X-Git-Url: https://www.hackdaworld.org/gitweb/?a=blobdiff_plain;f=moldyn.c;h=57ae62f75c69ffce130d8cae8af6e5ead6588965;hb=4e6604346459a4a8619bfc45f2a4b7dbd925ae86;hp=82749b2f10abf978c9636e213585e21c8393741a;hpb=85abe46fecc79a3d7885ff6124186b2be2ca96ac;p=physik%2Fposic.git

diff --git a/moldyn.c b/moldyn.c
index 82749b2..57ae62f 100644
--- a/moldyn.c
+++ b/moldyn.c
@@ -226,10 +226,16 @@ int force_lennard_jones(t_moldyn *moldyn) {
 	t_3dvec distance;
 	t_3dvec force;
 	double d,h1,h2;
+	double eps,sig6,sig12;
 
 	atom=moldyn->atom;	
 	count=moldyn->count;
 	params=moldyn->pot_params;
+	eps=params->epsilon;
+	sig6=params->sigma6;
+	sig12=params->sigma12;
+
+	for(i=0;i<count;i++) v3_zero(&(atom[i].f));
 
 	for(i=0;i<count;i++) {
 		for(j=0;j<i;j++) {
@@ -242,6 +248,13 @@ int force_lennard_jones(t_moldyn *moldyn) {
 				h2=d*d;				/* 1/r^8 */
 				h1*=d;				/* 1/r^6 */
 				h1*=h2;				/* 1/r^14 */
+				h1*=sig12;
+				h2*=sig6;
+				d=-12.0*h1+6.0*h2;
+				d*=eps;
+				v3_scale(&force,&distance,d);
+				v3_add(&(atom[j].f),&(atom[j].f),&force);
+				v3_sub(&(atom[i].f),&(atom[i].f),&force);
 			}
 		}
 	}