diff --git a/lammps/force_lj.c b/lammps/force_lj.c
index f876d06..e6b6ec0 100644
--- a/lammps/force_lj.c
+++ b/lammps/force_lj.c
@@ -132,7 +132,7 @@ double computeForceLJHalfNeigh(Parameter *param, Atom *atom, Neighbor *neighbor,
 
     for(int i = 0; i < Nlocal; i++) {
         neighs = &neighbor->neighbors[i * neighbor->maxneighs];
-        int numneighs = neighbor.numneigh[i];
+        int numneighs = neighbor->numneigh[i];
         MD_FLOAT xtmp = atom_x(i);
         MD_FLOAT ytmp = atom_y(i);
         MD_FLOAT ztmp = atom_z(i);
diff --git a/lammps/includes/neighbor.h b/lammps/includes/neighbor.h
index 949d515..86df386 100644
--- a/lammps/includes/neighbor.h
+++ b/lammps/includes/neighbor.h
@@ -31,6 +31,7 @@ typedef struct {
     int* neighbors;
     int maxneighs;
     int* numneigh;
+    int halfneigh;
 } Neighbor;
 
 extern void initNeighbor(Neighbor*, Parameter*);
diff --git a/lammps/main.c b/lammps/main.c
index acf4963..bde9abb 100644
--- a/lammps/main.c
+++ b/lammps/main.c
@@ -72,7 +72,7 @@ void init(Parameter *param)
     param->dtforce = 0.5 * param->dt;
     param->every = 20;
     param->proc_freq = 2.4;
-    param->halfneigh = 0;
+    param->halfneigh = 1;
 }
 
 double setup(
diff --git a/lammps/neighbor.c b/lammps/neighbor.c
index 549ddbc..cac2b1f 100644
--- a/lammps/neighbor.c
+++ b/lammps/neighbor.c
@@ -232,7 +232,7 @@ void buildNeighbor(Atom *atom, Neighbor *neighbor)
                 for(int m = 0; m < bincount[jbin]; m++) {
                     int j = loc_bin[m];
 
-                    if ( j == i ){
+                    if ( (j == i) || (neighbor->halfneigh && (j < i))) {
                         continue;
                     }