diff --git a/c/interaction/interaction.c b/c/interaction/interaction.c
index cf720e9..6014cf1 100644
--- a/c/interaction/interaction.c
+++ b/c/interaction/interaction.c
@@ -87,7 +87,7 @@ interaction_ufunc_float2D
 	, npy_intp * steps
 	, void * data)
 {
-	NPY_BEGIN_THREADS_DEF;
+	//NPY_BEGIN_THREADS_DEF;
 	npy_intp i;
 	npy_intp j;
 	npy_intp n = dimensions[0];
@@ -125,7 +125,7 @@ interaction_ufunc_float2D
 	float this_x_j;
 	float this_y_j;
 
-	NPY_BEGIN_THREADS;
+	//NPY_BEGIN_THREADS;
 
 	for(i = 0; i < n; i++)
 	{
@@ -183,7 +183,7 @@ interaction_ufunc_float2D
 			*(float *)(p_y_new + j*p_y_new_steps) -= dt*delta_p_y;
 		}
 	}
-	NPY_END_THREADS;
+	//NPY_END_THREADS;
 }
 static char interaction_types[] = 
 	{ NPY_FLOAT, NPY_FLOAT, NPY_FLOAT, NPY_FLOAT, NPY_FLOAT, NPY_FLOAT};