theta>1.0||cos_theta<-1.0) {
-               printf("THETA CORRECTION\n");
-               moldyn->debug++;
-               if(fabs(cos_theta)>1.0+ACCEPTABLE_ERROR)
-                       printf("[moldyn] WARNING: cos theta failure!\n");
-               if(cos_theta<0) {
-                       cos_theta=-1.0;
+       /* zeta_ij/dzeta_ij contribution only for d_ik < S */
+       if(d_ik<S) {
+
+               /* get constants_i from exchange data */
+               n=*(exchange->n_i);
+               c=*(exchange->c_i);
+               d=*(exchange->d_i);
+               h=*(exchange->h_i);
+               c2=exchange->ci2;
+               d2=exchange->di2;
+               c2d2=exchange->ci2di2;
+
+               /* cosine of theta_ijk by scalaproduct */
+               rijrik=v3_scalar_product(&dist_ij,&dist_ik);
+               dijdik=d_ij*d_ik;
+               cos_theta=rijrik/dijdik;
+
+               /* d_costheta */
+               tmp=1.0/dijdik;
+               d_costheta1=cos_theta/(d_ij*d_ij)-tmp;
+               d_costheta2=cos_theta/(d_ik*d_ik)-tmp;
+
+               /* some usefull values */
+               h_cos=(h-cos_theta);
+               d2_h_cos2=d2+(h_cos*h_cos);
+               frac=c2/(d2_h_cos2);
+
+               /* g(cos_theta) */
+               g=1.0+c2d2-frac;
+
+               /* d_costheta_ij and dg(cos_theta) - needed in any case! */
+               v3_scale(&temp1,&dist_ij,d_costheta1);
+               v3_scale(&temp2,&dist_ik,d_costheta2);
+               v3_add(&temp1,&temp1,&temp2);
+               v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
+
+               /* f_c_ik & df_c_ik + {d,}zeta contribution */
+               if(d_ik<R) {
+                       /* {d,}f_c_ik */
+                       // => f_c_ik=1.0;
+                       // => df_c_ik=0.0; of course we do not set this!
+
+                       /* zeta_ij */
+                       exchange->zeta_ij+=g;
+
+                       /* dzeta_ij */
+                       v3_add(dzeta_ij,dzeta_ij,&temp1);
                }
                else {
-                       cos_theta=1.0;
+                       /* {d,}f_c_ik */
+                       s_r=S-R;
+                       arg=M_PI*(d_ik-R)/s_r;
+                       f_c_ik=0.5+0.5*cos(arg);
+                       df_c_ik=-0.5*sin(arg)*(M_PI/(s_r*d_ik));
+
+                       /* zeta_ij */
+                       exchange->zeta_ij+=f_c_ik*g;
+
+                       /* dzeta_ij */
+                       v3_scale(&temp1,&temp1,f_c_ik);
+                       v3_scale(&temp2,&dist_ik,g*df_c_ik);
+                       v3_add(dzeta_ij,&temp2,&temp1);
                }
        }
 
-       d_costheta1=dijdik-rijrik*d_ik/d_ij;
-       d_costheta2=dijdik-rijrik*d_ij/d_ik;
+       /* dV_ji stuff (in b_ji there is f_c_jk) + dV_jk stuff! */
+
+       /* dist_jk, d_jk */
+       v3_sub(&dist_jk,&(ak->r),&(aj->r));
+       if(bc) check_per_bound(moldyn,&dist_jk);
+       d_jk=v3_norm(&dist_jk);
 
-       h_cos=(h-cos_theta);
-       d2_h_cos2=d2+(h_cos*h_cos);
+       /* jk constants */
+       num=aj->bnum;
+       if(num==ak->bnum) {
+               R=params->R[num];
+               S=params->S[num];
+       }
+       else {
+               R=params->Rmixed;
+               S=params->Smixed;
+       }
 
-       frac=c2/(d2_h_cos2);
-       g=1.0+c2d2-frac;
+       /* zeta_ji/dzeta_ji contribution only for d_jk < S_jk */
+       if(d_jk<S) {
+
+               /* constants_j from exchange data */
+               n=*(exchange->n_j);
+               c=*(exchange->c_j);
+               d=*(exchange->d_j);
+               h=*(exchange->h_j);
+               c2=exchange->cj2;
+               d2=exchange->dj2;
+               c2d2=exchange->cj2dj2;
+
+               /* cosine of theta_jik by scalaproduct */
+               rxxryy=v3_scalar_product(&dist_ij,&dist_jk); /* times -1 */
+               dxxdyy=d_ij*d_jk;
+               cos_theta=rxxryy/dxxdyy;
+
+               /* d_costheta */
+               d_costheta1=1.0/(d_jk*d_ij);
+               d_costheta2=cos_theta/(d_ij*d_ij); /* in fact -cos(), but ^ */
+
+               /* some usefull values */
+               h_cos=(h-cos_theta);
+               d2_h_cos2=d2+(h_cos*h_cos);
+               frac=c2/(d2_h_cos2);
+
+               /* g(cos_theta) */
+               g=1.0+c2d2-frac;
+
+               /* d_costheta_ij and dg(cos_theta) - needed in any case! */
+               v3_scale(&temp1,&dist_jk,d_costheta1);
+               v3_scale(&temp2,&dist_ij,-d_costheta2); /* ji -> ij => -1 */
+               v3_add(&temp1,&temp1,&temp2);
+               v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
+
+               /* dV_jk stuff | add force contribution on atom i immediately */
+               if(exchange->d_ij_between_rs) {
+                       tmp=pow(f_c_ij*g,(n_j-1.0)); /* zeta_jk ^ n_j-1 */
+                       v3_scale(&temp2,&temp1,f_c_ij)
+                       v3_scale(&temp3,&dist_ij,df_c_ij);
+                       v3_add(&temp3,&temp3,&temp2); /* dzeta_jk */
+               }
+               else {
+                       /* f_c_ij = 1, df_c_ij = 0 */
+                       tmp=pow(g,(n_j-1.0)); /* zeta_jk ^ n_j-1 */
+                       tmp
+                       /* dzeta_jk in temp1 */
+                       /* HIER WEITER !!! */
+               }
 
-       /* d_costheta contrib to db_ij (needed in all remaining cases) */
-       v3_scale(&temp,&dist_ij,d_costheta1);
-       v3_scale(&force,&dist_ik,d_costheta2);
-       v3_add(&force,&force,&temp);
-       v3_scale(&force,&force,-2.0*frac*h_cos/d2_h_cos2); /* f_c_ik missing */
+               /* f_c_jk + {d,}zeta contribution (df_c_jk = 0) */
+               if(d_jk<R) {
+                       /* f_c_jk */
+                       // f_c_jk=1.0; again, we do not set this!
 
-       if(d_ik<R) {
-               /* f_c_ik = 1, df_c_ik = 0 */   
-               /* => only d_costheta contrib to db_ij */
-               // => do nothing ...
+                       /* zeta_ji */
+                       exchange->zeta_ji+=g;
 
-               /* zeta, f_c_ik = 1 */
-               exchange->zeta+=g;
-       }
-       else {
-               s_r=S-R;
-               arg=M_PI*(d_ik-R)/s_r;
-               f_c_ik=0.5+0.5*cos(arg);
-               df_c_ik=-0.5*sin(arg)*(M_PI/(s_r*d_ik));
 
-               /* scale d_costheta contrib with f_c_ik */
-               v3_scale(&force,&force,f_c_ik);
+                       /* dzeta_ji */
+                       v3_add(dzeta_ji,dzeta_ji,&temp1);
+               }
+               else {
+                       /* f_c_jk */
+                       s_r=S-R;
+                       arg=M_PI*(d_jk-R)/s_r;
+                       f_c_jk=0.5+0.5*cos(arg);
 
-               /* df_c_ik contrib to db_ij */
-               v3_scale(&temp,&dist_ik,df_c_ik*g);
+                       /* zeta_ji */
+                       exchange->zeta_ji+=f_c_jk*g;
 
-               /* sum up both parts */
-               v3_add(&force,&force,&temp);
-               
-               /* zeta */
-               exchange->zeta+=f_c_ik*g;
+                       /* dzeta_ij */
+                       v3_scale(&temp1,&temp1,f_c_jk);
+                       v3_add(dzeta_ji,dzeta_ji,&temp1);
+               }
        }
-printf("%.30f\n",exchange->zeta);
-       
-       /* add to db_ij */
-       v3_add(&(exchange->db_ij),&(exchange->db_ij),&force);
-                               
+
        return 0;
 }
 
index 32025fd39a687306a0cb7edb9fb93c7301733937..d62ec47c6fa26841e9e6b1be9cb620badef7679e 100644 (file)
--- a/moldyn.h
+++ b/moldyn.h
@@ -183,23 +183,34 @@ typedef struct s_tersoff_exchange {
 
        double chi;
 
-       double *beta;
-       double *n;
-       double *c;
-       double *d;
-       double *h;
-
-       double c2;
-       double d2;
-       double c2d2;
-       double betan;
-       double n_betan;
+       double *beta_i;
+       double *beta_j;
+       double *n_i;
+       double *n_j;
+       double *c_i;
+       double *c_j;
+       double *d_i;
+       double *d_j;
+       double *h_i;
+       double *h_j;
+
+       double ci2;
+       double cj2;
+       double di2;
+       double dj2;
+       double ci2di2;
+       double cj2dj2;
+       double betaini;
+       double betajnj;
 
        u8 run3bp;
        u8 run2bp_post;
+       u8 d_ij_between_rs;
 
-       t_3dvec db_ij;
-       double zeta;
+       double zeta_ij;
+       double zeta_ji;
+       t_3dvec dzeta_ij;
+       t_3dvec dzeta_ji;
 } t_tersoff_exchange;
 
 /* tersoff multi (2!) potential parameters */