X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=moldyn.c;h=2631d6a675549e183a41fa91ca863dee215bed0f;hb=746278fb5c566b621b70c78b38d8b6c0b4e2677f;hp=716a087fa90f1b89b073411af22e2d55995aba8a;hpb=01be83f52829176f95a7fa6bb38a9f3518d44aa9;p=physik%2Fposic.git

diff --git a/moldyn.c b/moldyn.c
index 716a087..2631d6a 100644
--- 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);