From 52485a28c5f9812c0f7a2d4e0094cd8000167b24 Mon Sep 17 00:00:00 2001
From: hackbard <hackbard@sage.physik.uni-augsburg.de>
Date: Wed, 28 May 2008 12:35:34 +0200
Subject: [PATCH] added 2b bond check for tersoff

---
 moldyn.c             |  2 +-
 potentials/tersoff.c | 49 ++++++++++++++++++++++++++++++--------------
 potentials/tersoff.h |  1 +
 3 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/moldyn.c b/moldyn.c
index a4fef49..dd8a527 100644
--- a/moldyn.c
+++ b/moldyn.c
@@ -220,7 +220,7 @@ int set_potential(t_moldyn *moldyn,u8 type) {
 			moldyn->func3b_k1=tersoff_mult_3bp_k1;
 			moldyn->func3b_j2=tersoff_mult_3bp_j2;
 			moldyn->func3b_k2=tersoff_mult_3bp_k2;
-			// missing: check 2b bond func
+			moldyn->check_2b_bond=tersoff_mult_check_2b_bond;
 			break;
 		case MOLDYN_POTENTIAL_AM:
 			moldyn->func3b_j1=albe_mult_3bp_j1;
diff --git a/potentials/tersoff.c b/potentials/tersoff.c
index d322b69..3a0ed18 100644
--- a/potentials/tersoff.c
+++ b/potentials/tersoff.c
@@ -224,7 +224,8 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 
 	/* add forces */
 	v3_add(&(ai->f),&(ai->f),&force);
-	v3_sub(&(aj->f),&(aj->f),&force); // reason: dri rij = - drj rij
+	v3_scale(&force,&force,-1.0); // reason: dri rij = - drj rij
+	v3_add(&(aj->f),&(aj->f),&force);
 
 #ifdef DEBUG
 	if((ai==&(moldyn->atom[0]))|(aj==&(moldyn->atom[0]))) {
@@ -238,7 +239,7 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 #endif
 
 	/* virial */
-	virial_calc(ai,&force,&dist_ij);
+	virial_calc(aj,&force,&dist_ij);
 
 	/* energy 2bp contribution */
 	energy=f_r*f_c;
@@ -500,10 +501,6 @@ int tersoff_mult_3bp_j2(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 	}
 #endif
 
-	/* virial */
-	if(aj<ai)
-		virial_calc(ai,&force,&(exchange->dist_ij));
-
 	/* dzeta prefactor = - 0.5 f_c f_a db */
 	exchange->pre_dzeta=-0.5*f_a*f_c*db;
 
@@ -611,9 +608,6 @@ int tersoff_mult_3bp_k2(t_moldyn *moldyn,
 	}
 #endif
 
-	/* virial */
-	//virial_calc(ai,&force,&dist_ij);
-
 	/* derivative wrt j */
 	v3_scale(&force,&dcosdrj,fcdg*pre_dzeta);
 
@@ -629,9 +623,8 @@ int tersoff_mult_3bp_k2(t_moldyn *moldyn,
 #endif
 
 	/* virial */
-	//v3_scale(&force,&force,-1.0);
-	if(aj<ai)
-		virial_calc(ai,&force,&dist_ij);
+	v3_scale(&force,&force,-1.0);
+	virial_calc(ai,&force,&dist_ij);
 
 	/* derivative wrt k */
 	v3_scale(&force,&dist_ik,-1.0*dfcg); // dri rik = - drk rik
@@ -651,9 +644,8 @@ int tersoff_mult_3bp_k2(t_moldyn *moldyn,
 #endif
 
 	/* virial */
-	//v3_scale(&force,&force,-1.0);
-	if(aj<ai)
-		virial_calc(ai,&force,&dist_ik);
+	v3_scale(&force,&force,-1.0);
+	virial_calc(ai,&force,&dist_ik);
 	
 	/* increase k counter */
 	exchange->kcount++;	
@@ -661,3 +653,30 @@ int tersoff_mult_3bp_k2(t_moldyn *moldyn,
 	return 0;
 
 }
+
+int tersoff_mult_check_2b_bond(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
+
+	t_tersoff_mult_params *params;
+	t_3dvec dist;
+	double d;
+	u8 brand;
+
+	v3_sub(&dist,&(aj->r),&(ai->r));
+	if(bc) check_per_bound(moldyn,&dist);
+	d=v3_absolute_square(&dist);
+
+	params=moldyn->pot_params;
+	brand=ai->brand;
+
+	if(brand==aj->brand) {
+		if(d<=params->S2[brand])
+			return TRUE;
+	}
+	else {
+		if(d<=params->S2mixed)
+			return TRUE;
+	}
+
+	return FALSE;
+}
+
diff --git a/potentials/tersoff.h b/potentials/tersoff.h
index 4e12957..a23503a 100644
--- a/potentials/tersoff.h
+++ b/potentials/tersoff.h
@@ -83,6 +83,7 @@ int tersoff_mult_3bp_k1(t_moldyn *moldyn,
 int tersoff_mult_3bp_j2(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
 int tersoff_mult_3bp_k2(t_moldyn *moldyn,
                         t_atom *ai,t_atom *aj,t_atom *ak,u8 bc);
+int tersoff_mult_check_2b_bond(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
 
 /* tersoff potential paramter defines */
 
-- 
2.20.1