some bugfixes ... com'on

[physik/posic.git] / moldyn.c

diff --git a/moldyn.c b/moldyn.c
index 716a087..2631d6a 100644 (file)
--- a/moldyn.c
+++ b/moldyn.c
@@ -873,15 +873,7 @@ int potential_force_calc(t_moldyn *moldyn) {
                                           !(jtom->attr&ATOM_ATTR_3BP))
                                                continue;
 
-                       /*
-                        * according to mr. nordlund, we dont need to take the 
-                        * sum over all atoms now, as 'this is centered' around
-                        * atom i ...
-                        * i am not quite sure though! there is a not vanishing
-                        * part even if f_c_ik is zero ...
-                        * this analytical potentials suck!
-                        * switching from mc to md to dft soon!
-                        */
+                       /* neighbourhood of atom j is not needed! */
 
                        //              link_cell_neighbour_index(moldyn,
                        //                 (jtom->r.x+moldyn->dim.x/2)/lc->x,
@@ -1156,6 +1148,7 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        exchange=&(params->exchange);
 
        exchange->run3bp=0;
+       exchange->run2bp_post=0;
        
        /*
         * we need: f_c, df_c, f_r, df_r
@@ -1200,7 +1193,7 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        f_r=A*exp(-lambda*d_ij);
        df_r=-lambda*f_r/d_ij;
 
-       /* f_a, df_a calc + save for 3bp use */
+       /* f_a, df_a calc + save for later use */
        exchange->f_a=-B*exp(-mu*d_ij);
        exchange->df_a=-mu*exchange->f_a/d_ij;
 
@@ -1228,8 +1221,9 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        exchange->f_c=f_c;
        exchange->df_c=df_c;
 
-       /* enable the run of 3bp function */
+       /* enable the run of 3bp function and 2bp post processing */
        exchange->run3bp=1;
+       exchange->run2bp_post=1;
 
        /* reset 3bp sums */
        exchange->sum1_3bp=0.0;
@@ -1259,6 +1253,10 @@ int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        params=moldyn->pot2b_params;
        exchange=&(params->exchange);
 
+       /* we do not run if f_c_ij was dtected to be 0! */
+       if(!(exchange->run2bp_post))
+               return 0;
+
        db_ij=&(exchange->db_ij);
        f_c=exchange->f_c;
        df_c=exchange->df_c;
@@ -1266,6 +1264,7 @@ int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        df_a=exchange->df_a;
        betan=exchange->betan;
        n=*(exchange->n);
+       chi=exchange->chi;
        dist_ij=&(exchange->dist_ij);
 
        db_ij_scale1=(1+betan*exchange->sum1_3bp);
@@ -1274,19 +1273,24 @@ int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
        b_ij=chi*db_ij_scale1*help;
        db_ij_scale1=-chi/(2*n)*help;
 
+       /* db_ij part */
        v3_scale(db_ij,db_ij,(db_ij_scale1*db_ij_scale2));
        v3_scale(db_ij,db_ij,f_a);
 
+       /* df_a part */
        v3_scale(&temp,dist_ij,b_ij*df_a);
 
+       /* db_ij + df_a part */
        v3_add(&force,&temp,db_ij);
        v3_scale(&force,&force,f_c);
 
+       /* df_c part */
        v3_scale(&temp,dist_ij,f_a*b_ij*df_c);
 
        /* add energy of 3bp sum */
        moldyn->energy+=(0.5*f_c*b_ij*f_a);
-       /* add force of 3bp calculation */      
+
+       /* add force of 3bp calculation (all three parts) */
        v3_add(&(ai->f),&temp,&force);
 
        return 0;
@@ -1415,13 +1419,13 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
                bracket=0.0;
                bracket_n_1=0.0;
                bracket_n=0.0;
-               printf("Foo -> 0: ");
+               //printf("Foo -> 0: ");
        }
        else {
                bracket=f_c_ik*g;
                bracket_n_1=pow(bracket,n-1.0);
                bracket_n=bracket_n_1*bracket;
-               printf("Foo -> 1: ");
+               //printf("Foo -> 1: ");
        }
 //printf("%.15f %.15f %.15f\n",bracket_n_1,bracket_n,bracket);