lennard jones force

diff --git a/math/math.c b/math/math.c
index 9217c88..6488248 100644 (file)
--- a/math/math.c
+++ b/math/math.c
@@ -76,7 +76,7 @@ double v3_norm(t_3dvec *a) {
        return(sqrt(v3_absolute_square(a)));
 }
 
-int v3_per_bounds(t_3dvec *a,t_3dvec *dim) {
+int v3_per_bound(t_3dvec *a,t_3dvec *dim) {
 
        double x,y,z;
 

diff --git a/math/math.h b/math/math.h
index 5ef7163..77100f3 100644 (file)
--- a/math/math.h
+++ b/math/math.h
@@ -27,6 +27,6 @@ int v3_copy(t_3dvec *trg,t_3dvec *src);
 int v3_cmp(t_3dvec *a,t_3dvec *b);
 double v3_absolute_square(t_3dvec *a);
 double v3_norm(t_3dvec *a);
-int v3_per_bounds(t_3dvec *a,t_3dvec *dim);
+int v3_per_bound(t_3dvec *a,t_3dvec *dim);
 
 #endif

diff --git a/moldyn.c b/moldyn.c
index 82749b2..57ae62f 100644 (file)
--- 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);
                        }
                }
        }

diff --git a/moldyn.h b/moldyn.h
index b43ed8e..f515f41 100644 (file)
--- a/moldyn.h
+++ b/moldyn.h
@@ -75,5 +75,6 @@ double get_total_energy(t_moldyn *moldyn);
 t_3dvec get_total_p(t_atom *atom,int count);
 
 double potential_lennard_jones(t_moldyn *moldyn);
+int force_lennard_jones(t_moldyn *moldyn);
 
 #endif

diff --git a/posic.c b/posic.c
index 6d901b4..79654cd 100644 (file)
--- a/posic.c
+++ b/posic.c
@@ -75,6 +75,8 @@ int main(int argc,char **argv) {
        md.count=count;
        md.atom=si;
        md.potential=potential_lennard_jones;
+       md.force=force_lennard_jones;
+       md.cutoff_square=((LC_SI/4.0)*(LC_SI/4.0));
        md.pot_params=&lj;
        md.force=NULL;
        md.status=0;